Contents

Fundamentals of Radiology 1

Radionuclide Imaging and Radiotherapy 11

Respiratory Imaging : Part 1 20

Respiratory Imaging : Part 2 28

Cardiovascular and Neurological Imaging 41

Gastrointestinal and Genitourinary Tract Imaging 59

Women and Musculoskeletal Imaging 79

 Fundamentals of Radiology 1

FUNDAMENTALS OF RADIOLOGY ----- Active space -----

Symbols :

Trefoil : Radiation Hazard X-ray radiation hazard Sealed radiation source

Electromagnetic Spectrum & Radiation Units 00:02:23

ELECTROMAGNETIC SPECTRUM
Radio waves : Micro waves : Infrared : Visible light : Ultraviolet : X-rays : Gamma rays
(Minimum) Frequency and energy (Maximum)

Properties of EM Spectrum : Properties of X-rays :

Mass : Absent. Frequency : High.
Velocity : 3 x 108 m/s (Speed of light). Energy : High.
Types of waves : Crest and trough. Wavelength : 0.01 to 10 nm.
Energy content : 100 eV to 100 keV.
RADIATION UNIT
Conventional Unit S.I Unit
Coulomb/kg (Charge/
Radiation expoure Roentgen
weight)
Radiation absorbed Radiation absorbed dose (RAD) Gray (Gy)
Radiation Equivalent in Man
Absorbed dose equivalent Sievert (Sv)
(REM)
Radioactivity Curie Becquerel
Note : “Radioactivity” term coined by Henri Becquerel.

Effects of Radiation 00:10:12

Determining Factors :
• Duration
of exposure to radiation.
• Intensity
• Sensitivity of tissues to radiation.
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 2 Radiology

----- Active space ----- Law of Radiobiology/Law of Bergonie and Tribondeau :

Radiosensitivity ∝ Tissues with Maximum undifferentiated cel%s.
Active mitosis.

Most sensitive : Bone mar&ow > GIT > CNS/musculoskeletal system.

Acute Radiation Syndromes :

Stages :
Stage I : Prodromal (Minutes to hours).
Stage I' : Latent (Hours to days).
Stage I'I : Manifest Il%ness (Days to weeks).
Stage IV : Recovery/death (Weeks to years).
Syndromes :
In order of ap(earance :
Acute hematological syndrome Acute GI tract syndrome Acute CNS syndrome
Threshold dose 1 - 2 Gy (Least) 6 - 10 Gy >20 Gy
• Pancytopenia
Manifestations • Hemor&hage Diar&hoea (1st symptom) -
Death
• Infection

Types of Effects :
Deterministic Stochastic
• Acute radiation syndromes
• Carcinogenesis
• Cataract
Examples • Mutations/Chromosomal
• Skin damage
aber&ations
• Sterility (Gonadal damage)
Onset Acute to subacute Chronic/delayed
Threshold dose Determined Not determined
Severity Dose dependent Dose independent
Non-linear with threshold dose Linear with no threshold dose

Risk-Dose relationship Risk Threshold Risk

Dose

Dose Dose

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 Fundamentals of Radiology 3

Radiation Exposure 00:21:32 ----- Active space -----

Exposure
Types Scans
values (mSv)
PET Scan 25
CT/PET/radionuclide CT Abdomen 10
Danger studies (Highest CT Thorax 8
exposure) Bone Scan -
CT Head/Brain 3.5
Barium Enema 7
Intravenous Urogram -
Diagnostic
Barium Meal fol%ow through -
Warning procedures (Multiple
exposure) Barium Meal -
Barium Swal%ow -
Micturating Cystourethrography (MCU) 1.2
Lumbar Spine 1.0
Abdomen X-ray -
Spot radiographs Hip X-ray -
Safe (Exposure once/ Skul% X-ray -
twice)
Chest X-ray 0.02
Limb/Joint X-ray 0.01 (least)

Guidelines :
International guidelines : By International Commission on Radiological Protection
(ICRP) & International Commission on Radiation Units (ICRU).
Public exposure Oc)upational exposure
• 20 mSv/year or 50 mSv in any 1 yr.
Effective dose 1 mSv/year OR
• < 100 mSv in 5 years.
Annual Lens of eye 15 mSv 150 mSv
equivalent dose Skin 50 mSv 500 mSv
Pregnant females <1 mSv

Indian guidelines : By Atomic Energy Regulatory Board (AERB).

Same as international, except oc)upational exposure Effective dose of 30 mSv
in any 1 year provided <100 mSv in 5 years.

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 4 Radiology

----- Active space ----- X-ray Production & Interaction 00:31:33

Structure of X-ray Tube :

Tube envelope : Ceramic Tube housing :
(More durable) Lead lined Prevents radiation leakage

Vacu+m Oil bath :

• Electrical insulator
Large potential
• Heat dissipation
difference

Cathode
Anode

Tungsten Exit window

Tungsten + Rhenium al%oy

X-ray beam

X-rays are produced when electron beam strikes anode.

Mechanisms of X-Ray Production :

Continuous spectrum Characteristic spectrum

Shifting of e- from
Mechanism Ac)eleration/deceleration of e-
outer to inner shel%
Frequency of use 70-80% (M/C) 20-30%
AKA Bremsstrahlung/
Ad,itional points Used in mammography.
white/braking radiation.

X-ray Interactions :
Oc)urs inside patient’s body.
Compton effect (M/c) Photoelectric effect
AKA Mid energy phenomenon Low energy phenomenon
Interaction b/w X-ray photon & outer shel% e- X-ray photon & inner shel% e-
Outcome : ↑Deviation of X-ray No deviation
• Scat-er radiation More (↑Distortion) Absent
• Image resolution Low Bet-er
• Desired level ↓Effect ↑Effect

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 Fundamentals of Radiology 5

Factors Determining Exposure of X-ray Image : ----- Active space -----

Adjustments done on X-ray console based on image requirement.

Tube potential (TP) Tube cur&ent (TC)
Unit Kilovoltage Peak (kVp) Mil%i-Ampere second (mAs)
• ∝ Penetration
Determines 1 ∝ Image contrast
• ∝
Image contrast

Thermoluminescent Dosimeter (TLD) Badge :

Use : Monitors oc)upational radiation exposure.
Range : 0.01 mGy - 10Gy.
Composition : Phosphor crystals
• Lithium Fluoride (LiF).
• Lithium Borate.
• Beryl%ium Oxide (BeO).
Mechanism of action : TLD badge
Radiation
Absorbed by crystal
exposure
Excitation of electrons to higher energy levels
3 months

Trap(ed in high energy state

Tested by AERB/
Renentech Labs/ Heating of crystal
BARC
Electrons move to lower energy levels.

Emission of light (Lost energy)

Determine quantity of radiation exposure.

Computed Tomography (CT) 00:47:49

CT Room :
Equipment : CT equipment ro.m + CT console.
CT equipment ro.m :
• Lined by lead Prevent leakage of radiation.
• Thickness :
- Lead : 1/16th inch (OR)
- Concrete : 4-6 inches.
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 6 Radiology

----- Active space ----- Hounsfield Unit/CT Value Scale :

• Numerical value of tissues on CT scan.
μx - μwater
HUx = 1000 x
μwater
HUx : Hounsfield unit of tissue
μ : Linear at-enuation co-efficient
• It is determined by electron density.
• Values :
Air Water Bone
- 1000 0 + 1000
- +
Less dense - 800 - 100 + 45 to + 65 More dense
Lungs Fat Acute hemor&hage

Windowing : Adjusting image contrast using range of Hounsfield units ap(reciable to

human eye.

Brain window Bone window Mediastinal window Lung window

(0 to 100 Hu) (900 to 1000 Hu) (0 to 100 Hu) (-900 to -700 Hu)

CT Polytrauma/whole body CT/Pan-scan :

Standard protocol :
• Non contrast CT of the head + cervical spine.
• Contrast enhanced CT of the chest + abdomen + pelvis.
Note : Limb CT is not included.

Ultrasonography 00:57:45

Sound Spectrum :
Ultrasonic spectrum in diagnostic use : >1 MHz
1 MHz

20,000 Hz
USG probe has piezo electric crystals
20 Hz
(Lead zirconate titanate : M/c)
0 Hz
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 Fundamentals of Radiology 7

USG Basic Principle : ----- Active space -----

Reverse piezoelectric effect :
Electric cur&ent passing through the crystal produces vibrations in the tissues.
Piezoelectric effect :
Vibrations reflected by tissues are converted back into electric impulses.

Magnetic Resonance Imaging (MRI) 01:02:40

Principle :
Based on gyromagnetic property of hydrogen nucleus Magnetic field.

Contraindications :
Absolute C/I : Interference/effect of magnetic field Fatal consequences.
1. Metal%ic foreign body in eye.
2. Cardiac pacemaker.
3. Cochlear implants.
4. Fer&omagnetic hemostatic CNS aneurysm clips.

Relative C/I :
1. Claustrophobia : Sedate the pt. Then do MRI
2. Insulin pumps.
3. Nerve stimulators.
4. Prosthetic heart valves.
5. 1st trimester of pregnancy.
Faraday’s Cage :
Shielding : Prevents action/interference of MRI magnet on outside devices &
vice-versa.

Wo.den panels
wrap(ed with
cop(er wires

Faraday's cage
Contrast Media : 01:08:54

Imaging modality Contrast media

X-ray/CT Barium, Iodine
USG Stabilized microbub/les (Expired by lungs Safe in renal failure)
MRI Gadolinium
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 8 Radiology

----- Active space ----- BARIUM

BaSO4 suspension used.
Applications :
GI studies.
1. Barium swal%ow : 2. Barium meal :
To evaluate : To evaluate :
• Up(er pharynx. • Stomach.
• Esophagus. • Proximal
• Gastro-esophageal duodenum.
junction.

3. Barium meal fol%ow 4. Barium enema :

through (BMFT) To evaluate large
To evaluate smal% bowel. bowel.

Feathery ap(earance
of jejunal lo.p,
Featureless
ap(earance of ileum
(In central abdomen)

Contraindications :
Absolute : Perforation (Causes severe chemical peritonitis).
Relative :
• Smal% bowel obstruction (SBO).
• Hypersensitivity.
• Recto-vaginal/vesico-vaginal/tracheo-esophageal fistula.
• Left sided colonic obstruction : Excessive stasis Barium converts into
fecoliths.
IODINATED CONTRAST
Iodine (should be high to block X-rays)
Iodine-particle ratio :
Osmotical%y active particle
(Should be high) (Should be low to avoid adverse effects)

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 Fundamentals of Radiology 9

Types of Iodinated Contrast : ----- Active space -----

High osmolar Low osmolar

Ionic monomers Ionic dimers Non-ionic monomers Non-ionic dimers
• M/c used contrast • Iso-osmolar contrast
Features – – • Chemical%y stable : Low • Safest
adverse effects • High cost
I : P Ratio 3 : 2 (Worst) 6:2 3:1 6 : 1 (Best)
Salts of Diatrizoic acid :
• Trazografs • Iohexol/Omnipaque (M/c)
• Iotrol
• Urograffin • Ioxaglic acid • Iopamidol
Examples • Iotrolan
• Angiograffin • Iocarmic acid • Ioversol
• Iodixanol
• Gastrograffin • Amipaque
• Iothalmic acid (Conray)

Contrast Induced Nephropathy (CIN) :

Diagnostic criteria : ↑ S. creatinine
• >25% Per injection value
within 48-72 hrs of IV contrast.
• 0.5 mg/dL absolute increase

Laboratory Markers :
• S. creatinine .
• S. Cystatin C.
• Estimated GFR (eGFR) <60 mL/min.
• Plasma neutrophil gelatinase associated lipocalin (NGAL).

Risk Factors :
• Pre-existing chronic kidney disease • Elderly.
(CKD) : Most important. • Diabetes mel%itus.
• Anemia. • Multiple Myeloma.
• Hypovolemia/Dehydration. • Metabolic Syndrome.

Management :
• Self limiting condition : Maintain fluid and electrolyte balance.
• Hemodialysis (Rare).

Prevention : Pre-contrast
• Renal function tests : To rule out CKD. • N-Acetyl cysteine.
• Hydration. • Vitamin C.
• Bicarbonate therapy. • Rosuvastatin.

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----- Active space ----- MRI CONTRAST AGENTS

Types :

T1 relaxation agents T2 relaxation agents

Example Gadolinium (M/c) Super paramagnetic iron oxide (SPIO)
MRI sequence Bright on T1w Dark on T2w
• Paramagnetic agent Used to detect ↑ Kupffer cel% activity
Comments
• C/I in pregnancy (Focal nodular hyperplasia)

Hepatocyte specific contrast agents :

• Gd–Manganese DPDP.
• Mangafodipir trisodium.
• Gd–BOPTA.
• Gd–EOB-DTPA.

Nephrogenic Systemic Fibrosis :

Adverse effect of MRI contrast d/t pre-existing renal impairment.
Causative agents :
• Omniscan/Gadodiamide (M/c) : Banned.
• Magnevist/Gadopentetate dimeglumine (2nd m/c).
• Optimark/Gadoversetamide.

USG CONTRAST AGENTS

Safe in renal failures.

Classification :
1st Generation 2nd Generation 3rd Generation
Shel% None Protein Protein/lipid/polymer
Stability Least Moderate Highest (M/c used)

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 Radionuclide Imaging and Radiotherapy 11

RADIONUCLIDE IMAGING AND RADIOTHERAPY ----- Active space -----

Planar Scintigraphy vs. Single Photon Emission Computed Tomography

(SPECT) :

Radioisotope of iodine injected Uptake in thyroid tissues Detected by

cameras.

Based on no. of cameras

Planar scintigraphy SPECT

No. of planes Uniplanar Multiplanar
cameras Single multiple
Resolution Poor Good
Sensitivity Low High

PET Scan 00:04:40

Position Emission Tomography (PET).

Principle Annihilation : Positron & electron energy photon.
Co-incidence imaging : Only true signals detected by crystals.

Crystals

Collision

Coincidence
imaging
Photons

Ring of detectors

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 12 Radiology

----- Active space ----- Indication :

Cancer imaging (Most important) :
• Primary diagnosis. • Response to treatment.
• Staging & detection of metastases. • Recur%ence detection.

18-FDG (Fluoro-deoxy-glucose) :
• M/c used radionuclide for PET scan.
• Cancer cells : ↑ 18 FDG uptake than normal cells (D/t Warburg ef&ect).
Warburg ef&ect :
Aerobic Lactate (Even in presence of 0 ).
Pyruvate Glycolysis 2

Shunted for cell division intermediates.

PET vs. CT scan : Fusion imaging technique.
CT PET PET CT
Gives structural/anatomical Gives functional/metabolic Colour map superimposed on
information information as a colour map CT image

Drawbacks of PET Scan :

False negative (PET - , tumor + ) False positive (PET + , tumor - )
• Small tumor size (<1 cm) : Low output of
rays Undetected.
• Low grade malignancy (Slow proliferation
rate) : • Infections :
- Typical carcinoid tumor. - Cellulitis.
- Bronchoalveolar cancer. - Abscess.
- Mets from primary mucinous tumor. • Granulomatous conditions.
- Post Chemotherapy tumor.
• Hyperglycemia : Competitive inhibition of
FDG by excess glucose.

Newer FDA approved isotopes for PET :

Isotope Indication
Ga-68 PSMA
Prostate cancer
(Prostate specific membrane antigen)
Staging of prostate cancer : Detection of Mets in
Carbon-11 Choline
lungs, brain, GIT, Genito urinary tract
Fluorine-18 Florbetaben/Flutemetanol/
Detection of amyloid deposits in brain
Florbetapir
Co-64 Dotatate Somatostatin receptor + ; neuroendocrine tumors
Myocardial perfusion
Nitrogen-13 Am(onia & Rubidium-82
(Traditionally used : Thallium)

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 Radionuclide Imaging and Radiotherapy 13

Technetium-99m 00:19:15 ----- Active space -----

• M/c used isotope in nuclear medicine.

• Production & disintegration pathway.
Disintegration
Synthesized from Tc-99m : Tc-99
molybdenum-99 • Metastable isomer.
• T1/2 : 6 hrs. Disintegrates into
Ruthenium-99.
Applications :
Tc99 tag)ed with Use
I- Thyroid imaging
RBC Detect site of bleeding
Neutrophils Detect hid+en foci of infection (More specific than Ga-67)

Gallium-67 Scan 00:23:57

• Sensitive for detection of infection/inflam(ation (Pyrexia of unknown origin)

• Low specificity : False positive in Sarcoidosis (Panda sign/Lambda sign).
Lymphoma.

Organ Imaging 00:25:45

Renal Imaging :

Evaluation Radionuclide used Mechanism/Interpretation

Tc-99m DMSA
Static/Structural/Anatomical -
(Dimercapto suc,inic acid)
GFR estimation Tc DTPA Excreted exclusively by glomerular filtration
Excreted by glomerular fillation +
Dynamic/renal function evaluation Tc MAG3 (Mercaptoacetyltriglycine)
tubular secretion
Do Tc-99 DTPA Scan

Measure baseline GFR

Captopril Tc 99-DTPA
Renal artery stenosis (RAS) (Captopril
Give small dose of Captopril
causes ↓ GFR)
Measure GFR again by Tc-99 DTPA : GFR2
If GFR2 <GFR1 RAS

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 14 Radiology

----- Active space ----- Cardiac Imaging :

Imaging technique Radionuclide used Interpretation
• Thallium 201 (Ac,umulates in
• Normal myocardium : Hot spot
Cardiac perfusion imaging intracellular spaces like k+)
• Infarct : Cold spot (No perfusion)
• 13 N am(onia & Rubidium 82
Infarct maging/Infarct scintigraphy 99m TC-stannous pyrophosphate Infarct : Hotspot
Radionuclide ventriculography/ Cardiac output is assessed using EDV
99m Tc- RBCs
MUGA scan & ESV
Ischemic myocardium takes up 18 FDG
(Glucox : Energy source)
Myocardial viability assessment 18 FDG PET
Note : Normal myocardium utilises
fat-y acid as energy source.
MUGA : Multiple gated acquisition scan ; EDV : End diastolic volume ; ESV : End systolic volume.

Lung Imaging :
ventilation perfusion scan :
Evaluation Radionuclide Interpretation
Ventilation (v) Tc-99m aerosols • Normal lung : V/Q = 1
• Early PE :
V (Normal) Mismatch
Q (↓/Absent) defect
99m Macroag)regated • Advanced PE (PE + Lung infarct)
Perfusion (Q)
albumin
- CXR : Opacity
Triple
- V : Abnormal
match
- Q : Abnormal
PE : Pulmonary embolism.
GI Tract Imaging :
Radionuclide scan :
• High sensitvity.
• Threshold for detection of bleeding : 0.05 -0.1 ml/min.
Evaluate Radionuclide used
Active GI bleed 99m Tc sulfur colloid
Intermit-ent GI bleed 99m Tc RBCs
99m Tc pertechnate (IOC) :
Meckel’s diverticulum (Ectopic gastric mucosa)
Has af&inity for gastric mucosa

Hepatobiliary Imaging :
Hepatic Iminodiacetic acid (HIDA) scan :
IV HIDA Taken up by hepatocytes Secreted into bile

Biliary tree visualization.

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 Radionuclide Imaging and Radiotherapy 15

Normal : Entire biliary tree is visualised. ----- Active space -----

Acute cholecystitis :

Gall blad+er not

taking up contrast

Gall blad+er is not visualised on HIDA scan

Skeletal Imaging :
Tc-99 MDP (Methyl diphosphonate) bone scan :
Detects stress fractures/avascular necrosis/tumors.
Super scan :
• Excessively high uptake of Tc99 MDP in bones.
• No excretion via kidneys & urinary blad+er.
• Seen in :
- Hyperparathyroidism.
- Renal failure.
- Paget’s disease.
- Metabolic bone disease.

Neck Imaging : Super scan

Diagnostic use : Thyroid nodule imaging.
Radionuclide used : 99m Tc-pertechnetate/1123 Na-Iodide.
Cold nodule Warm nodule Hot nodule
No uptake Similar to normal More than normal
thyroid gland thyroid gland

Radionuclide uptake

Risk of malignancy Highest (20%) Moderate Least (2%)

Therapeutic use :
• Iodine-131 : Papillary thyroid cancer.
• Iodine - 125 : Brachytherapy.
Note :
Iodine 124 : Experimented for use in PET scan.
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 16 Radiology

----- Active space ----- Miscellaneous Imaging :

Tissue Scan Features
99m Tc-SestaMIBI scan IOC for parathyroid localization
Parathyroid 99m Tc tetrofosmin scan -
4D CECT scan IOC for parathyroid tumors
• Tumors : Cold spot.
Salivary gland 99m Tc pertechnate scan Except Warthin’s tumor/
Adenolymphoma : Hot spot.
Detects :
• Pheochromocytomas.
• Paragangliomas.
I131 MIBG scan • Medullary thyroid cancer.
(Meta-Iodo-Benzyl guanidine) • Neuroblastoma.
• Ganglioneuromas.
Neuroendocrine/ • Ganglio neuroblastomas.
Catecholamine producing • Carcinoid tumors.
tumor
IOC for adrenal
CE-MRI
pheochromocytoma
Ga-68 :
• DOTA peptide PET/CT IOC for extra-adrenal
• DOTATATE PET/CT pheochromocytoma
• DOTATOC PET/CT

Components of Radiotherapy 00:49:52

X ray (M/c used)

Damaging power max Min
Ionization Max Min
Penetration Min Max
• Phosphorous-32 :
Rx of polycythemia
rubra vera.
• Radium-223 : Rx of
• Strontium-89 : • Tc-99 :
painful bone mets.
Rx of bone mets. Diagnostic purpose.
Examples • Radon-222 : Air
• Yt-rium-90 : • Cobalt-60 :
pollutant & can
Trans arterial Teletherapy.
cause lung cancer.
Chemo embolisation
of hepatocellular
cancer.

Brag)’s peak :
Seen with heavy & charged particles particles.
Protons.
Note : Kerala has the maximum dose of natural radiation in India.
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 Radionuclide Imaging and Radiotherapy 17

Mechanisms : ----- Active space -----

Ionisation Double stranded DNA breaks.
FRACTIONATED RADIOTHERAPY
Total required dose is split into multiple fractions & then administered.
Conventional
Hypofractionation Hyperfractionation
fractionation
• I fraction of dose/
day for the week
Frequency of <5 fractions of dose/ > fraction of dose/
(Monday - Friday)
Radiotherapy week day
• Weekend : Holiday
period.
Ag)ressive tumors :
• Palliative care • Cerebral glioma
• melanoma • Small cell lung
Indication -
• Soft tissue cancer
sarcoma • Head, neck, face
cancer
5 Rs of fractionated radiotherapy :
1. Radiosensitivity : Baseline criteria to start RT.
2. Repair
↓ response to RT.
3. Repopulation
4. Reoxygenation
↑ response to RT.
5. Reassortment
CELL CYCLE SENSITIVITY TO RADIOTHERAPY
G2-M phase > M phase :
Maximum radiosensitivity

Synthetic phase :
Minimum radiosensitivity

TUMORS SENSITIVE & RESISTANT TO RADIOTHERAPY

Most radio resistant Most radiosensitive
Mnemonic MOP : Mnemonic WELMS :
Melanoma Wilms
Osteosarcoma Ewings
Pancreatic cancer Lymphoma
Multiple myeloma
Seminoma
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 18 Radiology

----- Active space ----- Types of Radiotherapy 01:03:58

1. External Beam Radiotherapy (EBRT)/Teletherapy (M/c) :

Radiation source is at a distance from patients body.
Types :

Cobalt-60 machine (M/c) Linear ac,elerators (LINAC) :

• Modified heavy duty X-ray tubes
• Output : High energy X-ray + e-
Disadvantage : Normal tissue lying in the path of beam is exposed to radiation.
Note :
Cobalt-59 : Natural form of cobalt.
2. Brachytherapy :
• Radiation source placed inside/on tumor.
• Reduces exposure to normal tissue.
Type Features Examples
Interstitial Empty metal shells placed within tumor

Remote after loading :Fills shells with

isotope Ca prostate

Radiation emit-ed for a few m(

(Only tumor is exposed to radiation)
Intracavitary

Radiation source placed inside a

Ca cervix
naturally oc,ur%ing body cavity

Mould

Radiation source placed on surface of

Ca of tip of finger
body/tumor

• 1131 : Papillary thyroid Ca

• P32 :
Systemic IV injection of isotope which gets Polycythemia rubra vera
concentrated in target organ • Strontium 89 &
Samarium 132 :
In bone mets

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 Radionuclide Imaging and Radiotherapy 19

Special Applications Of Radiotherapy (RT) 01:09:18 ----- Active space -----

Radiotherapy (RT) Feature Indication

Stationary mega voltage
Intraoperative Ca pancreas
electron beam
• Multiple beams of uniform
strength
Stereotactic radiosurgery • For ac,urate localisation
Brain tumors
(RS)/r Knife RS 3DCT/MRI done
• Leksell frames (Helmets) is
worn by the patient
Multiple beams of varying
Intensity modulated RT -
strength
Can be used prophylactically or
Craniospinal ir%adiation Highly ag)ressive tumors
also to limit spread as part of Rx

Emergency RT indications :
Tumor/Mets causing :
• ↑ Intracranial tension.
• Spinal cord compression.
• Cardiac tamponade.
• SVC compression.
• Tumor lysis syndrome.
• Hypercalcemia.

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 20

----- Active space ----- RESPIRATORY IMAGING : PART 1

CXR Views 00:00:30

PA View vs. AP View : PA view AP view

Children, unconscious or critically ill
Indication M/c used
patients, polytrauma
• Posterior Anterior
Direction of X-ray • Centered at inferior angle of • Anterior Posterior
beam scapula/T8 body/T7 spinous • Divergent
process
Tube-film distance 6 ft/72 inches/180 cm Less
Heart size Normal False cardiomegaly

PA view of lungs AP view of lungs

Techniques of Projection :
Penetration
kVp ∝
Image contrast
Low kVp technique High kVp technique
kVp 60 - 80 120 - 170
Enhancement Image contrast Penetration
• Miliary nodules Reassess hidden areas on
Detects
• Calcifications X-ray

CXR standard technique :

• PA view.
• Erect position.
• Suspended end inspiration.

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 Respiratory Imaging : Part 1 21

Indications for Expiratory CXR : ----- Active space -----

• Pneumothorax.
• Foreign body aspiration.
• Obstructive lung diseases (Chronic bronchitis, emphysema).
• Diaphragmatic palsy.

Other CXR Views :

CXR view Best visualised feature
Lateral decubitus view Minimal pleural effusion
• L lung
R Anterior oblique view • Esophagus (Barium study)
• Sternum
• R lung
L Anterior oblique view
• Aortic window
Posterior oblique view ( R & L ) Ipsilateral rib fractures
Apicogram Lung apices
Lordotic view Middle lobe pathologies

Pleural effusion : Right anterior oblique view Left anterior oblique view
Lateral decubitus view

Apicogram/Lordotic view Right posterior oblique view Left posterior oblique view

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 22 Radiology

----- Active space ----- Note :

Fluid ac&umulation IOC
Pleural effusion USG
Pericardial effusion Echocardiography
Ascites Focused assessment with sonography in trauma (FAST)
Air ac&umulation IOC
Pneumothorax
Pneumomediastinum CT
Pneumoperitoneum
Retroperitoneal organs :
CECT
Pancreas (Obscured by gastric air)
Renal/ureteric calculi NCCT

Normal CXR Interpretation 00:13:10

Level of Exposure :

Margins of lower thoracic vertebral

bodies just seen Adequate exposure

Centering : Spinous process

• If both yellow lines are equal : Well
centred. Medial end
of clavicle
• ↑Distance on L L rotation :
L lung seems darker U/L radiolucency.
• ↑Distance on R R rotation :
R lung seems darker U/L radiolucency.

Identification of Ribs :
Anterior ends of ribs Posterior ends of ribs
Distance from midline Away from midline Closer to midline
Orientation Oblique Horizontal
Indicator of adequate inspiration
6 10
(Min. no. of ends of ribs seen above diaphragm)

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Cardiothoracic (CT) Ratio : ----- Active space -----

• To assess cardiomegaly.
Max. transverse diameter of heart (A)
• CT ratio =
Max. transverse diameter of in(er thorax (B)
• CT ratio values :
Normal Cardiomegaly
PA view < 0.50 > 0.50
AP view < 0.55 > 0.55

Anterior end
Posterior end

B
Identification of ribs CT ratio assessment

Mediastinal margins : Right ventricle doesn’t contribute to any borders.

Aortic
knuckle
SVC
Main pulm.
artery

L atrial
R atrium ap)endage

IVC L ventricle

R mediastinal margin L mediastinal margin

Hilum :
• N hilum shape : Concave (Laterally).
Convex lobulated contours Lymphadenopathy (TB, sarcoidosis).
• Hilar point : L higher or equal to R .
L can never be lower than R .

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----- Active space -----

Superior pulmonary vein

(Smaller up)er limb)

Hilar point

Lower Lobe pulmonary artery

(Longer lower limb)
Hilar shadows
(Lower lobe veins have no contribution)
Lobar anatomy :

R up)er lobe
Horizontal fissure L up)er lobe

R middle lobe Oblique fissure

( R paracardiac area) Lingula ( L paracardiac
R lower lobe area)

Oblique fissure L lower lobe

Diaphragm :
Note :
Always check below
diaphragm for
pneumoperitoneum.

Diaphragmatic level
L side lower than R d/t Cardiophrenic angle
weight of heart ( R side lower in Costophrenic angle
dextrocardia)

Hidden Areas :
Areas not well-visualized
on CXR.

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Prosthetic Cardiac Valves & Incidental Findings on CXR 00:36:53 ----- Active space -----

Prosthetic Cardiac Valves :

From above to below :

PV : Pulmonary valve
AV : Aortic valve
MV : Mitral valve
TV : Tricuspid valve

PA view Lateral view

Dextrocardia with Situs Inversus :
A/W Kartagener syndrome.
• Dextrocardia.
• Situs inversus.
• Ciliary dysfunction :
- Recurrent infections. Heart on R side
- Bronchiectasis.
Fundic bub+le on R
- Infertility.
Dextrocardia with situs inversus

Cervical Rib :
• Articulates with transverse process
of cervical vertebra.
• A/w thoracic outlet syndrome :
Compression of subclavian vessels b/w
cervical rib & 1st rib Up)er limb ischemia.
Cervical rib
Post Mastectomy CXR : Scoliosis :

Lateral curvature
of spine
Absent L breast
shadow : Ca breast
Cob+’s angle
Used to quantify scoliosis

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----- Active space ----- Pneumoperitoneum :

Pneumoperitoneum Pseudopneumoperitoneum
X-ray features Free air below dome of diaphragm Air in bowel lo-p (Chilaiditi sign)
Cause Hollow viscus perforation Colon trap)ed b/w liver & diaphragm
Rx Laparotomy -

X-ray image

Note : Chilaiditi syndrome Chilaiditi sign + pain.

Differential Radiographic Density Signs 00:46:53

• Sharp borders visualized b/w structures of different radiographic densities.

• Radiographic densities in ↑order : Air < Fat < Water < Bone < Metal.
Silhouette Sign :
Positive silhouet,e sign : Inability to visualize a sharp border d/t adjacent
structures having same radiographic density.
Structure obscured Lobe involved
R up)er mediastinal border RUL (Anterior segment)
R heart border RML
R dome of diaphragm RL. > RML
Aortic knuckle LUL (Apicoposterior segment)
Lateral margin of descending thoracic aorta L.L (Superior/posterobasal segment)
L heart border Lingular segment of LUL Positive silhouet,e sign :
R heart border obscured
L dome of diaphragm L.L d/t RML consolidation

Loss of L dome Loss of R up)er Loss of R dome Loss of L heart border :

of diaphragm : mediastinal margin : of diaphragm : Lingular segment of LUL
L.L ( L heart border + ) RUL anterior segment RL. ( R heart border + )

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Air Bronchogram Sign : ----- Active space -----

Black branching lines (Air density) against the opacity of consolidation (Water
density).

Causes :
• Infective consolidation (M/c). • Pulmonary lymphoma.
• Pulmonary edema. • Pulmonary infarct.
• Interstitial lung disease. • Pulmonary hemorrhage.
• Bronchoalveolar Ca
(Low grade lung Ca).

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----- Active space ----- RESPIRATORY IMAGING : PART

Pneumonia 00:00:53

Staphylococcal Pneumonia :
History : Fever, cough + expectoration, breathlessness,
on antibiotics.
X-Ray : Single/multiple pneumatoceles (Air-filled cysts).
Differentials : Staphylococcus, pneumocystis (In HIV +ve).

Staphylococcal pneumonia
showing pneumatocele
Atypical/Mycoplasma Pneumonia :
History :
• prominent symptoms of LRTI.
• ↑constitutional symptoms.
X-Ray : Reticulonodular pat%ern of consolidation.

Legionella Pneumonia :
History : Atypical pneumonia
• Acute oubreak 2-8 days after an indo&r gathering
(Spreads through contaminated water in co&lers/AC).
• Signs of LRTI.
• GIT involvement : Nausea, vomiting, lo&se sto&ls.
• CNS involvement : Headache, confusion, lethargy.
• Electrolyte imbalance.
X-ray : B/L multifocal involvement.
Legionella pneumonia
Pneumocystis Pneumonia :
History :
• K/C/O HIV (CD4 <200 cells/m' ).
• Insidious dyspnea, non productive cough.
X-Ray : Reticular central opacities + pneumatoceles.
HRCT : Central perihilar ground glass opacities (G(O).
Pneumocystis pneumonia

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Cavitatory Lesions 00:06:39 ----- Active space -----

Lung Abscess :
History :
• Unconscious chronic alcoholic.
• Aspiration followed by cough + expectoration, high grade
fever.
Imaging : Cavitatory lesion + air-fluid level.
Lung abscess showing air-fluid
Aspergilloma :
History :
• Past h/o tuberculosis.
• Asymptomatic/occasional cough + hemoptysis.
Imaging : Monod sign Lung cavity with
mobile dependent contents.

Note :
Aspergilloma : Monod sign
Air crescent sign : Se)n is invasive aspergillosis.

Pediatric Imaging 00:09:08

Enlarged Adenoids :
History : Child with 2 episodes of otitis media, persistent
rhinorrhoea & nasal congestion.
X-Ray : ↑adenoid size in posterosuperior nasopharynx.

N Adenoids Enlarged adenoids

with narrow
nasopharyngeal airway
Acute Epiglottitis :
History :
• 4 yr old child with h/o H. influenza B infection.
• C/O fever, altered voice, difficulty in speaking,
inspiratory stridor.
X-Ray : Thickened epiglot%is
(Thumb sign).

N epiglot%is Acute epiglot%itis :

Thumb sign

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----- Active space -----

Croup/Acute Laryngotracheobronchitis :
History : Child with protracted barking cough
+ inspiratory stridor.
X Ray : Ste)ple sign (Subglot%ic area
resembles a ste)ple instead of
dome).
Croup : Ste)ple sign N dome-shaped
subglot%ic area

Tuberculosis 00:12:54

Post Primary TB :
M/c type in adults.

Cavitation Tre)-in-bud ap+earance :

(Never se)n in 1° • D/t endobronchial
TB) + surrounding spread of disease.
consolidation. • Not specific to TB.

X-Ray HRCT
Miliary TB :
• Multiple, tiny nodules of 1-3 m'
size.
• Diffusely scat%ered in B/L lungs
d/t hematogenous spread.

X-Ray HRCT
Note : Causes of miliary nodules.
• TB (M/c cause in India) • Silicosis
• Varicella Pneumoconiosis
• Coal worker’s pneumoconiosis
Infections • Blastomycosis
• Coccidiomycosis • Hypersensitivity pneumonitis
Allergic
• Cryptococcosis • Loeffler’s syndrome
• Lymphangitis carcinomatosa Cardiac causes • Chronic pulmonary edema
• Metastasis • Chronic mitral stenosis
Neoplasms
• Lymphoma • Sarcoidosis
• Leukemia Others
• Alveolar microlithiasis

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Eponyms in TB : ----- Active space -----

Meaning
Ghon’s focus/lesion Pulmonary parenchymal evidence of 1° TB infection.
Ghon’s complex Ghon’s focus + lymphatics + hilar lymph nodes.
Ranke’s complex Calcified ghon’s complex.
Simon’s complex Apical lung nodule d/t hematogenous spread.
Assman’s complex Reactivated Simon’s complex.
Puhl’s lesion/Aschoff Puhl reinfection Chronic pulmonary TB involving lung apex.
Weigert focus Caseating focus in pulmonary venous wall.
Rasmussen’s focus Pulmonary artery aneurysm close to TB lesions.

COVID-19 00:20:07

• 10C (Overall) : RT-PCR. • 1st imaging investigation : CXR.

• Imaging 10C : HRCT.

HRCT Findings :
• Peripheral, multifocal G(O. • Reverse halo/Atoll sign.

Normal lung on HRCT Ground glass opacity Consolidation :

De)p grey with white lines Hazy increase in density with Markedly increased density
& dots d/t the blo&d vessels visible blo&d vessels. with obscured blo&d vessels &
visible air bronchograms

Halo sign : Reverse halo/Atoll sign :

Central consolidation + peripheral halo Central G(O + Peripheral rim of
of G(O Invasive aspergillosis. consolidation COVID, organising pneumonia.

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----- Active space ----- CT Involvement Score :

Assess extent & severity of lung involvement.
Assess the % of each lung lobe involved Scoring scale
Lung lobe Score
Right up+er lobe • No involvement : 0 (Minimum)
Right mid,le lobe • <5% : 1
• 5-25% : 2
Right lower lobe 0-5
• 25-50% : 3
Left up+er lobe • 50-75% : 4
Left lower lobe • >75% : 5 (Maximum).
Total score 0-25

CORADS (Covid-19 Reporting and Data System) :

To predict the probability of covid-19 infection.
Type Chance of infection CT findings
CORADS 1 Highly unlikely Normal CT
CORADS 2 Unlikely Effusion/lymphadenopathy (Not se)n in covid)
CORADS 3 Equivocal Single central G(O
CORADS 4 Probable Few G(O
CORADS 5 Highly likely Peripheral multifocal G(O
CORADS 6 100% RT-PCR positive (Irrespective of CT findings)

le ral ff sion 00:27:55

Best CXR view : Lateral decubitus.

IOC : USG
Typical Findings :

Mediastinal shift
to op+osite side

Blunting of CP angle : Pleural meniscus sign : Opaque hemithorax/white out lung :

• Earliest sign on CXR. ↑fluid Fluid set%les & • D/t large effusion.
• Signifies 200-300 cc of fluid. forms meniscus. • IOC : CECT.
• 1St investigation : CXR.

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Note : D/D for for opaque hemithorax. ----- Active space -----

D/D Effect on mediastinum

Massive pleural effusion Pushed to op+osite side
Lung collapse Pulled towards affected side
Consolidation No shift

Atypical Findings :

Ap+arent ↑in density :

• Vascular markings + .
• Hilar shadows + .

1. Pleural effusion in A-P view 2. Lamellar pleural effusion

(Supine position)

• Mass like opacity in R mid,le zone

(D/t fluid accumulation in horizontal fissure).
• Disap+ears on treating heart failure (In 72 hrs).
• AKA vanishing/phantom lung tumor.

3. Loculated/fissural PE :
C/F : Elderly male with congestive heart failure
(Exertional dyspnea, basal crepitations, bipedal edema)

Pleural Ef&usion vs Empyema :

Plural effusion Empyema
Fluid distribution In dependent area Along thoracic wall
Enhancement - + d/t pus Split pleura signs
Clinical Features Cough, mild breathlessness ↑grade fever, ↑TLC

Visceral pleura
Parietal pleura

Split pleura sign

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----- Active space ----- Pneumothorax 00:37:00

Definition : Air within the pleural cavity.

C/F :
• Mechanical ventilation + . • Hypotension.
• Hypoxia. • ↑JvP.
• Tachycardia. Prominent mediastinal shift to
op+osite side
Visceral pleural line
Hyperlucency with absent
vascular markings
Expanded rib cage
De)p sulcus sign :
(D/t downward pushing of diaphragm)
Tension pneumothorax
• Best CXR view : Expiratory CXR.
• 10C : CT.
• Rx : Ne)dle thoracocentesis followed by intercostal drain tube insertion.
- Children : 2nd ICS in midclavicular line.
- Adults : 5th ICS anterior to midaxillary line.

Air-fluid level
in pleural cavity

Hydropneumothorax
USG Assessment - POCUS (Point of Care Ultrasonography) :
1. Sliding pleural line :
• Normal : Sliding movement of
pleural line with respiration.
• Pneumothorax : No sliding pleural line.

2. M mode : Pleural line

Chest wall (Waves)
Lungs (Sand)

Seashore sign : Normal Stratosphere/Barcode sign in pneumothorax

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3. B-lines & A-lines : ----- Active space -----

B-lines (Vertical) : Normal A-lines (Horizontal) in pneumothorax

Lobar collapse 00:46:10

RUL collapse :
Upward collapse Pulls horizontal fissure up.
Golden S sign :
RUL collapse Lateral concavity.
At central mass lesion
Mass in RUL Medial convexity.

Golden S sign
LUL collapse :
Luftsichel sign
Collapse forwards Pulls oblique fissure
Aortic knuckle
forwards.
Luftsichel sign : Aortic knuckle lined by superior
segment of hyperinflated L-L.

Collapsed LUL
Oblique fissure
Hyperinflated L-L

Normal lung LUL collapse

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----- Active space ----- Mediastinal Imaging 00:48:55

MEDIASTINAL MASSES
First investigation : CXR.
IOC : CECT scan.

Thymoma :
• Overall m/c mediastinal mass lesion.
• M/c anterior mediastinal mass lesion.

Middle Mediastinal Lesions :

• M/c : Lymphoma.
• M/c in children : Foregut duplication
cysts (Bronchogenic cysts).
Thymoma :
Posterior Mediastinal Lesions :
A/w myasthenia gravis
M/c : Neurogenic tumors.

Anterior Mediastinal Lesions : Fat

Mnemonic : 4T Calcification
1. Thymoma.
2. Teratoma.
3. Terrible lymphoma.
4. Thyroid lesions.
Teratoma
PNEUMOMEDIASTINUM
Clinical Features :
• H/o chest trauma/neck surgery (Causing tracheal or esophageal injury).
• Chest discomfort.
• Crepitations over neck/chest wall (D/t air specs).

Investigations :
Air in neck
(In erect position)

Chest wall emphysema

Pneumomediastinum
(Air inside mediastinum)

CXR (PA view) : Initial investigation CT (IOC)

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Signs : ----- Active space -----

1. Spin.aker sail/
Angel wing sign :
Sharp margins of lifted
lobes of thymus (D/t air
in mediastinum)
3. Naclerio's V-sign :
Lucency of air on left
2. Continuous side outlining lateral
diaphragm sign : margin of descending
D/t air betwe)n thoracic aorta and
heart and diaphragm. medial margin of
hemidiaphragm.

Lung Lesions 00:53:30

SOLITARY PULMONARY NODULE (<3 CM)

10C : CECT > PET CT.
Chest X-ray : 1st investigation.
Pulmonary Hamartoma :
A/w Carney’s triad :
• Multiple hamartomas.
• Gastro Intestinal Stromal Tumors (GIST).
• Functional extra-adrenal paragangliomas.

LUNG TUMORS
Initial investigation : Chest X-ray.

IOC : CECT.
Exception : Pancoast tumor (IOC : CE-MRI). Popcorn calcification

Corona radiata ap+earance : R L

Spiculations into adjacent lung tissue

Elevated right hemidiaphragm

(D/t phrenic nerve involvement)

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----- Active space ----- Pancoast Tumor :

Clinical features :
Com'on in elderly male smokers.
Presentation
Cervical sympathetic Brachial plexus nerve
ganglion involvement ro&ts involvement

Cough + Ipsilateral horner’s syndrome : Ipsilateral up+er limb

hemoptysis. • Ptosis. pain, paresthesia,
• Anhydrosis. weakness.
• Miosis.

Investigations :
Lung tumor in
IOC : CE-MRI (To visualize neural invasion). lung apex with
bone invasion &
destruction

Can(onball Lung Metastasis :

• Ball-like secondary metastasis tumors in
lung.
• Metastasize from ag/ressive primary
tumors :
- Renal cell carcinoma (M/c).
- Scrotal mass (Eg. : Germ cell tumor).
- Prostate cancer. Multiple ball
like lesions
- Endometrial carcinoma.

BRONCHIECTASIS
Clinical Features :
• Persistent cough + intermit%ent
hemoptysis in a mid,le aged female.
• Recurrent chest infections.
Multiple circular
Investigations : lucency with
thick walls
IOC : HRCT.
CXR

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Signs : ----- Active space -----

1. Tram-track sign : Damaged, dilated
Longitudinal dilatation. bronchi with stasis
2. String of beads sign : of secretions
(Irreversible)
Varicose dilatations
in long axis.
3. Cluster of grapes sign.
Blo&d vessel CT
4. Signet ring sign.
Dilated bronchus
SARCOIDOSIS
Clinical Features :
• Mild cough in a mid,le aged female. Lambda sign :
• Increased ACE levels. (D/t enlargement of
right paratracheal and
Investigations : B/L hilar lymph nodes)

Panda
Enlarged B/L hilar sign
lymph nodes

Convex and
lobulated margins
of hilar LN
X-ray CT Gallium scan

Foreign Body Aspiration 01:00:39

Acute onset respiratory distress (Usually in children).

Foreign body - Peanut :

• M/C aspirated foreign body.
• It is not radio-opaque.

Management : Bronchoscopy.
R L
Trachea shifted to right
Hyper-inflation d/t airtrap+ing :
Impacted foreign body prevents airflow
out of bronchus during expiration.
↑Radiolucency

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----- Active space ----- Foreign Body - Coin :

Coin in esophagus Coin in trachea

X-ray

Plane of orientation Coronal Sagit%al (D/t glot%ic folds and tracheal rings)
Ap+earance Coin en face Slit-like
Respiratory distress Absent Present
Management Esophagoscopy Bronchoscopy

Foreign Body - Button Battery :

Very dangerous, ne)ds im'ediate intervention (Bronchoscopy/esophagoscopy).

Double ring/halo sign : step-off sign

• Outer ring : Cathode.
• In.er ring : Anode
(More damaging).
gg Shell alci cation 01:05:01

Causes :
mnemonic : SLAB of calcium.
• Sarcoidosis.
• Scleroderma.
• Silicosis.
• Lymph nodes post
radiation.
• Amyloidosis.
• Blastomycoses.
• Coal worker’s pneumoconiosis.
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CARDIOVASCULAR AND NEUROLOGICAL IMAGING ----- Active space -----

Congenital Heart Conditions 00:00:08

Transposition of great
arteries (TGA) Tetralogy of Fallot Ebstein’s anomaly

Egg on side appearance Boot shaped heart/ Box shaped heart

Cœur-en-sabot
appearance

Total anomalous pulmonary venous Partial anomalous pulmonary

circulation - Supracardiac type venous circulation

Snowman/Figure of 8 Turkish sword/Scimitar sign

appearance Scimitar/hypogenetic lung syndrome :
• Right lung hypoplasia.
• Hypoplastic pulmonary artery with
anomalous supply from aorta.
• Scimitar vein : Anomalous vein draining
into IVC.

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----- Active space ----- Pericardial Effusion 00:01:18

X-ray (Initial investigation) : Echocardiography (IOC) :

Water bottle/ Oreo cookie sign on lateral Fluid sur)ounding heart

money-bag/ CXR : Ef(usion separating
flask shaped heart pericardial & epicardial fat
Coarctation of Aorta 00:03:41

M/c site : Distal to the site of origin of subclavian artery.

Figure of 3 sign Inferior rib notching sign/Roesler’s sign

Mitral Stenosis 00:04:42

Chest X-ray

2. 3. 5.
4.
Enlarged LA
Normal RA

Chest X-ray
Chest X-ray findings : D/t left atrial enlargement.
1. Fullnes% beneath the pulmonary artery shadow : Earliest finding.
2. Elevated left bronchus + splaying of carina >90°.
3. Straightening of left heart border.
4. Third mogul sign : Aorta + main pulmonary artery + Left Atrial (LA) appendage.
5. Double density sign : LA enlargement.
6. Walking man sign (Se&n in lateral view) : Left bronchi pushed posteriorly.
Echocardiography : IOC.
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Aberrant Right Subclavian Artery (ARSA) 00:06:38 ----- Active space -----

AKA Arteria lusoria.

R L
Right subclavian artery :
Arises from distal part of
aortic arch
Compres%es esophagus

Dysphagia lusoria.

Congestive Heart Failure :

Stage 1 Stage 2 Stage 3
PCWP 13-18 m+Hg 18-25 m+Hg >25 m+Hg

X-ray Cardiomegaly

• Cephalization of blood
flow/Stag antler sign/ • Alveolar edema
Hands up sign/Inverted • Interstitial edema • Bat-wing opacities
moustache sign • Kerley B line (Central perihilar opacities)
Aortic Dissection 00:10:18

Presentation : K/c/o hypertension +

severe tearing pain in lower chest/abdomen.
Investigations :
• Emergency : Transesophageal echo (TEE).
• IOC : CT angiography > MR angiography.
• Gold standard : Invasive angiography.
Clas%ification :

Descending aorta involved

Ascending aorta involved
Conservative Rx.
Surgical Rx.

Stanford A Stanford B :
DeBakey I DeBakey II DeBakey III

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----- Active space ----- CT findings :

Intimal flap : Divides lumen Cobweb sign Beak sign

into true & false lumen

Aortic Aneurysm 00:12:47

Diagnostic criteria :
• Absolute Ascending aorta : >5 cm in diameter.
Descending aorta : >4 cm in diameter.
Abdominal aorta : >3 cm in diameter.
• Relative : >50% enlargement of lumen.
M/c site : Abdominal aorta (Infrarenal part).
Imaging :
Non-specific Focal sac,ular dilatation Turbulent blood flow
mediastinal widening in aortic arch within the aneurysm

CXR CT Yin & Yang sign

Signs of impending rupture :

Crescent sign :
Hyperdense blood clot
Draped aorta sign :
Aorta draped around
vertebral body

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Constrictive Pericarditis : ----- Active space -----

Presentation : Dyspnea/orthopnea/hepatomegaly + ascites.
Imaging :
Rim of calcification
around pericardium

Pulmonary Embolism (PE) 00:15:24

Presentation : Young + prolonged im+obilization + acute breathles%nes% +

chest pain + hemoptysis.
ECG : S1 Q3 T3 (Right ventricular overload).
Imaging :

Main pulmonary A.
SVC
Embolus Polo mint sign :
Central filling
Descending aorta
defect in artery

• Pulmonary signs :
a. Hampton’s hump : Wedge-shaped pulmonary infarct.
b. Melting ice cube sign : Pulmonary infarct resolution
from periphery to center.
• Vascular signs :
a. Fleischner’s sign :
Enlarged R main pulmonary artery (PA).
b. Palla’s sign : Enlarged R descending PA.
c. Chong’s/knuckle sign : Enlarged R descending PA with abrupt cut of(.
• Westermark sign : Focal oligemia in lung fields.

Investigations :
• D-dimer test : Scre&ning test.
• CT angiography : IOC.
• V/Q scan : Not used.
• Invasive pulmonary angiography : Gold standard.

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----- Active space ----- Agatston score (Scre&ning) :

• Done on NC-T (Before coronary CT angiography).
• Semiquantitative method.
• As%es%es calcium burden on coronary arteries.
Score

<100 : Good 101-400 : Moderate. >400 : Heavily calcified (Poor prognosis).

Neurological Imaging 00:20:00

CT vs. MRI
CT MRI
Acute neurological
• IOC for most neurological abnormalities.
Indication presentations (Requiring
• Disadvantage : ↑imaging time.
im+ediate intervention).
• Brain tumor.
• Acute stroke • Multiple sclerosis.
Application
• Head trauma. • Child with developmental delay/mental retardation.
• To evaluate h/o convulsions (1 wk ago).
Imaging in Stroke 00:22:56

Indication Investigation
Acute stroke 1st Ix : CT (To rule out hemor)hage)
Acute infarct DWI MRI : Earliest diagnosis (Detectable 15-30 mins from onset)
Penumbra identification Perfusion weighted : CT/MRI
Vascular imaging TOF : MR angio > CT angio
Overall best MRI + DWI
Key :
• TIA : Transient • DW MRI : Dif(usion • TOF : Time of Flight.
Ischemic Attack. Weighted MRI.
Hyperacute Stroke (<6 hours) :
NC-T DWI

DWI ADC Map

1. Hyperdense MCA (Mid.le 2. Disappearing 3. DWI with ADC map :
Cerebral Artery) sign basal ganglia sign Restricted dif(usion
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 Cardiovascular and Neurological Imaging 47

Acute Stroke (≥6 hours) : ----- Active space -----

Hemispheric infarct Basal ganglia infarct

R MCA Basal ganglia

ter)itory

Lacunar infarct
Features :
• Wedge shaped infarct.
• Dif(use hypodensity : D/t vasogenic edema.
• Grey and white matter involved with los% of dif(erentiation.
• Mas% ef(ect : D/t edema.
- Compres%ion of frontal horn of lateral ventricle.
- Midline shift of parenchyma.
Central Venous Sinus Thrombosis (CVST) :
Presentation : Fever/dehydration/pregnancy + severe persistent headache.
Imaging :

(2)
(1)
(3)
NC-T Brain : Delta sign CECT Brain : Empty delta sign NC-T Brain : Cord sign

1. Hyperdense triangular area. Thrombus in superior

2. Hyperdense walls with hypodense central area. sagittal sinus.
3. Hyperdense cord area Transverse sinus thrombosis.
Global Cerebral Hypoperfusion (GCH) injury :
• Presentation :
H/o cardiac ar)est/severe hypotension/anoxia/hypoxia + altered sensorium.
• Poor prognosis.

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 48 Radiology

----- Active space ----- Imaging :

1. White matter : Hyperdense.
(2) Reversal sign.
2. Grey matter : Hypodense.
3. White cerebellum sign : Hyperdense
(1)
cerebellum with respect to cerebrum
(D/t relative sparing of posterior circulation).

(3)
CT Brain
Moya Moya Disease :
• Presentation : Child + multiple episodes of fainting
+ L hemiplegia + focal neurological
deficits.
• Pathology : Progres%ive nar)owing of Internal
Carotid Artery (ICA)
MR Angiogram :
Development of numerous collaterals. Puf( of smoke appearance

Hypertensive Bleed 00:36:22

Se&n mostly in basal ganglia.

M/c site : Putamen > thalamus > pons.
Clinical presentation :
• Uncontrolled hypertension.
• Deviation of eyes + focal deficit + altered sensorium.
Imaging :
Frontal horn of lateral ventricle
Head of caudate nucleus
External capsule
Putamen (1) (1)
Lentiform nucleus Globus pallidus
Insula (wavy cortex)
Internal capsule
Thalamus
Atria of lateral ventricle
Anatomy of the basal ganglia CT brain

(1) : Hyperdense/bright area (D/t ble&d) sur)ounded by rim of hypodense area

(D/t edema) in basal ganglia.
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 Cardiovascular and Neurological Imaging 49

(2) : Swirl sign. ----- Active space -----

• D/t continuous ongoing ble&d.
(2)
• Hypodense area within the
hyperdense ble&d (Clot).
• Indicates ble&d expansion.

Subarachnoid Hemorrhage (SAH) 00:39:05

Etiology : Rupture of ber)y aneurysm (Aneurysm of circle of Willis at basal cistern).

Clinical presentation :
• Mid.le aged.
• Thunderclap headache (Worst headache of life).
• Altered sensation.
Radiological imaging :
• IOC CT : Acute SAH.
MRI : Subacute/Chronic SAH.
• Gold standard : Digital subtraction angiography.
Note : IOC for ber)y aneurysm CT Angiography.

Ber)y aneurysm

CT brain : Hyperdense NC-T brain CT angiography

basal cisterns
Vein of Galen Malformation :
• Presentation : Newborn male with congestive
heart failure.
• O/E : Elevated fontanelles + loud cranial bruit.

Posterior Reversible Encephalopathy Dilated vein at center of straight sinus

Syndrome :
Parietal
Clinical presentation :
• Pregnant female with pre-eclampsia.
• Altered sensorium.
Oc,ipital
Pathology : Transiently af(ect posterior circulation
(Reversible condition). Axial section Coronal FLAIR-MRI
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----- Active space ----- CT in Head Trauma & Brain Tumors 00:42:17

CT Interpretation Protocol :
Hemor)hagic contusion EDH SDH SAH

CT

Location Within brain Outside brain Outside brain

Outside (Sulcal space)
of ble&d parenchyma parenchyma parenchyma
Edema Present Absent Absent Absent
Shape - Biconvex Crescent Linear
Mid.le meningeal
Source - Bridging cortical veins -
artery
• Lucid interval
As%ociation - - -
• Talk & die syndrome
Bleeding Stages on CT :
Intracranial ble&d

Acute ble&d Sub-acute ble&ds Chronic ble&d

Hyperdense Isodense : Hypodense :
• ↑density d/t clots. • Few days to we&ks. • Few we&ks to months.
• ↓density d/t • ↓density d/t replacement
breakdown of clot. of blood with fluid.
• IOC : MRI.
Hypodense
fluid

Diffuse Axonal Injury :

Clinical features :
• H/o head trauma with normal early CT brain.
• Non-improving altered sensorium.

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Investigations : ----- Active space -----

MRI (IOC) :
• Detection of petechial hemor)hages at site of axonal injury.
• Use blood sensitive sequences Gradient echo images (GRE).
Blood appears as Susceptibility weighted imaging (SWI).
• Black spots
Sites : Blooming
- Gray-white matter
junction (GWJ) : M/c.
- Corpus callosum.
- Brain stem.
SWI
Tension Pneumocephalus :
• M/c cause : Trauma, post neurosurgery.
• Presentation : Asymptomatic/headache/↑ICT/bruit hydroaerique (Splashing
sound on head movement).
• CT Imaging :
Air in cranial cavity

EDH
Compres%ion of brain
d/t high pres%ure of
air pockets

Mount Fuji sign/

Peaking sign
Pneumocephalus Tension pneumocephalus

Brain Tumors 00:52:23

Acoustic/Vestibular Pituitary macroadenoma Pituitary microadenoma

schwan/oma : (>10 m+ in size) (<10 m+ in size)

Icecream cone appearance : Snowman/figure of 8 appearance : Small tumor in pituitary :

• Tumor at cerebello-pontine • Bilobed tumor with constriction • Enhances les% than
angle with extension into in sellar & suprasellar region. adjacent pituitary gland.
internal auditory meatus.
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----- Active space ----- Craniopharyngioma :

• Af(ects children.
• Cystic + solid lesion.
• Site : Suprasellar region.
• Calcifications.

Tuberous sclerosis :

Converts
(in foramen of Monro)

Subependymal nodules : Subependymal giant

Calcific nodules around cell astrocytoma.
lateral ventricular margins.
Ependymoma : Medulloblastoma :

Mets

Arises from floor of 4th ventricle. • Arises from roof of 4th ventricle.
• Aggres%ive : Drop metastasis to
spine (Zuckergus%).
Meningioma :
• CT findings :
2.
1. Broad base towards dura.
1. 2.
2. Dural tails. 2.
3. Hyperdense on NC-T.
• A/w MISME (Multiple Inherited 2.
Schwan/oma Meningiomas &
Ependymoma) syndrome.
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----- Active space -----

3. 2.

2.
2.

2.

Glioblastoma :

Ir)egular
Heterogenicity enhanced peripheral rim
Central area of necrosis

Thick peripheral rim

of enhancement
Grade IV (GBM) : Glioblastoma Butterfly glioma

Corpus callosum lipoma : Oligodendroglioma :

Fat
Calcified
Bracket cortical mas%
calcification

Curvilinear type Tubulo-nodular type Se&n in young & mid.le aged

Juvenile nasopharyngeal angiofibroma (JNAF) :

• Presentation : Adolescent male + epistaxis + nasal
blockade.
• Site : Sphenopalatine foramen.
• Spread :
- Nose.
- Paranasal sinus.
- Infratemporal fos%a.

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----- Active space ----- Familial brain tumors :

Tumor As%ociation Imaging
• Optic glioma
Neurofibromatosis
• Brain stem glioma -
(NF) 1
• Plexiform NF

NF 2 MISME syndrome

B/L acoustic schwan/oma (NF2)

• Hemangioblastomas of
cerebellum, retina
Von Hippel Lindau • Renal cell carcinoma
• Pancreatic cyst adenomas
• Cysts in : Liver, sple&n

Ring Enhancing Lesions & CNS Spotters 01:01:06

Ring Enhancing Lesions :

Tubercular meningitis :

1.
1.

3.

3.

1. Basal enhancing exudates. 3. Tuberculomas : Disc/ring enhancing lesions.

2. Hydrocephalus. 4. Vasculitic basal ganglia infarcts.
Neurocysticercosis :
Clinical profile :
• Headache.
• Seizures.
Ring enhancing lesions
Imaging : with ec,entric dot
• Ring enhancing lesions.
• Cyst with a dot sign (Dot : Scolex).

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Brain absces% : ----- Active space -----

Clinical profile :
• Young-mid.le aged.
• H/O sinusitis/Chronic ear
discharge (CSOM). Pus
• Fever, headache, altered
sensorium. Ring enhancing lesion Restricted dif(usion
• Signs of meningitis.
Imaging : Temporal lobe ring enhancing lesion.
Toxoplasmosis :
Clinical profile :
• HIV +ve patient.
• CD4 count <200.
• Fever, malaise, headache.
Imaging signs :
• Ring enhancing lesion in basal ganglia, grey-white matter junction (GM-WM).
• Target sign/concentric/ec,entric target sign.

Target sign
Ring enhancing
Target sign lesion
Ring enhancing
lesion

Glioblastoma/Grade 4 glioma :
Clinical profile :
• Mid.le aged : Elderly.
• Seizures.
• Focal deficits.
Imaging sign :
• Ir)egular ring enhancing lesion.
• Thick peripheral rim of enhancement
with central necrosis.
Metastasis :
Clinical profile :
• Elderly. • Seizure, focal deficits.
• K/c/o 1° tumour.
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----- Active space ----- Imaging sign :

• Ring/dif(usely enhancing lesion at GM-WM junction.
• Sur)ounding edema.

Ir)egular ring
enhancing lesion

CNS Spotters :
Herpes encephalitis :
Clinical profile : Headache, high grade fever, altered sensorium.
Structures involved : Cingulate gyrus
Insular cortex Limbic system.
Fronto-temporal lobe
IOC : MRI.
Rx : IV Acyclovir.

Insular cortex Frontal lobe

Cingulate gyrus

Temporal lobe

Multiple sclerosis :
Clinical profile :
• Young patient.
• Multiple neuro deficits.
• Cranial nerve palsy.
• Relapsing - Remitting symptoms.

Dawson’s fingers
Imaging :
MRI Dawson’s fingers (Longitudinal white matter plaques)
Post contrast MRI

Enhancing lesions are active D/t demyelination

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HIV : ----- Active space -----

HIV encephalopathy : Periventricular Multifocal Leukoencephalopathy :

Atrophy of brain : Infection of oligodendrocytes with JC polyoma virus :
• Slownes%, forgetfulnes%. • Motor deficits.
• Dementia. • Ataxia.
• Seizures, altered sensorium.
Gliosis

Large
ventricle

Hypodensities along white matter

Alcohol related CNS manifestations :

Wernicke encephalopathy/ Marchiafava bignami disease : Central pontine myelinolysis/

Wernicke Korsakof( syndrome : • Seizures + motor. Osmotic demyelination syndrome :
• Thiamine deficiency. • Cognitive disturbances. • Hyponatremia rapidly cor)ected.
• Ataxia, acute confusion, • Altered sensorium. • Altered sensorium.
ophthalmoplegia.
Hyperintensities of mamillary
bodies & tectal plate

Corpus callosum (Splenium) Pons

Periaqueductal white matter

(Thalamus & tectal region)

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----- Active space ----- Arnold Chiari type 1 :

Cerebellar herniation
(Peg-shaped tonsil)

Syrinx formation

Arnold Chiari type 2 :

Colpocephaly Meningomyelocele
(Tear drop
lateral ventricle)

Corpus callosum dysgenesis

(Small posterior fos%a Cerebellum pres%ed against pons)

Dandy -Walker malformation : Joubert syndrome :

Pons

Cyst in posterior Molar tooth

fos%a appearance

Schizencephaly : Hallervorden Spatz syndrome :

Cleft

Eye of tiger sign

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GASTROINTESTINAL AND GENITOURINARY ----- Active space -----

TRACT IMAGING

ifferentials or Acute Abdomen 00:00:05

Pneumoperitoneum :

Air under
diaphragm

A. Erect abdominal xray B. Erect chest xray C. CT abdomen (IOC)

X-Ray : Erect chest x-ray (Best) > L lateral decubitus view.

Signs Appearance (D/t differential densities of air and tissues on radiograph)

1. Football sign Collection of air in center of anterior abdominal wall Oval lucency.
2. Cupola sign Air along central tendon of diaphragm from below.
3. Falciform
Sharp demarcated falciform ligament lined by air on either sides.
ligament sign
4. Liver/GB edge Sharp margin of liver and sharp margin of outer serosal surface of gall
sign blad&er.
5. Rigler's double
Sharp margin betwe'n in(er mucosal and outer serosal layer of bowel.
wall sign
6. Doge's cap sign Ec)entric triangular shape d/t air trapped within Morrison's pouch.
1
2
6 3

5
4

D. Supine abdomen xray

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----- Active space ----- Bowel Obstruction :

Small bowel Large bowel
Diameter of dilated loop >3 cm >5 cm
Location of bowel loop Central Periphery
Number of loops Multiple Few
Air fluid levels Multiple & short Few & long
Gas in large bowel No gas Dilated proximal to obstruction

Bowel wall markings

Valvulae con(iventes : Haustrations :

Complete transverse mucosal Incomplete transverse folds
folds extending across lumen
CT : IOC.
Signs :

Small bowel feces sign : String of beads sign :

Fecal mat+er like appearance in Air trapped in valvulae con(iventes.
small bowel (D/t prolonged stasis).

Transition point :
• Most reliable CT criteria.
• Point of sud&en transition from dilation to narrowing.
• Site of obstruction.

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Gall Stone Ileus : ----- Active space -----

X-ray : CT : IOC

3. Small bowel obstruction :

Dilates bowel loops

1. Pnuemobilia : Air in biliary tre' 2. Gall stone impacted at terminal

ileum (Right iliac fossa)

Duodenal Atresia : Rigler’s triad

• Presentation : Bilious vomiting at birth.
• X-ray :

Stomach
Proximal duodenum
Note :
Other bub,le signs :
• Single bub,le sign : Pyloric stenosis.
• Triple bub,le sign : Jejunal atresia.
Double bub,le sign

Infantile Hypertrophic Pyloric Stenosis (IHPS) :

• Presentation : Non bilious vomiting at 6-12 we'ks.
• Imaging :

a. X-ray & barium meal study :

Mushroom sign : Mushroom like duodenum.

Hypertrophic
Caterpillar sign : Hypercontractile stomach.
pylorus

Shoulder sign : Impression of hypertrophied

pylorus on stomach.
Stomach
Narrowed
pyloric canal Double tract/string sign : Narrowed pylorus.

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1. Circumferential hypertrophy of pyloric muscle. 6

----- Active space -----
1 2
2. Caterpillar sign : D/t hypercontraction of stomach.
3. Shoulder sign : Extrinsic impression on pylorus. 3
4. Beak sign : At opening of pylorus. 5
4
5. String sign : Narrow lumen of pyloric canal.
6. Mushroom sign : Appearance of proximal duodenum.

b. USG :
• IOC.
• Diagnostic criteria : Pylorus thickness >4 m& & length >16 m&.

Volvulus :
• Presentation : Abdominal distension & absolute constipation.
• Risk factors : Elderly female, K/C/O psychiatric illness.
• Sites of volvulus : Sigmoid colon (M/c) > caecum, stomach.
• IOC : CECT.
• Sigmoid vs cecal volvulus :
Sigmoid volvulus Cecal volvulus
Age Elderly Young
Incidence M/c L/c
Haustrations Lost Present

X-Ray
• Friman( - Dahl sign : Walls of I dilated loop + few proximal bowel
sigmoid colon converge as 3 dense loops dilated
lines to the site of obstruction
• 2 dilated loops (Cof)e' bean sign)
without proximal bowel loop dilated

Congenital Diaphragmatic Hernia (CDH) :

• Presentation : Newborn with respiratory distress.
• Types BochdaLek (M/c) : L sided.
MoRgagni (L/c) : R sided.
• Prognostic factor : Degre' of underlying
pulmonary hypoplasia.
CDH (Bochdalek)
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Acute Appendicitis : ----- Active space -----

• Presentation : Acute pain in RIF & tenderness at McBurney’s point.
• Imaging :

a. USG b. CECT

• Edematous blind ended loop & • Dilated appendix with periappendiceal

echogenic inflam&ed omentum. inflam&atory changes.
• IOC in children. • IOC in adults.
Intussusception :
• Presentation : Child with intermittent pain + red currant jelly stools.
• M/c site : Ileocolic.
• Imaging

a) USG : b) Barium enema : c) CECT :

IOC in adults.

• Target/Bull’s eye/ Coiled string appearance

Doughnut sign.
• IOC in children.

Claw sign

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----- Active space ----- FAST & Barium Spotters 00:21:56

FAST
Focused assessment with sonography in trauma.
FAST Protocol :

Subxiphoid view

Longitudinal RUQ view : Longitudinal LUQ View

Best view (Morrison’s
pouch is visualised)
Suprapubic view

eFAST (Extended FAST) :

Assessment is extended to thoracic cavity :
• Posterior dependent part of thorax : To r/o hemothorax.
• Anterior non-dependent part of thorax : To r/o pneumothorax.

Management Algorithm in Abdominal Trauma :

Perform eFAST
• First investigation. Liver
• Fre' fluid in hepatorenal/Morrisons pouch Right
Kidney
FAST + : Hemoperitoneum

Check hemodynamic status

Pt stable Pt unstable

CECT Abdomen : Emergency exploratory

IOC for solid organ laparotomy.
injury.

POCUS (Point of care ultrasound) : Bedside ultrasound in emergency.

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BARIUM SPOTTERS ----- Active space -----

Esophagus :

Esophageal
web

a) Esophageal web : b) Ca Esophagus :

• Se'n in Plum&er-Vinson/ • Rat tail appearance.
Paterson Brown Kelly syndrome : • Dysphagia : Solids > liquids.
- Esophageal web • IOC :
- Dysphagia Triad. - Overall : Esophagoscopy + biopsy.
- Iron deficiency anemia - For staging (Mets) : PET-CT.
• Complication : Hypopharyngeal - For T-N staging : Endoscopic USG.
squamous cell cancer.

c) Zenker’s diverticulum (M/c) : d) Killian-Jamieson diverticulum : e) Achalasia cardia :

• Directed posteriorly. Directed antero-laterally. • Birds beak sign.
• Complication : Aspiration (M/c). • Dysphagia : Liquids > solids.
• Site : Killian’s dehiscence
(B/w oblique & transverse
fibres of cricopharyngeus).

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----- Active space -----

f) Dif)use esophageal spasm : g) Feline esophagus/Esophageal shiver :

Cork screw/Rosary bead/ • Striated appearance d/t muscularis
Curling esophagus. mucosa contractions.
• Se'n in :
- Reflux esophagitis.
- Hiatus hernia.
- Eosinophilic esophagitis.

Colon :

Colonic
Sawtooth lumen
Sign Tumor
Apple
core sign

a) Colonic diverticulosis : b) Ca colon :

• Presentation : Pain in LIF + fever. • Presentation : Elderly + altered bowel
• M/c site : Sigmoid colon. habits + tenesmus + blood in stools.
• Barium enema : Sawtooth sign. • M/c site : Sigmoid colon (L > R).
• CECT (Iodinated contrast) : IOC. • Barium enema : Apple core sign.

c) Ulcerative colitis :
• Presentation : Mid+le aged + pain/tenesmus +
blood in stools.
• Lead pipe colon (Loss of haustrations).
• Complication : Toxic megacolon.
- Site : Transverse colon.
- Diameter : >6 cm.

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HEPATOBILIARY SYSTEM ----- Active space -----

Liver :
1. Hepatocellular cancer, fibrolamellar HC, & liver mets :

HC, Fibrolamellar HC, Liver metastasis

Age Elderly male Young Elderly
• K/C/O cirrhosis K/C/O Ca colon :
Presentation No comorbidities
• Hepatitis B anorexia + jaundice
↑Neurotensin B
Tumor marker AFP (Alpha feto protein) -
(Normal AFP)
• Multiphase CECT
(10C for diagnosis) :
CECT : • CECT :
- Arterial phase :
Heterogenous - Multiple hypodense
Lesion enhancement
Imaging enhancing lesion in lesions (D/t
- Delayed phase :
liver with central hypovascular mets)
Washout
stellate scar • PET/CT : Hotspots
• USG (IOC for scre'ning) :
Done 6 monthly in cirrhosis
Prognosis Poor Better than HC, -

HC, : enhancing on arterial phase HC, : washout on delayed phase

Fibrolamellar HC,

CECT PET scan

Liver mets
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----- Active space ----- 2. Liver abscess :

• Presentation : Fever + pain in right hypochondrium + jaundice + elevated TLC.
• Imaging :

USG CECT (IOC)

• Hypoechoic lesion with thick Hypodense lesion Cluster sign :

contents. with peripheral rim • Small abscess Cluster Large
• Follow up USG, done after of enhancement. abscess.
drainage. • Se'n in pyogenic abscess.

3. Liver hemangioma :
• Incidentally detected.
• Imaging :

USG CT T2MRI

Well defined Initially : Peripheral Later : Centripetal Light bulb sign

hyperechoic lesion in nodular contrast filling in of contrast
liver parenchyma enhancement

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Gall Bladder Imaging 00:41:38 ----- Active space -----

Cholecystitis :

Acute GB calculus Calculous cholecystitis

• Intermittent RHC pain • Severe pain in RHC + fever + elevated TLC
Features
• M/c type : Mixed calculi (↓Ca2+) • Murphy sign +

GB
Imaging
(10C : USG) Liver Sple'n

• Hyperechoic area Fat strands around GB

• Dense posterior shadow
• Mercedes benz sign

GB spotters :
1. Normal 2. Porcelain GB 3. Phrygian cap

Normal anechoic • Calcified GB wall. • Anatomical variant.

gall blad+er • Predisposes to GB • Fundus folds over body
adenocarcinoma. of GB.

4. Choledocholithiasis

GB CBD

a) T2 MRCP : Impacted b) ERCP :

calculus in CBD (Filling • Gold standard.
defect). • Diagnostic + therapeutic.

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----- Active space ----- MRCP spotters :

a) Choledochal cyst - Type 1 : b) Caroli’s disease :

Fusiform dilation of CBD Central dot sign : Multiple intrahepatic biliary

dilatations, through which portal vessel passes

d) Benign stricture : e) Malignant stricture :

Smooth/elongated Abrupt stricture

stricture Proximal dilation
of biliary tre'

Pancreas & Liver Imaging 00:47:40

Pancreatitis :
Acute pancreatitis Pancreatic pseudocyst Chronic pancreatitis
• Around 6-8 we'ks after H/o multiple episodes of pancreatitis +
Epigastric pain + pancreatitis abdominal discomfort
Features radiating to back + • Heaviness/fullness in upper • IOC : MRCP with secretin stimulation
↑S. Amylase/lipase abdomen • Gold standard : ERCP (Shows ductal
• M/c site : Lesser sac dilatation)

CT/ Calcification
X-ray a. Fuz-y margins in pancreas
Fluid filled cystic
b. Enlarged pancreas
collection in pancreas
c. Hazy mesentery
d. Hypodense areas (Fluid)

Severity : Balthazar grading/

CT severity index
• Determines prognosis.
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Hydatid Cyst : ----- Active space -----

Stages :

1. Simple cyst 2. Snowstorm sign 3. Peripheral curvilinear

(D/t Mobile hydatid sand). calcifications

4. Daughter cysts 5. Whe'l spoke sign 6. Honeycomb’s sign

within mother cyst (Hydatid sand trapped in b/w (Entire mother cyst filled
daughter cyst). up with daughter cyst).

7. Floating membrane sign

(Degenerated membrane
floats within mother cyst).
Hydatid Cyst in Lung :

1. Air crescent sign 2. Inverse crescent sign. 3. Air bub.le sign

Air on the dependent part
of the cyst
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----- Active space -----

4. Cumbo sign : 5. Whirl/serpent sign : 6. Floating waterlily sign/

2 air-fluid levels, one in the (Membrane degenerates Camalote sign :
wall & one within the lumen of & floats within the cyst) Few of the membranes
the cyst float on the surface

7. Rising sun sign/mass within a cavity sign : Empty cyst sign :

Contents clumped at the bottom of the cyst All contents expectorated out
& cavity becomes empty

Genitourinary Tract 00:54:05

Acute Renal Colic :

• Presentation : Acute lumbar pain + radiating from loin to groin + burning
micturition.
• Imaging :
Initial : USG > X-ray KUB.

Renal calculus Staghorn/Struvite/triple Non obstructive renal calculus : • Hydronephrosis.

phosphate calculus A. Hyperechoic area. • IOC : USG.
B. Dense posterior shadow.

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NC,T ----- Active space -----

IOC for renal calculus :

Renal calculus Jackstone vesical calculus Ureteric calculus : Soft tissue rim sign
(Urinary blad+er) Helps dif)erentiate ureteric calculus
from phlebolith.

Complications of Obstructive Uropathy :

Emphysematous Xanthogranulomatous
Acute pyelonephritis
pyelonephritis pyelonephritis
Fever + ↑TLC +
Sepsis + diabetes/ Chronic calculus disease
Presentation abundant pus cells in
Im&unocompromised pt + Proteus/E.coli infection
urine

B C A

Axial view
A. Renal calculus
B. Perinephric fat
stranding
Imaging C. Edematous kidney

Bear paw sign :

Impacted calculus at
Air in renal center + dilated calyces
parenchyma at periphery
C A
B
Coronal view
Renal Tuberculosis :
• Presentation : Pulmonary Koch’s + low grade fever + sterile pyuria.
• IOC :
Overall : CECT Renal parenchymal calcification.

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----- Active space -----

Moth eaten calyx : Putty kidney : Thimble blad+er :

Earliest finding on IVU Kidney calcification in long standing Chronic inflam&ation Small
(lOC for earliest diagnosis). cases Autonephrectomy. & contracted urinary blad+er.

Polycystic kidney Diseases (PCKD) :

Autosomal recessive PCKD Autosomal dominant PCKD Multicystic dysplastic
Gradual onset renal
Child + enlarged kidneys + Abdominal lump in
Presentation impairment in 4th-5th
microcyst ± liver fibrosis neonates + macrocysts
decade + macrocysts

Antenatal
Normal
USG

Echogenic enlarged kidneys Renal macrocysts

Renal & Bladder Imaging 01:04:46

Renal Angiomyolipoma :
• Presentation :
- Asymptomatic : Incidental finding.
- Wunderlich syndrome : Pain + nausea + shock (D/t ble'ding).
• A/w tuberous sclerosis.
• Imaging :
Hyperechoic lesion in renal cortex Soft tissue enhancement

Fat Kidney

USG CT

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Renal Cell Carcinoma : ----- Active space -----

• Presentation : Elderly + gross painless hematuria.
• M/c subtype : Clear cell Ca.
• Staging :
- Robsons staging.
- TNM.
• IOC Overall : CECT.
For renal vein/IVC invasion : CE-MRI.
• CT :

IVC

RC,

Transitional Cell Carcinoma :

• Presentation : Elderly + gross painless hematuria + H/o smoking or
cyclophosphamide treatment.
• Imaging :
USG CT

Dif)use nodular
thickening along urinary
blad+er wall

• Retrograde pyelography : Goblet sign/champagne glass sign (Filling defect d/t

tumor).

Renal Artery Stenosis (RAS) :

• Presentation : Young pt + hypertension.
• Investigations :
- First : Renal artery doppler.
- IOC : CT angiography > MR angiography.
- Gold standard : Invasive catheter angiography.
- To detect functional significance of RAS :
Captopril-DTPA scan.
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----- Active space ----- Fibromuscular Dysplasia :

String of beads appearance
(Alternate dilations & constrictions).

IVU Spotters :
a) Horseshoe Kidney : b) Cross fused ectopic left kidney :

• Flower vase appearance/Handshake • L kidney fused with R kidney

sign : Kidneys fused across midline. ( L renal fossa : Empty)
• A/w Turner syndrome (XO). • L Ureter crosses midline &
• Asymptomatic. drains into L side of urinary
blad+er.

c) Duplex pelvicalyceal system :

• 2 pelvicalyceal systems on one side.
• Weigert-Meyer law :

Upper moeity (U-MI-U) Lower moeity

upper ureter (Lower-Lax-reflux) lower ureter

Medial-Inferior Lax/Loose
insertion into UB insertion into UB

Prone to ureterocele. Prone to vesicoureteric reflux.

Duplex pelvicalyceal system

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d) Duplex pelvicalyceal system with obstructed upper system : ----- Active space -----
Drooping lilly sign (D/t dilated obstructed upper urinary system).

e) Pelvi ureteric junction (PUJ) obstruction with hydronephrosis :

Dilated pelvicalyceal system Dilated renal pelvis

crossing midline

g) Vesicoureteric reflux : f) Ureterocele :

• Presentation : Recurrent UTI in Cobra head/ad+er head/spring onion
child + hydronephrosis on USG. appearance : Focal cystic dilatation of
• IOC : terminal ureter.
- Initial : Micturating
Cystourethrogram (MCU).
- For follow up : Radionuclide
cystogram.

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----- Active space ----- h) Posterior urethral value (PUV) :

CONTRAST in UB

a. Antenatal USG : Keyhole sign b. MCU : PUV

Overdistended UB with small
posterior urethra.
i) Urethral rupture : j) Urethral stricture :

• Presentation : Presentation : Recurrent

Unable to pass urine. UTI + incomplete & frequent
Trauma + Blood at ext. meatus. micturition.
High riding prostate on DRE.
• Initial IOC : Retrograde urethrogram (RGU).
• Catheterization : Suprapubic (Transurethral C/I).

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WOMEN AND MUSCULOSKELETAL IMAGING ----- Active space -----

Breast Imaging 00:00:18

IOC for Ca breast :

1. Imaging IOC (Overall) : Dynamic contrast enhanced (CE) MRI.
2. Diagnostic IOC (Overall) : Trucut biopsy (Bx).
3. Staging IOC : PET-CT.
4. Screening IOC for Ca breast : Mammography.

Mam&ography :
American society of Breast Surgeons recommendations for Ca breast - 2019 :
Formal clinical risk assessment at 25 years Divided into groups based on risk.

Group based on risk Investigation Screening started at

MRI (An&ually till 30 yrs age) 25 yrs
BRCA 1 or 2 mutation car%ier status/prior
chest wall ir%adiation at 10-30 years age
Mammography 30 yrs
Strong +ve family history/
Mammography 35 yrs
predicted lifetime risk >20%
Average risk (No risk factors) Mammography 40 yrs

Benign vs malignant lesions :

Benign lesions Malignant lesions

USG

Shape Oval (Wider > Taller) Ir%egular (Taller > Wider)

Margins Smooth Ir%egular
Spiculations/Lobulations None/few lobulations Present
Architectural distortion
Absent Present
& echogenic halo

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----- Active space ----- Benign lesions Malignant lesions

Microcalcifications Microcalcifications (<1 mm)

Popcorn
Calcifications calcification :
Involuting
fibroadenoma
Pleomorphic clustered
micro-calcifications

Breast Imaging Reporting And Data System (BIRADS) :

For USG, MRI & mammography.
Score Category Risk of malignancy (%) Management
0 Incomplete evaluation — Ad(itional imaging
1 Negative 0
Routine screening
2 Benign 0
3 Probably benign >0 to <2 Short interval follow-up (6 months)
2-10 (Low)
4 Suspicious 10-50 (Intermediate)
Tissue biopsy
50-95 (High)
5 Highly s/o malignancy >95
6 Biopsy proven malignancy 100 Plan Rx

Dynamic Contrast Enhanced MRI :

Steps :
Non-contrast Rapid IV injection Rapid image Dynamic
MRI images of Gadolinium using acquisition enhancement
obtained first pressure injector (For 5-6 mins) curves (DEC).
Types of curves :
I : Initial phase (2 min)
D : Delayed phase

Washout
(Excretion)
Slow
Plateau
rising
Slow Rapid Rapid
upslope upslope upslope
I D I D I D
Benign lesion Intermediate lesion Malignant lesion

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Gynecological Imaging 00:09:47 ----- Active space -----

Mullerian Duct Anomalies :

• IOC : 3D-USG > MRI. • Gold standard : Laparoscopy.
ESHRE classification : (Updated terminology)
Class U0/ Class U1/ Class U2/
Normal uterus Dysmorphic uterus Septate uterus

<10 mm >10 mm

a. T-shaped b. Infantilis a. Partial b. Complete

c. Others

Class U3/Bicorporeal uterus Class U4/Hemi uterus Class U5/Aplastic uterus

Thick
septum
a. Partial b. Complete c. Bicorporeal a. With b. Without a. With b. Without
septate rudimentary rudimentary rudimentary rudimentary
cavity cavity cavity cavity

Hemiuterus (U4b) on Bicorporeal uterus (U3b)

hysterosalpingography (HSG) on HSG

Infertility - HSG :

Retort shaped
blocked fallopian Filling
tube defect

Hydrosalpinx Left sided cornual block Uterine synechiae/adhesions

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----- Active space ----- Obstetric Imaging 00:13:34

Early Pregnancy :

Intradecidual sac sign

Single hyperechoic rim

around gestational sac
(GS)

~4 weeks 4-5 weeks

• Thick endometrium.
• Gestational sac - Decidua capsularis Decidua parietalis Endometrial
(In&er rim) (Outer rim) cavity

Double decidual sac sign

Definitive sign of
intrauterine (IU)
pregnancy. (Dif)ers from
psuedogestational sac of
ectopic pregnancy.)
4-5 weeks

Double bleb sign :

Yolk sac : • Yolk sac
1 structure
st
• Amnion
seen in GS.

5-6 weeks

NT
6 weeks Nuchal translucency (NT) scan (Normal scan)
Embryo + cardiac activity + Done when CRL : 45-84 mm OR
11 weeks 0 days - 13 weeks 6 days.

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Feature visualised Transvaginal sonography (TVS) Transabdominal sonography (TAS) ----- Active space -----

Gestational sac 4 weeks 0 days - 4 weeks 3 days 5 weeks 0 days

Yolk sac 5 weeks 0 days 5 weeks 3 days
Cardiac activity 5-6 weeks 6 weeks 0 days

Fetal Anomalies : Cardiac vessels

Lack of development
above orbits
Orbits
Thickened NT Pre-maxillary triangle
Mandible
Aneuploidy Anencephaly
E.g. : Trisomy 21, 18, 13 • Mickey-mouse/Frog-eyes sign
• Earliest anomaly detected on USG (10-11 weeks)

Banana sign :
Lemon sign : Curved cerebellum
• Dilated wraps around
ventricles. brainstem in
• Frontal posterior fossa.
compression
of skull.

Lumbar
meningomyelocele

Arnold-Chiari malformation - Type 2

Vitamin Deficiencies & Hyperparathyroidism 00:19:05

Vitamin Deficiency :
Defective in scurvy
Hydroxylation of
Vit C Cross linking
proline & lysine Osteoid formation
of collagen
residues Bone formation
Mineralisation

Defective in rickets

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 84 Radiology

1. Scurvy (Vit C deficiency) :

----- Active space ----- Pelkan spur
Subperiosteal hematoma
Trum%erfield’s zone
can also be seen. of rarefaction
White line of Frankel :
Only ir&eversible sign
Wimberger epiphysis

2. Rickets (Vit D deficiency) :

• Loss of provisional zone of calcification.
• Widening of physeal growth plate.
• Widening/splaying & cupping of metaphysis.
• Fraying of metaphysis.
• Rachitic rosary :
Cartilage hypertrophy at costochondral junction.

• Line of
metaphyseal
calcification
• Cupping -
Rachitic rosary Healing rickets
3. Osteomalacia :
Looser’s zones/
Pseudofractures/
Milkman fractures :
• Horizontal
Protrusio
cortical defects.
acetabuli
• M/c site :
Neck of femur.
Tri-radiate pelvis in osteomalacia

Hyperparathyroidism :
Subperiosteal
resorption (Radial)
Brown tumor (Lucent
lesion d/t complete
bone resorption)
↓Bone density

Rug(er jersey spine

D/t 2° hyperparathyroidism in Salt and pepper skull/
renal osteodystrophy. Pepper pot skull
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Bone Tumors 00:24:53 ----- Active space -----

Age Distribution :
O-20 yrs 20-40 yrs >40 yrs
Benign :
• Simple bone cyst (SBC)
• Aneurysmal bone cyst (ABC) • Enchondroma • Chondrosarcoma
• Eosinophilic granuloma • Osteoblastoma (M/c site : Pelvis)
(M/c cause of vertebra plana in children) • Osteoma • Metastatic tumors
• Fibrous dysplasia (FD) • Giant cell tumor (GCT) (M/c site : Skull, axial skeleton)
• Osteoid osteoma • Parosteal osteosarcoma • Multiple myeloma
• Osteoclastoma
Malignant :
• Ewing’s sarcoma
• Osteosarcoma
Site Distribution :
Epiphysis Diaphysis Metaphysis
• Ewing’s sarcoma
• Chondroblastoma
• Osteoid osteoma
(Children) All other tumors
• Adamantinoma
• GCT (Adults)
• Fibrous dysplasia

Spotters :
1. SBC/Unicameral BC 2. Adamantinoma :
M/c site : Proximal humeral metaphysis. M/c sites : Tibial shaft > Mandible

Im%ature skeleton (Child)

Cystic lesion : Soap bub)le

• If fracture + appearance
Hinged fragment sign.
• If the fractured
fragment falls
Fallen fragment sign.
Tibial shaft Mandible

3. Enchondroma 4. Hemangioma
M/c site : Short tubular M/c site : Spine, skull
bones of hands & feet
Striated/Corduroy cloth/
Polka dot vertebra :
D/t resorption +
thickened trabeculae.

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----- Active space -----

Cortical lesion going away
from adjacent joint :
• Cartilage cap +
• Multiple lesions
‘O’-shaped lesion in
Diaphyseal aclasia/
cortex + sur&ounding
hereditary multiple
thick periosteal bone
exostosis.
formation
(20% malignant risk)
5. Osteoid osteoma 6. Osteochondroma/Exostosis
M/c site : Femur, lumbar spine (M/c benign tumor)
Eccentric Lytic Bone Lesions :

Blown out Soap bub)le

appearance/ appearance
Finger in
balloon sign

ABC (Child) GCT (Adult)

Reaches epiphysis
Lesions with Zone of Transition (ZOT) :

Benign lesion Malignant lesion

• Nar&ow ZOT (Well-defined margin) • Wide ZOT (Ill-defined margin)
• Exception : Mets/multiple myeloma (>40 yrs age) • Exception : Infection/eosinophilic granuloma
Lesions with Periosteal Reactions :
Solid Lamellated Sunburst/Spiculated Codman’s triangle

Periosteal
thickening
Imaging
Lesion at
nidus

Dx Osteoid osteoma Ewing’s sarcoma Osteosarcoma/Ewing’s Osteosarcoma

Malignancy Increasing risk of malignancy
risk
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Ewing’s sarcoma vs. osteosarcoma : ----- Active space -----

Ewing’s sarcoma Osteosarcoma

Age 5-15 yrs 15-25 yrs
Location Diaphyseal Metaphyseal
Periosteal Lamellated/Onion-peel reaction Codman’s triangle
reaction Sunburst appearance ±
Groomed/trim%ed whisker appearance Cumulus cloud appearance

Named
appearances Codman’s
triangle

Bone to bone mets Hematogenous spread

Spread
(Skip lesions + ) (Cannon ball lung mets)

Multiple Myeloma :
Clinical presentation :
• Elderly patient.
• Weight loss.
• Generalized weakness.
• Vertebra plana.
Rain-drop skull
Bone Tumour Syndromes :

Associations Risk of malignancy

Ollier’s disease Multiple enchondroma 10%
Maf+uc,i syndrome Multiple enchondroma + hemangioma 25%
Diaphyseal aclasia Multiple exostosis 20%
GI polyposis + multiple osteoma +
Gardener’s syndrome -
epidermal cyst + desmoid tumors

Inflammatory & Spine Lesions 00:36:28

Rheumatoid Arthritis (RA) :

• Earliest joint involved : Metacarpophalangeal (MCP) & proximal interphalangeal
(PIP) joints.
• Earliest finding at wrist joint : Erosion of ulnar styloid process.
• RA factor : + in 70% cases.
• Deformities : Seen in advanced RA.
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----- Active space -----

Uniform loss of
joint space at
radiocarpal joint Erosions &
deformities +
Juxta-articular
osteopenia
(D/t hypereamia)
Early RA Advanced RA

Flexion at
DIP
Hyperflexion at PIP Fixed flexion at DIP
Hyperflexion at DIP joint Hyperextension
at PIP

Severe loss
Hyperextension of space with
at MCP and IP erosions at
Hyperextension at joints of thumb
Hyperextension radiocarpal
PIP joint
at DIP joints
Boutonniere Swan neck Mallet finger Hitch-iker’s thumb
deformity deformity

Ankylosing Spondylitis :
• Young adult with back pain.
• RA factor - (Seronegative arthritis), HLA-B27 + .

Signs in AS :
1. Shiny corner sign : Sclerotic corners of vertebral bodies d/t enthesitis.
2. Romanus lesion : Erosions of vertebral bodies at the corners.
3. Squaring of vertebra.
4. Bamboo spine/Poker’s spine : Fusion of adjacent vertebral bodies d/t bridging
syndesmophytes resulting in a bamboo-like appearance.
5. Car&ot stick fracture : Fracture of the fragile vertebra.
6. Anderson’s lesion : Pseudoarthrosis at the fractured site d/t poor healing.
7. Dag(er sign : Calcification of interspinous ligaments.
8. Railroad track sign : Calcification of B/L paraspinous ligaments.
9. Trolley track sign : Calcification of both interspinous & paraspinous ligaments.

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 Women and Musculoskeletal Imaging 89

----- Active space -----

Dag(er Railroad Trolley

sign track sign track sign
Sacroilitis (Earliest joint) Bamboo spine
Early detection : MRI

Gout :
• Mid.le-aged patient with severe Erosion
pain & swelling of 1st MTP (M/c).
• Hyperuricemia. Overhanging
margin

Martel’s G sign
Spine Lesions :

Dripping candle wax

appearance/ Ossified
flame-shaped osteophytes : posterior
Hyperostosis along anterior longitudinal
longitudinal ligament of ligament
cervical spine

Dif+use idiopathic skeletal Japanese disease

hyperostosis (DISH)

Osteomyelitis 00:42:09

Role of imaging modalities : Vascularised

granulation tissue
Imaging Features
X-Ray/CT Latent period : 10 days (Limbs), 21 days (Spine)
99m Tc MDP bone scan Earliest but non-specific
MRI IOC

Chronic Osteomyelitis :
Pathophysiology :
Penumbra sign on MRI
Bone destruction Healing Periosteal reaction. Sign of infection.
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----- Active space ----- Features :

• Sequestrum : Dead bone d/t infection
(Reservoir of infection).
• Involucrum (White ar&ow) :
Thick periosteal new bone formation
(Tries to isolate sequestrum).
• Cloaca (Yellow ar&ows) : Defects in involucrum
(Empyema necessitans). Chronic osteomyelitis

Subacute Osteomyelitis/Brodie’s Abscess :

• M/c presentation : Male child with nocturnal proximal leg pain
(Relieved by analgesics).
• M/c site : Proximal tibia.
• M/c organism : S. aureus.

Cystic lesion
with dark
sclerotic rim Lesion
with white
sclerotic rim
MRI image X-Ray image

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