BARIUM STUDIES BARIUM MEAL

This is the study of the gastrointestinal tract This is the radiological study of oesophagus,
by instillation/ ingestion of barium stomach, duodenum and proximal jejunum.
suspension made up of/made from pure
barium sulphate. Indications
 Symptoms of vomiting, epigastric pain,
BARIUM SWALLOW heart burn, dyspepsia
It is the contrast study from the oral cavity up  Upper abdominal mass
to the fundus of the stomach.  Gastrointestinal haemorrhage
 Gastric or duodenal obstruction
Indications  Malignancies
1. Dysphagia and obstruction
2. Odynophagia Contraindications
3. Assessment of mediastinal masses • Suspected perforation
4. Motility disorders of oesophagus- • Suspicion of aspiration
achalasia, scleroderma. • Large bowel obstruction

Relative contraindications Procedure

1. Tracheo-oesophageal fistula  An undiluted barium suspension is given
2. Perforation and deglutition is seen under fluoroscopy.
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 Once barium reaches the stomach, the
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Procedure patient is rotated so as to coat the entire

 One mouthful of contrast media is given
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stomach and filming is done.

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and the act of deglutition is observed  More barium is given to distend the
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fluoroscopically. stomach wall.

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 After a mouthful of barium, films are  Filming is done as contrast enters the
exposed to the region of interest. duodenum and opacifies proximal
jejunum.
Interpretation of study
1. Malignant obstructions are seen as BARIUM ENEMA
annular constrictions. This is the radiographic study of the large
2. Benign strictures are long segment bowel by administration of contrast media
narrowings with no mucosal through the rectum.
abnormalities.
3. Achalasia cardia is evident as 'rat tail' Indications
appearance of the lower end of the 1. Change in bowel habit
oesophagus. 2. Melaena
3. Mass suspected to be arising from colon
4.Features of large gut obstruction (subacute)
Contraindications
1. Toxic megacolon
2. Pseudomembranous colitis
RADIOLOGICAL INVESTIGATION DR.V.S.PAWAR
3. Rectal biopsy done recently  The composite picture is actually a
collection of Hounsfield numbers.
Procedure  Each Hounsfield number being assigned a
 Bowel is prepared with low residue diet, specific shade of grey, thus producing a
purgation and cleansing water enema. picture that might be easily understood.
 High density barium suspension is  Some of the common densities to be
allowed to flow up to the ileocaecal encountered in practice are as follows
junction and reflux into the terminal (Hounsfield units = HU):
ileum.
 Single contrast filming is done.
 The patient is asked to evacuate the
barium and a post evacuation film is
taken.

COMPUTED TOMOGRAPHY (CT)

This is an imaging procedure where detailed
information is obtained from thin sections in
collimated X-rays.
 In order to increase the contrast that may
Indications exist between the structures in the body,
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 Structural evaluation of intracranial intravenous contrast (iodine
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containing) is administered.
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lesions
 Detailed evaluation of lung, mediastinal  Certain tissues show enhancement of their
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pathologies density and various pathologies also show

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 Intra-abdominal and pelvic masses where fairly characteristic contrast uptake

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exact site of origin and relation to adjacent patterns.

structures can be evaluated.  The advantages of CT over conventional
 Extra-osseous and soft tissue extension of radiology are that it can visualise
bone tumours. extremely small pathology, not evident on
 Vascularity of the normal organ and the conventional films, is cost-effective as
abnormal tissue can be evaluated and multiple X-ray films and procedures can
compared. be avoided.
 It is noninvasive and the radiation levels
Contraindications (relative) applied to the patient are extremely low.
• Pregnancy
• Restless patients

Interpretation of images
 Structures imaged appear densely white to
densely black depending on the
absorption of X-rays and the emerging
resultant X-rays which are detected.
RADIOLOGICAL INVESTIGATION DR.V.S.PAWAR
 3. Noninvasive
ULTRASONOGRAPHY 4. Owing to the relatively small size of the
Principle apparatus, it is fairly portable, and can
 This imaging modality is based on the thus be brought to the bedside of the
piezoelectric effect which is the property moribund patient.
of certain substances to convert electrical 5. It does not involve the use of ionising
energy to sound energy. radiation, and can therefore be safely used
 These are the active portions of the in a pregnant patient and can be repeatedly
ultrasonic transducers. used as a follow-up modality.
 The commonly used substance in the
transducer is lead zirconate titanate Limitations of ultrasonography
(PZT). 1. Its use is limited in thorax
2. Limited use in the abdomen when there is
Applications gaseous distension
 Ultrasonic beam of high frequency gives 3. Operator expertise is all important
excellent resolution images of only 4. It cannot image bone
superficial structures. This is used for
study of musculoskeletal system, joints, MAGNETIC RESONANCE IMAGING
thyroid, scrotum, etc. (MRI)
 For imaging deeper structures of Principle
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abdomen, a low frequency probe with  Certain atomic nuclei, which possess
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greater penetrancy is used. unpaired protons or neutrons, have an

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inherent spin.
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Interpretation of images  The nucleus is positively charged and

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 Images are dependent on the intensity of therefore creates a small magnetic field
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echoes received back by the transducer. around itself, when it spins.

 Structures which reflect all the sound  The human body contains in abundance
waves back an depicted as bright echoes such spinning nuclei in the atoms of
and termed hyperechoic. hydrogen which is found in water and
 Structures which reflect moderate level lipids.
of sound wave appear as uniform grains  When the tissues containing these nuclei
and are termed isoechoic. are within a strong magnetic field, the
 Fluid filled structures which transmit all nuclei tend to align themselves along the
the sound waves. do not reflect any lines of the force.
echoes and are termed hypoechoic.  The spinning protons now tend to precess,
 The reflection of sound waves in the form i.e. wobble about the axis of the main
of echoes depend on the density of the magnetic field.
organ and the transmission of sound  Now a radiofrequency (RF) is applied,
through the same. being of the same frequency as the
Advantages of ultrasonography processing but at right angles to the main
1. It is a cost-effective investigation. magnetic field.
2. It is widely available
RADIOLOGICAL INVESTIGATION DR.V.S.PAWAR
 This excites the protons at low energy 3. It gives high intrinsic contrast
states into higher energy states. 4. Direct transverse, sagittal and nonnal
 Thus, an absorption of energy takes place, imaging possible
which is used, as the excited protons 5. No bone/air artefact
'relax' back to their original energy level 6. It has no known biological hazard
when the radiofrequency is switched off.
 The relaxation of protons back to Disadvantages of MRI
equilibrium and lower energy state is 1. The imaging time is long. Hence,
termed spin-lattice relaxation or movement of the patients may produce
longitudinal relaxation. artefacts.
 It is exponential and referred to by the 2. Due to variety of protocol options during
time constant T l . scanning, the final image is highly
 When the RF pulse is applied the protons operator-dependent and this requires
process together in synchronism or in expert technical staff.
phase with each other. 3. Expensive
 During relaxation, however, they go 4. Poor bone and calcium detail
quickly out of phase due to small 5. Patients with pacemakers, metallic
variations in local magnetic fields. This implants and critically ill patients
loss of phase is termed spin-spin cannot be scanned.
relaxation or transverse relaxation.
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 It is also an exponential and referred to by POSITRON EMISSION TOMOGRAPHY
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the time constant T2. (PET SCAN)

 Depending on the type of tissue under  PET scan is a medical imaging technique
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study, the T 1 and T2 relaxation times will that combines computed tomography
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differ, thus giving rise to differences in the (CT) and nuclear scanning.
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image.  It is used to determine the metabolic or

 The MRI image depends upon 4 main biochemical activity in the brain, heart
factors: and other organs by tracking the
1. The T 1 relaxation time movement and concentration of a
2. The T2 relaxation time radioactive tracer injected into the blood
3. The proton density stream.
4. The blood flow  A camera records the tracer's signal as it
 Depending on the characteristics of the travels through the body and collects
above four parameters, the signal intensity information about the organs.
of the image will vary, thus deciding the  A computer then converts the signals into
appearance that any given tissue will 3D images of the examined organ, which
finally cast. provide a clear view of all abnormality.
 One of the main differences between PET
Advantages of MRI scan and other imaging tests like CT or
1. It is noninvasive MRI is that the PET scan reveal: the
2. It does not involve the use of ionising cellular level metabolic changes occurring
radiation. Hence, it is safe in that respect.
RADIOLOGICAL INVESTIGATION DR.V.S.PAWAR
 in an organ and functional changes at
cellular level.
 A PET scan detects these changes very
early, whereas CT or MRI detect changes
a little later as the disease begins to cause
structural changes in organs or tissues.
 Positron emission tomography (PET-CT)
constitutes major progress in management
of cancer patients for the initial diagnosis,
staging and follow-up of various
malignancies PET-CT is also useful in the
follow-up of patients following
chemotherapy or surgical resection of
tumour, since, most of them have a
confusing appearance at CT or MR
imaging due to postoperative changes or
scar tissue.

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RADIOLOGICAL INVESTIGATION DR.V.S.PAWAR