MRI DEVICES CORPORATION
Technical Report
4445 SW 35TH Terrace
Suite 270
Gainesville, FL 32608
TITLE: GE MEDICAL SYSTEMS SERVICE MANUAL – OEM VERSION –
PHASED ARRAY SHOULDER COIL, E8800M and E8800MA
REPORT #: TR0003S
AUTHOR: David A. Molyneaux
PARENT PART:
APPROVED BY: ___David A. Molyneaux________________ MRIDC Project Leader
SCOPE: This is a service manual for the Phased Array Shoulder Coils for 1.5T,
E8800M, and 1.0T, E8800MA.
© MRI Devices Corporation, 1998
Unpublished work - all rights reserved under the copyright laws of the United States
ALL SHEETS OF THIS DOCUMENT CONTAIN PROPRIETARY AND CONFIDENTIAL INFORMATION OF MRI DEVICES CORPORATION AND ARE INTENDED FOR
EXCLUSIVE USE BY CURRENT MRI DEVICES CORPORATION PERSONNEL. COPYING, DISCLOSURE TO OTHERS, OR OTHER USE IS PROHIBITED WITHOUT THE
EXPRESS WRITTEN AUTHORIZATION OF MRI DEVICES CORPORATION.
TR0003S: Rev 1.1
REVISION HISTORY
Rev Level Date Change Description
A 11/2/98 First issue
1 11/20/98 Workcenter Release
1.1 4/30/99 Modification
© MRI Devices Corporation, 1998, proprietary and confidential information, refer to front page.
2
TR0003S: Rev 1.1
I. Scope
This is a service manual for the Phased Array Shoulder Coils for 1.5T and 1.0T.
II. Reference Documents
2202492GSP GE Medical Systems Surface Coil ECAT Requirements Specification
2111842DRS GE Medical Systems Design Requirements Specification for Surface Coils
TR0003B MRIDC OEM Design Specification – GE PA and Quad Shoulder Coils
2124201-3 GE Service Documentation
2160623-3 GE Service Documentation
III. Products Included
MRIDC No. GE Part No.
800012 1.5T Phased Array Shoulder Coil System 2225252
800013 1.0T Phased Array Shoulder Coil System 2225474
IV. Service Information
Theory of operation: (refer to block diagram)
The Phased Array Shoulder Coils consist of a pair of large and small coils. The both coils contain
4 elements. Two of the elements are loop coils and two of the elements are Helmholtz coils. Each
element contains items 1, 2, and 3. Item 1 is a tuning and decoupling circuit, which uses passive
decoupling via back to back fast acting diodes which are enabled by the RF pulses. When the
diodes short, the network creates a high impedance block to eliminate decoupling artifact and
interaction with the excitation field. Item 2 is a tuning, matching, and decoupling circuit which not
only tunes and matches the coil to the system resonant frequency and matches the coil to 50 ohms
when loaded, it also provides decoupling when the DC bias on the center conductor of the input
cable is positive. Item 3 provides the proper phase shift between the system preamplifier and item
2 to create the phased array decoupling required during receive.
Configuration file and setup/calibration information:
The configurations below are for programming soft keys for the Array Shoulder Coil Set on the
plasma display console. The selection is 4SHOULDR.
1. If not already in C Shell window touch [UTILITIES] then [C Shell] at operator’s console to
open up a tty window.
2. Touch the Touch Screen in the window to get input control, then perform the following in the
window.
© MRI Devices Corporation, 1998, proprietary and confidential information, refer to front page.
3
TR0003S: Rev 1.1
> cd /w/config enter
> addcoil enter
COIL CONFIG
Add A New Coil!
The computer will query you for the fourteen values that must be supplied to add a new coil to
the CoilConfig.cfg file. Then, you will be asked whether or not to actually update the files. Enter
^c (control c) at any time to exit the program and cancel. Entering a blank line for a value gets
you help information.
CoilName (8 characters or less): 4SHOULDR
korecName (4 characters or less): Enter a space return
CoilType (l-Head 2-Body 3-Surface): 3 enter
Extremity Coil (yes, no): no
Cable Loss (float): 1.5T System: 1.05
1.0T System: 1.24
Coil Loss (float): 1.5T System: 60 cm. bore 1.72, 55 cm. bore 0.313
1.0T System: 60 cm. bore 0.549, 55 cm. bore -------
Recon Scale Factor: 1.0
Linear vs Quadrature (0 or l): 1
Multiple Receiver Coil? [yes, no]: yes
Number of Receivers: 4
Starting Receiver ID (integer): 0
Ending Receiver ID (integer): 3
mcPortEnable (an integer): 6
mcErrorEnable (an integer): 6
XMITATTEN (An integer from 1 to 100, units are tenths of dB: 0
NumFastRec: 0
StartFastRec: 4
End FastRec: 4
(Coil values you have just entered are displayed.)
Write these values to the config files? (yes/no): yes
Config files updated.
You can add another coil or quit. Add another coil? (Y/N) N
Signa software of release 5.4 and below does not currently support AUTOSHIM for a coil with
more than 2 channels. The operator may circumvent this restriction by autoshimming using the
BODY COIL selection after having prescribed the proper offsets and FOV for the patient's
shoulder. Once AUTOSHIM has been completed, continue the same patient study now selecting
the 4SHOULDR coil selection.
© MRI Devices Corporation, 1998, proprietary and confidential information, refer to front page.
4
TR0003S: Rev 1.1
Signa software of release 5.5 and newer supports the AUTOSHIM feature using a 4 channel coil
by defaulting to the body coil for shimming. Once the operator has prescribed the proper offsets
and FOV for the patient's shoulder, AUTOSHIM using the 4SHOULDR coil selection, and
proceed with the scan.
Scanner and coil verification testing procedures:
Be sure that you choose the correct coil, and activate the desired coils from the menu selection on
the surface coil screen. The coil chosen must be 4SHOULR.
Position the Array Coil at the head end of the patient cradle. Place the 16 cm diameter head
phantom in the shoulder portion of the coil. Activate the 4SHOULDR coil from the soft key on
your operator's console.
Scan using Auto Pre-scan. If Auto Pre-scan does not complete successfully, do not use the coil
clinically. Upon completion of pre-scan, execute the scan. Window the scan as you normally
would (window levels vary from system to system depending upon your hardware revision level).
The scan should appear uniform.
If the image has signal voids, distortions, or black streaks, discontinue use of the coil. If the image
is excessively noisy, repeat the scan using the GE 5 inch general purpose coil for 1.5T or
alternate coil for 1.0T supplied with your system. If the 5 inch coil image or alternate coil image
exhibits similar artifacts, the problem likely lies with the MRI system.
Scanner and digital multimeter diagnostic procedure:
A digital multimeter can be used to measure the PIN diode drop in each of the four elements. A
single PIN diode drop of ~0.7 volts should be seen according to the block diagram at each of the
four inputs. The positive lead should go to the signal pins, S3-S7, and the negative lead should go
to any of the ground pins, GND. Reversing the leads should read an open circuit. If either reading
is a short circuit, the diode or the cable is shorted and the coil must be replaced. If forwarding
biasing the diode results in an open circuit, the diode or cable is open and the coil must be
replaced. The scanner will typically detect open and shorted channels and display a scan error.
The back to back passive diodes cannot be checked external to the coil.
List of applicable FRUs:
MRIDC No. GE Part No.
100165 (QSC-200-4C) Phased Array Large Shoulder, 1.5T 2225252-6
100164 (QSC-165-4C) Phased Array Small Shoulder, 1.5T 2225252-7
100167 (QSC-200-4C-42) Phased Array Large Shoulder, 1.0T 2225474-3
100166 (QSC-165-4C-42) Phased Array Small Shoulder, 1.0T 2225474-2
100181 Baseplate 2225252-5
100180 Pad E8800MD
© MRI Devices Corporation, 1998, proprietary and confidential information, refer to front page.
5
TR0003S: Rev 1.1
Block Diagram:
© MRI Devices Corporation, 1998, proprietary and confidential information, refer to front page.
