• Topic ID: id_13106876
  • Version: 3.0
  • Date: Aug 29, 2019 1:52:08 AM

1.5T Head Neck Spine (HNS) Coil Troubleshooting

Personnel Requirements

Required Persons Procedure
1 30 min

Overview

The tips in this document can be used to troubleshoot common problems with the 1.5T HNS coil.

Preliminary Requirements

Tools and Test Equipment

Some tests may require Phantoms for IQ Testing.

Digital Multi Meter.

Replacement Parts

HNS Rev 2
Part Number FRUs Accessories
2423192 Head Neck Unit 1.5T Brain Spine FRU No
2423193 Neck Chest Unit 1.5T BRAIN SPINE FRU No
2423194 TL Unit 1.5T Brain Spine FRU No
2423319 8-Channel HNS EXC III Upgrade System Cable FRU No
2423317 8-Channel HNS EXC II System Cable FRU No
2423320 16-Channel EXC III HNS Forward Production System Cable FRU No
2424269 16-Channel HNS key-connector system cable FRU No
2423318 HNS TL Unit Cable FRU No
2419521 Mirror Assembly, FRU, 1.5T Yes
2418081 Pad Kit Yes
5343347 TL Unified Phantom -
5342679 Large Cylindrical Unified Phantom -
5342680 Small Cylindrical Unified Phantom -
5344844 Phantom Positioner, HNS -
5344844 Unified Phantom Positioner Yes
5343347 TL Unified Phantom No
5342679 Large Cylindrical Unified Phantom No
5342680 Small Cylindrical Unified Phantom No
2418076 TL Phantom Kit Yes
2418078 HN Phantom Kit Yes
G3335RK HNS Phantom Kit Yes

Required Conditions

The following coil configurations must be installed to run the MCQA test for the coil:

HNS Head
HNS BrachPlex
HNS CTLBOT

Refer to the operator manual for all coil configurations.

Troubleshooting Overview

Refer to the following sections when troubleshooting the HNS coil:

Receiving No Signal

Receiving No Signal

Problem:

You are unable to pre-scan or are scanning, yet receiving no signal, and receiving part of signal from coil elements.

Possible Solution:

Verify that the port which is used to plug in the coil either has a green light illuminated (Port A or Port B) or a green lock (Port P1, P2, P3 or P4) indicated. This indicates the coil is properly plugged into the system and the coil I.D. on the coil is properly installed.

note:

For Forward Production systems, we use Port A (Hypertronics, 8-channel) for TL (Thoracic Lumbar), and Port B (Hypertronics, 16-Channel) for Head Neck. If the TL is used by itself, then it can be connected to port B too.

For upgrade systems: we use Port A (Hypertronics, 8-Channel) for TL (Thoracic Lumbar), Port B (Hypertronics, 8-Channel) and 8-Channel Bendix (Legacy) connector for Head Neck.

For Discovery systems, use Port P1 or Port P2 (P-connector, 16-Channel) for HNU and use Port A (Hypertronics, 8-Channel) for TL Unit.

Figure 1. Currently Connected Coils Window in the Scan Screen

Verify that the system has correctly detected the coil by checking in the Currently Connected in the GUI to select coils in Rx as shown in Figure 2.

Figure 2. Currently Connected Coils Window for MR450 and MR450w

  • Ensure the anterior or adaptor block is fully latched.

  • If the Neck Chest unit is used, ensure its connector is fully engaged to the receptacle on the posterior Head Neck unit.

  • Verify that the landmark is correct and that the cradle has not unlatched.

  • Verify that the scan locations and any FOV offsets are correct.

  • Perform a continuity check on the output cable (Output Cable Check) if you lose some signals from some of coil channels. The continuity check must be performed by a GE authorized Service Engineer.

  • Verify that the coil is positioned with the cable exiting towards the bore.

If you still cannot get a signal, try to scan (transmit and receive) with the body coil. For this test, be sure to remove the imaging coil from the magnet bore before you scan with the body coil. If you still receive no signal the problem probably lies with the MR system. If the scan completes successfully, there is probably a problem with the Brain Spine coil. Contact GE for further assistance. If you are unable to scan with the substitute coil, there may be a system problem related to this particular coil type.

Image Quality

Problem:

Poor IQ, shaded images, or if MCQA fails

Possible Solution:

  • Perform a continuity check on the output cable (Output Cable Check). The continuity check must be performed by a GE authorized Service Engineer.

  • Verify that there are no loops in the cables.

  • Verify that there are no metal or ferromagnetic objects close to the coil, patient or magnet (i.e., safety pin, hair pin).

  • Verify that the coil is properly positioned.

  • Verify that your center frequency is within the frequency adjustment range for your system.

  • Verify that the R1, R2 and TG values from the pre-scan are within normally expected ranges.

If you have not done so already, perform a system Quality Assurance MCQA test. If the values you obtain do not fall within normal operating parameters, investigate this further by performing a phantom scan with the body coil. For this test, be sure to remove the imaging coil from the magnet bore before you scan with the body coil. If you still have the same problems, there is probably an MR system problem. If the body coil scan is satisfactory, acquire a scan using both another coil of the same type (receive-only, phased array or transmit/receive, whichever applies) and the same system coil selection. If the image quality is visibly improved, there may be a problem with the Head Neck Spine coil. Contact GE for further assistance. If the image quality still suffers, there may be a system problem related to imaging with this type of coil.

Artifacts

Problem:

There is a black line, strip lines, or signal void on the image.

Possible Solution:

  • Verify that there is no metal present in the area being scanned in or on the patient.

  • Verify that no hair is caught trapped in the connectors between the anterior and posterior sections of the Head Neck unit. This may appear as an intermittent oscillations.

  • Verify the cable connector of the Neck Chest unit is fully plugged into the receptacle on the posterior section of the Head Neck unit. If the connector is not fully plugged in, there may be a coil not present error or there may be intermittent oscillations.

  • If you have oscillation of the preamp you will see striped lines.

Output Cable Check

Before removing the cable assembly from the coil, visually inspect all coaxial connectors and pins on the system plug. If there are any broken, deformed or recessed pins or coaxial connectors, replace the cable assembly. When you replace the cable assembly, you need to make sure the configuration of jumpers on the interface board for upgrade and forward production systems.

Remove the cable assembly from the coil. See 1.5T HNS Coil Cable Replacement.

Forward Production System HNS Rev 2

We use 8-Channel “A” Hypertronics connector cable for TL unit and 16-Channel “B” Hypertronics connector cable for HN unit on forward production system.

Figure 3. Pin Layouts of Hypertronics Connectors (A and B) for Forward Production System

RF Signal Channels Check

note:

The center pins of the System Connector receive coaxial connectors are extremely fragile. Do not attempt to make any measurements at these center pins.

The following procedure will rule out a short to GND for each of the signal pins detailed in the following table and ensure the integrity of the ground connection for each RF coax cable. This check does not determine continuity for each of the RF signal connections.

With the coil cable disconnected, use a multimeter to assure no open circuit condition exists between the RF ground shields of the RF coax connector in the system side and the coils side (Refer to Table 1 or Table 2.) Use the multimeter to assure an open circuit condition exists between the center pin and the shield for each RF connector in the coil side.

Table 1 8-Channel “A” Connector RF Allocation
System Side Connector RF GND Shield Coil Side Connector RF Center Pin
C1 J4
C2 J5
C3 J6
C4 J7
D1 J8
D2 J9
D3 J10
D4 J11

Figure 4. 8-Channel “A” Connector RF Cables from Coils Side

Table 2 16-Channel “B” Connector RF Allocation
System Side Connector RF GND Shield Coil Side Connector RF Center Pin
C1 CH1
C2 CH2
C3 CH3
C4 CH4
D1 CH5
D2 CH6
D3 CH7
D4 CH8
G1 CH9
G2 CH10
G3 CH11
G4 CH12
H1 CH13
H2 CH14
H3 CH15
H4 CH16

Figure 5. 16-Channel “B” Connector RF Cables from Coils Side

If one or more of the readings indicate a short, replace the cable. If all of the above readings indicate an open circuit condition, proceed to the DC Lines Continuity Check.

DC Lines Continuity Check

With the coil cable disconnected, use a multimeter to determine continuity between the designated pins for each control line below. Also test the continuity between the pairs of pins within system connector that are listed in the tables below. If any line or pair of pins indicates an open, replace the output cable.

Table 3 “A” Connector DC Allocation
System Side Connector DC Pin Coil Side Connector DC Center Pin
M3 J1-1
M6 J1-2
J1 J2-1
K1 J2-2
J2 J2-3
K2 J2-4
J3 J2-5
K3 J2-6
J4 J2-7
K4 J2-8
M7 J3-1
M8 J3-2
Short A1 to A2 N/A
Short J9 to J10 N/A
Short M9 to M10 N/A

Figure 6. “A” Connector DC Cables from Coils Side

Table 4 “B” Connector DC Allocation
System Side Connector DC Pin Coil Side Connector DC Pin
A1 J54-1
A2 J54-2
A3 J2-1
A4 J2-2
A5 J2-3
A6 J2-4
A7 J2-5
A8 J2-6
A9 J2-7
A10 J2-8
M2 J54-7
M5 J54-8
M6 J1-2
M7 J54-3
M8 J54-4
Short J9 to J10 N/A
Short M9 to M10 N/A

Figure 7. “B” connector DC Cables from Coils Side

Forward Production System HNS Rev 3

We use 8-Channel “A” Hypertronics connector cable for TL unit and 16-Channel “B” Hypertronics connector cable for HN unit on forward production system.

Figure 8. Pin Layouts of Hypertronics Connectors (A and B) for Forward Production System

RF Signal Channels Check

note:

The center pins of the System Connector receive coaxial connectors are extremely fragile. Do not attempt to make any measurements at these center pins.

The following procedure will ensure the integrity of the ground connection for each RF coax cable detailed in the following tables.

With the coil cable disconnected, use a multimeter to assure an open circuit condition exists between the RF ground shields of the RF coax connector in the system side and the coils side.

Table 5 8-Channel “A” Connector RF Allocation
System Side Connector RF GND Shield Coil Side Connector RF GND Shield Pin # (All located on Gang connector J28)
C1 8
C2 1
C3 7
C4 2
D1 6
D2 3
D3 5
D4 4

Figure 9. 8-Channel “A” Connector RF Cables from Coils Side

Table 6 16-Channel “B” Connector RF Allocation
System Side Connector RF GND Shield Coil Side Connector RF GND Shield Pin # (All located on Gang connector J67) System Side Connector RF GND Shield Coil Side Connector RF GND Shield Pin # (All located on connector J68)
C1 4 G1 8
C2 5 G2 4
C3 6 G3 7
C4 7 G4 1
D1 2 H1 3
D2 3 H2 5
D3 8 H3 2
D4 1 H4 6

Figure 10. 16-Channel “B” Connector RF Cables from Coils Side

If one or more of the readings indicate an open, replace the cable. If no open is found for the ground of the RF cables, proceed to the DC Lines Continuity Check.

DC Lines Continuity Check

With the coil cable disconnected, use a multimeter to determine continuity between the designated pins for each DC control line below. Also test the continuity between the pairs of pins within system connector that are listed in the tables below. If any line or pair of pins indicates an open, replace the output cable.

Table 7 “A” Connector DC Allocation
System Side Connector DC Pin Coil Side Connector DC Pin
M3 J1-1
M6 J1-2
M8 J1-3
M7 J1-4
J1 J14-1
K1 J14-2
J2 J14-3
K2 J14-4
J3 J14-5
K3 J14-6
J4 J14-7
K4 J14-8
Short A1 to A2
Short J9 to J10 N/A
Short M9 to M10

Figure 11. “A” Connector DC Cables from Coils Side

Table 8 “B” Connector DC Allocation
System Side Connector DC Pin Coil Side Connector DC Pin
A3 J2-1
A4 J2-2
A5 J2-3
A6 J2-4
A7 J2-5
A8 J2-6
A9 J2-7
A10 J2-8
A1 J54-1
A2 J54-2
M7 J54-3
M8 J54-4
M2 J54-7
M5 J54-8
M3 J1-1
M6 J1-2
Short J9 to J10 N/A
Short M9 to M10 N/A

Figure 12. “B” Connector DC Cables from Coils Side

Upgrade System HNS Rev 2

For upgrade systems, we use 8-Channel “A” Hypertronics connector cable for TL unit and 8-Channel “B” Hypertronics connector cable and 8-Channel Bendix (Legacy) connector cable for HN unit.

The upgrade Rev 2 coil uses the same 8-Channel “A” Hypertonics connector cable for TL unit as the forward production Rev 2 coil. Refer to Forward Production System HNS Rev 2 for checking the connector A cable.

Figure 13. Pin Layouts of 8-Channel “B” Hypertronics Connector for Upgrade System

Figure 14. Pin Layouts of 8-Channel Bendix Connector for Upgrade System

RF Signal Channels Check

note:

The center pins of the System Connector receive coaxial connectors are extremely fragile. Do not attempt to make any measurements at these center pins.

With the coil cable disconnected from the coil assembly, use a multimeter to ensure no open circuit condition exists between the RF ground shields of the RF coax connector in the system side and the coils side. Refer to Table 9 and Table 10 and Figure 7 and Figure 13 for 8-Channel “B” Hypertronics connector cable and 8-Channel Bendix (Legacy) connector cable. For the Bendix connector cable, use any ground pin in Table 10 for the RF ground of coil side. Also use the multimeter to assure an open circuit condition exists between the center pin and the shield for each RF connector in the coil side.

Table 9 8-Channel “B” Connector RF Allocation
System Side Connector RF GND Shield Coil Side Connector RF Shield
C1 CH1
C2 CH2
C3 CH3
C4 CH4
D1 CH5
D2 CH6
D3 CH7
D4 CH8

Figure 15. 8-Channel “B” Connector RF Cables from the Coils Side

Table 10 8-Channel Bendix Connector RF Allocation
System Side Connector RF GND Pin Coil Side Connector RF Shield

All following pins are grounded together. Using any of the pins is sufficient for this test. A12, A14, A16, A18, A20, A22, A24, A26, B2, B4

 CH9
CH10
CH11
CH12
CH13
CH14
CH15
CH16

Figure 16. 8-Channel Bendix Connector RF Cables from the Coils Side

If one or more of the readings indicate an open, replace the cable. Otherwise, proceed to the DC Lines Continuity Check.

DC Lines Continuity Check

With the coil cable disconnected, use a multimeter to determine continuity between the designated pins for each control line below. Also test the continuity between the pairs of pins within system connector that are listed in the tables below. If any line or pair of pins indicates an open, replace the output cable. Please note that the DC continuity test does not apply to Bendix cable.

Table 11 “B” Connector DC Allocation for Upgrade System
System Side Connector DC Pin Coil Side Connector DC Pin
A1 J54-1
A2 J54-2
A3 J2-1
A4 J2-2
A5 J2-3
A6 J2-4
A7 J2-5
A8 J2-6
A9 J2-7
A10 J2-8
K1 J60-2
K2 J60-8
K3 J61-4
K4 J61-2
K5 J61-8
K6 J60-4
K7 J60-6
K8 J61-6
M2 J54-7
M3 J1-1
M5 J54-8
M6 J1-2
M7 J54-3
M8 J54-4
J1 J60-1
J2 J60-7
J3 J61-3
J4 J61-1
J5 J61-7
J6 J60-3
J7 J60-5
J8 J61-5
Short J9 to J10 N/A
Short M9 to M10 N/A

Figure 17. “B” Connector DC Cables from the Coils Side

Upgrade System HNS Rev 3

For upgrade systems, we use 8-Channel “A” Hypertronics connector cable for TL unit and 8-Channel “B” Hypertronics connector cable and 8-Channel Bendix (Legacy) connector for HN unit.

The upgrade Rev 3 coil uses the same 8-Channel “A” Hypertonics connector cable for TL unit as the forward production Rev 3 coil. Refer to Forward Production System HNS Rev 3 for checking the connector A cable.

Figure 18. Pin Layouts of 8-Channel “B” Hypertronics Connector for Upgrade System

Figure 19. Pin Layouts of 8-Channel Bendix Connector for Upgrade System

RF Signal Channels Check

note:

The center pins of the System Connector receive coaxial connectors are extremely fragile. Do not attempt to make any measurements at these center pins.

With the “B” Connector cable disconnected from the coil assembly, use a multimeter to ensure a short circuit condition exists between the designated RF GND shields detailed in the table below. Refer to Table 12 and Figure 18 and Figure 20.

Table 12 8-Channel “B” Connector RF Allocation
C1 4
C2 5
C3 6
C4 7
D1 2
D2 3
D3 8
D4 1

Figure 20. 8-Channel “B” Connector RF Cables From The Coils Side

With the Bendix Connector cable disconnected from the coil assembly, use a multimeter to ensure a short circuit condition exists between the designated GND shields. Refer to Table 13 and Figure 18 and Figure 21. Use any ground pin in Table 13 for the RF ground of coil side.

Table 13 8-Channel Bendix Connector RF Allocation
System Side Connector RF GND Shield Coil Side Connector RF Shield (All located on Gang J68)

All following pins are grounded together. Using any of the pins is sufficient for this test. A12, A14, A16, A18, A20, A22, A24, A26, B2, B4

 1
2
3
4
5
6
7
8

Figure 21. 8-Channel Bendix Connector RF Cables From The Coils Side

If one or more of the readings indicate an open, replace the cable. Otherwise, proceed to the DC Lines Continuity Check.

DC Lines Continuity Check

With the coil cable disconnected, use a multimeter to determine continuity between the designated pins for each DC control line below. Also test the continuity between the pairs of pins within system connector that are listed in the tables below. If any line or pair of pins indicates an open, replace the output cable. Please note that this DC continuity test does not apply to Bendix connector.

Table 14 “B” Connector DC Allocation For Upgrade System
System Side Connector DC Pin Coil Side Connector DC Pin
A1 J54-1
A2 J54-2
A3 J2-1
A4 J2-2
A5 J2-3
A6 J2-4
A7 J2-5
A8 J2-6
A9 J2-7
A10 J2-8
J1 J10-1
J2 J10-7
J3 J11-3
J4 J11-1
J5 J11-7
J6 J10-3
J7 J10-5
J8 J11-5
K1 J10-2
K2 J10-8
K3 J11-4
K4 J11-2
K5 J11-8
K6 J10-4
K7 J10-6
K8 J11-6
M2 J54-7
M3 J1-1
M5 J54-8
M6 J1-2
M7 J54-3
M8 J54-4
Short J9 to J10 N/A
Short M9 to M10 N/A

Figure 22. “B” Connector DC Cables from the Coils Side

Discovery MR450 System and Optima MR450w System HNS Rev 3

8ch “A” Hypertonic connector cable is attached to the TL unit and 16ch “P” P-connector plug cable is attached to HNU on the Discovery system.

Figure 23. Pin Layout of “P” P-connector

Figure 24. “A” Hypertronics connector

note:

The center pins of the system connector that receive coaxial connectors are extremely fragile. Do not attempt to make any measurements at these center pins.

The following procedure will ensure the integrity of the ground section for each RF coax cable, which are detailed in the following tables.

  1. With the coil cable disconnected, use a multimeter to ensure an open circuit condition exists between the RF ground shields of the RF coax connector in the system side and the coils side.

  2. If one or more of the readings indicate an “open”, replace the cable. If no “open” is found for the ground of the RF cables, proceed to the DC Lines Continuity Check.

Table 15 8-Channel “A” Connector RF Allocation
System Side Connector

RF GND Shield

Coil Side Connector RF GND Sheild Pin#

(All located on Gang Connector J28)

C1 8
C2 1
C3 7
C4 2
D1 6
D2 3
D3 5
D4 4

Figure 25. 8-Channel “A” Connector RF Cables from Coil Side

Table 16 16-Channel “P” P-connector RF Allocation
System Side

Connector RF GND Shield

Coil Side Connector

RF GND Shield Pin#

(All located on the Gang Connector J67)

System Side Connector

RF GND Shield

Coil Side Connector

RF GND Shield Pin#

(All located on connector J68)

R1 4 R9 3
R2 5 R10 5
R3 6 R11 2
R4 7 R12 6
R5 2 R13 8
R6 3 R14 4
R7 8 R15 7
R8 1 R16 1

Figure 26. 16-Channel “P” Connector RF Cables from Coil Side

DC Lines Continuity Check

With the coil cable disconnected, us a multimeter to determine continuity between the designated Pins for each DC control line, as indicated below. Also, test the continuity between the pairs of Pins within the system connector that are listed in the table below. If any line or pair of Pins indicates an “open”, replace the output cable.

Table 17 “A” Connector DC Allocation
System Side Connector

DC Pin

Coil Side Connector

DC Pin

M3 J1-1
M6 J1-2
M8 J1-3
M7 J1-4
J1 J14-4
K1 J14-2
J2 J14-3
K2 J14-4
J3 J14-5
K3 J14-6
J4 J14-7
K4 J14-8
Short A1 to A2 NA
Short J9 to J10 NA
Short M9 to M10 NA

Figure 27. “A” connector DC Cables from Coils Side

Table 18 “P” P-connector DC Allocation
System Side Connector

DC Pin

Coil Side Connector

DC Pin

7 J2-1
8 J2-2
9 J2-3
10 J2-4
11 J2-5
12 J2-6
13 J2-7
14 J2-8
1 J54-1
2 J54-2
5 J54-3
6 J54-4
20 J54-7
21 J54-8
18 J1-1
19 J1-2
Short 4 to 3 NA

Figure 28. “P” P-connector DC Cables from Coil Side

Configuration of Jumpers on the Interface Board for Upgrade and Forward Production System

When you replace the cable assembly, you need to make sure the configuration of jumpers on the interface board for upgrade and forward production systems.

Figure 29. Interface Board for HNS Rev 2 Coil

Table 19 Configuration of Jumpers on the HNS Rev 2 Interface Board
Upgrade System Forward Production HDx System Discovery System
Jumpers Put the jumpers JMPR4, 5, 6, 7, 8, 9, 10 None None

Figure 30. Interface Board for HNS Rev 3 Coil

Table 20 Configuration of Jumpers on the HNS Rev 3 Interface Board
Upgrade HDx System Forward Production HDx System Discovery System
Jumpers Put the jumpers JMPR 5, 8, 28, 39, 40, 41, 55 None None

* *The part number of Jumper for shorting is U1-410002.