1 of 31

Approach to VP Shunt Catheter

From a Radiologic Standpoint

2 of 31

https://documents.umc.edu/viewpolicy.aspx?pid=h-im-mri-gen-po-00013

​

Published Date: 4/15/2015 Effective Date: 12/18/2014 HIMMRIGENPO00013

MRI Patient Screening and Implant Devices (excerpt for shunts)

UMC Policy

3 of 31

ACR Guidance Document on MR Safe Practices: 2013�JOURNAL OF MAGNETIC RESONANCE IMAGING 37:501–530 (2013)

  • All patients and non-MR personnel with a history of potential ferromagnetic foreign object penetration must undergo further investigation before being permitted entrance to Zone III. Examples of acceptable methods of screening include patient history, plain X-ray films, prior CT or MR studies of the questioned anatomic area, or access to written documentation as to the type of implant or foreign object that might be present. (written documentation preferred)

4 of 31

ACR Guidance Document on MR Safe Practices: 2013�JOURNAL OF MAGNETIC RESONANCE IMAGING 37:501–530 (2013)

  • Final determination of whether or not to scan any given patient with any given implant, foreign body, etc. is to be made by the level 2 designated attending MR radiologist, the MR medical director, or specifically designated level 2 MR personnel following criteria for acceptability predetermined by the medical director.

5 of 31

ACR Guidance Document on MR Safe Practices: 2013�JOURNAL OF MAGNETIC RESONANCE IMAGING 37:501–530 (2013)

  • Level 2 MR Personnel
  • Individuals who have been more extensively trained and educated in the broader aspects of MR safety issues, including, issues related to the potential for thermal loading or burns and direct neuromuscular excitation from rapidly changing gradients, will be referred to as level 2 MR personnel (e.g., MRI technologists, radiologists, radiology department nursing staff.)

6 of 31

Approach to Shunt Catheter

​

7 of 31

Non-Programmable Valves

  • Many types/names (this list not exhaustive):
    • Fixed differential pressure valves
    • Anti-siphon valves
    • Gravity activated valves
    • Delta valves
    • Flow control valves

​

​

8 of 31

Non-Programmable Valves

  • Either “MR Safe” or “MR Conditional” According to ASTM F2503. Generally, valves demonstrate no known hazards when an MRI is performed under the following conditions:
    • MRI can be performed at any time after implantation
    • Use an MR system with a static magnetic field of 3-T or less
    • Use an MR System with a spatial gradient of 720 gauss/cm or less
    • Limit the exposure to RF energy to a whole-body-averaged specific absorption rate (SAR) of 3 W/kg for 15 minutes (per pulse sequence) (ranges from 2-4 W/kg)

​

9 of 31

Aesculap Fixed MiniNAV 

Codman Hakim Precision Fixed Pressure Cylindrical 

Codman Hakim Precision Fixed Pressure Micro 

Codman Hakim Precision Fixed Pressure In-Line

Medtronic Contoured Regular 

Pressure indicator symbols:

10 of 31

Medtronic Ultra Small

Medtronic Button

Medtronic Burr Hole

Medtronic Contoured Small 

Aesculap Gravity Activated Valve

Chhabra Gravity Activated Z- Flow Valve

11 of 31

Codman Gravity Activated Hakim Precision Fixed Pressure In-Line Valve with Siphonguard Device

Anti-siphon valve performance level indicator.

Medtronic Delta Valve, Regular

Delta Valve, Small

Delta Valve, Neonatal

Delta Valve, Burr Hole

Delta Chamber 1.0

12 of 31

13 of 31

14 of 31

15 of 31

16 of 31

17 of 31

18 of 31

Integra Flow Regulating Valve

Integra OSV II Valve

Integra OSV II Low Pro Valve

Flow Regulating Valves: Non-programmable but considered Magnetic Resonance (MR) Conditional in accordance with ASTM F2503. Note that one of these has no arrow.

19 of 31

Programmable/ Valves

  • “MR Conditional” According to ASTM F2503. Generally, valves demonstrate no known hazards when an MRI is performed under the following conditions:
    • NSGY must sign off before performed.
    • Must be interrogated after scan.
      • Setting may be changed by magnet.
        • May need re-adjusting by NSGY.
    • MRI can be performed at any time after implantation
    • Use an MR system with a static magnetic field of 3-T or less
    • Use an MR System with a spatial gradient of 720 gauss/cm or less
    • Limit the exposure to RF energy to a whole-body-averaged specific absorption rate (SAR) of 3 W/kg for 15 minutes (per pulse sequence) (ranges from 2-4 W/kg)

​

20 of 31

Programmable Valves

  • Neurosurgery DOES have interrogation and adjustment devices on hand.
    • Interogation/adjustment equipment is MRI UNSAFE.
  • We do not typically place PROGRAMMABLE valves at UMC, but other institutions do.

​

21 of 31

Codman Hakim Programmable

22 of 31

Codman Hakim Programmable

23 of 31

Codman Valves

Hakim Programmable Cylindrical Valve

Hakim Programmable Micro Valve with Rickham Reservoir

Hakim Programmable In-Line Valve

Hakim Programmable In-Line Valve with Siphonguard Device

24 of 31

Codman Valves

Hakim Programmable Cylindrical Valve

Hakim Programmable Micro Valve with Rickham Reservoir

Hakim Programmable In-Line Valve

Hakim Programmable In-Line Valve with Siphonguard Device

25 of 31

Medtronic Valves

Strata NSC Valve Regular

Strata NSC Valve Small

Strata II Valve Regular

Strata II Valve Small

26 of 31

Aesculap Miethke Valves

proGAV

proSA

27 of 31

Interrogator/Programmer �NOT MRI safe

28 of 31

Sophysa Polaris Programmable Valve

Supposedly MRI stable with locking system, but don’t count on it.

29 of 31

Other VP Shunts Exist

  • Look for them so we can best utilize MRI.
  • If you don’t know, ask. If you can’t find an answer, recommend CT.

30 of 31

Take Home Points for VP Shunts

  • Screen for them so we can best utilize MRI.
  • Rule of thumb:
    • If arrow/dot only = non-programmable
    • If dial +/- arrow/dot = programmable
  • If you don’t know, ask. If you can’t find an answer, recommend low contrast VP shunt protocol CT.

31 of 31

Resources

​

​