Medtronic InterStim MRI Guidelines

This document provides essential guidelines for performing Magnetic Resonance Imaging (MRI) examinations on patients with implanted Medtronic InterStim™ systems. It is crucial to read this entire manual before conducting any MRI scan.

These instructions apply exclusively to Medtronic InterStim implanted systems and do not cover other implantable products or devices. Medtronic does not make any safety claims for MRI scans involving modified InterStim system components or non-Medtronic components.

For questions, please contact Medtronic using the information provided at the back of this manual.

Schedule MRI

To schedule an MRI for a patient with a fully implanted Medtronic InterStim system:

Prior to the MRI appointment, patients should:

Neurostimulator and Lead Model Numbers

Medtronic InterStim systems have been found to be MR Conditional through non-clinical testing. These guidelines are for approved indications to safely perform MRI scans on patients with a fully implanted Medtronic InterStim system for sacral neuromodulation therapy.

These guidelines apply to neurostimulator model numbers listed in Table 1, when implanted as a system including a neurostimulator and lead (and extension, if applicable).

IMPORTANT: Review the entire manual, including the "ELIGIBILITY IDENTIFICATION" section and the checklist starting on page 12, to determine the patient's MRI scan-type eligibility and appropriate scan conditions.

Table 1. InterStim systems – implanted neurostimulator and lead model numbers associated with these MRI guidelines

Neurostimulator Lead MRI scanner
Model 97810 InterStim Micro SureScan™™ MRI rechargeable neurostimulator Model 978A1 SureScan lead If eligible, 3-Tesla (T) and 1.5-T MR Conditional. Check "ELIGIBILITY IDENTIFICATION" on page 12 before scanning. Ask the patient to recharge the neurostimulator before the MRI appointment.
Model 97800 InterStim X OR Model 3058 InterStim II neurostimulator Model 978B1 SureScan lead If eligible, 3-T and 1.5-T MR Conditional. Check "ELIGIBILITY IDENTIFICATION" on page 12 before scanning.
[Type of lead:] No need to determine the InterStim lead model for this scenarioa. If eligible, 1.5-T MR Conditional Head Scan Eligible with Detachable Head Transmit/Receive Volume Coil. Check "ELIGIBILITY IDENTIFICATION" on page 12 before scanning.
Model 3023 InterStim neurostimulator No need to determine the InterStim lead model for this scenarioa. If eligible, 1.5-T MR Conditional Head Scan Eligible with Detachable Head Transmit/Receive Volume Coil only. Check "ELIGIBILITY IDENTIFICATION" on page 12 before scanning.
No MRI scans for serial numbers: Less than NBV132955H, Between NBV133037H and NBV133063H, Between NBV628045S and NBV628263S. Note: If a programmer is used to check the neurostimulator serial number, the letter suffix (H or S) may not be included in the serial number displayed.
Model 7427T InterStim Twin neurostimulator No MRI scans No MRI scans

a When implanted per approved indications, InterStim system components are outside of the head coil.

Non-Medtronic components or accessories are not supported by these MRI guidelines.

Patient ID Card

Patients should provide their most up-to-date patient ID card at the MRI appointment. MRI personnel can use this card to identify Medtronic as the manufacturer.

Obtain the Latest MRI Guidelines Labeling

Always obtain the latest MRI guidelines. Visit www.medtronic.com/mri and enter the neurostimulator model number. Guidelines received directly from the website or Medtronic on the same day as the appointment are the most up-to-date.

External Control Device

For Medtronic InterStim systems, external control devices (patient control device, handset with therapy app, or clinician programmer) are used to determine MRI scan-type eligibility and prepare the system for the scan.

IMPORTANT: Ensure the patient brings a patient control device to the MRI appointment, as it is necessary for determining eligibility per the "ELIGIBILITY IDENTIFICATION" section.

For the Model 3023 neurostimulator, if the patient uses a control magnet to turn the system on or off, a clinician must first disable the magnet switch using the Model 8840 Clinician Programmer.

Patient Control Device Identification and Operation: Refer to "ELIGIBILITY IDENTIFICATION" on page 12 and the identification checklist. If the patient control device cannot communicate with the implanted system, MRI scan-type eligibility cannot be confirmed. Research the implanted system configuration from medical records or see "Appendix C: X-ray identification – InterStim systems" for guidance. Unless the implanted system configuration is known and deemed safe for MRI under specific conditions, do not conduct the scan.

Note: Illustrations of patient control device hardware are representative; actual hardware may differ.

Image Artifacts and Distortion (for full-body eligible scans only)

Significant image distortion can occur due to the presence of the neurostimulator and leads. Consider these factors when selecting the field of view and imaging parameters, and when interpreting MRI images.

General Information on MRI Procedures and Neurostimulation System Interactions

MRI systems generate electromagnetic fields that can interact with implanted neurostimulation system components. These interactions, particularly heating, can be hazardous and lead to serious or permanent patient injury. The following information outlines potential interactions and control measures to minimize risks.

Information for Prescribers

Risks Associated with Implanted Neurostimulation Systems in the MRI Environment

Exposing a patient to MRI settings other than those specified in this manual may injure the patient or damage the neurostimulator. Potential risks include:

Warnings

MRI During Therapy Evaluation (Temporary Evaluation): Ensure all temporary evaluation components are explanted if an MRI scan is required. Do not prescribe MRI for patients undergoing therapy evaluation or with non-fully implanted components. MRI has not been evaluated with therapy evaluation components. External neurostimulators are unsafe in the MR environment.

Limitations for Scanning Patients with Fully Implanted Neurostimulation Systems:

Failure to follow warnings and conditions may result in patient discomfort, device damage, or serious/permanent patient injury due to excessive heating or other risks.

Precautions

MR Unsafe External Devices: Do not allow the following Medtronic external devices into the MRI scanner room:

ELIGIBILITY IDENTIFICATION

Do not proceed with MRI instructions if the patient lacks a patient control device for their InterStim system. A patient control device is necessary for the MRI clinician to determine eligibility.

Identify the Patient's MRI Scan-Type Eligibility

Use the eligibility identification checklist to determine the patient's MRI scan-type eligibility and the appropriate MRI equipment, scan requirements, and RF field requirements.

MRI scan-type eligibility depends on factors related to the patient's implanted neurostimulation system.

Eligibility Identification Checklist

If the patient provides an MRI eligibility form from their clinician, use it to confirm information on the patient control device.

1. What type of patient control device did the patient bring?

Patient control device A with MRI icon:

Patient control device A without MRI icon:

Patient control device B:

No patient control device:

2. Determine the option displayed on patient control device A with MRI icon:

Notes:

Full-Body Eligible MRI Scan Conditions

MR Conditional Full Body Scan Eligible

Confirm via the "ELIGIBILITY IDENTIFICATION" section (page 12) that the patient's system is MR Conditional for full-body scans. Patients identified as "MR Conditional Full Body Scan Eligible" can undergo 3-T and 1.5-T scans of any anatomy part if all specific conditions are met.

Full-body eligible – MRI Equipment and Scan Requirements

Use Table 2 (page 17) to track patient model numbers and MRI equipment. Check boxes as applicable.

Warning: Scans must adhere to the MRI equipment, scan, and RF field requirements specified in this manual. Failure to comply may result in patient discomfort, device damage, or serious/permanent injury due to excessive heating or other risks.

General MRI Conditions:

Table 2. Model 97810, Model 97800, and Model 3058 full-body eligible conditions – 3-T and 1.5-T MRI equipment and scan requirements

MRI scanner
Confirm the neurostimulator and lead model numbers on the patient control device. [Select one:]

Confirm battery status (Model 97810 neurostimulator only). Confirm with the patient that the neurostimulator is charged to at least 30% before scanning. Do not proceed if not sufficiently charged.
Confirm scan-type eligibility and that MRI mode is activated on the patient control device. Placing the device in MRI mode turns therapy off. The text and symbols indicate full-body MRI scan eligibility and that the system is in MRI mode.
MR MR Conditional Full Body Scan Eligible
MRI system types [Select one:]
Maximum gradient slew rate specification ≤ 200 T/m/s per axis
Maximum spatial field gradient 20 T/m (2000 gauss/cm)
Scan time limit Maximum 30 minutes of continuous scan time, followed by a 5-minute wait time if limit is reached.

Proceed to MRI scan regions and RF field requirements in Table 3 (3-T) on page 18 or Table 4 (1.5-T) on page 19.

Table 3. Full-body eligible 3-T MRI scan regions and RF field requirements

① Depicts a transverse plane at the C7 vertebra.

Scan region 3-T RF coil 3-T RF exposure level
② At or superior to the C7 vertebra [Select one:]
3-T: Normal Operating Mode or First Level Controlled Operating Mode
③ Inferior to the C7 vertebra [Select one:]
3-T: B1+rms ≤ 2.0 μT. Values before scanning; for MRI scanners that do not report B1+rms, limit SAR to ≤ 1.4 W/kg.

Note: 3-T MRI systems using two transmit channels (or fewer) may operate in Multichannel-2 (MC-2) or Circularly Polarized (CP) configurations. Systems using more than two transmit channels have not been studied but could be operated in CP or MC-2 configurations.

Table 4. Full-body eligible 1.5-T MRI scan regions and RF field requirements

① Depicts a transverse plane at the C7 vertebra.

Scan region 1.5-T RF coil 1.5-T RF exposure level
② At or superior to the C7 vertebra [Select one:]
1.5-T: Normal Operating Mode or First Level Controlled Operating Mode
③ Inferior to the C7 vertebra [Select one:]
1.5-T: B1+rms ≤ 4.0 μT. Values before scanning; for MRI scanners that do not report B1+rms, limit SAR to ≤ 2.0 W/kg.

Note: RF Whole Body Transmit Coil - 1.5-T MRI systems should only be operated in CP configuration.

Proceed to "Full-body eligible – Preparing the patient before the MRI scan" on page 20.

Full-body eligible – Preparing the patient before the MRI scan

Warnings:

Table 5. Full-body eligible – Preparing the patient before the MRI scan

Ensure that MRI mode is activated. The text and symbols indicate full-body MRI scan eligibility and that the system is in MRI mode.
MR MR Conditional Full Body Scan Eligible
Check core body temperature. Confirm the patient's body temperature is ≤38 °C (100 °F). Do not use blankets.
Patient position Position the patient in a prone or supine position in the MRI bore.

Notes:

After confirming these conditions, proceed to "Full-body eligible – During the MRI scan" on page 21.

Full-body eligible – During the MRI scan

After the scan, proceed to "Full-body eligible – Post-MRI scan" on page 21.

Full-body eligible – Post-MRI scan

Cautions:

Table 6. Full-body eligible – Post MRI scan

Turn therapy back on After the scan, instruct the patient (outside the scanner room) to turn therapy back on. From the MRI Eligibility screen, ask the patient to place the communicator over the device and tap DEACTIVATE when prompted to deactivate MRI mode, then tap YES to return to previous therapy settings.

Notes:

Head-only Eligible MRI Scan Conditions

MR Conditional Head Scan Eligible with Transmit/Receive Head Coil

Confirm via the "Head-only eligible – Handset identification" section that a head-only scan is appropriate. Patients identified as head-only eligible can have 1.5-T MRI scans of the head using a Detachable Head Transmit/Receive Volume Coil, in addition to other specified conditions.

Head-only eligible – Handset Identification

1. What type of patient control device did the patient bring?

Patient control device A with MRI icon:

Patient control device A without MRI icon:

Patient control device B:

Head-only eligible – MRI Equipment and Scan Requirements

Warning: Scans must adhere to the MRI equipment, scan, and RF field requirements specified in the head-only section of this manual. Failure to comply may result in patient discomfort, device damage, or serious/permanent patient injury due to excessive heating or other risks.

General MRI Conditions:

Cautions:

Table 7. Model 97800 and Model 3058 head-only eligible conditions – 1.5-T MRI equipment and scan requirements

MRI scanner
Confirm the neurostimulator model number on the patient control device. [Select one:]
Confirm that MRI mode is activated or therapy is off. [Select one:]
MRI system type
Maximum gradient slew rate specification ≤ 200 T/m/s per axis
Maximum spatial field gradient 20 T/m (2000 gauss/cm)
RF coil type
RF exposure level Normal Operating Mode

Note: When implanted per approved indications, InterStim system components are outside of the head coil.

Proceed to "Head-only eligible – Preparing the patient before the MRI scan" on page 26. If the patient has a Model 3023 neurostimulator, see Table 8 on page 25.

Table 8. Model 3023 head-only eligible conditions – 1.5-T MRI equipment and scan requirements

MRI scanner
Confirm the neurostimulator model number. Check ineligible serial numbers for the Model 3023 neurostimulator in Table 1 on page 8.
Confirm patient cannot use a control magnet. Do not conduct an MRI scan if the patient can use a control magnet to turn the neurostimulator on or off, unless a clinician has first disabled the magnet switch.
Confirm that MRI mode is activated or therapy is off. [Select one:]
MRI system type
Maximum gradient slew rate specification ≤ 200 T/m/s per axis
Maximum spatial field gradient 20 T/m (2000 gauss/cm)
RF coil type
RF exposure level Normal Operating Mode

Note: When implanted per approved indications, InterStim system components are outside of the head coil.

Proceed to "Head-only eligible – Preparing the patient before the MRI scan" on page 26.

Head-only eligible – Preparing the patient before the MRI scan

Head-only eligible – During the MRI scan

Head-only eligible – Post-MRI scan

Cautions:

Table 9. Head-only eligible – Post MRI scan

Turn therapy back on. [Select one:]
After the scan, instruct the patient (outside the scanner room) to turn therapy back on using patient control device A or B.
For patient control device A with MRI: From the MRI Eligibility screen, ask the patient to place the communicator over the device and tap DEACTIVATE when prompted to deactivate MRI mode, then tap YES to return to previous therapy settings.
For patient control device A without MRI icon: Ask the patient to turn therapy on. 1. Place the communicator over the implanted neurostimulator site. 2. On the patient therapy app Home screen, swipe the On/Off Switch from Off to On.
For patient control device B: Ask the patient to press the Sync ⚙️ key. Then the patient can use normal procedures to turn therapy back on.

Notes:

Appendix A: Patient Control Device A Instructions

HH90 Handset Instructions

Use these instructions to guide the patient in using patient control device A (HH90 Handset and TM90 Communicator) to prepare the system for the MRI scan.

Part 1. Patient Control Device A with MRI icon: Activating MRI Mode

If MR appears on patient control device A, use the handset to place InterStim systems in MRI mode before an MRI scan. Ensure you are outside the MRI scanner room. Scan Eligibility icons will appear.

Note: During the MRI scan, keep the InterStim system in MRI mode. Do not deactivate MRI mode. Therapy must remain off.

  1. Press on the communicator to turn it on. The communicator will attempt to connect to the handset but cannot until the patient therapy app is launched. The blue LED light blinks to indicate it is on and in discovery mode.
  2. Open the patient therapy app on the handset to initiate the connection.
  3. Once the communicator connects to the handset, the blue LED light will be solid. Place the communicator over the neurostimulator implant area and tap FIND DEVICE on the handset.

Note: If the communicator fails to connect, readjust its position over the neurostimulator and tap RETRY.

  1. Once the communicator successfully connects to the implanted neurostimulator, you will be taken to the patient therapy app Home screen.
  2. Tap in the corner of the patient therapy app Home screen and select MRI.

Note: If the handset screen says "Not Ready for MRI Scan" and "Not Eligible", STOP. The neurostimulator is not eligible for MRI scans, and MRI mode is unavailable. Do not scan. Contact clinician.

  1. Tap ACTIVATE to activate MRI mode. (Activating MRI mode stops therapy.)
  2. Determine the message on the MRI eligibility screen:

Note: If the handset screen says "MRI eligibility cannot be determined", STOP. Further clinician assessment is required. Contact clinician before scanning.

  1. Return to Step 2 on page 14 in the ELIGIBILITY IDENTIFICATION section and follow instructions for the images and text on patient control device A with MRI.

Note: If the patient has patient control device A without the MRI icon, proceed to "Part 2. Patient Control Device A without MRI icon: Stopping Therapy" on page 30.

Part 2. Patient Control Device A without MRI icon: Stopping Therapy

If the patient has patient control device A without the MRI icon, use the handset to stop therapy to prepare the neurostimulator for the MRI scan. Ensure you are outside the MRI scanner room.

Note: During the MRI scan, keep the InterStim system off. Therapy must remain off.

  1. Press on the communicator to turn it on. The communicator will attempt to connect to the handset but cannot until the patient therapy app is launched. The blue LED light blinks to indicate it is on and in discovery mode.
  2. Open the patient therapy app on the handset to initiate the connection.
  3. Once the communicator connects to the handset, the blue LED light will be solid. Place the communicator over the neurostimulator implant area and tap FIND DEVICE on the handset.

Note: If the communicator fails to connect, readjust its position over the neurostimulator and tap RETRY.

  1. Once the communicator successfully connects to the implanted neurostimulator, you will be taken to the patient therapy app Home screen where you can turn off therapy (turn off the neurostimulator).

Confirm the neurostimulator model number and serial number:

Turn therapy off:

Proceed with head-only eligible Table 7 for Model 3058 on page 24 or Table 8 for Model 3023 on page 25.

Cautions:

Appendix B: Patient Control Device B Instructions

Model 3037 Patient Programmer Instructions

Use these instructions to guide the patient in using patient control device B (InterStim iCon Model 3037 Patient Programmer) to display the screen showing the neurostimulator model (IM) or serial number (IS) and to turn therapy off for the MRI scan.

Stopping Therapy for MRI

  1. Synchronize the patient control device and neurostimulator. Hold the programmer over the neurostimulator and press the Sync ⚙️ key.

Note: A suspected EOS (End of Service) neurostimulator requires MRI eligibility confirmation from a clinician. See "MRI Scan-Type Eligibility Form" near the back of this manual.

  1. Using the patient's Model 3037 Patient Programmer, press the Up arrow on the Navigator key.
  2. Press the Left arrow on the Navigator key once to select information screens.
  3. Press the Down arrow on the Navigator key.
  4. Press the Left or Right arrows on the Navigator key to scroll through each information screen to find the model number (Figure 4, left).

For a Model 3023 neurostimulator, check the serial number (IS) by pressing the Left or Right arrows until the IS screen appears (Figure 4, right). Consult Table 1 on page 8 to confirm that the Model 3023 neurostimulator is MR Conditional Head Scan Eligible with Transmit/Receive Head Coil.

Figure 4. Neurostimulator model (IM) (left) and serial number (IS) (right) screens.

  1. After confirming whether the neurostimulator is head-scan eligible, hold the programmer over the neurostimulator and press the Neurostimulator off key.
  2. If the neurostimulator is head-scan eligible, proceed with head-only eligible Table 7 for Model 3058 on page 24 or Table 8 for Model 3023 on page 25.

Cautions:

Appendix C: X-ray Identification – InterStim Systems

X-ray identification allows determination of the manufacturer and InterStim neurostimulator model number using standard X-ray procedures. The Medtronic symbol identifies Medtronic. To identify the lead, use X-ray imaging and look for a transition in lead body diameter size near the lead electrodes. In an InterStim SureScan MRI lead, the braided part of the lead body has a wider radiographic diameter than the lead body at the lead-electrode (distal) end. See Table 10.

InterStim System X-ray Identification

Table 10. Neurostimulator ID code and X-ray identification of the lead

INS radiopaque ID code X-ray identification of the lead
NMF Full-body MR Conditional with InterStim SureScan MRI lead Model 978A1XX (See Note below.)
① Lead body with braiding
② Lead body radiographic diameter transition near distal end
ID code NMF – Model 97810 InterStim Micro rechargeable neurostimulator
ANJY Full-body MR Conditional with InterStim SureScan MRI lead Model 978B1XX (See Note below.)
① Lead body with braiding
② Lead body radiographic diameter transition near distal end
ID code NJY – Model 97800 InterStim X neurostimulator OR Model 3058 InterStim II neurostimulator
Head-scan MR Conditional with Detachable Head Transmit/Receive Volume Coil with lead Model 3093
(1)
Head-scan MR Conditional with Detachable Head Transmit/Receive Volume Coil with lead Model 3889
1
1 Lead body without braiding
NBV If eligible, head-scan MR Conditional with Detachable Head Transmit/Receive Volume Coil with any InterStim lead model
ID code NBV – Model 3023 InterStim neurostimulator
No MRI scans if the Model 3023 serial number is:
Less than NBV132955H
Between NBV133037H and NBV133063H
Between NBV628045S and NBV628263S
Model 7427T is not eligible for MRI scans.
(2) 1. Neurostimulator Connector Block
2. NFE
ID code NFE – Model 7427T InterStim Twin Neurostimulator

Note: "XX" in 978A1XX and 978B1XX in labeling refers to the lead length. Wherever 978A1 and 978B1 are used, this refers to all lead lengths.

Appendix D: MRI Scan-Type Eligibility Form

Medtronic Neurostimulation System MRI Scan-Type Eligibility Form

At the time of the MRI appointment:

  1. See labeling for MRI scan conditions: www.medtronic.com/mri.
  2. Using the patient control device, confirm that MRI mode is activated (HH90 Handset and TM90 Communicator) or therapy is off (InterStim iCon Model 3037 Patient Programmer) prior to the MRI scan.
Patient name:
Physician name, office, address, and phone number:
Date and time eligibility was determined: Neurostimulator model number: Neurostimulator serial number:
MR Conditional Full Body Scan Eligible
MR Conditional Head Scan Eligible with Transmit/Receive Head Coil
The neurostimulation system MRI scan-type eligibility cannot be determined.

Important: Use the clinician or patient control device to determine scan eligibility and enter the information below.

Information code:

Models: 97810, InterStim Systems, 97810 InterStim Systems

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