MR imaging during endovascular procedures: an evaluation of the potential for catheter heating

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Radiology

Background:

• Catheter use in Magnetic Resonance Imaging (MRI) poses safety concerns due to potential focal heating.
• Metallic braids in catheters, essential for physical properties, are implicated in thermal risks during MRI.
• Assessing catheter heating is crucial for patient safety during neurovascular procedures requiring brain MRI.

Purpose of the Study:

• To evaluate the potential for catheter heating during MRI in a simulated neurovascular procedure.
• To determine the influence of various factors on catheter heating, including immersion length, offsets, device position, MRI system, and Specific Absorption Rate (SAR).

Main Methods:

• An in vitro model simulating a neurovascular procedure with brain MRI was developed.
• Fluoroptic temperature probes were used to measure heating adjacent to endovascular devices in polyacrylamide gel.
• Heating was assessed under variable immersion lengths, offsets, device positions, MRI systems, and SAR levels.

Main Results:

• A rapid temperature rise was observed near endovascular devices during MRI scanning.
• Heating varied with immersion length, position within the MRI bore, measurement point, and MRI system.
• Peak heating rates were below 1°C/min even at maximal SAR with realistic geometries; negligible heating occurred below 0.2 W/kg SAR.

Conclusions:

• Catheter heating during MRI is influenced by several factors but can be managed.
• Linear scaling of heating with SAR was observed, with low SAR values (<0.2 W/kg) producing minimal heating.
• Substantial SAR restrictions and limited imaging durations are proposed as sufficient to ensure MRI safety for catheterized patients in neurovascular applications.