# MRgLITT under general anesthesia using extended non-ferromagnetic components in a non-MR-compatible environment-a case report

## TL;DR

A case report describes a successful MR-guided laser therapy using adapted non-MR-compatible anesthesia equipment in a patient with epilepsy.

## Contribution

An innovative anesthesia strategy using extended non-ferromagnetic components in a non-MR-compatible environment is demonstrated.

## Key findings

- Extended non-ferromagnetic components enabled safe general anesthesia during MRgLITT without MR-compatible equipment.
- Pre-procedural testing confirmed the safety and effectiveness of adapted devices for vital sign monitoring.
- The patient remained stable and recovered quickly using the modified anesthesia setup.

## Abstract

Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) is a novel minimally invasive treatment that requires precise implementation within a magnetic resonance (MR) environment. Given the procedure’s lengthy duration and the need for absolute immobility, general anesthesia (GA) with endotracheal intubation (ETT) and an MR-compatible ventilator is recommended. However, in facilities lacking a hybrid MR operating room or MR-compatible anesthesia equipment, alternative anesthesia strategies must be employed to ensure patient safety while complying with American Society of Anesthesiologists (ASA) recommendations for sedation and GA in the MRI environment, including monitoring of heart rate, pulse oximetry, and blood pressure.

A 43-year-old male ASA II patient, with epilepsy and cavernous hemangioma, was scheduled for elective MRgLITT. The critical second phase of this procedure required GA with ETT within the MRI environment. Due to the absence of MR-conditional anesthesia equipment in the MR suite, extended-length, MR-safe components were adapted from existing equipment. These modifications included a prolonged breathing circuit, an extended-length cable for the pulse oximeter probe, an extended air-conduction tube for non-invasive blood pressure (NIBP), and a prolonged sampling line for the capnograph. The effectiveness and safety of these adapted devices were verified against standard monitoring equipment and a conventional anesthesia machine in the pre-procedural test conducted during the first phase of MRgLITT. Furthermore, arterial blood gas analysis provided additional confirmation of patient safety using the modified hardware. By using these extended lines, conventional ventilators and monitors can be positioned outside the MR scanner room, enabling continuous support and monitoring of the patient’s vital signs throughout the procedure. The patient was very stable intraoperatively, particularly in the MR suite, which required extended equipment. Ultimately, the MRgLITT was successfully completed using this innovative anesthesia management approach. The patient recovered very quickly.

In the absence of MR-compatible equipment, adapted non-ferrous devices with extended-length components can provide necessary physiologic support and monitoring, aligning with ASA guidelines for sedation and GA in an MRI environment. However, rigorous pre-procedural testing of such modified equipment is essential to ensure patient safety. The innovative anesthesia approach we implemented for MR-guided procedures demonstrates clinical utility and offers a practical model for anesthesiologists managing similar resource-constrained scenarios.