Low-Field Portable Magnetic Resonance Imaging for Post-Thrombectomy Assessment of Ongoing Brain Injury

BACKGROUND: Timely imaging is essential for patients undergoing mechanical thrombectomy (MT). Our objective was to evaluate the safety and feasibility of low-field portable magnetic resonance imaging (pMRI) for bedside evaluation following MT. METHODS: Patients with suspected large-vessel occlusion undergoing MT were screened for eligibility. All pMRI examinations were conducted in the standard ferromagnetic environment of the interventional radiology suite. Clinical characteristics, procedural details, and pMRI features were collected. Subsequent high-field conventional MRI within 72 +/- 12 hours was analyzed. If a conventional MRI was not available for comparison, computed tomography within the same time frame was used for validation. RESULTS: Twenty-four patients were included (63% women; median age, 76 years [interquartile range, 69-84 years]). MT was performed with a median access to revascularization time of 15 minutes (interquartile range, 8-19 minutes), and with a successful outcome as defined by a thrombolysis in cerebral infarction score of >= 2B in 90% of patients. The median time from the end of the procedure to pMRI was 22 minutes (interquartile range, 16-32 minutes). The median pMRI examination time was 30 minutes (interquartile range, 17-33 minutes). Of 23 patients with available subsequent imaging, 9 had infarct progression compared with immediate post-MT pMRI and 14 patients did not have progression of their infarct volume. There was no adverse event related to the examination. CONCLUSION: Low-field pMRI is safe and feasible in a post-MT environment and enables timely identification of ischemic changes in the interventional radiology suite. This approach can facilitate the assessment of baseline infarct burden and may help guide physiological interventions following MT.