MRI-guided Laser Ablation for Hemorrhagic Deep Brain Cavernous Malformations

Introduction: Subcortical cavernous malformations (CMs) that have bled pose an increased risk of repeat hemorrhage and symptomatic progression. While open surgical resection can be highly successful, accessing CMs in certain subcortical locations poses significant risk of procedural morbidity. MRI-guided laser interstitial thermal therapy (MRgLITT) has seen rapid adoption for the treatment of deep-seated brain tumors and epileptogenic foci, including several small series of epileptogenic CMs. The safety and efficacy of MRgLITT for hemorrhagic subcortical CMs has not been widely reported.

Methods: We retrospectively reviewed the medical records of all patients who underwent MRgLITT of a subcortical CM with a history of prior symptomatic hemorrhage at our center.

Results: Six patients underwent MRgLITT of subcortical CMs located in the thalamus-midbrain region (n=4), dentate nucleus (n=1), and frontal periventricular white matter (n=1). All patients had a history of at least 1 symptomatic prior hemorrhage and 5 had residual neurological symptoms at the time of treatment. All procedures were performed with a stereotactic frame-based system and intraoperative CT guidance followed by MRgLITT with a single 3mm fiber. There were no symptomatic or radiographic hemorrhages perioperatively or at any point in the follow-up period (mean 12.8 months, range 2-31 months). All patients were discharged home postoperative day 1 (n=5) or 2 (n=1). Three patients experienced transient neurological symptoms localized to the ablation target that resolved (returned to preoperative baseline or better) sooner than 30 days after surgery. At last follow-up, 4 patients had improvement of preoperative symptoms, 1 was stable 2 months after surgery, and 1 remained asymptomatic.

Conclusion : MRgLITT is a promising treatment for hemorrhagic subcortical CMs with low procedural morbidity and favorable early radiographic and rebleed outcomes in our series of 6 patients, possibly the largest to date. Larger studies with long-term follow-up are needed to determine safety and efficacy.