Current Applications of MRI-Guided Laser Interstitial Thermal Therapy in the Treatment of Brain Neoplasms and Epilepsy: A Radiologic and Neurosurgical Overview

Abstract

SUMMARY:Minimally invasive stereotactic tumor ablation is a viable option for the treatment of benign and malignant intracranial lesions. Although surgical excision constitutes first-line therapy for various brain pathologies, it can cause irreversible neurologic deficits. Additionally, many patients who may benefit from surgery do not qualify as surgical candidates due to multiple comorbidities. Recent advancements in laser interstitial thermal therapy, namely the ability to monitor ablation in real-time under MR imaging, have improved the safety and efficacy of the procedure. MRI-guided laser interstitial thermal therapy is currently used as a minimally invasive treatment for brain metastases, radiation necrosis, glioma, and epilepsy. This article will discuss the principles, suggested indications, complications, and imaging characteristics of MRI-guided laser interstitial thermal therapy as they pertain to the treatment of brain pathology. ABBREVIATIONS:GBM ϭ glioblastoma multiforme; LITT ϭ laser interstitial thermal therapy; MRgLITT ϭ MRI-guided laser interstitial thermal therapy; MRTI ϭ MRI thermal imaging; RN ϭ delayed radiation necrosis; SRS ϭ stereotactic radiosurgery

Magnetic Resonance Imaging-Guided Laser Interstitial Thermal Therapy for Treatment of Drug-Resistant Epilepsy

“…After 40 days, the size of the peripheral zone gradually decreases [9]. The peripheral contrast-enhancing rim outlines the disrupted bloodbrain barrier and granulation tissue, which on MRI appears as a thin concentric layer of T1 contrast enhancement around the peripheral zone [9][10][11]. The diameter of the peripheral rim initially fluctuates with the size of the peripheral zone, or may remain stable through the initial few days, weeks, and months after ablation.…”

“…In subsequent images, the central zone may appear hypointense on T1 and hyperintense on T2 MRI sequences depending on the age of blood products and relative concentration of denatured proteins [10]. The peripheral zone contains thrombosed vessels, and shrunken and distended neuronal bodies that undergo delayed liquefaction necrosis [9][10][11]. The peripheral zone appears hypo-or isointense on T1 and hyperintense on T2 MRI sequences [9,10].…”

“…The peripheral zone contains thrombosed vessels, and shrunken and distended neuronal bodies that undergo delayed liquefaction necrosis [9][10][11]. The peripheral zone appears hypo-or isointense on T1 and hyperintense on T2 MRI sequences [9,10]. The peripheral zone increases in size during the first 40 days following the procedure as damaged cells undergo delayed liquefaction necrosis.…”

“…MR images performed within 24 h may show the central zone to be hyperintense on T1 and hypointense on T2 MRI sequences, owing to high protein levels and heat-induced methemoglobin conversion from deoxyhemoglobin [9,10]. In subsequent images, the central zone may appear hypointense on T1 and hyperintense on T2 MRI sequences depending on the age of blood products and relative concentration of denatured proteins [10]. The peripheral zone contains thrombosed vessels, and shrunken and distended neuronal bodies that undergo delayed liquefaction necrosis [9][10][11].…”

Intracerebral laser interstitial thermal therapy followed by tumor resection to minimize cerebral edema

“…5 It has also become a viable option for select patients who would otherwise be unsuitable surgical candidates because of comorbidities or anesthesia risks. 1 Given its minimally invasive nature, LITT is an appealing tool for neurosurgeons under the appropriate circumstances.…”