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

Concentric zones: T1 contrast-enhanced (T1C) and T2WI 24 hours after laser ablation of a recurrent right cerebellar metastatic lesion in a 71-year-old female patient with history of breast carcinoma: 1) probe track, 2) central zone, 3) peripheral zone, 4) peripherally enhancing rim, 5) marginal zone. Note that the concentric zones appear as inverse images on T1C and T2 images.

T1 contrast-enhanced images demonstrating the normal evolution of a LITT-treated metastatic left cerebellar lesion, which recurred after SRS in a 70-year-old female patient with history of ovarian adenocarcinoma. Note the expected increase in the size of the treated lesion at 2-month follow-up and a steady decrease in size on subsequent follow-up.

T2WI demonstrating the normal evolution of an LITT-treated left splenial low-grade astrocytoma in a 30-year-old male patient with a history of type 1 neurofibromatosis. Note the expected increase in the size of the lesion and marginal zone at 1-month follow-up and subsequent decrease at 3 months.

Disease recurrence after treatment with LITT. T1 contrast-enhanced images in a 58-year-old man with GBM status post surgical excision, chemoradiation, and SRS for a recurrent left parietal lobe lesion. The second recurrence was treated with LITT. Note irregular peripheral nodular enhancement at 1-month follow-up (white arrow), which progressively increases in size at 2 and 6 months. Findings are consistent with disease recurrence.

LITT of radiation necrosis with subsequent disease recurrence in a 68-year-old female patient with lung squamous cell carcinoma status post surgical excision and SRS of a metastatic brain lesion in the left parietal lobe, which subsequently resulted in radiation necrosis. Medically intractable radiation necrosis was treated with LITT. Pre-LITT imaging demonstrated an enhancing lesion in the left parietal lobe on T1 contrast-enhanced (not shown) with significant vasogenic edema on T2 images (dashed white arrow on T2 image labeled “pre”). Dynamic imaging pre-LITT (not shown) did not demonstrate a significant increase in CBF or CBV. The patient was not treated with bevacizumab, and RN was favored over recurrence. Note a significant decrease in vasogenic edema 1 month after treatment (dashed white arrow), coinciding with symptomatic improvement. T2 images obtained at 4-month follow-up demonstrate a significant increase in peritumoral vasogenic edema. There is significant thickening of the peripheral zone of enhancement (white arrow) on T1 contrast-enhanced images at 4 months compared with 1 month. Findings are concerning for tumor recurrence within a treated RN lesion, which was corroborated on PET CT (not shown).