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

Occasionally, the increased cost of new technology can be justified by the enhanced diagnostic yield. The ability to avoid unnecessary surgery or, conversely, to continue to search for otherwise occult pathology that can be surgically corrected justifies routine application of these new tools. However, this study has shown that, despite a cost of approximately ten times more for dynamic pelvic magnetic resonance imaging than for videoproctography, no clinical changes were made. Thus, on the basis of this study, we cannot endorse the routine application of dynamic pelvic magnetic resonance imaging for the evaluation of constipated patients. In certain selected individuals, it may play a role, but further study is necessary to clarify its exact role.

Hemifacial spasm (HFS) has been defined as consisting of brief clonic jerking movements of the facial musculature, beginning in the orbicularis oculi with downward spreading to other facial muscles. HFS, perhaps the most common of the abnormal involuntary facial movements, has been classically ascribed to vascular loop compression at the root exit zone of the facial nerve. Causes other than such vascular loops are rare in the medical literature. Here we present three case studies in which the phenomenology of the HFS was atypical in onset and evolution. Using these three patients as introduction to the topic, we reviewed the literature of all cases of HFS with causes other than the vascular loop. In these three cases, HFS was caused by (1) a parotid gland tumor, (2) a cerebellopontine angle meningioma, and (3) an acoustic schwannoma. We also discuss the radiological findings as well as possible differences in the genesis of HFS and phenomenology in such cases and present recommendations on how to evaluate these patients.

This therapy is, rarely, associated with complications, mostly related to infections, seizures or stimulationinduced side effects. We report a case of a 71-year-old man with a 10-year history of PD who underwent bilateral placement of subthalamic nucleus DBS. As a complication, the patient showed subjective postoperative cognitive decline, and subsequent MRI showed peri-lead oedema, which progressed to large cystic cavitation around the leads without indication of infection. The patient received steroid therapy and the cavitations regressed without surgical intervention. BACKGROUND

BACKGROUND Laser interstitial thermal therapy (LITT) is quickly emerging as an effective surgical therapy for temporal lobe epilepsy (TLE). One of the most frequent complications of the procedure is postoperative visual field cuts, but the physiopathology of these deficits is unknown. OBJECTIVE To evaluate potential causes of visual deficits after LITT for TLE in an attempt to minimize this complication. METHODS This retrospective chart review compares the case of a 24-year-old male who developed homonymous hemianopsia following LITT for TLE to 17 prior patients that underwent the procedure and suffered no visual deficit. We examined both features of the surgical approach (trajectory, laser energy, ablation size) and of preoperative surgical anatomy, derived from volumetric tracings of mesiotemporal structures. RESULTS For the patient with postoperative homonymous hemianopsia imaging suggested inadvertent ablation of the lateral geniculate nucleus (LGN), although the laser was positioned entirely within the hippocampus. This patient’s laser trajectory, ablation number, energy delivered and ablation size were not significantly different from the prior patients. However, the subject with the visual deficit did have significantly smaller choroidal fissure CSF volume. CONCLUSION Visual deficits are the most common complication of LITT for mesiotemporal epilepsy and patients at most risk may have small CSF volume in the choroidal fissure, allowing heat to spread from the hippocampal body to the LGN. When such anatomy is identified on preoperative MRI we recommend lowering laser trajectory, decreasing ablation power through the hippocampal body and using temperature safety markers at the lower thalamic border.