Targeting the vim by direct visualization of the cerebello-thalamo-cortical pathway in 3 T proton density MRI: correlation with focused ultrasound lesioning.

Surgical targeting of the ventral intermediate nucleus of the thalamus (VIM) has been historically done using indirect strategies. Here we depict the cerebello-thalamo-cortical tract (CTCT) through 3 T proton density (PD) in a cohort of patients who underwent high-intensity focus ultrasound (HIFUS) thalamotomy. Forty-seven patients treated in our institution with MR-guided HIFUS VIM thalamotomy were included in this study. PD weighted 3 T MRI used for presurgical planning was compared with postoperative MRI obtained 1 month after surgery. Images were processed with ISTX software (Brain lab, Munich, Germany). The coordinates of the VIM lesion concerning the inter-commissural line (ICL) were annotated. Deterministic tractographies using three ROIs were used to verify the different tracts. The triangle seen in the 3 T PD sequence at the level of the mesencephalic-diencephalic junction was systematically recognized. The posterior angle of this triangle at the junction of the CTCT and the ZI was denominated as "point P." The area of this triangle corresponds to the posterior subthalamic area (PSA) harboring the Raprl fibers. The CTCT was visible from 1 to 2.5 mm below the ICL. The average center of the final HIFUS lesion (point F) was 11 mm from the medial thalamic border of the thalamus (14.9 mm from the midline), 6.4 mm anterior to PC, and 0.6 mm above the ICL. The FUS point was consistently 1-2 mm directly above point P. The anterior border of the external angle of this triangle (point P) can be used as an intraparenchymal point for targeting the ventral border of the VIM. Three ROIs placed in a single slice around this triangle are a fast way to originate tractography of the CTCT, lemniscus medialis, and pyramidal tract.

Bilateral hyperplasia of choroid plexus with severe CSF production: a case report and review of the glymphatic system.

BACKGROUND: An important feature of hydrocephalus is the alteration of the cerebral spinal fluid (CSF) homeostasis. New insights in the understanding of production, secretion, and absorption of CSF, along with the discovery of the glymphatic system (GS), can be useful for a better understanding and treatment of hydrocephalus in disorders with CSF overproduction. CASE DESCRIPTION: A 1-year-old patient was diagnosed with communicating hydrocephalus; ventricle peritoneal shunt (VPS) is installed and ascites developed. VPS is exposed, yielding volumes of 1000-1200ml/day CSF per day. MRI is performed showing generalized choroidal plexus hyperplasia. Bilateral endoscopic coagulation of thechoroid plexus was performed in 2 stages (CPC) however the high rate of CSF production persisted, needing a bilateral plexectomy through septostomy, which finally decreased the CSF outflow. DISCUSSION: New knowledge about the CSF physiology will help to propose better treatment depending on the cause of the hydrocephalus. The GS is becoming an additional reason to better study and develop new therapies focused of the modulation of alternative CSF reabsorption. CONCLUSION: Despite the current knowledge about hydrocephalus, we remain without a complete understanding of the pathophysiology of this condition. GS could be more important than conventional concept of reabsorption of CSF in the arachnoid villi, therefore GS could be a new key point, which will guide future investigations.

Primary intracranial smooth muscle tumor associated with Epstein-Barr virus in immunosuppressed children: two cases report and review of literature.

Primary intracranial smooth muscle tumors are rare. Most cases are related to Epstein-Barr virus proliferation in immunocompromised patients such as organ solid recipients. Only a few cases have been reported in pediatric patients. The clinical features are very variable depending mainly on the location and size of the smooth muscle tumor (SMT) and the pathogenesis is poorly understood. We describe two cases of intracranial SMT localized in the temporal lobe and associated with EBV in immunosuppressed children. A review of the literature associated with intracranial leiomyomas was also done.