The entire dural sinus tree is compressed in patients with idiopathic intracranial hypertension: a longitudinal, volumetric magnetic resonance imaging study.

INTRODUCTION: The objective of this study was to explore the volumetric alterations of dural sinuses in patients with idiopathic intracranial hypertension (IIH). METHODS: Standardized cranial magnetic resonance imaging (MRI) was used in 17 patients prior to and following treatment of IIH and in seven controls. Magnetic resonance venographies (MRV) were employed for (a) judgement of circumscript dural sinus stenoses and (b) computation of sinus volumes. Cross-sectional areas (CSA) of the superior sagittal sinuses (SSS) were measured on T2-weighted images. Results of the initial MRIs were compared to those on follow-up MRIs and to results of controls. RESULTS: Stenoses of the transverse sinuses (TS) resulting in cranial venous outflow obstruction (CVOO) were present in 15/17 (88%) patients, normalizing in 7/15 cases (47%) after treatment of IIH. CVOO was not detected in the control group. Segmentation of MRV revealed decreased dural sinus volumes in patients with IIH as compared to controls (P = 0.018). Sinus volumes increased significantly with normalization of intracranial pressure independent from disappearing of TS stenoses (P = 0.007). The CSA of the SSS were normal on the initial MRIs of patients with IIH and increased on follow-up after treatment (P < 0.001). However, volumetries displayed overlap in patients and controls. CONCLUSIONS: Patients with IIH not only exhibit bilateral stenoses of the TS as has been reported, but volume changes of their entire dural sinus system also occur. The potential etiopathological and diagnostic roles of these changes are discussed.

Awake craniotomy and intraoperative magnetic resonance imaging: patient selection, preparation, and technique.

OBJECTIVES: Intraoperative magnetic resonance imaging (iMRI) has been reported to augment radical brain tumor resection. "Awake craniotomy" is a technique to conserve function during brain tumor surgery. We report on the combination of these 2 techniques, with special emphasis on potential adverse effects, caveats, and patient preparation. METHODS: Thirty-four patients had 38 awake craniotomies with cortical stimulation within an integrated MRI-operating room with a 1.5-T unit. Thirty-two lesions were left hemispheric, 6 on the right side. RESULTS: Preparation for iMRI per patient amounted to 20 to 25 minutes, in addition to scan time. The procedure was well tolerated by all patients. Thirty-two stated that they would undergo this procedure again, if necessary. Four underwent a second "awake" surgery in the iMRI for recurrent disease. Intraoperative MRI had no adverse effect, such as seizures. Cortical stimulation could be performed without restrictions outside the 5-gauss line. CONCLUSIONS: The combination of iMRI and awake craniotomy is demanding but well tolerated by patients. Careful preoperative evaluation is essential to ensure compliance. There is no adverse effect through iMRI on the awake patient or the results of cortical stimulation. Since the introduction of the iMRI in our department in 2005, all awake craniotomies were done in this setting. The implementation of these 2 techniques into our procedures is demanding, and necessitates thorough preparation but has broadened our basis for surgical decision making. However, to substantiate our positive perception, more clinical data are being compiled.

Hydrocephalus in children with posterior fossa tumors: role of endoscopic third ventriculostomy.

OBJECT: Controversy exists regarding the indication for endoscopic third ventriculostomy (ETV) in children with hydrocephalus caused by posterior fossa tumors. The authors present their treatment modalities and discuss the role of ETV in the management of hydrocephalus. METHODS: The authors retrospectively reviewed the cases of 58 children who were admitted to their clinic consecutively with posterior fossa tumors between January 1999 and December 2003. Fifty-two patients presented with hydrocephalus. The mean age at the time of admission was 6 years and 3 months. The mean follow-up period was 25 months. The authors evaluated how many children required a cerebrospinal fluid (CSF) draining procedure (external ventricular drain [EVD], ventriculoperitoneal [VP] shunt, or ETV) prior to or following tumor removal. Only six patients (11.5%) required permanent treatment for hydrocephalus. Four patients received a VP shunt and two patients underwent ETV. A temporary EVD was placed in five patients (two required a shunt). Forty-six patients (88.5%) did not require a permanent CSF draining procedure. CONCLUSIONS: For children with posterior fossa tumors, ETV is not indicated as a standard operation either prior to or following tumor removal. Only six of 52 children presenting with hydrocephalus required a permanent CSF draining procedure. Endoscopic third ventriculostomy may be suitable for patients with fourth ventricle outflow obstruction and persisting or progressive hydrocephalus following tumor removal.