Analysis of endoscopic third ventriculostomy patency by MRI: value of different pulse sequences, the sequence parameters, and the imaging planes for investigation of flow void.

PURPOSE: The aim of the study is to evaluate the efficiency of turbo spin-echo (TSE), three-dimensional constructive interference in the steady state (3D CISS) and cine phase contrast (Cine PC) sequences in determining flow through the endoscopic third ventriculostomy (ETV) fenestration, and to determine the effect of various TSE sequence parameters. MATERIALS AND METHODS: The study was approved by our institutional review board and informed consent from all patients was obtained. Two groups of patients were included: group I (24 patients with good clinical outcome after ETV) and group II (22 patients with hydrocephalus evaluated preoperatively). The imaging protocol for both groups was identical. TSE T2 with various sequence parameters and imaging planes, and 3D CISS, followed by cine PC were obtained. Flow void was graded as four-point scales. The sensitivity, specificity, accuracy, positive and negative predictive values of sequences were calculated. RESULTS: Bidirectional flow through the fenestration was detected in all group I patients by cine PC. Stroke volumes through the fenestration in group I ranged 10-160.8 ml/min. There was no correlation between the presence of reversed flow and flow void grading. Also, there was no correlation between the stroke volumes and flow void grading. The sensitivity of 3D CISS was low, and 2 mm sagittal TSE T2, nearly equal to cine PC, provided best result. CONCLUSION: Cine PC and TSE T2 both have high confidence in the assessment of the flow through the fenestration. But, sequence parameters significantly affect the efficiency of TSE T2.

A standardisable model of focal cerebral ischaemia innormotensive rats.

In this study various techniques with different periods of ischaemia have been used in order to describe a standardisable and reproducible model of reversible focal cerebral ischaemia in normotensive rats. Cerebral blood flow to the left hemisphere of the rats was temporarily interrupted by middle cerebral artery occlusion only in four rats of each group, by simultaneous middle cerebral artery and ipsilateral common carotid artery occlusion in six rats of each group, and by middle cerebral artery and bilateral common carotid artery occlusion in six rats of each group. Within each group temporary ischaemia lasted for 1, 2 or 3 h and animals survived for 24 h following reperfusion. An infarct of significant size with low standard deviation was observed after 3 h of distal middle cerebral artery and bilateral common carotid artery occlusion followed by 24 h of reperfusion. We have found that the ratio of the infarct volume to the supratentorial brain volume is a more reliable criterion (with less standard deviation) than infarct volume alone and could be used for comparison of results obtained in experimental studies.

Congenital pineoblastoma and parameningeal rhabdomyosarcoma: concurrent two embryonal tumors in a young infant.

BACKGROUND: Pineoblastomas are very rare brain tumors in fetus and neonates, comprising only 0.9% of congenital brain tumors. The occurrence of multiple tumors of different histopathologic types in the same individual is a rare event, most often encountered in hereditary cancer syndromes. CASE REPORT: We report a female fetus presented with a congenital pineoblastoma at the 32nd week of gestation, with hydrocephalus and concurrent parameningeal embryonal rhabdomyosarcoma in early infancy. RESULTS: Cytogenetic analysis showed normal karyotype in the peripheral blood of the patient, and p53 mutational analysis revealed no germ line mutations. DISCUSSION: This is the first case with concurrent congenital pineoblastoma and parameningeal embryonal rhabdomyosarcoma in early infancy. We suggest that concurrence of these tumors could be due to mutations in other tumor suppressor genes or secondary to exposure to unknown in utero factors.