Endoscopic third ventriculostomy associated 3D-construcive inference steady state MRI for obstructed hydrocephalus: A retrospective study

Abstract

BackgroundEndoscopic third ventriculostomy (ETV) is a developing therapeutic stratagem for obstructive hydrocephalus (OH). The aim of this study was to determine the relevance of third ventricle diagnostic imaging by three-dimensional constructive inference in steady state (3D CISS) MRI in patients with OH and to access the preoperative and postoperative values of this technique in patients undergoing endoscopic third ventriculostomy (ETV). MethodsForty-six patients with an existing obstruction below the posterior part of the third ventricle underwent 3D CISS sequence MRI on a 1.5T superconductive MR scanner and were included into this retrospective study. 19 patients were treated with ETV. Regression analysis of the correlation between third ventricle enlargement (TVE) and hydrocephalus degree (HD) and between TVE and third ventricle floor thickness (TVFT) was calculated. In the 19 ETV cases the incisions were marked according to MR images, and the 3D-CISS sequence imaging and the surgical outcome were compared before and after ETV. ResultsBy virtue of 3D-CISS 97.83% third ventricle floors and 91.30% basilar arteries (BA) could be visualized, and there was a positive correlation between TVE and HD and a negative correlation between TVE and TVFT in this group. All incision sites on the scalp could be marked correctly. The degree of enlargement of the third ventricle allowed a prediction of the technical challenge to puncture the third ventricle floor. The position and route of BA could be demonstrated avoiding intraoperative iatrogenic lesions. At follow-up, 100% of the fistulas of the third ventricle floor could be measured on 3D-CISS images. The mean diameter of the fistulas was 6.12±0.96mm; in 91.67%, new CSF fluid directions could be demonstrated; in 83.33%, enlarged ventricle system got withdrawn, and 91.67% patients showed relief of initial symptoms. 1 patient needed the implantation of a ventriculoperitoneal shunt 7 months after EVT. The preoperative HD compared with postoperative HD (P<.01); the preoperative TVE compared with postoperative TVE (P<.05). ConclusionImages of the 3D-CISS sequence on MRI can visualize the third ventricle accurately and provide a reliable method for the evaluation of ETV pre- and postoperatively. The degree of enlargement of the third ventricle in patients with obstructive hydrocephalus is associated with the thickness of third ventricle floor and allows a prediction of the difficulty to puncture in ETV.