CSF flow imaging in the management of third ventriculostomy with a reversed fast imaging with steady-state precession sequence.

The aim of this study was evaluation of a fast and slow-flow sensitive 2D steady-state free-precession sequence for its capability to prove the patency of endoscopic third ventriculostomy (TVS) in obstructive hydrocephalus, and to exclude communicating third ventricle prior to TVS. We compared gated and ungated variants of this sequence for this purpose. Twenty-three patients with obstructive hydrocephalus underwent 36 MR examinations with a 2D reversed fast imaging with steady-state precession (PSIF) sequence in a retrospectively cardiac gated (cine) and a faster but ungated version beside T1- and T2-weighted sequences in three planes. Thirteen patients were examined both before and after TVS, 4 patients solely before, and 6 patients solely after TVS. Imaging diagnoses were compared with intraoperative findings and clinical findings after TVS. Preoperative diagnosis of non-communicating third ventricle and cisterns was intraoperatively confirmed in 16 of 17 cases. Preoperative MRI was inconclusive in 1 case. Postoperative MRI revealed sufficient TVS in 16 of 19 cases and obstructed TVS in 3 of 19 cases due to several reasons. Findings at MRI were consistent in 19 of 19 cases with the clinical course and intraoperative results. The faster but ungated PSIF sequence was found to be diagnostically equivalent to the cardiac gated cine sequence. The CSF flow imaging with a 2D reversed fast imaging with steady-state precession sequence in conjunction with conventional T1- and T2-weighted images is a fast and reliable tool for pre- and postoperative functional evaluation in third ventriculostomy.