Alp Dincer MD, Presenter: Nothing to Disclose

Erdem Yildiz, Abstract Co-Author: Nothing to Disclose

Memet Özek, Abstract Co-Author: Nothing to Disclose

M. Olcay Cizmeli MD, Abstract Co-Author: Nothing to Disclose

Functional analysis of third ventriculostomy patency by MRI mainly rely on demonstration of flow void in the floor of the third ventricle. The aim of this study was to determine the accuracy of various pulse sequences and whether the sequence parameters and the imaging planes influence determination of flow void.

We examined 24 patients with endoscopic third ventriculostomy by MRI. The success of the ventriculostomy was determined by clinical follow-up and confirmed by CinePC. Axial TSE T2 (5mm section thickness without flow compansation), sagittal TSE T2 (5mm section thickness with flow compansation), sagittal TSE T2 (2mm section thicknes with and without flow compansation), coronal TSE T2 (3mm section thickness with flow compansation), sagittal 3D CISS (0.5mm section thickness), sagittal CinePC, oblique CinePC parallel to the floor of the third ventricle were obtained at 3T.The flow void for all sequences is graded qualitatively.

Sagittal CinePC showed qualitatively flow at the site of ventriculostomy in all patients. The stroke volume at the site of ventriculostomy ranged from 10 mm3 to 110 mm3. Values>60 mm3, there was flow void at ventriculostomy site in all sequences and imaging planes. Values<60 mm3, 3D CISS and sagittal thick section TSE T2 and coronal TSE T2 with flow compansation occasionally demonstrated flow void. Axial TSE T2 without flow compansation, sagittal thin section TSE T2 with or without flow compansation showed flow void in all patients. But flow void was best appreciated with axial TSE T2 and sagittal thin section TSE T2 without flow compansation.

The determination of the flow void depends on not only the pulse sequences but also sequence parameters and imaging planes. Axial thick section TSE T2 and sagittal thin section TSE T2 without flow compansation are the best choices to show the patency of ventriculostomy and 3D CISS is not always neccesary for postoperative evaluation in third ventriculostomy.

TSE T2 is a reliable sequence for detecting the patency of a third ventriculostomy.But, the sequence parameters, especially section thickness, and imaging plane can influence the reliability.

Dincer, A, Yildiz, E, Özek, M, Cizmeli, M, Analaysis of Endoscopic Third Ventriculostomy Patency by MRI: Value of the Different Pulse Sequences, the Sequence Parameters and the Imaging Planes for Investigation of Flow Void.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5004754.html