Srikanth Suryanarayanan PhD, Abstract Co-Author: Nothing to Disclose

Sudhakar N. Pipavath MD, Abstract Co-Author: Nothing to Disclose

Arjun Kalyanpur MD, Presenter: Nothing to Disclose

Nadeem Ahmed MD, Abstract Co-Author: Nothing to Disclose

Yogish Mallya MS, Abstract Co-Author: Nothing to Disclose

To study the clinical utility of bone-free 3-D volume rendering of CTA Neuro vasculature. Evaluate presentation of individual vessel segments and assessment of pathologies such as aneurysms and AVMs.

Study included 20 anonymized CTA head (circle of Willis) data sets from various MDCT scanners (GE Healthcare). The radiologists used Volume Viewer of Advantage Windows (AW) Workstation (GE Healthcare) to launch a prototype automatic bone segmentation algorithm that took 30 s per case for a COW data set of size 512 x 512 x 200 to remove bone. Radiologists evaluated each case using the Volume Rendering and Maximum Intensity Projection (MIP) modes. The opacity map (for VR) and the Window/Level (for MIP) settings were adjusted for optimal rendering of each case. The head volume was broken up into several components based on anatomy and the prevalence of corresponding pathology. Each component was rated for clarity of anatomy, residual bone interference, and confidence in assessing pathology based on the ability of the 3D reconstructions to provide the required information. Ratings were based on a 1-5 scale, 5 representing the best rating with the radiologist completely interpreting each segment from the 3-D. Rating was downgraded when the radiologist was required to refer to the source images and found evidence of missing vessel segments or bone fragments at critical anatomical locations.

The right and left circulation component was rated 3.6 (0.7) and the posterior circulation was rated 3.9 (0.7). Aneurysms were rated 3.3 (1.5) based on the presentation of the neck and orientation. AVMs rated 3.5 based on the presentation of the draining veins. The ICA bifurcation and MCA segments (with aneurysms) were rated very well across the cases (4.5+/-0.53). Radiologists reported difficulty in evaluating hypoplastic segments (typically PCOM) from 3-D and managing vessel clutter at COW.

Bone free 3-D volume rendering of CTA Vasculature using an automated algorithm gives good anatomic detail and assessment of the pathology. It can be an excellent noninvasive road map for interventional radiologists and neurosurgeons in treatment of vascular malformations.

Suryanarayanan, S, Pipavath, S, Kalyanpur, A, Ahmed, N, Mallya, Y, Clinical Value of Bone-free 3-D Volume Rendering of CTA for Examining Neuro Anatomy and Pathology.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4413342.html