Frank John Rybicki MD, PhD, Presenter: Research grant, Toshiba Corporation Technical Advisor, Toshiba Corporation Research grant, Bracco Group Technical Advisor, Bracco Group Advisory Board, Vital Images, Inc

Dimitris Mitsouras PhD, Abstract Co-Author: Nothing to Disclose

Ahmet U Coskun PhD, Abstract Co-Author: Nothing to Disclose

Michael Lally Steigner MD, Abstract Co-Author: Nothing to Disclose

Fredrick G Welt MD, Abstract Co-Author: Nothing to Disclose

Charles L Feldman DSc, Abstract Co-Author: Nothing to Disclose

Peter Howard Stone MD, Abstract Co-Author: Nothing to Disclose

Amanda Gray Whitmore BA, Abstract Co-Author: Nothing to Disclose

Jason Signorelli, Abstract Co-Author: Nothing to Disclose

Michail I Papafaklis MD, PhD, Abstract Co-Author: Nothing to Disclose

Konstantinos Koskinas MD, Abstract Co-Author: Nothing to Disclose

To determine feasibility of ESS coronary profiling using single heart beat CT angiography (CTA) compared with intravascular ultrasound (IVUS) based shear stress maps.

Single-center CTA versus IVUS coronary profiling was prospectively compared in 12 patients (thirteen arteries) scheduled for conventional angiography. Written informed consent was obtained. Coronary blood flow computer simulation used commercial computational fluid dynamics software (Phoenics, CHAM) under standard assumptions (viscosity estimated from hematocrit, zero-discharge pressure, inflow estimated from catheter angiography). Previously validated gold-standard ESS maps used lumen geometry reconstructed from IVUS and biplane angiography. 320 x 0.5 mm detector-row single R-R axial CTA was performed within 35 days of conventional angiography; lumen geometry was obtained with commercial software for the identical coronary segments that underwent IVUS. CTA profiling used blood flow simulation parameters from IVUS. Relative “low” ESS regions were defined as areas with the lowest 10% of ESS values over at least 3 mm length plus 5 mm2 endothelium surface area. True positive (TP) CT ESS regions were defined by overlap with IVUS based low regions; false positive (FP) CT ESS regions had no overlap with IVUS. A false negative (FN) CT ESS region was defined when no low ESS area from CT matched a low ESS region identified by IVUS; true negative (TN) regions had no low ESS for either modality. Coronary segments with stents or post-angioplasty were excluded.

Gold standard IVUS and biplane angiography identified 27 low ESS regions that spanned 23% of the total arterial length. There were 19 TP, 8 FP, 28 TN, 8 FN; prevalence 0.43 (95%CI 0.31-0.56). 320-detector row CT coronary profiling had a sensitivity = 0.70 (95%CI 0.50-0.86) and a specificity = 0.78 (95%CI 0.60-0.89).

Based on comparison with validated IVUS and catheter-based coronary profiling, relative ESS mapping using wide area detector CT is feasible. The advantage with respect to IVUS is a noninvasive approach that includes the entire coronary tree.

Whole heart ESS vascular profiling can potentially complement clinical data currently obtained from coronary CTA; feasibility of CT ESS maps supports future work to increase accuracy. 

Rybicki, F, Mitsouras, D, Coskun, A, Steigner, M, Welt, F, Feldman, C, Stone, P, Whitmore, A, Signorelli, J, Papafaklis, M, Koskinas, K, Coronary Artery Profiling Using Endothelial Shear Stress (ESS) Estimated from Single Heart Beat 320 x 0.5 mm Detector-Row CT Angiography.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9004899.html