Ronen Rubinshtein MD, Presenter: Fellowship funded, Koninklijke Philips Electronics NV

Tamar Gaspar MD, Abstract Co-Author: Nothing to Disclose

Sara Gips MD, Abstract Co-Author: Nothing to Disclose

Maya Mor MD, Abstract Co-Author: Nothing to Disclose

David Anthony Halon MBChB, Abstract Co-Author: Nothing to Disclose

Nathan Peled MD, Abstract Co-Author: Nothing to Disclose

SPECT is a highly sensitive technique to detect myocardial perfusion abnormalities and for prognostic stratification in a wide range of patient populations. However, the significance of mild reversible perfusion defects (RPD) is less clear. Multidetector cardiac CT (MDCT) is a reliable tool for the non-invasive imaging of coronary stenosis. We utilized MDCT to examine the prevalence of significant stenosis in coronary arteries supplying myocardial territories with low grade RPD on SPECT.

We examined 51 symptomatic pts [60.1±11.2 yrs, 21 (41%) female] undergoing both 64-slice MDCT (Brilliance 64, Philips) and SPECT dual-isotope imaging (39 exercise, 12 dypiridamole). Fourteen pts had a prior history of myocardial revascularization. SPECT analysis was performed using a 17-segment model and findings graded visually into grade 0 (normal), grades 1-3 (slightly/moderately/significantly reduced uptake respectively) and grade 4 (fixed defect). Pts with Grade 1 RPD (slightly reduced uptake) were then evaluated for the presence of significant coronary stenosis on MDCT (>50%) in the relevant vascular territory. Reliability of MDCT data was confirmed with invasive angiography when available.

The study included 41 coronary vascular territories (in 29 pts) with grade 1 RPD. Eleven (27%) vascular territories [in 10 (34%) pts] were associated with a corresponding obstructive (>50%) coronary stenosis on MDCT. Invasive coronary angiography was subsequently performed in 7/10 pts and confirmed significant stenosis in 7/8 vessels found to be stenotic on MDCT (in 6/7 pts, 1 false positive stenosis on MDCT). In the remaining 30 vascular territories with no obstructive stenosis on MDCT and Grade 1 RPD, 16 had non-obstructive atheroma.

1. MDCT excluded obstructive coronary narrowing in two thirds of patients (73% vascular territories) with grade 1 RPD on SPECT. 2. MDCT was a useful tool for further assessment of patients with indeterminate SPECT findings. 3. The relevance of anatomically non-obstructive atheroma to mild perfusion defects on SPECT requires further physiological assessment.

Coronary CT Angiography is a useful tool to assess patients with indeterminate SPECT findings.

Rubinshtein, R, Gaspar, T, Gips, S, Mor, M, Halon, D, Peled, N, Sixty-Four-slice Cardiac CT is a Helpful Tool to Assess Low Grade Reversible Perfusion Defects in Patients Undergoing Single-Photon Emission Computed Tomography (SPECT).  Radiological Society of North America 2006 Scientific Assembly and Annual Meeting, November 26 - December 1, 2006 ,Chicago IL. http://archive.rsna.org/2006/4431331.html