Amita Kamath MD, Presenter: Nothing to Disclose

Alessandro Cianfoni, Abstract Co-Author: Nothing to Disclose

William J. Powers MD, Abstract Co-Author: Nothing to Disclose

William P. Dillon MD, Abstract Co-Author: Contract, CoAxia, Inc Contract, sanofi-aventis Group Adjudicator, Actelion Ltd Research grant, General Electric Company

Tom Videen PhD, Abstract Co-Author: Nothing to Disclose

Max Wintermark MD, Abstract Co-Author: Consultant, PAION AG

Wade S. Smith MD, PhD, Abstract Co-Author: Nothing to Disclose

Bruce Finley PhD, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

As part of the Carotid Occlusion Surgery Study (COSS), patients with chronic carotid occlusive disease are selected for carotid artery bypass surgery based on the results of 15O2/H215O PET imaging. The purpose of this study was to compare the results of Perfusion-CT (PCT) with those of PET in a subset of the COSS patients.

Six patients enrolled in COSS underwent a standard-of-care PCT in addition to the PET study used for treatment decision. Relative measurement of cerebral blood flow (CBF) and oxygen extraction fraction (OEF) without arterial sampling were calculated from two PET scans, one for 15O2 inhalation and one for H215O injection. PCT datasets were processed using different arterial input functions, on the side of the carotid occlusion ("ischemic" inputs) and on the contralateral side ("nonischemic" inputs). The same sets of symmetric regions of interests were drawn on both hemispheres on matching slices from both imaging modalities (PCT and PET). Relative PCT and PET CBF values ("ischemic" side divided by "nonischemic" side) were compared using linear regression model, in order to determine the most appropriate arterial input function for PCT. As a secondary analysis, PCT values of relative CBF, cerebral blood volume (CBV) and mean transit time (MTT) using the most accurate arterial input function were evaluated for linear regression with respect to relative PET OEF/CBF values, which are used for treatment decision in COSS.

The most accurate PCT CBF maps are obtained with respect to the gold standard PET CBF, when CBF values for each arterial territory are calculated using a dedicated arterial input function within this territory ("ischemic" input function for "ischemic" territories, and "nonischemic" input function for "nonischemic" territories) (R2=0.796, p<0.001). PCT MTTxCBV product is the parameter that shows the best agreement with PET OEF/CBF values (R2=0.694, p<0.001).

PCT compares favorably to PET in patients with chronic carotid occlusion when processed appropriately.

Prospective investigations are needed to assess whether PCT can be used as an alternative to PET in selecting patients for bypass surgery.

Kamath, A, Cianfoni, A, Powers, W, Dillon, W, Videen, T, Wintermark, M, Smith, W, Finley, B, et al, , et al, , Perfusion-CT Compared to H215O/15O2 PET in Patients with Chronic Carotid Occlusive Disease.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5002457.html