Rozemarijn Vliegenthart MD, PhD, Presenter: Nothing to Disclose

Markus Weininger MD, Abstract Co-Author: Nothing to Disclose

Thomas Henzler MD, Abstract Co-Author: Nothing to Disclose

Matthys Oudkerk MD, PhD, Abstract Co-Author: Nothing to Disclose

Gorka Bastarrika MD, Abstract Co-Author: Speaker, Bayer AG Speaker, General Electric Company Speaker, Siemens AG

U. Joseph Schoepf MD, Abstract Co-Author: Speakers Bureau, Bayer AG Speakers Bureau, Siemens AG Medical Advisory Board, Bayer AG Research grant, Bayer AG Research grant, Bracco Group Research grant, General Electric Company Research grant, Siemens AG

To compare perfusion characteristics at dynamic myocardial perfusion CT imaging of ischemic and infarcted versus normal myocardium.

Thirty patients with a rest-stress SPECT underwent rest-stress perfusion cardiac MRI and dynamic adenosine-stress myocardial perfusion imaging on a 2nd generation dual-source CT scanner. The study was IRB approved; informed patient consent was obtained. CT data were acquired every other cardiac cycle, with the table shuttling back and forth between two positions during image acquisition. A color-coded CT perfusion map was derived with semi-automated analysis software on an image processing workstation. This study included the 15 patients (11 male; mean age±standard deviation, 61±7 years) with a myocardial perfusion defect (PD) on MRI and/or SPECT. The CT perfusion map was evaluated for presence of PD, corresponding to the PD on MRI and/or SPECT. A region of interest was selected in the PD as well as in a healthy control segment 180º from the PD. Perfusion characteristics were determined and compared for the PD, the control segment, and the entire myocardium, using paired, two-tailed t tests.

Mean dose-length product for the dynamic perfusion CT study was 675±143 mGy*cm. Eleven patients had a myocardial infarct (2 with peri-infarct ischemia), and 4 showed reversible ischemia on MRI and/or SPECT. On the CT perfusion maps, a corresponding PD was detected in all patients. Mean blood flow of the PD was 60±12 ml/min/100g, lower than that of the entire myocardium and of the control segment (131±34 and 143±26 ml/min/100g; p<0.001). Peak CT enhancement within the PD was reduced compared to the entire myocardium and the control segment (29.2±8.7 versus 47.5±12.7 and 57.7±11.9 Hounsfield Units (HU); p<0.001). Time-to-peak enhancement was longer for the PD compared to the entire myocardium and the control segment (12.8±1.9 versus 11.5±1.2 and 11.6±2.1 s; p<0.05 compared with entire myocardium). Peak CT enhancement was lower for infarcts than for ischemic zones (26.5 ± 6.6 HU for infarct versus 36.8±10.2 HU for ischemic zone; p<0.05).

Dynamic stress myocardial CT perfusion imaging identifies areas of abnormal flow reserve and infarction with a high degree of correlation to SPECT and MRI.

On dynamic stress myocardial CT perfusion imaging ischemic and infarcted zones can be distinguished from normal myocardium based on quantitative parameters of myocardial perfusion.

Vliegenthart, R, Weininger, M, Henzler, T, Oudkerk, M, Bastarrika, G, Schoepf, U, Comparison of Perfusion Characteristics of Normal, Ischemic, and Infarcted Myocardium at Dynamic Myocardial Perfusion CT.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11007938.html