Ralf W. Bauer MD, Presenter: Nothing to Disclose

Josef Matthias Kerl MD, Abstract Co-Author: Nothing to Disclose

Nadine Fischer BS, Abstract Co-Author: Nothing to Disclose

Thorsten Burkhard MD, Abstract Co-Author: Nothing to Disclose

Maya Christina Larson, Abstract Co-Author: Nothing to Disclose

Thomas Josef Vogl MD, Abstract Co-Author: Nothing to Disclose

To evaluate the performance of dual energy CT (DECT) for the detection of ischemic myocardial areas during first pass arterial phase compared to MRI late enhancement (LE) in a patient collective with high prevalence of cardiovascular events.

38 patients with coronary artery bypass grafts were referred to coronary CT angiography for the assessment of bypass graft patency. Scans were performed on a dual source CT scanner (Siemens Definition) in dual energy mode with the following protocol: tube potential/current 140 kV/95 mAs on tube A and 100 kV/165 mAs on tube B, collimation 2 x 32 x 0.6 mm, 70-90 ml contrast material (400 mgI/ml) injected at 5 ml/s with a triphasic protocol. Myocardial iodine distribution was calculated from the dual energy data and superimposed on the MPR grey scale images in short axis view as a color map. Afterwards patients completed a contrast-enhanced MRI examination to detect areas with ischemic-typical late enhancement (LE) areas. The presence of LE and reduced iodine content, i.e. perfusion defects, were assessed using the AHA 17-segment model. DECT were read in consensus by two experienced radiologists who were blinded to the results of MRI.

Of totally 646 myocardial segments in 38 patients, 94 segments in 22 patients showed LE at MRI. DECT detected these ischemic areas with 65% sensitivity, 98% specificity, 83% PPV and 94% NPV. Band-like artifacts arising from the rip cage and sternal wires were the major limiting factor for the reliable use of DECT.

DECT during coronary angiographic phase for the detection of chronically ischemic myocardial areas already shows promising specificity and NPV, but further technical improvements have to be made to lower artifact load and improve sensitivity.

Coronary CTA with DECT as a “one-stop-shop” method to assess both vascular obstruction and chronic myocardial ischemia is not yet on par with dedicated established imaging modalities for the myocar

Bauer, R, Kerl, J, Fischer, N, Burkhard, T, Larson, M, Vogl, T, Dual-energy CT for the Detection of Ischemic Myocardial Areas in Patients with Chronic CAD Compared to MRI Late Enhancement.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8011490.html