Robert Paul Götti, Presenter: Nothing to Disclose

Gudrun Feuchtner MD, Abstract Co-Author: Nothing to Disclose

Paul Stolzmann MD, Abstract Co-Author: Nothing to Disclose

Sebastian Leschka MD, Abstract Co-Author: Nothing to Disclose

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

Hatem Alkadhi MD, Abstract Co-Author: Nothing to Disclose

To evaluate the diagnostic accuracy of delayed enhancement (DE) CT in the high-pitch mode for the diagnosis of myocardial infarction (MI) and assessment of myocardial viability with MR as the standard of reference.

Twenty-four patients (22 men, age 66.9±9.2years) with coronary artery disease (CAD) underwent DE imaging with both CT and MR on the same day. CT scans were performed on a 128-slice dual-source CT system (prospective electrocardiography(ECG)-triggered acquisition; pitch 3.2; rotation time 280ms; 100kV; 320mAs). MR scans were performed on a 1.5 Tesla system (TR 7.4ms; TE 4.3ms; inversion time 200–350ms; flip angle 20°; contiguous 8mm slices). Two independent observers assessed DE transmurality per segment and measured signal intensity (MR) or attenuation (CT) and their standard deviations in infarcted and healthy myocardium as well as the left ventricular blood pool for calculation of contrast-to-noise ratios (CNR).

Interobserver agreements for the assessment of DE per segment were excellent for MR (κ=0.871) and were good for CT (κ=0.776). 75/408 (18.4%) segments in 18/24 patients (75.0%) showed DE in MR imaging, of which 28 segments (37.3%) in 10/24 patients (41.7%) were non-viable (i.e. scar tissue transmurality >50%). Sensitivity, specificity and accuracy of CT for the detection of DE were 78.7%, 96.4% and 93.1% per segment and were 100%, 83.3% and 95.8% per patient. For the detection of non-viability they were 60.7%, 96.8% and 94.4% per segment and 90.0%, 92.9% and 91.7% per patient. CNR was significantly higher (p=0.018) in MR (7.4±3.0) and image noise (11.6±5.7) significantly lower (p=0.019) as compared to CT (4.6±1.5 and 15.0±4.5, respectively). Estimated radiation dose of CT was 0.89±0.07 mSv.

In patients with CAD, DE imaging is feasible with high-pitch CT at a low radiation dose and enables the diagnosis of MI and viability assessment with a good accuracy as compared to the reference standard of MR, although associated with a lower CNR and higher noise.

Low-dose CT (<1mSv) delayed enhancement myocardial viability imaging is valuable alternative for patients with contraindications for MR imaging, associated with a good diagnostic accuracy.

Götti, R, Feuchtner, G, Stolzmann, P, Leschka, S, Frauenfelder, T, Alkadhi, H, Delayed Enhancement Imaging of Myocardial Viability: Low-Dose High-Pitch CT vs MRI.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11010723.html