Non-invasive coronary angiography by electron beam tomography: Methods and clinical evaluation in the follow-up after PTCA

Electron beam tomography (EBT) is a computed tomography technique with unique spatial and temporal resolution. The aim of the study was to establish and evaluate a protocol for the non-invasive visualization and detection of stenoses of the coronary arteries. Following phantom studies, 103 patients were investigated. Among these, 25 patients after coronary angioplasty (PTCA) were included in a prospective, blinded comparison to coronary angiography. After injection of contrast agent in a peripheral vein, 40 axial cross sections of the heart were acquired, triggered to the ECG (slice thickness 3 mm, 1 mm overlap, pixel size 0.29 x 0.29 mm). Three-dimensional reconstructions of the heart and coronary arteries were performed in the form of ''shaded surface display,'' the results were compared to coronary angiography. In the reconstructions, the proximal and mid section of the LAD was visualized in 94 % and 85 %, image quality was reduced for the right coronary artery (89 %/64 %) and left circumflex (74 %/54 %), mainly due to movement artifacts. EBT displayed a sensitivity of 100 % (9/9) for the detection of occlusions and high-grade restenoses in patients after PTCA, due to one false-positive result, specificity was 92 % (12/13). Three PTCA patients could not be evaluated due to respiration artifacts. Contrast-enhanced electron beam tomography (EBT) permits the visualization of coronary arteries and the detection of stenoses and occlusions with high sensitivity and specificity.