Methodology for improved detection of coronary stenoses with computed tomographic angiography

Noninvasive angiography is a promising technique for visualization of the coronary lumen; however, current methodologies lead to limited accuracy. We assessed the accuracy of electron beam computed tomographic angiography (EBA) for detection of coronary stenoses, using improved triggering techniques and thinner slice collimation.

Eighty-six patients with suspected coronary disease were studied with EBA and conventional invasive coronary angiography. Electrocardiographic triggering was performed at a fixed time in end systole to reduce cardiac motion. Thin (1.5 mm) slices were obtained with 1.5 mm table incrementation. In axial (2-dimensional) EBA images and 3-dimensional reconstructions, all coronary arteries and side branches with a diameter of >or=1.5 mm were assessed for the presence of stenoses with >50% diameter reduction. Both EBA and invasive angiographic images were assessed in a blinded manner.

In comparison to invasive coronary angiography, EBA correctly classified 49 of 53 patients (92%) as having at least 1 coronary stenosis. Overall, 103 stenoses with >50% diameter reduction were present, and 93 of these lesions were correctly detected by EBA (sensitivity 90%, specificity 93%, positive predictive value 84%, and negative predictive value 96%). Only 5% of vessels could not be assessed, predominantly due to significant calcification.

Thinner slice collimation and end-systolic electrocardiographic triggering improves accuracy and assessment of coronary EBA for the detection of obstructive coronary artery disease, making this study clinically useful in the evaluation of obstructive coronary artery disease.