Coronary Stent on Coronary CT Angiography: Assessment with Model-Based Iterative Reconstruction Technique

A sizable segment of the population will undergo coronary artery stent implantation in their lifetime. They require frequent follow-up for stent patency; hence, noninvasive, low radiation dose imaging technique to rule out in-stent re-stenosis is desirable (1). Coronary CT angiography (CCTA) has been used for this purpose, and the evaluation of larger (≥ 3 mm) coronary artery stents is considered appropriate according to current guidelines (1-7). Two recent meta-analyses demonstrate the high diagnostic value of CCTA with sensitivities and specificities > 90% when non-evaluable stents are excluded (1, 8, 9). However, these studies also confirm CCTA’s long recognized limitations of blooming artifact, which can cause a decrease in diagnostic image quality or even render studies non-diagnostic (1, 4). Therefore, it is important to reduce both noise and blooming artifact for a better quality CCTA image, in the evaluation of coronary artery stents. Improved computing power has led to the introduction of iterative reconstruction into the clinical arena, and its beneficial effects throughout the body are reported (1). Improved image quality, reduction in image noise, and the potential for radiation dose savings are demonstrated, as compared with traditional filtered back projection (FBP) (1, 10-12). Several studies showed that iterative reconstruction techniques could reduce image noise and blooming artifacts when heavy calcifications or stent are present in coronary arteries (1, 13). Adaptive statistical iterative reconstruction (ASIR) techniques are reported to significantly imCoronary Stent on Coronary CT Angiography: Assessment with Model-Based Iterative Reconstruction Technique