Ultra-high-resolution coronary ct angiography for assessment of patients with severe coronary artery calcification: Initial experience

Purpose: Conventional CT technology yields only modest accuracy of coronary artery stenosis assessment in severely calcified lesionReported herein are this study’s initial observations on the potential of ultra-high-resolution CT (UHR-CT) for evaluating severely calcified coronary arterial lesions. Materials and Methods: Fifteen patients 45 years of age or older, with history of coronary artery disease, referred for invasive coronary angiography, were prospectively enrolled. Patients underwent UHR-CT within 30 days prior to cardiac catheterization. Image noise levels and diagnostic confidence (level 1–5) using UHR-CT were compared with reconstructed images simulating conventional CT technology. Stenosis assessment for the major coronary arteries and the left main coronary artery with UHR-CT and invasive angiography were compared. Results from clinically driven coronary CT using conventional technology were considered for comparison when available. Results: Mean patient age was 67 years (range, 53–79 years). Thirteen patients were men, nine had obesity. Radiation dose was 9.3 mSv owing to expanded x-ray exposure to accommodate research software application (70%–99% of R-R cycle). Overall image noise was considerably greater for UHR-CT (50.9 6 7.8 [standard deviation]) versus conventional CT image reconstruction (19.5 6 8.3, P, .01), yet diagnostic confidence scores for UHR-CT were high (4.3 6 0.9). Average calcium score in patients without stents (n = 6) was 1205, and of 86 vessels evaluated, 22 had 70% or greater stenosis depicted with invasive angiography (26%). Stenosis comparison with invasive angiography yielded 86% (19 of 22) sensitivity and 88% (56 of 64) specificity (95% CI: 65%, 97%; and 77%, 95%, respectively). Conclusion: Initial observations suggest UHR-CT may be effective in overcoming the limitation of conventional CT for accuratelevaluating coronary artery stenoses in severely calcified vessels.