Learning curve for coronary CT angiography: what constitutes sufficient training?

PURPOSE: To prospectively evaluate the effect of experience with coronary computed tomographic (CT) angiography on the capability to detect coronary stenoses of 50% or more. MATERIALS AND METHODS: The institutional review board approved the study protocol. All patients gave consent to undergo CT angiography before conventional coronary angiography after being informed of the additional radiation dose. They also consented to the use of their data for future research. Three radiologists and one cardiologist inexperienced with coronary CT angiography attended this institution's cardiac CT unit for a 1-year fellowship. Fellows were involved in the acquisition and reading of 12-15 coronary CT angiograms per week (about 600 per year). To assess the progression in diagnostic performance, fellows (readers) independently read 50 CT angiographic test cases in patients who also underwent conventional coronary angiography. Cases were repeatedly assigned in random order at baseline and at 4, 8, 26, and 52 weeks. The same cases were examined by two experts in consensus. Sensitivity, specificity, and diagnostic odds ratios (DORs) were calculated and compared with conventional coronary angiography as the reference standard. RESULTS: Respective reader ranges for sensitivity, specificity, and DOR were 33%-72%, 70%-94%, and 3.8-8.1 at baseline; 43%-80%, 71%-88%, and 8.8-15.2 after 6 months; and 66%-75%, 87%-92%, and 14.7-25.8 after 1 year. For expert physicians, respective results were 95%, 93%, and 255.9. Between baseline and 6 months, readers 1-3 showed nonsignificantly improved sensitivities, while specificities remained similar. Reader 4 showed significantly improved specificity, while sensitivity remained similar; all readers nonsignificantly improved DORs. Between baseline and 1 year: readers 1 and 2 significantly improved sensitivity but not specificity; reader 4 significantly improved specificity but not sensitivity; readers 1, 2, and 4 improved DOR significantly; reader 3 nonsignificantly improved sensitivity, specificity, and DOR. CONCLUSION: Increasing experience with coronary CT angiography improved the diagnostic performance of inexperienced physicians. However, acquiring expertise in coronary CT angiography was slow and may take more than 1 year.

Coronary computed tomography angiography in patients after percutaneous coronary intervention (PCI): focus on post-processing and visualization techniques.

UNLABELLED: Coronary stent imaging with computed tomography is challenging because of high-density artifacts. However, noninvasive coronary angiography with computed tomography is gaining acceptance as a valid alternative to cardiac catheterization in a broader array of clinical settings, and the work-up of patients after coronary stent implantation represents an application of pressing clinical utility. Only a minority of patients who develop recurrent chest pain after stent implantation have myocardial ischemia, thus a sensitive noninvasive study is desirable. With an awareness of the limitations of the technique, the systematic application of dedicated strategies of data post-processing and display techniques permits partial compensation of the technical limitations brought about by metallic struts. ADVANCES IN KNOWLEDGE: 1. The role of coronary computed tomography angiography in the diagnostic work-up of patients with symptoms after stent placement 2. Systematization of post-processing, display, and review techniques for optimal evaluation of coronary stents with coronary computed tomography angiography. SUMMARY STATEMENT: The follow-up of patients after coronary stenting is an appealing but challenging application of coronary computed tomography angiography. The presence of intrinsic limitations requires the use of dedicated post-processing and visualization techniques.

Prevalence of anatomical variants and coronary anomalies in 543 consecutive patients studied with 64-slice CT coronary angiography.

The aim of our study was to assess the prevalence of variants and anomalies of the coronary artery tree in patients who underwent 64-slice computed tomography coronary angiography (CT-CA) for suspected or known coronary artery disease. A total of 543 patients (389 male, mean age 60.5 +/- 10.9) were reviewed for coronary artery variants and anomalies including post-processing tools. The majority of segments were identified according to the American Heart Association scheme. The coronary dominance pattern results were: right, 86.6%; left, 9.2%; balanced, 4.2%. The left main coronary artery had a mean length of 112 +/- 55 mm. The intermediate branch was present in the 21.9%. A variable number of diagonals (one, 25%; two, 49.7%; more than two, 24%; none, 1.3%) and marginals (one, 35.2%; two, 46.2%; more than two, 18%; none, 0.6%) was visualized. Furthermore, CT-CA may visualize smaller branches such as the conus branch artery (98%), the sinus node artery (91.6%), and the septal branches (93%). Single or associated coronary anomalies occurred in 18.4% of the patients, with the following distribution: 43 anomalies of origin and course, 68 intrinsic anomalies (59 myocardial bridging, nine aneurisms), three fistulas. In conclusion, 64-slice CT-CA provides optimal visualization of the variable and complex anatomy of coronary arteries because of the improved isotropic spatial resolution and flexible post-processing tool.