ABSTRACT
A comprehensive whole-body approach to noninvasive evaluation of coronary and extracoronary vasculature is currently not available. The objective of our study was to assess the potential of 64-slice computed tomography angiography (64-CTA) for whole-body evaluation of atherosclerosis burden. Seventy-eight patients referred for coronary imaging underwent whole-body 64-CTA using an adjusted strategy for the administration of contrast medium with dose-saving algorithms involving ECG modulation and reduced tube voltage. Arterial segments (15 coronary, 32 systemic) were evaluated for significant (> or =50%) steno-occlusive disease while arterovenous density was evaluated at seven extracoronary locations. Homogeneous attenuation (mean 321 +/- 20 HU) was obtained throughout the systemic vasculature. Atherosclerosis was observed in 238/995 (24%) coronary and 368/2441 (15%) systemic segments. Significant stenoses/occlusions were present in 214 (21%)/24 (2.5%) coronary segments while asymptomatic clinically relevant stenoses were present in 49 systemic segments. Sensitivity, specificity, positive and negative predictive values of coronary 64-CTA among 52 patients who also underwent quantitative coronary angiography were 92%, 95%, 81% and 98%, respectively. ECG modulation decreased radiation exposure to 14.1-15.4 mSv per patient. Comprehensive, noninvasive assessment of atherosclerosis can be performed by whole-body 64-CTA and may have a positive impact on secondary prevention.
Subject(s)
Angiography/methods , Atherosclerosis/diagnostic imaging , Radiographic Image Interpretation, Computer-Assisted/methods , Tomography, X-Ray Computed/methods , Whole Body Imaging/methods , Feasibility Studies , Female , Humans , Male , Radiographic Image Enhancement/methods , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
To evaluate the performance of a computer-aided detection (CAD) algorithm in the detection of pulmonary nodules on high-resolution multidetector row computed tomography images in a large, homogeneous screening population, and to evaluate the effect of the system output on the performance of radiologists, using receiver operating characteristic analysis. Three radiologists with variable experience (1 to 7 y), independently read the 200 computed tomography scans and assigned each nodule candidate a confidence score (1-2-3: unlikely, probably, and definitely a nodule). CAD was applied to all scans; successively readers reevaluated all findings of the CAD, assigning, in consensus, a confidence score (1 to 3). The reference standard was established by the consensus of 2 experienced radiologists with 30 and 15 years of experience. Results were used to generate an free-response receiver operating characteristic analysis. The reference standard showed 125 nodules. Sensitivity for readers I-II-III was 57%, 68%, and 46%. A double reading resulted in an increase in sensitivity up to 75%. With CAD, sensitivity was increased to 94%, 96%, and 94% for readers I, II, and III. The area under the free-response receiver operating characteristic curve (Az) was 0.72, 0.82, 0.55, and 0.84 for readers I, II, III, and the CAD, when considering all nodules. Differences between readers I-II and CAD were not significant (P=0.9). There was a significant difference between reader III and the CAD. For nodules <6-mm Az was 0.40, 0.47, 0.14, and 0.72 for readers I, II, III, and the CAD. Differences between all readers and the CAD were significant (P<0.05). CAD can aid in daily radiologic routine detecting a substantial number of nodules unseen by radiologists. This is true for both board-certified radiologists and for less experienced readers especially in the detection of small nodules.
