CCTA in patients with positive troponin and low clinical suspicion for ACS: a useful diagnostic option to exclude obstructive CAD.

PURPOSE: It is uncertain whether patients with elevated troponin and non-classical presentation of acute coronary syndrome (ACS) should receive coronary CT angiography (CCTA). A proportion of these patients will have no coronary artery disease (CAD) and would benefit from non-invasive investigations and expedited discharge. Objectives were to determine most common diagnoses and rate of ACS among patients with positive troponin and low clinical suspicion of ACS who received CCTA. METHODS: IRB approved retrospective analysis of 491 consecutive patients in a level I trauma center ED referred for CCTA between April 4, 2015 to April 2, 2017. Patients were included if there was an elevated troponin (TnI > 0.045 µg/L) and atypical chest pain within 24 h prior to imaging. One hundred one patients met inclusion criteria; 17 excluded due to technical factors or history. Scans performed on dual-source CT. RESULTS: Eighty-four patients (47 men, 37 women) with median TnI of 0.11 ± 0.21 µg/L underwent CCTA 8.20 ± 6.41 h after first elevated Tn. Mean age was 53.2 ± 14.6 years. CCTA demonstrated absence of CAD in 39 patients (46.4%; 20 M, 19 F). CAD < 25% stenosis was observed in 24 (28.6%; 9 M, 15 F). CAD with 25-50% stenosis was observed in seven (8.3%; six M, one F). CAD > 50% stenosis was observed in 11 (13.1%; 9 M, 2 F), and non-diagnostic in three (3.6%, 3 M, 0 F). Forty-six (56.8%) were discharged directly from ED with median stay 15.82 ± 6.41 h. CONCLUSIONS: Use of CCTA in ED patients with elevated troponin and low clinical suspicion for ACS allowed obstructive CAD to be excluded in 83%.

Detection of Bone Marrow Edema in Nondisplaced Hip Fractures: Utility of a Virtual Noncalcium Dual-Energy CT Application.

Purpose To quantify the sensitivity and specificity of dual-energy computed tomographic (CT) virtual noncalcium images in the detection of nondisplaced hip fractures and to assess whether obtaining these images as a complement to bone reconstructions alters sensitivity, specificity, or diagnostic confidence. Materials and Methods The clinical research ethics board approved chart review, and the requirement to obtain informed consent was waived. The authors retrospectively identified 118 patients who presented to a level 1 trauma center emergency department and who underwent dual-energy CT for suspicion of a nondisplaced traumatic hip fracture. Clinical follow-up was the standard of reference. Three radiologists interpreted virtual noncalcium images for traumatic bone marrow edema. Bone reconstructions for the same cases were interpreted alone and then with virtual noncalcium images. Diagnostic confidence was rated on a scale of 1 to 10. McNemar, Fleiss κ, and Wilcoxon signed-rank tests were used for statistical analysis. Results Twenty-two patients had nondisplaced hip fractures and 96 did not have hip fractures. Sensitivity with virtual noncalcium images was 77% and 91% (17 and 20 of 22 patients), and specificity was 92%-99% (89-95 of 96 patients). Sensitivity increased by 4%-5% over that with bone reconstruction images alone for two of the three readers when both bone reconstruction and virtual noncalcium images were used. Specificity remained unchanged (99% and 100%). Diagnostic confidence in the exclusion of fracture was improved with combined bone reconstruction and virtual noncalcium images (median score: 10, 9, and 10 for readers 1, 2, and 3, respectively) compared with bone reconstruction images alone (median score: 9, 8, and 9). Conclusion When used as a supplement to standard bone reconstructions, dual-energy CT virtual noncalcium images increased sensitivity for the detection of nondisplaced traumatic hip fractures and improved diagnostic confidence in the exclusion of these fractures. © RSNA, 2017 Online supplemental material is available for this article. An earlier incorrect version of this article appeared online. This article was corrected on March 17, 2017.