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PURPOSE: Recent studies have shown the feasibility of dual-energy CT (DECT) virtual non-contrast (VNC) for determining infarct extent. In this study, patients presenting with large-vessel occlusion (LVO) acute ischemic stroke (AIS), we assess whether ASPECTS on DECTA-VNC differs from non-contrast CT (NCCT). METHODS: After IRB approval, LVO-AIS patients undergoing NCCT and DECTA between October 2016 and September 2018 were retrospectively reviewed. DECTA-VNC images were derived using Syngo.via (Siemens, Erlangen, Germany). ASPECTS was scored by two blinded neuroradiologists. Square-weighted kappa statistic, diagnostic performance, Wilcoxon signed-rank tests between groups, and CT doses were calculated. RESULTS: Fifty-one patients met inclusion criteria, with median age of 76 (IQR 67-82); 26/51 (51%) were female. Median time between last-known-well and CT was 120 min (IQR 60-252). DECTA-VNC ASPECTS score differed by ≤ 1 from consensus NCCT in 49/51 (96%) patients for reader 1 and in 46/51 (90%) for reader 2. ASPECTS on DECTA-SI and consensus NCCT differed by ≤ 1 in 45/51 (88%) for both readers. On a per ASPECTS-region basis, DECTA-VNC had 87% sensitivity, 95% specificity, 0.82% PPV, and 0.96% NPV. ASPECTS inter-rater agreement was highest for DECTA-VNC (κ = 0.71), DECTA-SI (κ = 0.48), and NCCT (κ = 0.40). NCCT median CTDIvol was 63.7 mGy (IQR 60.7-67.2); DLP was 1060.0 mGy·cm (IQR 981.0-1151.5). DECTA-VNC dose was lower: median CTDIvol was 20.9 mGy (IQR 19.8-22.2); DLP was 804.1 (IQR 691.6-869.4), p < 0.0001. CONCLUSION: DECTA-derived VNC yielded similar ASPECTS scores as NCCT and is therefore non-inferior in early ischemia-related low attenuation edema/infarct detection in acute LVO-AIS patients. Further evaluation of the role of DECTA-VNC in AIS imaging is warranted.

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STUDY DESIGN: Diagnostic accuracy study. OBJECTIVE: To evaluate the diagnostic accuracy of the Thessaly test compared with an arthroscopic examination in patients with suspected meniscal tears. BACKGROUND: The Thessaly test was introduced to improve the diagnostic accuracy of the clinical examination in detecting meniscal tears. This test appears to be a valuable alternative to other meniscal clinical tests usually performed, but additional diagnostic accuracy data are required. METHODS: Patients with suspected meniscal tears, referred to a hospital for arthroscopic surgery, were eligible. The Thessaly test alone and the combination of the Thessaly and McMurray tests were considered as index tests, and arthroscopy was used as the reference test. Experienced physical therapists performed the Thessaly test at 20° of flexion and the McMurray test for both knees. The physical therapist was blinded to patient information, the affected knee, and the results from possible earlier diagnostic imaging. An orthopaedic surgeon blinded to the clinical test results from the physical therapist performed the arthroscopic examination. RESULTS: A total of 593 patients were included, of whom 493 (83%) had a meniscal tear, as determined by the arthroscopic examination. The Thessaly test had a sensitivity of 64% (95% confidence interval [CI]: 60%, 68%), specificity of 53% (95% CI: 43%, 63%), positive predictive value of 87% (95% CI: 83%, 90%), negative predictive value of 23% (95% CI: 18%, 29%), and positive and negative likelihood ratios of 1.37 (95% CI: 1.10, 1.70) and 0.68 (95% CI: 0.59, 0.78), respectively. The combination of positive Thessaly and McMurray tests showed a sensitivity of 53% and specificity of 62%. CONCLUSION: The results of the Thessaly test alone or combined with the McMurray test do not seem useful to determine the presence or absence of meniscal tears. LEVEL OF EVIDENCE: Diagnosis, level 2b.

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