Etienne Ketelslegers | PubMed Health

PubMed2005

Urinary calculi: improved detection and characterization with thin-slice multidetector CT.

The aim of this study was to assess the effect of reconstructed slice thickness on the detection and characterization of human urinary calculi on a multidetector helical CT scanner. Nineteen human urinary calculi of various chemical composition measuring 1.0-3.7 mm were embedded into agar in a chamber of a nylon body phantom. The phantom was imaged with a four detector-row CT scanner. The number of detected calculi increased as the reconstructed slice thickness decreased. Measured diameters and density of the visible calculi decreased as the slice thickness increased. The results of the present study support the use of thin reconstructed slices to detect and characterize urinary calculi.

Humans↗

PubMed2004

Coronary artery stenosis: direct comparison of four-section multi-detector row CT and 3D navigator MR imaging for detection--initial results.

PURPOSE: To prospectively compare the diagnostic accuracy of multi-detector row computed tomography (CT) and of three-dimensional (3D) navigator magnetic resonance (MR) imaging in patients referred for conventional coronary angiography for detection of coronary artery stenosis. MATERIALS AND METHODS: All patients gave written informed consent for the study, which was approved by the local ethics committee. Twenty-seven patients underwent multi-detector row CT and 3D navigator free-breathing MR imaging a mean of 5 days before undergoing invasive coronary angiography. The acquired multi-detector row CT and MR images were graded for the presence of greater than 50% stenosis in vessels larger than 1.5 mm in diameter. The diagnostic accuracies of the two examinations were compared with that of quantitative coronary angiography (QCA) by using the McNemar test. RESULTS: Owing to claustrophobia, MR images were not acquired in one patient; thus, 26 patients were included for analysis. According to QCA findings, 21 of the 26 patients had significant coronary artery disease and 58 (20%) of a total of 294 coronary artery segments larger than 1.5 mm in diameter had significant (>50%) stenosis. Multi-detector row CT had significantly higher sensitivity (46 [79%] of 58 segments) than MR imaging (36 [62%] segments, P < .05) for detection of segments with significant stenosis. Conversely, MR imaging had significantly higher specificity (198 [84%] of 236 segments) than did CT (168 [71%] segments, P < .001) for exclusion of segmental coronary artery stenosis. Both examinations had high negative predictive value for exclusion of segmental stenosis: 93% (168 of 180 segments) for CT and 90% (198 of 220 segments) for MR imaging. The overall diagnostic accuracy of MR imaging (80% [234 of 294 segments]) was significantly higher than that of CT (73% [214 segments], P < .05). CONCLUSION: MR imaging had significantly higher diagnostic accuracy than multi-detector row CT in the evaluation of coronary artery stenosis. Both techniques have high negative predictive value, making them particularly useful for ruling out coronary artery disease in symptomatic patients.

Adult↗

PubMed2001

Validation of the Ottawa knee rules in an emergency teaching centre.

Our objective was to determine the value of the Ottawa knee rules when applied by users with different levels of clinical training. We used a prospective patient survey by the medical students and surgery residents of a European university trauma centre. The study group consisted of 261 eligible patients who presented with acute knee trauma during a 6-month period. Radiography or follow-up was obtained for each patient. Data were separately analysed according to the degree of qualification of the initial examiner. The Ottawa knee rules had a sensitivity and a negative predictive value of 1.00. Variable degree of medical competence of the users did not alter the accuracy of the rules. Application of the rules would have reduced knee radiography requests by 25%. The Ottawa knee rules remain highly sensitive when applied by medical users with different levels of qualification, such as encountered in a teaching setting.

Adolescent↗