38 research outputs found
The accuracy of Multi-detector row CT for the assessment of tumor invasion of the mesorectal fascia in primary rectal cancer
PURPOSE: To evaluate the accuracy of Multi-detector row CT (MDCT) for the prediction of tumor invasion of the mesorectal fascia (MRF). MATERIALS AND METHODS: A total of 35 patients with primary rectal cancer underwent preoperative staging magnetic resonance imaging (MRI) and MDCT. The tumor relationship to the MRF, expressed in 3 categories (1--tumor free MRF = tumor distance > or = 1 mm; 2--threatened = distance < 1 mm; 3--invasion = distance 0 mm) was determined on CT by two observers at patient level and at different anatomical locations. A third expert reader evaluated the MRF tumor relationship on MRI, which served as reference standard. Receiver operating characteristic curves (ROC-curves) and areas under these curves (AUC) were calculated. The inter-observer agreement of CT was determined by using linear weighted kappa statistics. RESULTS: The AUC of CT for MRF invasion was 0.71 for observer 1 and 0.62 for observer 2. The inter-observer agreement was kappa = 0.34. The performance of CT at mid-high rectal levels was statistically significant better compared to low anterior (obs.1: AUC = 0.88 vs. 0.50; obs 2: AUC = 0.84 vs. 0.31; P < or = 0.040). CONCLUSION: Multi-detector row CT has a poor accuracy for predicting MRF invasion in low-anterior located tumors.The accuracy of CT significantly improves for tumors in the mid-high rectum. There is a high inconsistency among readers
Central and noncentral components of the preedom-wildenthal interaction
The influence of the various components of the Preedom-Wildenthal interaction - viz., central, tensor, spin-orbit (LS) and antisymmetric spin-orbit (ALS) - on properties of A = 20,21 nuclei is investigated. The effects of the LS and ALS components on the one hand and of the central and tensor components on the other hand are found to be very similar. It turns out to be possible to remove the ALS component in favour of an enhanced LS component without spoiling the agreement with experiment
Central and noncentral components of the preedom-wildenthal interaction
The influence of the various components of the Preedom-Wildenthal interaction - viz., central, tensor, spin-orbit (LS) and antisymmetric spin-orbit (ALS) - on properties of A = 20,21 nuclei is investigated. The effects of the LS and ALS components on the one hand and of the central and tensor components on the other hand are found to be very similar. It turns out to be possible to remove the ALS component in favour of an enhanced LS component without spoiling the agreement with experiment