Skovbjerg Pierce (netbeast6)

5% in 33 patients when using optimal z-axis coverage for CCTA. In the group that was scanned with a collimation of 14 cm, radiation dose could have been reduced by 14.3% in 90 patients, and 28.6% in 30 patients, whereas in the group that was scanned with a collimation of 12 cm, dose could have been reduced by 16.7% in 2 patients. CONCLUSIONS Using correct z-axis coverage in CCTA on a latest-generation 256-slice scanner yields average dose reductions of 22.0% but may be as high as 37.5%.PURPOSE The aim of this study was to identify possible predictors for findings of left atrial appendage (LAA) filling defects in patients with atrial fibrillation (AF) on cardiac computed tomography (CT). MATERIALS AND METHODS We retrospectively evaluated findings of LAA filling defects on the early phase of cardiac CT of 63 patients with history of AF and compared those images with those of 63 control subjects. We investigated potential predictors for LAA filling defects. RESULTS Filling defects of the LAA correlated significantly with patient history of persistent AF (P = 0.045; odds ratio [OR], 3.17), chicken wing morphology (P = 0.013; OR, 4.12), and with LAA volume (P = 0.0032; OR, 1.19) of 12.53 cm or greater (sensitivity, 87.3%; specificity, 69.8%). CONCLUSIONS We observed persistent AF, the chicken wing type of LAA morphology, and LAA volume as independent predictors of LAA filling defects on cardiac CT. These findings might improve cardiac CT scanning protocol.OBJECTIVE To prospectively compare the performance of model-based and model-free dynamic contrast-enhanced (DCE) pharmacokinetic parameters in monitoring breast cancers' early response to neoadjuvant chemotherapy (NACT). METHODS Sixty patients, with 61 pathology-proven breast cancers, were examined using DCE magnetic resonance imaging before, after the first cycle, and after full cycles of NACT. Both model-based (Ktrans and others) and model-free parameters, mainly time-intensity curve (TIC), were measured. According to Miller-Payne grading, patients were divided into response and nonresponse group. Mann-Whitney U test, Fisher exact test, multivariate logistic regression, and receiver operating characteristic curve were used in analysis. RESULTS After the first cycle, among all the parameters, Ktrans and TIC were strongly associated with tumors' early response. There was no significant difference between the areas under receiver operating characteristic curve of Ktrans and TIC (0.768, 0.852, respectively). CONCLUSIONS Model-based and model-free DCE parameters, especially Ktrans and TIC, have similar performance in predicting the efficacy of NACT for breast cancers.OBJECTIVE The purpose of this study was to assess the diagnostic performance of multiphasic computed tomography (CT) in the discrimination of metastatic lymph nodes (LNs) of papillary thyroid cancer by using quantitative parameters. METHODS This study enrolled 272 pathologically proven metastatic and benign LNs. Multiphasic CT was utilized by using nonenhanced, arterial (25-second delay), and venous (80-second delay) phases. Mean tissue attenuation values (MAVs) of metastatic and benign LNs were measured, and normalized MAV (common carotid artery and paraspinal muscle) and wash-in and wash-out percentages were also calculated. RESULTS The arterial phase showed the highest diagnostic performance in differentiation (area under the curve ± standard error, 0.97 ± 0.02; 95% confidence interval, 0.94-1.0; P less then 0.001). Cutoff values for MAVs, normalized MAVs, and wash-in and wash-out percentages to predict metastatic LNs were calculated as 109 HU, 0.33, 1.93, 122.5, and -5.6 (sensitivity 93.4%, 93.3%, 90.4%, 94.1%, and 97.8%, and specificity 99.3%, 90.4%, 98.5%, 92.6%, and 99.3%, respectively). CONCLUSIONS Early-phase enhanced CT and the use of quantitative parameters derived from multiphasic CT improve the detection of cervical lymph node metastasis from papillary thyroid cancer.OBJECTIVE We aimed to determine the eff