The value of quantitative CT texture analysis in differentiation of angiomyolipoma without visible fat from clear cell renal cell carcinoma on four-phase contrast-enhanced CT images.

AIM: To investigate the diagnostic performance and usefulness of texture analysis in differentiating angiomyolipoma (AML) without visible fat from clear cell renal cell carcinoma (ccRCC) on four-phase contrast-enhanced computed tomography (CECT). MATERIALS AND METHODS: Seventeen patients with AML without visible fat and 50 patients with ccRCC of size ≤4.5 cm who had also undergone preoperative four-phase CECT were included in this study. The histogram, grey-level co-occurrence matrix (GLCM), and grey-level run length matrix (GLRLM) were evaluated. Sequential feature selection (SFS) and support vector machine (SVM) classifier with leave-one-out cross validation were used. RESULTS: Using the SFS and SVM classifiers, five texture features were selected; mean (unenhanced), standard deviation (unenhanced and excretory), cluster prominence (nephrographic), and long-run high grey-level emphasis (corticomedullary). Diagnostic performance of the five selected texture features for all CT phases was as follows: 82% sensitivity, 76% specificity, 85% accuracy, and 85 area under the receiver operating characteristic curve (AUC). In the subgroup analysis, the AUCs of each phase were significantly >0.5 (p<0.05). In the pairwise comparison of AUCs between four phases, there were no significant differences between the four phases except the unenhanced and corticomedullary phases (p=0.015), i.e., the unenhanced phase showed slightly higher AUC than the corticomedullary phase. CONCLUSIONS: Texture analysis of small renal masses (≤4.5 cm) on four-phase CECT can accurately differentiate AML without visible fat from ccRCC and showed good diagnostic performance for both the unenhanced and enhanced phases.

Differentiating between hepatocellular carcinoma and intrahepatic cholangiocarcinoma using contrast-enhanced MRI features: a systematic review and meta-analysis.

AIM: To identify magnetic resonance imaging (MRI) features for differentiating hepatocellular carcinoma (HCC) from intrahepatic cholangiocarcinoma (IHCC) and summarise their diagnostic accuracy. MATERIALS AND METHODS: PubMed and EMBASE were searched for studies that employed MRI features to differentiate HCC from IHCC. Overlapping descriptors used to denote the same imaging finding in different studies were subsumed under a single feature. The pooled diagnostic accuracies, including the diagnostic odds ratios (DORs) and 95% confidence intervals (CIs) of the identified features, were calculated using a bivariate random-effects model. RESULTS: In total, 1,370 patients with HCC and 687 patients with IHCC in 14 studies were included. Fifty-two descriptors were subsumed under 15 MRI features. Of these, 11 features were informative for differentiating HCC from IHCC. The five MRI features favouring HCC were capsule, arterial diffuse enhancement, portal venous washout, conventional washout, and intralesional fat; the six MRI features favouring IHCC were surface retraction, arterial rim enhancement, progressive enhancement, target appearance on diffusion-weighted and hepatobiliary phase (HBP) images, and bile duct dilatation. These features tended to show high specificity, but low sensitivity. Useful MRI features with high DORs (>20) were capsule (34; 95% CI, 5-215) and intralesional fat (23; 4-85) for HCC and arterial rim enhancement (31; 6-160), progressive enhancement (24; 8-73), and target appearance on HBP images (29; 3-261) for IHCC. CONCLUSION: Eleven informative MRI features for differentiating HCC from IHCC were identified. These features will assist in the accurate diagnosis of these diseases and in disease outcome prediction.

Posterior root of lateral meniscus: the detailed anatomic description on 3T MRI.

BACKGROUND: Although there have been some attempts to reveal the anatomy of the posterior root of the lateral meniscus (PRLM) through cadaver studies, arthroscopy, or imaging, it has not yet been described fully. PURPOSE: To describe clearly the unique features of the PRLM, including its course, configuration, and size, using 3.0-T magnetic resonance imaging (MRI). MATERIAL AND METHODS: A total of 105 knee 3.0-T MR examinations of 103 patients with arthroscopically proven intact PRLM were reviewed retrospectively. Based on fat-saturated, proton-density-weighted (PDW) axial/coronal images and PDW sagittal images, the course, configuration, and attachment sites of the PRLM were evaluated. RESULTS: The majority of PRLM (76.2%) had two attachment sites: the medial tubercle along the intertubercular crest, just posteromedial to the tibial attachment of the anterior cruciate ligament (ACL), and the posterior slope of the lateral tubercle. The remaining cases (23.8%) had a solitary insertion on the intertubercular area (17 cases), or the posterior slope of the lateral tubercle (eight cases). The PRLM of the intertubercular area appeared as a dark signal line parallel to the tibial plateau on the mid-sagittal image and dark signal foci traversing the intertubercular crest on contiguous coronal images. CONCLUSION: The PRLM inserts mainly in the intertubercular area with a thin, long anterior extension to the point just posteromedial to the tibial attachment of the ACL. It is well delineated on PDW 3.0-T MRI as a dark signal line parallel to the tibial plateau on mid-sagittal images and dark signal foci traversing the intertubercular crest on contiguous coronal images.