Radiological Features of T1a Renal Cell Carcinoma on Axial Unenhanced Computed Tomography.

CT has become a commonly used diagnostic procedure in clinical practice, particularly in emergency healthcare delivery. Accordingly, the increase in CT usage has increased the likelihood of incidental detections (ID) of renal cell carcinomas (RCCs). This article discusses key points and limitations associated with the diagnosis and characterization of T1a RCC (≤4 cm in diameter) and shows how to improvise on the differentiation of T1a RCC with unenhanced CT (UE-CT). We retrospectively reviewed UE-CT findings of cases associated with the histopathologic diagnosis of T1a RCC and examined the discrimination capacity and radiological characteristics with regard to small RCCs (SRCCs). Detection and characterization of T1a RCC based on UE-CT are not easy in many cases due to limitations in CT findings, but there are notable radiological features to facilitate detection and differentiation. The growth pattern is important for the detection of SRCCs. Internal characteristic features (average attenuation, heterogeneity) are useful for the characterization of the RCC. In addition, CT image visualization techniques may help improve the detectability of RCCs on UE-CT. Radiological features are important in detecting SRCCs and facilitating further examination. In this study, we discuss some cases of T1a RCCs and evaluate the radiological characteristics of the tumors seen on UE-CT.

T2 hypointense signal discovered incidentally at the posterior edge of the adenohypophysis on MRI: its prevalence and morphology and their relationship to age.

PURPOSE: T2 hypointense signal at the posterior edge of the adenohypophysis (T2HSPA) on magnetic resonance imaging (MRI) is incidentally encountered. We aimed to investigate the prevalence and morphology of T2HSPA and their relationship to age. METHODS: A total of 212 cases between 3 and 88 years old were examined. Sagittal T2-weighted image (T2WI) was evaluated for the presence of T2HSPA, which classified by its morphology into two types (belt-like or nodal). The Wilcoxon rank sum test and chi-square test were used to evaluate the differences between the groups. The T2HSPA was extracted by ImageJ software and measured as a cross-sectional area (CSA) quantitatively by threshold setting. We examined the relationship between CSA of T2HSPA and age, and Spearman's correlation coefficients were used for statistical analysis. RESULTS: Of the 212 cases, 80 (37.7%) were identified with T2HSPA. The groups with T2HSPA were significantly younger than the groups without it (p = .01). Groups with belt-like T2HSPA were significantly younger than the groups with nodal T2HSPA (p = .01). There was a weak negative correlation between CSA of T2HSPA and age (p = .02). CONCLUSION: T2HSPAs were incidentally detected in 37.7% of all cases, tended to be more common in younger cases, and their morphology was related to age. They seem to have little clinical significance as they tend to decrease in size with age.

T1a renal cell carcinoma on unenhanced CT: analysis of detectability and imaging features.

BACKGROUND: Increasing use of unenhanced computed tomography (CT) has been associated with the increasing incidental detection of renal cell carcinoma (RCC) at an earlier stage. PURPOSE: To evaluate the characteristics in detecting and differentiating T1a RCCs on unenhanced CT. MATERIAL AND METHODS: We retrospectively reviewed 68 patients with 68 T1a RCCs and 39 benign regions. Two radiologists interpreted the images on unenhanced axial CT and performed a blinded and independent review of T1a RCCs. The readers evaluated the presence of RCC and differentiated the detected lesions. RESULTS: The consensus of two readers detected 53 (78%) RCCs. Of the 53 detected RCCs, 42 (62%) RCCs were correctly diagnosed and 11 (16%) masses were misdiagnosed as benign. Of the 39 benign regions, 29 (74%) cysts were diagnosed correctly, but 10 (26%) cysts were misdiagnosed as malignant. The following values of the radiologists were obtained by consensus: sensitivity = 61.8% (42/68); specificity = 74.4% (29/39); positive predictive value = 80.8% (42/52); negative predictive value = 55.0% (29/55); accuracy = 66.4% (71/107). The receiver operating characteristic curve of consensus was 0.754. Inter-observer correlation was κ = 0.849. There was a significant difference in tumor size (P = 0.019) and the contour type of tumor (P = 0.0207) between correctly diagnosed RCCs and not correctly diagnosed RCCs. CONCLUSION: Our findings showed that tumor size and contour type could affect the detection and differentiation of T1a RCC on unenhanced CT. To detect and differentiate T1a RCC on unenhanced CT is difficult. However, the findings from this study may help detection of RCCs on unenhanced CT.

Magnetic resonance imaging features of massive ovarian edema in pregnancy: utility for decisions in expectant management.

INTRODUCTION: Massive ovarian edema (MOE) is a rare disease and few reports have described the magnetic resonance (MR) imaging manifestations in pregnancy. CASE DESCRIPTION: We report here a case of MOE in a patient at 12 weeks' gestation. Abdominal T2-weighted MR images showed asymmetric ovarian enlargement in a teardrop configuration, hyperintense peripherally displaced follicles, and twisting of the vascular pedicle between the enlarged ovary and uterus. The diagnosis of MOE due to ovarian torsion was confirmed by exploratory laparotomy. Preoperative imaging, especially the MR imaging could distinguish MOE from other conditions and demonstrate the relations of adjunct organ, and allowed for untwisting during laparotomy with successful preservation of the ovary. DISCUSSION AND EVALUATION: Ultrasonography is important in detecting, evaluating, and determining the malignant potential of adnexal masses in pregnancy, but its findings may be nonspecific and then MR may assist characterization. This case was tentatively diagnosed as typical MOE by preoperative imaging, but the shape and location of the hugely enlarged ovarian mass suggested torsion of the ovarian pedicle. In our case, the diagnosis was confirmed by exploratory laparotomy and the pedicle was successfully untwisted. CONCLUSION: MR imaging proved useful for decisions on expectant management of MOE in pregnancy, and the patient's affected ovary could be preserved.