Huanjun Wang

Multiparametric 3-T MRI for Differentiating Low-Versus High-Grade and Category T1 Versus T2 Bladder Urothelial Carcinoma

OBJECTIVE. The purpose of this study was to determine an optimal multiparametric MRI protocol for characterizing tumors of low versus high grade and differentiating tumors as T1 versus T2 for preoperative staging of bladder urothelial carcinoma. SUBJECTS AND METHODS. Thirty-nine patients underwent MRI within 1 week before surgery. Three image sets-T2-weighted plus diffusion-weighted MRI (DWI), T2-weighted plus dynamic contrast-enhanced MRI (DCE-MRI), and T2-weighted plus DCEMRI plus DWI-were independently interpreted by two readers at 2-week intervals. ROC curves were plotted for both readers to compare the diagnostic efficacy of the three sets for detrusor muscle invasion for each reader, and the areas under the ROC curve were compared by use of the Bonferroni test. The apparent diffusion coefficient (ADC) values were correlated with histopathologic grade. RESULTS. A total of 49 category T1 and T2 lesions were analyzed. The average ADC of 11 low-grade tumors (1.141 ± 0.164 × 10(-3) mm(2)/s) was significantly (p < 0.05) higher than that of 20 high-grade malignant tumors (0.766 ± 0.091 × 10(-3) mm(2)/s). Neither reader considered T1 tumors as probably having muscle invasion (category T2) in the T2-weighted plus DWI image sets or the T2-weighted plus DWI plus DCE-MRI image sets. Using the T2-weighted plus DCE-MRI sets, the two readers overstaged 13 and 15 of 36 tumors by misdiagnosing category T1 as T2. With the cutoff ADC value of 0.899 × 10-3 mm(2)/s, the sensitivity and specificity for differentiating high- and low-grade bladder urothelial carcinoma were 100% and 95%. CONCLUSION. Multiparametric MRI with T2-weighted plus DWI plus DCE technique is the optimal protocol for preoperative staging of organ-confined bladder urothelial carcinoma. The ADC of low-grade tumors is significantly higher than that of high-grade tumors with 100% sensitivity and 95% specificity at a cutoff ADC value of 0.899 mm(2)/s.

MR diffusion tensor imaging of normal kidneys

To assess the feasibility of diffusion tensor imaging (DTI) of normal kidneys and the influence of hydration state.

Comparison of Early Submucosal Enhancement and Tumor Stalk in Staging Bladder Urothelial Carcinoma.

OBJECTIVE The purpose of this study was to compare the efficacy of submucosal enhancement on dynamic contrast-enhanced MRI (DCE-MRI) and detection of a stalk on DWI for differentiating stage T1 from stage T2 bladder urothelial carcinoma. SUBJECTS AND METHODS Our prospective study was approved by the institutional medical ethics committee and informed consent was obtained from all patients. Fifty-nine patients (92 tumors in total) with urothelial bladder cancer underwent MRI within 2 weeks before surgery. Two image sets of T2-weighted MRI with DWI and T2-weighted with DCE-MRI were interpreted independently at 2-week intervals by two uroradiologists without any knowledge of the surgical or histologic findings. The tumor was categorized as stage T1 or lower when a stalk was evident at the tumor base on DWI or when continuous linear submucosal enhancement was detected in the early phase of DCE-MRI. Tumors without stalks or with discontinuous linear submucosal enhancement were categorized as stage T2. RESULTS Of the 42 tumors with stalks on DWI, 41 showed continuous and one had discontinuous submucosal enhancement on DCE-MRI. In 50 carcinomas without stalks on DWI, submucosal enhancement was absent in 34, continuous in 12, and discontinuous in four. The staging accuracy of DWI (91.3%, 84/92) and DCE-MRI (91.3%, 84/92) was improved to 94.6% (87/92) by combining the interpretations of both DWI and DCE-MRI. CONCLUSION Submucosal linear enhancement under the tumor base on DCE-MRI complements tumor stalk detection on DWI for differentiating stage T1 from stage T2 bladder urothelial carcinoma.

Evaluation of the sacral nerve plexus in pelvic endometriosis by three-dimensional MR neurography

To investigate the feasibility of three‐dimensional MR neurography (3D MRN) for the sacral plexus using sampling perfection with application‐optimized contrasts using different flip angle evolution (SPACE) sequences, and to demonstrate structural abnormalities in the pelvic nerve of women with pelvic endometriosis.

Diffusion-Weighted and Magnetization Transfer Imaging in Testicular Spermatogenic Function Evaluation: Preliminary Results: Testicular Spermatogenic Function Evaluation

To assess the use of functional magnetic resonance imaging (MRI), including diffusion‐weighted MRI (DWI) and magnetization transfer MRI (MTI) in evaluating male infertility.

Ovarian collision tumors: imaging findings, pathological characteristics, diagnosis, and differential diagnosis

Collision tumors are uncommon neoplasms in which elements of differing histologic origins coexist in a single mass. Ovarian collision tumors are a rare subtype of such lesions. The identification of collision tumors by radiologic examinations is essential to ensure that comprehensive biopsies are performed to guide appropriate treatments. According to the clinical and imaging findings of 12 patients and reviews of previous studies, ovarian collision tumors are mixtures of different combinations of epithelial tumors, germ cell tumors, and sex-cord-stromal tumors. The smaller tumors are usually located inside (“nested tumor”) or on the wall (“back to back”) of the larger tumors. Each type of ovarian collision tumors presents specific CT/MRI features in accordance with their histologic origins and collision patterns. Knowledge of the imaging features of ovarian collision tumors is crucial to aid preoperative diagnostic accuracy.

Quantitative Identification of Nonmuscle-Invasive and Muscle-Invasive Bladder Carcinomas: A Multiparametric MRI Radiomics Analysis: Radiomics for Identifying NMIBC and MIBC

Preoperative discrimination between nonmuscle‐invasive bladder carcinomas (NMIBC) and the muscle‐invasive ones (MIBC) is very crucial in the management of patients with bladder cancer (BC).

Efficacy of 3D VIBE Dixon fat quantification for differentiating clear-cell from non-clear-cell renal cell carcinoma

AIM To assess the efficacy of three-dimensional (3D) volumetric interpolated breath-hold examination (VIBE) magnetic resonance imaging (MRI) with Dixon quantification for differentiating clear-cell from non-clear-cell types of renal cell carcinoma (RCC). MATERIALS AND METHODS The 3D VIBE Dixon renal MRI examinations of 44 patients with 45 histologically confirmed RCCs was analysed. The fat fractions and signal intensity indexes (SIindex) of the solid portions of clear-cell and non-clear-cell RCCs were measured and compared using Students t-test and receiver operating characteristic (ROC) curves. The agreement of measurements among observers was evaluated by the intraclass correlation coefficient (ICC), and Bland-Altman plots. RESULTS The mean values of fat fraction (13.16±7.16%) and SIindex (22.64±15.7%) in clear-cell RCCs were significantly higher than that in non-clear-cell RCCs (7.7±2% and 7.9±4.8%; p<0.001, respectively). With the area under the ROC curve (AUC) of the fat fraction at 0.811, 75% (95% CI: 55.1-89.43%) sensitivity and 76.5% (95% CI: 50.1-93.2%) specificity for diagnosing clear-cell RCC were obtained at a cut-off fat fraction value of 8.9%. With a cut-off value of 8.89%, the diagnostic sensitivity and specificity were 85.7% (95% CI: 67.3-96%) and 70.6% (95% CI: 44-89.7%), respectively. The AUC of the SIindex was 0.870 (0.766-0.973). ICC and Bland-Altman plots show excellent agreement of the tumour fat fraction and SIindex measurement between the two observers. CONCLUSION Intracellular lipid content analysis using the 3D Dixon technique can help to differentiate clear-cell from non-clear-cell RCCs.

Preliminary study of diffusion-weighted MRI in the preoperative diagnosis of cystitis glandularis

AIM To assess the efficacy of diffusion-weighted (DWI) magnetic resonance imaging (MRI) in distinguishing cystitis glandularis (CG) from bladder urothelial carcinoma. MATERIALS AND METHODS Ultrasound, computed tomography (CT), conventional MRI, and DWI of 30 patients with histopathologically confirmed CG were analysed retrospectively and the imaging findings were correlated to the findings at histology. RESULTS Ultrasound was non diagnostic in 11/18 and misdiagnosed malignancy in 7/18; CT was non diagnostic in 6/10 and misdiagnosed malignancy in 4/10; MRI was non diagnostic in 0 and misdiagnosed malignancy in 4/5 respectively. One patient with diffuse bladder wall thickening was correctly diagnosed as CG at MRI. All six patients who underwent additional DWI were accurately diagnosed as having CG with no or minimal reduction of diffusion. CONCLUSIONS Diffusion is not reduced or shows minimal reduction in CG. DWI may aid the differential diagnosis of CG.