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Purpose: To assess the usefulness of morphological characteristics of diffusion-weighted imaging (DWI) for differentiating malignant renal tumors from benign renal tumors, and clear cell renal cell carcinoma (RCC) from non-clear cell RCC at 3.0 T.Methods: The study included 249 patients with 251 histopathologically confirmed renal tumors that showed high signal on DWI. For each tumor, two radiologists independently evaluated apparent diffusion coefficient (ADC) values and morphological characteristics of DWI. The differences in the quantitative and qualitative magnetic resonance imaging (MRI) features determined by the readers were assessed. The ADC values between malignant and benign renal tumors and between clear cell and non-clear cell RCC were compared using Mann-Whitney tests. The proportional differences of morphological characteristics of DWI between malignant and benign renal tumors and between clear cell and non-clear cell RCC were compared using Chi-square tests.Results: There were no significant differences in the quantitative and qualitative MRI features determined by the readers. The ADC values for malignant renal tumors were statistically significantly higher than those for benign renal tumors (p < 0.05), and the ADC values for clear cell RCC were statistically significantly higher than those for non-clear cell RCC (p < 0.05). The proportion of morphological characteristics of DWI between malignant and benign renal tumors was statistically significantly different at ring, nodular, flaky high signal. The proportion of morphological characteristics of DWI between clear cell and non-clear cell RCC was statistically significantly different at uniform high signal.Conclusions: The morphological characteristics of DWI are useful in differentiating renal tumors. [ABSTRACT FROM AUTHOR]

Purpose: To prospectively estimate measurement and scan reproducibility of parameters of intravoxel incoherent motion (IVIM) in renal tumors, normal renal cortex, and medulla.Methods: Twenty-four consecutive patients (twelve males and twelve females; median age 56.7 years, range 32-71 years) with 25 renal tumors (20 renal cell carcinomas, one urothelium carcinoma, three angiomyolipomas, and one oncocytoma) were examined twice using IVIM1 and IVIM2 with 9 and 16 b values, respectively, at 3.0 T. All the patients were re-scanned in 24-48 h. Regions of interest (ROIs) were placed in solid part of tumor, normal cortex, and medulla to derive IVIM parameters D (true diffusion coefficient), D* (pseudodiffusion coefficient), and f (perfusion fraction of pseudodiffusion). Differences in parameters between two IVIM sets and intra-observer, inter-observer, and scan-rescan differences were assessed using paired t tests. Intra-observer, inter-observer, and scan-rescan reproducibility were assessed by measuring coefficient of variation and Bland-Altman limits of agreements.Results: Intra-observer reproducibility of renal tumors, normal renal cortex, and medulla was excellent for apparent diffusion coefficient (ADC; CV: 3.45%-5.34%, BA-LA: −14% to 18%) and D (CV: 3.65% to 6.04%, BA-LA: −18% to 19%), good for f (CV: 11.96%-16.08%, BA-LA: −76.4% to 92.1% except f of medulla with CV of 32.59% and BA-LA of −76.4% to 92.1% in IVIM1), and poor for D* (CV: 25.0% to 75.4%, BA-LA: −111% to 150%). The same order was in inter-observer reproducibility analysis. Scan-rescan reproducibility was the worst of the three parameters. Renal medulla showed worse reproducibility than renal tumors and the normal cortex. The metrics of IVIM2 had better reproducibility than IVIM1.Conclusion: Excellent reproducibility evaluation for ADC and D, good for f, and poor for D* derived from IVIM was performed in renal tumors, normal renal cortex, and medulla. D* has limited reliability and scan-rescan reproducibility should be improved. [ABSTRACT FROM AUTHOR]

The aim of this study was to improve the diagnostic efficiency for juxtaglomerular cell tumors (JCTs) and to determine whether clinical and magnetic resonance imaging features can help to differentiate JCTs from clear cell renal cell carcinoma (ccRCC). The clinical features of eight patients with JCTs and 27 patients with ccRCCs were analyzed. A flow diagram for young people with hypertension was applied to facilitate the diagnosis. Clinical presentations were analyzed, including age, hypertension, and hypokalemia. The results of our study produced a flow diagram that narrowed the scope of diagnosis. The statistical results demonstrated that patients with a renal mass aged 14 to 30 years, had grade 3 hypertension, or had moderate hypokalemia had a greater possibility of having a JCT than a ccRCC (P<.0000, P<.01, P<.0005, respectively). In addition, the flow diagram and magnetic resonance imaging features were useful to distinguish JCTs from other renal tumors. [ABSTRACT FROM AUTHOR]