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To quantitatively compare the diagnostic values of conventional region of interest (ROI)-based and volumetric histogram analysis derived from CT enhancement in differentiating malignant and benign renal tumors. A total of 230 patients with pathologically confirmed renal tumors who had undergone CT enhancement were classified into clear cell renal cell carcinoma (ccRCC) (n = 133), non-ccRCC (n = 56), and benign renal tumor(n = 41) group. Parametric CT enhancement of each tumor from volumetric histogram were obtained using in-house software, including 10th percentile, 25th percentile, median, 75th percentile, 90th percentile, mean, standard deviation, as well as skewness, kurtosis and entropy, and histogram metrics among these groups were analyzed. ROI-based enhancement density was also analyzed. The entropy and SD values of ccRCCs were higher than those of non-ccRCCs and benign renal tumors (p < 0.05). The 10th percentile, 25th percentile, median, 75th percentile, 90th percentile and mean values of ccRCCs were lower than those of benign renal tumors, however, higher than those of non-ccRCCs (p < 0.05). The ROI-based enhancement density of non-ccRCCs were lower than those of ccRCCs and benign renal tumors(p < 0.05). Receiver operating characteristic (ROC) curve analyses showed that entropy and mean values had the highest diagnostic efficacy in differentiating ccRCCs/non-ccRCCs and benign renal tumors. ROC curve analyses showed that mean values had the highest diagnostic efficacy in differentiating ccRCCs and non-ccRCCs. In terms of pairwise comparisons of ROC curves and diagnostic efficacy, ROI-based CT enhancement density was worse than volumetric histogram analysis (p < 0.05). Volumetric histogram analysis parameters can effectively distinguish malignant and benign renal tumors. 1. Entropy and mean values had the highest diagnostic efficacy in differentiating ccRCCs/ non-ccRCCs and benign renal tumors. 2. Mean values had the highest diagnostic efficacy in differentiating ccRCCs and non-ccRCCs. 3.Volumetric histogram analysis had better performance than ROI-based enhancement density. [ABSTRACT FROM AUTHOR]

To quantitatively compare the diagnostic values of conventional diffusion-weighted imaging (DWI) and introvoxel incoherent motion (IVIM) analysis of microstructural differences for clear cell renal cell carcinoma (ccRCC). Multiple b value DWIs and IVIMs were performed in patients with 146 ccRCCs, 42 with Grade Ⅰ, 46 with Grade Ⅱ, 28 with Grade Ⅲ and 30 with Grade Ⅳ. These tumours were divided into low (Ⅰ+Ⅱ, n = 88) and high grades (Ⅲ+Ⅳ, n = 58). The diagnostic efficacy of various diffusion parameters for predicting ccRCC grades was compared. The mean signal-to-noise ratios (SNRs) of IVIM images at b = 0, 800 and 1500 s/mm2 were 31.9, 12.3 and 8.4, respectively. The apparent diffusion coefficient (ADC), D and D* values correlated negatively with ccRCC grading (r = -0.786,–0.913, −0879, p < 0.05). f values correlated positively with ccRCC grading (r = 0.811, p < 0.05). The ADC, D and D* values were higher for Grade Ⅱ ccRCC than that of Grade Ⅲ ccRCC (p < 005), however, f values were higher for Grade Ⅲ ccRCC than that of Grade Ⅱ ccRCC (p < 005). Receiver operating characteristic curve analyses showed that D values had the highest diagnostic efficacy in differentiating low/high and Ⅱ/Ⅲ ccRCC grading. The area under the curve, sensitivity, specificity and accuracy of the D values were 0.963, 0.960; 90.9%, 89.1%; 81.0%,78.6 and 89.0%, 87.8%, respectively. For pairwise comparisons of receiver operating characteristic curves and diagnostic efficacy, ADC was worse than IVIM (all p < 0.05). IVIM parameters have better performance than ADC in differentiating ccRCC grading, given an adequate SNR of IVIM images. 1. D values had the highest diagnostic efficacy in differentiating low/high and Ⅱ/Ⅲ ccRCC grading. 2. IVIM parameters have better performance than ADC in differentiating ccRCC grading, given an adequate SNR of IVIM images. 3. The ADC, D and D* values correlated negatively with ccRCC grading, however, f values correlated positively with ccRCC grading. [ABSTRACT FROM AUTHOR]

To investigate the feasibility of magnetic resonance diffusion kurtosis imaging (DKI) and intravoxel incoherent motion (IVIM) for distinguishing Type 1 and 2 of papillary renal cell carcinoma (PRCC). A total of Type 1 (n = 20) and Type 2 (n = 16) of PRCC were examined by pathology. For DKI and IVIM, mean diffusivity (MD), fractional anisotropy (FA), mean kurtosis (MK), kurtosis anisotropy (KA), radial kurtosis (RK), diffusivity (D), pseudodiffusivity (D*) and perfusion fraction (f) were performed in assessment of type of PRCC. The mean SNRs of IVIM and DKI images at b = 1500 and 2000 s/mm2 were 8.6 ± 0.8 and 7.8 ± 0.6. Statistically significant differences were observed in MD and D values (1.11 ± 0.23 vs 0.73 ± 0.13, 0.91 ± 0.24 vs 0.49 ± 0.13, p < 0.05) between Type 1 and Type 2 of PRCC, while comparable FA, RK, D* and f values were found between Type 1 and Type 2 of PRCC (p > 0.05). Statistically significant differences were observed in MK and KA values (1.23 ± 0.16 vs 1.91 ± 0.26, 1.49 ± 0.19 vs 2.36 ± 0.39, p < 0.05) between Type 1 and Type 2 of PRCC. Areas of MD, MK, KA and D values under ROC curves for differentiating Type 1 and Type 2 of PRCC were 0.836, 0.818, 0.881 and 0.766, respectively. Using MD, MK, KA and D values of 0.93, 1.64, 1.94, 0.68 as the threshold value for differentiating Type 1 from Type 2 of PRCC, the best result obtained had a sensitivity of 85.0%, 80.0%, 90.0%, 85.0%, a specificity 75.0%, 68.7%, 87.5%, 81.2%, and an accuracy of 83.3%, 80.5%, 88.9%, 86.1%, respectively. DKI and IVIM are feasible techniques for distinguishing type of PRCC, given an adequate SNR of IVIM and DKI images. 1. MD and D values are higher for Type 1 of PRCC and lower for Type 2 of PRCC. 2. MK and KA values are higher for Type 2 of PRCC and lower for Type 1 of PRCC. 3. DKI and IVIM can be used as clinical biomarker for PRCC type's differential diagnosis, given an adequate SNR. [ABSTRACT FROM AUTHOR]

Objective: To quantitatively compare the diagnostic values of conventional diffusion‐weighted imaging (DWI) and diffusion kurtosis imaging (DKI) analysis of microstructural differences for clear cell renal cell carcinoma (CRCC). Methods: A total of 108 patients with pathologically confirmed CRCC, including 38 Grade I, 37 Grade II, 18 Grade III and 15 Grade IV, were enrolled and divided into groups according to tumor grade [low grade (Ⅰ+Ⅱ, n = 75) and high grade (Ⅲ+Ⅳ, n = 33)]. Apparent diffusion coefficient (ADC), mean diffusivity (MD), mean kurtosis (MK), kurtosis anisotropy (KA) and radial kurtosis (RK) were performed. Results: Both the ADC (r = −0.803) and MD (−0.867) values showed a negative correlation with tumor grading (p < 0.05) and MK (r = 0.812), KA (0.816) and RK (0.853) values a positive correlation with tumor grading (p < 0.05). Mean FA values showed no significant differences among CRCC grades (p > 0.05). ROC curve analyses showed that MD values had the highest diagnostic efficacy in differentiating low/high and Ⅱ/Ⅲ tumor grading. MD values gave AUC: 0.937 (0.896); sensitivity: 92.0% (86.5%); specificity: 78.8% (77.8%) and accuracy: 90.7% (87.3%). ADC performed worse than MD, MK, KA or RK (all p < 0.05) during pair‐wise comparisons of ROC curves to show diagnostic efficacy. Conclusion: DKI analysis performs better than ADC in differentiating CRCC grading. Advances in knowledge: Both the ADC and MD values correlated negatively with CRCC grading. The MK, KA and RK values correlated positively with CRCC grading. MD values had the highest diagnostic efficacy in differentiating low/high and Ⅱ/Ⅲ CRCC grading. [ABSTRACT FROM AUTHOR]

To explore the feasibility of diffusion kurtosis imaging (DKI) in differentiating different types of renal cell carcinoma (RCC). 36 patients with clear cell RCC (CCRCC, low-grade,n = 20 and high-grade, n = 16), 19 with papillary RCC, 11 with chromophobe RCC, and 9 with collecting duct carcinoma (CDC) were examined with DKI technique. b values of 0, 500 and 1000 s/mm2 were adopted. The DKI parameters, i.e., mean diffusivity (MD), mean kurtosis (MK), kurtosis anisotropy (KA), radial kurtosis (RK) and signa-to-noise ration (SNR) of DKI images at different b values were used. The mean SNRs of DKI images at b = 0, 500 and 1000 s/mm2 were 32.8, 14.2 and 9.18, respectively. For MD parameter, a significant higher value was shown in CCRCC than those of papillary RCC, chromophobe RCC and CDC (p < 0.05). In addition, both chromophobe RCC and CDC have larger MD values than papillary RCC (p < 0.05), however, there was no significant differences between chromophobe RCC and CDC (p > 0.05). For MK, KA and RK parameters, a significant higher value was shown in papillary RCC than those of CCRCC, chromophobe RCC and CDC (p < 0.05). Moreover, both chromophobe RCC and CDC have significantly larger values of MK, KA and RK than CCRCC (p < 0.05). Our preliminary study demonstrated significant differences in the DKI parameters between the subtypes of RCCs, given an adequate SNR of DKI images. 1.The MD value is the best parameter to distinguish CCRCC from other RCCs. 2.The MK, KA and RK values are the best parameters to distinguish papillary RCC from other RCCs. 3.DKI is able to provide images with sufficient SNRs in kidney disease. [ABSTRACT FROM AUTHOR]

Objective: To characterize the multidetector CT imaging features of invasive renal parenchyma urothelial carcinoma (IRPUC)., Methods: 29 patients with IRPUC were retrospectively evaluated. Tumour location, density, cystic or solid appearance, calcification, capsule sign, enhancement pattern and metastases were assessed., Results: IRPUC involved the right kidney in 82.7% of patients. Medullary involvement was observed in 93.1% of patients. In 89.6% of patients, the reniform contour of the kidney was preserved. Tumours showed an infiltrative appearance (100%) with a poorly defined margin (100%), but an expansile component was also present (20.7%). Linear calcification was present (20.7%). Evidence of intra-abdominal metastatic disease (in 37.9% of cases) and regional lymphadenopathy (in 27.5% of cases) was present. Tumour attenuation was less or equal compared with the renal cortex or medulla on unenhanced CT (p-value> 0.05), after i.v. contrast administration; 100% were of homogeneous low attenuation compared with the normal renal cortex and medulla (p-value< 0.05)., Conclusion: IRPUC tends to be more prevalent in the right kidney, poorly defined margin, medullary involvement, with homogeneous enhancement less than the cortex and medulla in all phases., Advances in Knowledge: IRPUC was more prevalent in the right kidney. IRPUC enhancement was less than that of the cortex and medulla on all phases. IRPUC showed poorly defined margin with medullary involvement and preserved reniform contour.

Objective: To characterize the multidetector CT (MDCT) imaging characteristics of mucinous tubular and spindle cell carcinoma (MTSCC) and collecting duct carcinoma (CDC) of the kidney., Methods: 21 patients with MTSCC and 18 patients with CDC were studied retrospectively. MDCT was undertaken to investigate differences in tumour characteristics., Results: Five patients with MTSCC had calcifications as did nine patients with CDC (p = 0.108). In three patients with MTSCC and four patients with CDC, the tumours had a clear boundary (p = 0.682). No patient with MTSCC had retroperitoneal lymph node metastasis as did five patients with CDC (p = 0.015). 16 patients with MTSCC showed homogeneous enhancement, whereas 11 patients with CDC showed heterogeneous enhancement (p = 0.025). The attenuation value of CDC tumours was greater than that of MTSCC and normal renal parenchyma on an unenhanced CT (p = 0.027). MTSCC and CDC tumour enhancement was less than the normal renal cortex and medulla in all phases (p < 0.001). Tumour enhancement was greater for CDC than that for MTSCC in all phases (p = 0.011, p = 0.006 and p = 0.052)., Conclusion: Unenhanced and dynamic MDCT may aid in diagnosis and differentiation of MTSCC and CDC of the kidney., Advances in Knowledge: This is the first series evaluating the imaging findings of MTSCC and CDC of which we are aware, and identification of such findings may improve diagnosis of these two rare tumours.