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Objective@#To investigate the value of combined chemical exchange saturation transfer (CEST) and conventional magnetizationtransfer imaging (MT) in detecting metabolic and structural changes of renal fibrosis in rats with unilateral ureteral obstruction(UUO) at 3T MRI. @*Materials and Methods@#Thirty-five Sprague-Dawley rats underwent UUO surgery (n = 25) or sham surgery (n = 10). Theobstructed and contralateral kidneys were evaluated on days 1, 3, 5, and 7 after surgery. After CEST and MT examinations,18F-labeled fluoro-2-deoxyglucose positron emission tomography was performed to quantify glucose metabolism. Fibrosis wasmeasured by histology and western blots. Correlations were compared between asymmetrical magnetization transfer ratio at1.2 ppm (MTRasym(1.2ppm)) derived from CEST and maximum standard uptake value (SUVmax) and between magnetization transferratio (MTR) derived from MT and alpha-smooth muscle actin (α-SMA). @*Results@#On days 3 and 7, MTRasym(1.2ppm) and MTR of UUO renal cortex and medulla were significantly different from those ofcontralateral kidneys (p < 0.05). On day 7, MTRasym(1.2ppm) and MTR of UUO renal cortex and medulla were significantly differentfrom those of sham-operated kidneys (p < 0.05). The MTRasym(1.2ppm) of UUO renal medulla was fairly negatively correlated withSUVmax (r = -0.350, p = 0.021), whereas MTR of UUO renal medulla was strongly negatively correlated with α-SMA (r = -0.744, p <0.001). @*Conclusion@#CEST and MT could provide metabolic and structural information for comprehensive assessment of renal fibrosisin UUO rats in 3T MRI and may aid in clinical monitoring of renal fibrosis in patients with chronic kidney disease.
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Objective To explore the utility of ADC histogram analysisin differentiation of clear cell renal cell carcinoma(ccRCC)and non-clear cell renal cell carcinoma(non-ccRCC)with r-Fov DWI. Methods Sixty-six renal tumors(46 patients with 47 ccRCCs and 18 patients with 19 non-ccRCCs)in 64 patients, who underwent preoperative routine renal MRI sequences and r-FOV DWI, were retrospectively evaluated. The whole-lesion ADC values derived from histogram anlysis(including ADC mean, ADC median, ADC_5th, ADC_25th, ADC_75th, ADC_95th, skew and kurtosis)were measured for each patient. All parameters between ccRCC and non-ccRCC were compared by using the Student's t test or Mann-Whitney U test. ROC analysis was used to assess the diagnostic performance of ADC histogram in distinguishing the two groups. Results The postive skewness of ADC histograms were mostly seen in the non-ccRCC group, while the negtative skewness were present in the majority of ccRCCs. The skewness was significantly higher in non-ccRCCs than those of ccRCCs(P0.05). 75th percentile ADC achieved the highest AUC(0.987)in differentiating ccRCC and non-ccRCC, whena cutoff value was 1.81× 10-3 mm2/s. The sensitivity and specificity were 100.0％and 94.7％. Conclusion ADC histograms of r-FOV DWI may be helpful to differentiate ccRCC from non-ccRCC, and the diagnostic accuracy of 75th percentile ADC is highest.
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Objective MRI manifestations of infiltrative renal pelvis carcinoma were analyzed and evaluated,to improve its diagnostic accuracy. Methods MRI features of 21 cases of infiltrative renal pelvis carcinoma confirmed pathologically were analyzed retrospectively.All patients underwent plain MRI scan and DWI examination,3 cases underwent PWI examination.Results The center of lesions for all cases were located in the renal collection system,with no change of the renal contour.Most lesions were presented as low signal intensity on T1 WI and slightly low signal intensity on T2 WI,and heterogeneous signal intensity were showed on T1 WI and T2 WI in 5 cases.All lesions were presented as high signal intensity on DWI.After contrast enhancement,mild and moderate enhanced lesions were demonstrated in 3 cases.Renal arteries were wrapped by renal pelvis carcinoma on renal AMRA in 3 cases.4 patients were accompanied with venous tumor thrombus and 1 1 patients with retroperitoneal lymph node metastasis.Adrenal gland metastases were showed in 3 cases.1 case was accompanied with ureter urothelial carcinoma,and 2 cases with bladder carcinomas.Conclusion MRI has a multi-parameter imaging capability and high resolution of soft tissue,and can clearly show the boundary of lesions and surroundings.MRI plays an important role in the diagnosis and differential diagnosis of infiltrative renal pelvis carcinoma.