Objective To explore the value of abnormal imaging findings on susceptibility weighted imaging (SWI) in delayed graft function (DGF). Methods The conventional MRI and SWI images of 26 cases with DGF and 20 cases with normal renal function of transplanted kidneys were retrospectively analyzed. Patients with cysts and angiomyolipomas were excluded. Normal structures of transplanted kidney were identified. If lesions of abnormal signal intensity were found in the transplanted kidney, the location, border and signal intensity compared to renal cortex would be analyzed. The differences in signal intensity between the abnormal signal lesions and normal renal cortex in the same SWI layer of DGF were compared by using independent-sample t test. The differences in positive detection rate of discovering the abnormal signal lesions in DGF between conventional MRI and SWI were compared by using McNemar test. Results Of the 26 cases with DGF, one case was found to exhibit abnormally low signal lesions with fuzzy boundary located at junctional zone between cortex and medulla on both conventional MRI and SWI images. Ten cases were found to exhibit abnormally low signal lesions with fuzzy boundary located at junctional zone between cortex and medulla on SWI images only. Fifteen cases exhibited no abnormal signal lesions on both conventional MRI and SWI images. Twenty cases with normal renal function of transplanted kidney, no abnormal signal lesions were found on both conventional MRI and SWI images. The differences in signal intensity between the abnormally low signal lesions (130±20) and normal renal cortex (177±25) in the same SWI layer of 11 cases with DGF were statistically significant (t=-4.582,P<0.01). The differences in positive detection rate of discovering the abnormally low signal lesions in DGF between conventional MRI [3.8%(1/26)] and SWI [42.3% (11/26)] were statistically significant (χ2=8.100,P=0.002). Conclusions Abnormally low signal lesions with fuzzy boundary located at junctional zone between cortex and medulla on SWI images suggest the presence of DGF. Compared with conventional MRI, SWI appears to be superior in detecting the abnormally low signal lesions.

Objective To explore the value of susceptibility weighted imaging (SWI) in the quantitative analysis of ischemia-reperfusion injury (IRI) of the rabbit kidneys . Methods Thirty New Zealand white rabbits were randomly assigned to IRI group (n=24, operation with clamping) and Sham group (n=6, operation without clamping). Left renal ischemia-reperfusion was performed by occlusion (calmping) of the left renal arterial for 60 minutes, followed by reperfusion. All the rabbits underwent MRI including T2WI and SWI before and 0.5 h, 12 h, 24 h and 48 h after the establishments of models . Three rabbits in IRI group were randomly sacrificed 0.5 h, 12 h, and 24 h after the establishment of model. The rest of the rabbits in IRI group and 6 rabbits in sham group were sacrificed for pathological examination 48 h after the establishment of model All specimen were cut into slices and stained with hematoxylin-eosin (HE). Region of interest ( ROI) was manually created by outlining the inner medulla, inner stripe of outer medulla, outer stripe of outer medulla, and cortex, then relative signal-to-noise ratio of the kidney (rSNR) to muscle in SWI sequence was recorded. and compared with histopathologic features. One-way ANOVA was performed to compare difference of rSNR to muscle in respective location at 5 time-points between Sham group and IRI group, and the differences between groups were tested using repetitive measure analysis of variance, repetitive measure analysis of variance was performed to compare difference of rSNR to muscle in respective location at respective time-points between Sham group and IRI group. Results rSNR value in the inner medulla 0.5 h, 12 h, 24 h and 48 h after the establishments of models were 0.28 ± 0.04, 0.98 ± 0.14, 0.69 ± 0.07, 0.57±0.06, 0.43±0.03, respectively (F=69.82,P<0.01), the inner stripe of outer medulla at the five time-points 0.08 ± 0.03, 0.57 ± 0.05, 0.32 ± 0.07, 0.16 ± 0.02, 0.04 ± 0.01, respectively(F=16.59,P<0.01), the outer stripe of outer medulla were 0.31 ± 0.04, 0.86 ± 0.09, 0.65 ± 0.07, 0.55 ± 0.06 0.43 ± 0.04(F=67.52,P<0.01), respectively,the cortex 0.05±0.01, 0.80±0.04, 0.68±0.07, 0.47±0.07, 0.36±0.08, respectively(F=118.96,P<0.01). The difference of the rSNR was statistically significant in the inner medulla, inner stripe of outer medulla, outer stripe of outer medulla, and cortex at the five different time-points. The differences between two groups were significant (F=206.29, 14.25, 42.8, 39.12, P all<0.05). The pathological findings in Sham group included normalglomerular structure l, clear cavity of tubular, no interstitial hyperemia and edema. The pathological findings in IRI group demonstated, at 0.5 h after IRI, Bowman's capsule cavity expansion, glomerular shrinkage, swelling of renal tubular epithelial cells, vacuoles degeneration, the tube cavity expansion, interstitial edema and congestion ecta became slender, andat 12 h after IR, Bowman's capsule expansion became more obvious, foam degeneration of renal tubular epithelial cells, apoptosis, partial loss of the brush border of the proximal convoluted tubule, formation of protein cast, and a small amount of inflammatory cells appeared in the renal interstitium, swelling of endothelial cells of the vasa recta, congestion of small vessels, and at 24 and 48 h after IRI, more serious injury of renal tubular in the outer stripe of outer medulla , massive necrosis of renal tubular epithelial cells, apoptosis, parts of the renal tubular had the contour lines, and renal tubular outline, increment in inflammatory cells, red cell and protein cast. Conclusion rSNR of SWI in the inner medulla, inner stripe of outer medulla, outer stripe of outer medulla, and cortex of the kidney varies with the degree of IRI over time, and is consistent with corresponding pathological feature, suggesting SWI is useful imaging tool to detect early damage of renal IRI quantitatively.

Objective To explore the value of susceptibility-weighted imaging (SWI) for the assessment of chronic renal injury. Methods Thirty-nine patients with clinical diagnosis of chronic renal injury (RI group) who underwent routine renal MRI and SWI examination were retrospectively analyzed. They were divided into mild injured group (15 cases) and moderate to severe injured group (24 cases) by estimated glomerular filtration rate (eGFR). At the same time, 17 volunteers without chronic renal injury who had normal serum creatinine (Scr) and blood urea nitrogen were recruited as control group. All subjects underwent routine renal MRI and SWI examination. The ratios of cortex to medulla were measured and calculated in both kidneys' magnitude image and susceptibility weighted image, which were indicated as C/MMAG and C/MSWI. Independent sample t test was used to compare the differences of C/MMAG and C/MSWI between control group and RI group, and paired sample t test was used to compare the differences betweenC/MMAG and C/MSWI in each group. One-way ANOVA was used to compare the difference of C/MMAG and C/MSWI between the control group and the different RI groups. ROC was employed to assess the diagnostic efficacy of C/MMAG and C/MSWI in renal injury. Pearson linear correlation analysis was used to evaluate the correlation between C/MMAG, C/MSWI and eGFR, Scr in patients with renal injury. Results The C/MMAG and C/MSWI in the RI group were 1.101±0.039 and 1.071±0.046, respectively. C/MSWI was obviously lower than C/MMAG, and the difference was statistically significant (t=5.056, P<0.01). There was no significant difference between C/MMAG and C/MSWI in the control group (P>0.05). The C/MMAG and C/MSWI in the RI group were obviously lower than those in the control group, and the difference was statistically significant (t=4.564, 6.122;P<0.01).The C/MMAG and C/MSWI in the mild injured group and the moderate to severe injured group were significantly lower than those in the control group, the difference was statistically significant (P<0.05). While the differences of those between mild injured group and moderate to severe injured group showed no statistical significance (P>0.05). The area under ROC of C/MMAG and C/MSWI in diagnosis of renal injury were 0.853 and 0.952, respectively. C/MMAG was positively correlated with eGFR (r=0.460,P<0.01). Conclusions Susceptibility-weighted imaging can be used to assess chronic renal injury. Although it cannot reflect the degree of renal function damage, it has some value in the early diagnosis of mild renal injury.

Objective: To detect the values of CT texture features in the preoperative prediction of Fuhrman grade of clear cell renal cell carcinoma (ccRCC). Methods: The CT data of 206 patients with ccRCC admitted to the Third Affiliated Hospital of Soochow University from January 2011 to December 2016 were retrospectively analyzed, and the ccRCC cases were graded using Fuhrman grading system, including 38 cases of Grade Ⅰ, 107 cases of Grade Ⅱ, 50 cases of Grade Ⅲ and 11 cases of Grade Ⅳ. All subjects undergone plain and enhancement CT scans. There were two methods used for the extraction of texture features, including histogram (2 features: Kurtosis and Skewness) and gray-level co-occurrence matrix (6 features: Contrast, Correlation, Energy, Entropy, Homogeneity and Variance). Each texture feature during Grade Ⅰ to Ⅳ was compared using a one-way analysis of variance following the log-ratio transformation, and a Newman-Keuls test was performed for all pairwise comparisons. An independent sample t test was used to find the differences of each texture feature between low (Grade Ⅰ+Ⅱ) and high grade (Grade Ⅲ+Ⅳ) ccRCC. A Spearman Rank test was performed to quantify the correlation of each texture feature with Fuhrman grade in ccRCC. Receiver operating characteristic curve (ROC) was employed to compare the diagnostic performance of the texture features to differentiate the low grade from high grade ccRCC. Results: Six texture features, including Contrast, Correlation, Entropy, Homogeneity, Variance and Kurtosis, were different during Grade Ⅰ to Ⅳ (all P<0.05) with the exception of the two features of Energy and Skewness (all P>0.05). Furthermore, five textures, such as Correlation, Entropy, Homogeneity, Variance and Kurtosis, were not significantly different between Grade Ⅲ and Ⅳ ccRCC. There was no clinical application value for the features of Correlation, Energy, Entropy, Variance and Skewness with the absolute coefficients of<0.3, in contrast, the correlation coefficients were -0.54, 0.39 and 0.32 for the features of Contrast, Homogeneity and Kurtosis, respectively (all P<0.05). Compared with that in the low grade ccRCC, the values of Contrast and Variance reduced in the high grade ccRCC (all P<0.05), while the values of Kurtosis, Correlation and Homogeneity increased significantly in the high grade ccRCC (all P<0.05), and no difference was found for the features of Skewness, Energy and Entropy between the low and high grade ccRCC (all P>0.05). When those features were used to differentiate the high from low grade ccRCC, the Contrast exhibited the biggest area under ROC of 0.806 (P<0.05), followed by the Correlation of 0.641, Homogeneity of 0.687, Kurtosis of 0.668 and Variance of 0.659. Conclusion CT texture features can preoperatively predict the Fuhrman grade of ccRCC, and the Contrast will likely be the potential imaging biomarker for the clinical application.

Objective:To explore the relationship between MRI texture features with the histopathology in early renal ischemia-reperfusion injury (IRI).Methods:Forty-eight healthy New Zealand rabbits were randomly divided into the IRI group ( n=40) and the sham group ( n=8). As for the IRI group, rabbits underwent the left kidney surgery by clamping the left renal artery for 60 mins and then releasing the clamp to establish renal IRI model. The rabbits in the sham group underwent the same operation, but without clamping the left renal artery. MR examination were performed before and at 1 h, 12 h, 24 h, and 48 h after the operations. As for the IR group, eight rabbits were randomly sacrificed at each time point immediately after MR exam. The eight rabbits in the sham group were sacrificed after MR exam at 48 h after the operation. The left kidney was harvested for histopathological examination. The single item score of the histopathological features, the microvessel density (MVD), and the pathological total score were calculated. Differences in the single item score of the histopathological features, MVD, and the pathological total score among IRI group with different time points and sham group were determined using the Kruskal-Wallis test. MRI texture features of the left kidney were extracted. Multiple dimensionality reduction for MRI texture features were performed, and the features associated with the pathological total score were selected. The relationship between MRI texture features with the single item score of the histopathological features and MVD was assessed by Pearson correlation coefficients. Results:There were significant differences in renal tubular brush border destruction, renal tubular epithelial edema, necrosis, cast, interstitial inflammatory cell infiltration, MVD, and the pathological total score in IRI group among the different time points (all P<0.05). T 2WI_S (3, -3) InvDfMom had the highest correlation with renal tubular brush border destruction, renal tubular epithelial edema, necrosis, and cast ( r=0.56, -0.58, 0.62, 0.69, all P<0.01). BOLD_S (4, -4) Correlat had the highest correlation with interstitial inflammatory cell infiltration ( r=0.63, P<0.01). SWI_S (4, 4) DifEntrp had the highest correlation with MVD ( r=0.61, P<0.01). Conclusion:MRI texture analysis can provide valuable information for evaluating early renal IRI.

Objective:To explore the feasibility of chemical exchange saturation transfer (CEST) imaging at 3.0 T MRI in quantifying renal redox metabolism in vitro models and experimental animals.Methods:Redox metabolites in vitro models with physiological concentrations were prepared, including reduced metabolites (glutamate, alanine, glutathione) and oxidized metabolites (2-ketoglutarate, pyruvate, glutathione disulfide, ammonium hydroxide). CEST examinations were performed at 3.0 T MRI. The imaging parameters were as follows: CEST images with different saturation pulse intensity (B 1) (1, 2, 3, 4 μT) and a fixed radio frequency (RF) duration of 2 000 ms; CEST images with different RF durations (1 500 and 2 000 ms) were acquired with a fixed B 1 value of 2 μT to obtain the optimal scanning parameters. CEST examinations with optimized parameters were performed on the left kidneys of seven healthy rabbits, and the differences in magnetic resonance ratio asymmetry (MTR asym) between rabbit renal cortex and outer medulla were measured. A paired t-test was used to compare the differences. Results:The optimal B 1 for CEST examination of redox metabolites was 2 μT, and the optimal RF duration was 2 000 ms. The MTR asym peaks of glutathione disulfide, glutathione, glutamic acid, and alanine were at 3.75, 3.5, 3, and 1.5 ppm, respectively. The MTR asym peaks of pyruvate, 2-ketoglutarate, and ammonium hydroxide were at 1 ppm. The MTR asym peak values of reduced metabolites were higher than those of oxidized metabolites. When the B 1 value was 2 μT and the RF duration was 2 000 ms, the MTR asym signal of the renal cortex was (2.60±1.10) %, (2.86±1.32) %, (3.04±1.06) %, and (2.98±0.91) % at 1, 3, 3.5, and 3.75 ppm, respectively. The MTR asym signal of the outer medulla was (1.00±0.56) %, (2.43±0.94) %, (2.29±0.88) % and (1.98±0.58) %, respectively. The MTR asym signal of the renal cortex was higher than that of the outer medulla, and the differences were statistically significant ( t=3.04, P=0.023; t=2.56, P=0.043; t=3.50, P=0.013; t=3.45, P=0.014). Conclusion:CEST imaging at 3.0 T MRI can be used to quantitatively evaluate redox metabolism of healthy rabbit kidneys in vitro model and normal experimental rabbits.

Objective:To investigate the feasibility of 3.0 T glutamate chemical exchange saturation transfer (GluCEST) imaging in evaluating renal redox metabolism in renal ischemia-reperfusion injury (IRI).Methods:Rabbits in the IRI group ( n=56) underwent surgery by clamping the left renal artery for 45 min and then releasing to establish IRI. Rabbits in the sham group ( n=8) underwent the same operation without clamping the left renal artery. GluCEST MRI was performed before and at 1 h, 12 h, 1 day, 3 days, 7 days, and 14 days after the operations, with eight rabbits in the IRI group sacrificed immediately after each scanning and eight in the sham group sacrificed at 14 days after scanning. The left kidneys were removed for histopathological examination and reactive oxygen species (ROS) fluorescence staining. Differences in the magnetic resonance ratio asymmetry (MTR asym) of the renal cortex and outer medulla among different groups were compared. Correlations between the MTR asym and ROS were analyzed. Results:The MTR asym of the renal cortex in the sham and IRI subgroups were higher than that of the outer medulla ( t=8.16, P<0.001; t=4.78, P=0.002; t=4.94, P=0.002; t=5.76, P=0.001, t=6.68, P<0.001; t=6.40, P<0.001; t=5.16, P=0.001; t=3.30, P=0.013). The MTR asym of the renal cortex and outer medulla in the IRI-1h, IRI-12h, IRI-1d, IRI-3d, IRI-7d, and IRI-14d groups were lower than in the sham and IRI-pre groups (all P<0.05). The MTR asym of the renal cortex and outer medulla in the IRI-1h group were lower than in the IRI-12h, IRI-1d, IRI-3d, IRI-7d, and IRI-14d groups (all P<0.05). The MTR asym of the renal cortex in the IRI-12h group was lower than in the IRI-7d and IRI-14d groups (1.84%±0.09% vs.2.42%±0.19%, 2.41%±0.31%, all P<0.05). The MTR asym of the renal cortex in the IRI-1d group was lower than in the IRI-7d group (1.99%±0.17% vs. 2.42%±0.19%, P=0.008). The MTR asym of the outer medulla in the IRI-12h group was lower than in the IRI-3d, IRI-7d, and IRI-14d groups (1.32%±0.27% vs. 1.79%±0.31%, 1.98%±0.18%, 1.66%±0.40%, respectively, all P<0.05]. The MTR asym of the outer medulla in the IRI-7d group was higher than in the IRI-1d and IRI-14d groups (1.98%±0.18% vs. 1.52%±0.31%, 1.66%±0.40%, all P<0.05). The MTR asym of the renal cortex and outer medulla had a strong negative correlation with the mean fluorescence intensity of ROS ( ρ=-0.889, P<0.001; ρ=-0.784, P<0.001). Conclusion:3.0 T GluCEST imaging can indirectly reflect the changes of renal redox metabolism in renal IRI.

Objective:To explore the value of susceptibility-weighted imaging (SWI) in quantitative evaluation of iron load in diabetic kidneys.Methods:Thirty two healthy New Zealand white rabbits were randomly divided into diabetic group (DM, n = 20) and control group (NC, n = 12). DM model was established by injecting 5% alloxan solution (100 ml/kg) through ear vein. 12 rats were finally enrolled into the group. NC group was injected with the same dose of normal saline. DM group and NC group were intramuscularly injected with 60 mg/kg iron dextran. The left kidney was scanned by MRI immediately after iron injection (0 weeks) and 12 weeks after feeding. The left kidney was killed after 12 weeks of scanning. The left kidney was examined by Prussian blue staining and atomic absorption spectrophotometer. The value of SWI in quantitative evaluation of renal iron content was evaluated by using the iron content measured by atomic absorption spectrophotometer as the gold standard. On SWI phase diagram, the region of interest (ROI) was manually drawn along the renal cortical vagal area, and the measured phase values were converted into angular radians. Mann Whitney U test was used to compare the blood glucose value and the angle radian value at 0 week and 12 week between the two groups; independent sample t test was used to compare the difference of iron content between the two groups; nonparametric Wilcoxon signed rank test was used to compare the difference of angle radian between DM group and NC group at 0 and 12 weeks; Spearman correlation analysis was used to study the correlation between angle radian value and atomic absorption spectrophotometer results. Results:The blood glucose level in DM group [28.0 (10.6) mmol/L] was significantly higher than that in NC Group [6.5 (1.9) mmol/L], and the difference was statistically significant (U = 0, P<0.001). At week 0, there was no significant difference between DM group [-0.04 (-0.02)] and NC Group [-0.02 (0.06)] in angle radian value (U=105.50, P>0.05); at 12 weeks, the angle radian value of DM group [0.22 (0.17)] was higher than that of NC Group [0.17 (0.05)], the difference was statistically significant (U=35.50, P<0.05). The angle radian of DM group and NC group at 12 weeks were higher than that of 0 weeks, and the differences were statistically significant ( P<0.05). Prussian blue staining showed that iron was mainly deposited in renal cortex, and the blue staining in DM group was more obvious than that in NC group. The signal intensity of renal cortex on SWI images in DM group was significantly lower than that in 0 week group at 12 weeks, and slightly decreased in NC group. The iron content of DM group and NC group were (171.39±20.13) mg/kg and (116.21±28.90) mg/kg, respectively, and the difference was statistically significant ( t=5.428, P<0.001). Spearman correlation analysis showed that the angle radian was positively correlated with iron content ( r=0.67, P<0.001). Conclusions:Diabetic kidneys have more iron deposits than normal kidneys. As a non-invasive, simple and convenient examination technique, SWI has the potential to quantitatively evaluate the iron load of diabetic kidneys.

Objective:To investigate the value of multimodal MRI radiomics in the preoperative prediction of Fuhrman nuclear grade of clear cell renal cell carcinoma (ccRCC).Methods:A total of 129 patients with ccRCC confirmed by pathology from April 2011 to April 2021 in Third Affiliated Hospital of Soochow University were collected, and the imaging and clinicopathological data were retrospectively analyzed. All patients were divided into training set ( n=90) and validation set ( n=39) at the ratio of 7∶3 using random indicator method. According to the postoperative pathological results, Fuhrman grades Ⅰ and Ⅱ were included in the low grade group (96 cases, 65 cases in the training set and 31 cases in the validation set), and Fuhrman grades Ⅲ and Ⅳ were included in the high grade group (33 cases, 25 cases in the training set and 8 cases in the validation set). Two radiologists manually delineated regions of interest (ROI) on T 1WI, T 2WI, Dixon-water, Dixon-fat, susceptibility weighted imaging (SWI), blood oxygen level dependent (BOLD) images, and 396 texture features were extracted from each ROI. In the training set, intra-class correlation coefficient, Mann-Whitney U test, minimum redundancy maximum relevance and least absolute shrinkage and selection operator method were used to reduce the dimension of features to obtain the best texture features. The logistic regression was used to develop the multimodal radiomics model, and the receiver operating characteristic (ROC) curve was used to evaluate the effectiveness of the model in identifying high and low-grade ccRCC in training set and validation set. Results:Four SWI, one T 2WI and one BOLD texture features were selected for modeling. The areas under the ROC curve (95%CI) of the multimodal radiomics model for identifying high and low grade ccRCC in the training and validation sets were 0.859 (0.770-0.923) and 0.883 (0.740-0.964), with the specificity at 95.4% and 87.1%, the sensitivity at 68.0% and 87.5%, the accuracy at 87.8% and 87.2%, respectively. Conclusion:The multimodal MRI radiomics model based on T 2WI, SWI and BOLD images has high effectiveness in preoperative predicting Fuhrman nuclear grade of ccRCC.

To investigate the clinical characteristics of metastatic hormone sensitive prostate cancer and explore the strategy of combination of new endocrine drugs.In April 2019, an 69-year-old man was admitted to the First People’s hospital of Changzhou with "gross hematuria" . Physical examination showed prostatic hyperplasia with an unsmooth hard surface. CT showed a mass in bladder and possible metastasis in right lung. Diagnostic TUR-Bt pathology showed prostatic acinar adenocarcinoma, and PET-CT showed malignant lesion of prostate with bladder invasion, multiple pelvic lymph node metastasis and lung metastasis. The diagnosis of mHSPC with lymphatic and lung metastasis was considered. The patient was treated with bicalutamide and then switched to goserelin plus acetate abiraterone with prednisone. Total prostate specific antigen (tPSA) decreased to 0.705 ng/ml after 1 month of ADT+ AAP treatment, and decreased to 0.007 ng/ml after 4 months, and then maintained at 0.003 ng/ml until January 2021. Serum testosterone decreased to 0ng/dl and maintained the whole follow-up period. After 3 months of treatment, the pulmonary metastasis was not obvious. Till the last follow-up at January 2021, the patient reported good quality of life with no serious adverse events. The efficacy of ADT combined with acetate abiraterone in the treatment of mHSPC with lung cancer was significant.