Capability of arterial spin labeling and intravoxel incoherent motion diffusion-weighted imaging to detect early kidney injury in chronic kidney disease.

OBJECTIVES: To prospectively investigate the capability of arterial spin labeling (ASL) and intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) for the identification of early kidney injury in chronic kidney disease (CKD) patients with normal estimated glomerular filtration rate (eGFR). METHODS: Fifty-four CKD patients confirmed by renal biopsy (normal eGFR group [eGFR ≥ 90 mL/min/1.73 m2]: n = 26; abnormal eGFR group [eGFR < 90 mL/min/1.73 m2]: n = 28) and 20 healthy volunteers (HV) were recruited. All subjects were examined by IVIM-DWI and ASL imaging. Renal blood flow (RBF) derived from ASL, true diffusion coefficient (D), pseudo-diffusion coefficient (D*), and perfusion fraction (f) derived from IVIM-DWI were measured from the renal cortex. One-way analysis of variance was used to compare MRI parameters among the three groups. The correlation between eGFR and MRI parameters was evaluated by Spearman correlation analysis. Diagnostic performances of MRI parameters for detecting kidney injury were assessed by receiver operating characteristic (ROC) curves. RESULTS: The renal cortical D, D*, f, and RBF values showed statistically significant differences among the three groups. eGFR was positively correlated with MRI parameters (D: r = 0.299, D*: r = 0.569, f: r = 0.733, RBF: r = 0.586). The areas under the curve (AUCs) for discriminating CKD patients from HV were 0.725, 0.752, 0.947, and 0.884 by D, D*, f, and RBF, respectively. D, D*, f, RBF, and eGFR identified CKD patients with normal eGFR with AUCs of 0.735, 0.612, 0.917, 0.827, and 0.733, respectively, and AUC of f value was significantly larger than that of eGFR. CONCLUSION: IVIM-DWI and ASL were useful for detecting underlying pathologic injury in early CKD patients with normal eGFR. KEY POINTS: • The renal cortical f and RBF values in the control group were significantly higher than those in the normal eGFR group. • A negative correlation was observed between the renal cortical D, D*, f, and RBF values and SCr and 24 h-UPRO, while eGFR was significantly positively correlated with renal cortical D, D*, f, and RBF values. • The AUC of renal cortical f values was statistically larger than that of eGFR for the discrimination between the CKD with normal eGFR group and the control group.

Evaluation of interstitial fibrosis in chronic kidney disease by multiparametric functional MRI and histopathologic analysis.

OBJECTIVES: To investigate the diagnostic value of functional MRI to assess renal interstitial fibrosis in patients with chronic kidney disease (CKD). METHODS: We prospectively recruited 80 CKD patients who underwent renal biopsies and 16 healthy volunteers to undergo multiparametric functional MRI examinations. The Oxford MEST-C classification was used to score the interstitial fibrosis. The diagnostic performance of functional MRI to discriminate interstitial fibrosis was evaluated by calculating the area under the receiver operating characteristic (ROC) curves. RESULTS: IgA nephropathy (60%) accounted for the majority of pathologic type in the CKD patients. Apparent diffusion coefficient (ADC) from diffusion-weighted imaging (DWI) was correlated with interstitial fibrosis (rho = -0.73). Decreased renal blood flow (RBF) derived from arterial spin labeling (rho = -0.78) and decreased perfusion fraction (f) derived from DWI (rho = -0.70) were accompanied by increased interstitial fibrosis. The T1 value from T1 mapping correlated with interstitial fibrosis (rho = 0.67) (all p < 0.01). The areas under the ROC curve for the discrimination of ≤ 25% vs. > 25% and ≤ 50% vs. > 50% interstitial fibrosis were 0.87 (95% confidence interval, 0.78 to 0.94) and 0.93 (0.86 to 0.98) by ADC, 0.84 (0.74 to 0.91) and 0.94 (0.86 to 0.98) by f, 0.93 (0.85 to 0.98) and 0.90 (0.82 to 0.96) by RBF, and 0.91 (0.83 to 0.96) and 0.77 (0.66 to 0.85) by T1, respectively. CONCLUSIONS: Functional MRI parameters were strongly correlated with the interstitial fibrosis of CKD. Therefore, it might a powerful tool to assess interstitial fibrosis of CKD noninvasively. KEY POINTS: • In CKD patients, the renal cortical ADC value decreased and T1 value increased significantly compared with healthy volunteers. • Functional MRI revealed significantly decreased renal perfusion in CKD patients compared with healthy volunteers. • The renal cortical ADC, f, RBF, and T1 values were strongly correlated with the interstitial fibrosis of CKD.

Preliminary Exploration of the Application of Vesical Imaging-Reporting and Data System (VI-RADS) in Post-treatment Patients With Bladder Cancer: A Prospective Single-Center Study.

BACKGROUND: Vesical Imaging-Reporting and Data System (VI-RADS) has been shown to be effective in diagnosing muscle invasion of bladder cancer (BC) in primary patients. PURPOSE: To evaluate the diagnostic efficacy of VI-RADS in a BC target population which included post-treatment patients, and to determine the repeatability. STUDY TYPE: Prospective. POPULATION: Seventy-three patients (42 with primary BC, 31 with post-treatment BC). FIELD STRENGTH/SEQUENCE: 3.0 T MRI with propeller fast spin-echo T2 WI, echo planer imaging diffusion-weighted imaging (DWI), and dynamic contrast-enhanced imaging (DCEI). ASSESSMENT: VI-RADS scores were independently assessed by five radiologists with different levels of experience. The diagnostic efficiency in each group (primary and post-treatment) and of each radiologist was assessed. STATISTICAL TESTS: Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), and area under the curve (AUC) in receiver operating characteristic curve analysis were calculated to evaluate VI-RADS diagnostic performance. Interobserver agreement was assessed using weighted Kappa statistics. A P value <0.05 was considered statistically significant. RESULTS: At the corresponding cut-off, AUC values of three groups range from 0.936 to 0.947 and AUC values of five observers range from 0.901 to 0.963. There was no significant difference between the AUCs in the primary and post-treatment groups (P = 0.870). The cut-off of the whole group and the post-treatment group was ≥4, and the cut-off of the primary group was ≥3. The Kappa values of interobserver agreements range from 0.709 to 0.923. CONCLUSIONS: After expanding the target population to include post-treatment patients, VI-RADS still has good diagnostic efficacy and repeatability. VI-RADS could potentially be a preoperative staging tool for post-treatment patients. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY STAGE: 2.

Does intraoperative cyst rupture of malignant cystic renal masses really have no negative impact on oncologic outcomes?

BACKGROUND: To assess the impact of malignant cystic renal masses (CRM) rupture on oncologic outcomes. METHODS: The study included 406 cases with partial nephrectomy (PN) and 17 cases with cyst decortication confirmed as malignant CRM by pathology. Recurrence-free survival (RFS), metastasis-free survival (MFS), cancer-specific survival (CSS), and overall survival (OS) were analyzed by the Kaplan-Meier method and log-rank test. Cox regression was used to identify risk factors associated with RFS, MFS, CSS, and OS. Logistic regression was performed to explore predictors of rupture. RESULTS: Tumor rupture occurred in 32 of 406 cases (7.9%). With median follow-up of 43 months, 4 (12.5%) and 5 (1.3%) cases experienced recurrence in rupture and non-rupture group, respectively (P = 0.003). Estimated RFS, MFS, and CSS were shorter in cyst ruptured (CR) group than non-ruptured (nonCR) cases (P < 0.001; P = 0.001; P < 0.001). Cox regression analysis indicated that CR was an independent prognostic factor for RFS (HR = 7.354; 95% CI = 1.839-29.413; P = 0.005), MFS (HR = 8.069; 95% CI = 1.804-36.095; P = 0.006), and CSS (HR = 9.643; 95% CI = 2.183-42.599; P = 0.003). Multivariable logistic regression showed that Bosniak IV was a protective factor for CR (OR = 0.065; 95% CI = 0.018-0.239; P < 0.001). However, compared to Bosniak III and I-IIF, Bosniak IV CRMs showed higher rate of clear cell renal cell carcinoma (ccRCC) (76.8% vs 36.5% vs 81.4%) (P < 0.001) and lower rate of Fuhrman I staging (11.2% vs 66.7% vs 7.4%) (P < 0.001). Therefore, in ruptured cases, the recurrence rate was higher in CRM with Bosniak IV (50%, 2/4) than Bosniak I-III (4.4%, 2/45) (P = 0.029). CONCLUSIONS: Intraoperative malignant CRM rupture had negative impacts on oncologic outcomes. Bosniak IV was more aggressive than Bosniak I-III and had a higher risk of recurrence after rupture. However, Bosniak IV had a lower risk of rupture, which could weaken even cover-up of the true effect of tumor rupture on oncologic outcomes.

Value of T1 Mapping in the Non-invasive Assessment of Renal Pathologic Injury for Chronic Kidney Disease Patients.

PURPOSE: The objective of this study was to evaluate renal function and pathologic injury in chronic kidney disease (CKD) using T1 mapping. METHODS: We recruited fifteen healthy volunteers (HV) and seventy-five CKD patients to undergo T1 mapping examination, and renal parenchymal T1 values were measured. Spearman correlation analysis was used to evaluate the relevance between the pathologic injury score, estimated glomerular filtration rate (eGFR), and renal parenchymal T1 values. The diagnostic efficiency of T1 value in evaluating renal pathologic impairment was assessed. RESULTS: In all subjects, renal cortical T1 value was remarkably lower than renal medullary T1 value (P < 0.01). The renal medullary T1 value of HV was considerably lower than that of CKD patients in all stages (P < 0.05). The T1 values were negatively correlated with eGFR (cortex, r = -0.718; medulla, r = -0.645). The T1 values were positively correlated with glomerular injury score (cortex, r = 0.692; medulla, r = 0.632), tubulointerstitial injury score (cortex, r = 0.758; medulla, r = 0.690) (all P < 0.01). The area under the curve (AUC) of renal cortical and medullary T1 values were 0.914 and 0.880 to distinguish moderate-severe from mild renal injury groups. To differentiate mild renal injury group from control group, the AUC values of renal cortical and medullary T1 values were 0.879 and 0.856. CONCLUSION: T1 mapping has potential application value in non-invasively assessing renal pathologic injury in CKD.

Prognostic value of tumour contour irregularity on surgical strategies for T1bN0M0 renal cell carcinoma: A multi-institutional study.

PURPOSE: To determine the prognostic value of tumour contour irregularity degree (CID) in surgical strategy options for T1bN0M0 renal cell carcinoma (RCC). MATERIALS AND METHODS: We performed a retrospective multi-institutional review of 489 patients with T1bN0M0 RCC treated between January 2009 and June 2019. Cox regression and Kaplan-Meier analyses were performed to analyse the impact of CID on disease-free survival (DFS). RESULTS: The median follow-up time was 55 months (interquartile range, 40-81 months) for 55 (11.2 %) patients with metastasis or recurrence. Logistic analysis indicated that CID was associated with World Health Organization/International Society of Urological Pathology (WHO/ISUP) grades III-IV (odds ratio, 1.015; 95 % confidence interval [CI], 1.008-1.023; p < 0.001). After being classified into high CID (≥50 %) and low CID (<50 %) groups, those with a high CID showed a significantly higher ratio of WHO/IUSP grades III-IV (74/277 [26.7 %] vs 25/212 [11.8 %]) and shorter DFS than the low CID group (p < 0.001). Multivariable Cox regression showed that partial nephrectomy (PN; hazard ratio [HR], 1.889; 95 % CI, 1.020-3.499; p = 0.043), high CID (HR, 6.685; 95 % CI, 2.776-16.100; p < 0.001), and WHO/ISUP grade III-IV (HR, 1.950; 95 % CI, 1.100-3.458; p = 0.022) were independent prognostic factors for DFS. The Kaplan-Meier plot showed that PN had a DFS rate comparable to that of radical nephrectomy (RN; p = 0.994). In the low CID group, patients who underwent PN showed comparable DFS to those who underwent RN (p = 0.903). Furthermore, patients with a high CID tended to have worse DFS in the PN versus RN group (p = 0.044). Multivariable Cox regression showed that PN (HR, 2.049; 95 % CI, 1.065-3.942; p = 0.032) and WHO/ISUP grade III-IV (HR, 2.148; 95 % CI, 1.189-3.881; p = 0.011) were independent prognostic factors of DFS in the high CID group. CONCLUSIONS: CID is a reliable preoperative parameter which is positively correlated with WHO/ISUP grade and can help with surgical decision-making in patients with T1bN0M0 RCC.

Detecting the muscle invasiveness of bladder cancer: An application of diffusion kurtosis imaging and tumor contact length.

PURPOSE: To evaluate the diagnostic efficacy of diffusion kurtosis imaging (DKI) parameters and tumor contact length (TCL) among clinical and radiological factors for preoperative prediction of muscle-invasive bladder cancer (MIBC). METHOD: A total of ninety-seven patients underwent 3.0 T MRI scan with propeller fast spin-echo T2WI, echo planar imaging diffusion-weighted imaging (DWI), and dynamic contrast-enhanced imaging (DCE). Two radiologists independently viewed multiparametric MRI (mpMRI) of each patient, graded the VI-RADS, drew the region of interest (ROI) and measured TCL. Interclass correlation coefficients (ICCs), Kappa statistics, Kolmogorov-Smirnov test, Mann-Whitney U tests, chi-square tests, logistic regression analyses, Hosmer-Lemeshow tests, receiver operating characteristic curve (ROC) analysis, and area under the curve (AUC) were applied. RESULTS: The mean Kapp of NMIBC group (0.62 ± 0.01) was significantly lower than that of MIBC group (0.79 ± 0.08). The mean TCL of MIBC group (4.66 ± 1.89) was significantly larger than TCL of NMIBC group (1.88 ± 1.50) (all p < 0.01). At the corresponding cut-off, AUC of TCL, Kapp, VI-RADS and the combination of Kapp and TCL were 0.87, 0.92, 0.90, and 0.95, respectively. TCL and Kapp were risk factors of BC muscle invasion at both univariate and multivariate analysis. CONCLUSIONS: Kapp performed better than conventional DWI in predicting MIBC. Kapp and TCL were independent risk factors of MIBC and could complement VI-RADS for predicting muscle invasion. The combination of Kapp and TCL had the largest AUC and highest accuracy among all parameters.

Predictive value of renal tumor contour irregularity score in pathological T3a upstaging of clinical T1 renal cell carcinoma: A multi-institutional study.

PURPOSE: To explore the predictive value of renal tumor contour irregular degree (CID) in pathological T3a upstaging of clinical T1 renal cell carcinoma (RCC). MATERIALS AND METHODS: We performed a retrospective multi-institutional review of 1,487 patients with clinical T1N0M0 RCC between January 2009 and June 2019. Kaplan-Meier survival curve and Cox regressions were used to analyze the prognostic factors of disease-free survival (DFS). Logistic regressions were performed to determine predictors of pathological T3a upstaging in clinical T1 RCC. RESULTS: Among 1,487 patients with cT1 RCC, 96 (6.5%) were pathological T3a upstaging. Multivariable logistic regression analysis showed that age (odds ratio [OR] = 1.022, 95% confidence interval [CI] = 1.001-1.042, P = 0.036), tumor maximum diameter(OR = 1.242, 95% CI = 1.042--1.480, P = 0.015) and CID (OR = 1.067, 95% CI = 1.051-1.083, P < 0.001) were independent predictors of pathological T3a upstaging. The area under the curve (AUC) of the prediction model that included the CID was 0.846, while the AUC of the prediction model that did not include CID was only 0.741, the difference was statistically significant (P < 0.001). Kaplan-Meier survival curve showed that patients with pathological T3a upstaging had significantly worse DFS than patients without pathological T3a upstaging (P < 0.001). Multivariable Cox analysis showed that pathological T3a upstaging (HR = 1.836, 95% CI = 1.013-3.329, P = 0.002) is an independent prognostic factor for DFS in patients with cT1N0M0 RCC. CONCLUSIONS: The predictive model of CID combined with tumor maximum diameter and age significantly improved the ability to predict pathological T3a upstaging in clinical T1 RCC, compared with the prediction model of tumor maximum diameter combined with age. The predictive model of CID combined with tumor maximum diameter and age may be applicable to patients considering partial vs. radical nephrectomy.

Prediction of muscle invasion of bladder cancer: A comparison between DKI and conventional DWI.

OBJECTIVES: To prospectively compare the diagnostic efficacy of conventional diffusion-weighted imaging (DWI) and diffusion kurtosis imaging (DKI) in differentiating between muscle-invasive bladder cancer (MIBC) and non-muscle-invasive bladder cancer (NMIBC). METHODS: Multiple b value DWIs were performed using a 3-T magnetic resonance (MR) imaging unit in fifty-one patients with bladder cancer including MIBC and NMIBC confirmed by histopathological findings. DWI data were postprocessed using mono-exponential and DKI models to calculate the apparent diffusion coefficient (ADC), apparent diffusional kurtosis (Kapp), and kurtosis-corrected diffusion coefficient (Dapp). Receiver-operating characteristic (ROC) analysis was performed to compare the diagnostic efficacy of all diffusion parameters. RESULTS: All parameters differed significantly between MIBC and NIMBC including increased Kapp, decreased Dapp and ADC (all p < 0.001). Only the combination of Dapp and Kapp was significantly higher than ADC (p < 0.05), whilst Dapp and Kapp were not statistically different from ADC. CONCLUSIONS: Both conventional DWI and DKI models are beneficial in differentiating between MIBC and NMIBC, whilst the combination of Dapp and Kapp can produce a more robust value than conventional ADC value in evaluating aggressiveness of bladder cancer.