Comparisons of in-hospital fee and surgical outcomes between robot-assisted, laparoscopic, and open radical cystectomy: a Japanese nationwide study.

OBJECTIVE: To evaluate in-hospital fees and surgical outcomes of robot-assisted radical cystectomy (RARC), laparoscopic radical cystectomy (LRC) and open radical cystectomy (ORC) using a Japanese nationwide database. METHODS: All data were obtained from the Diagnosis Procedure Combination database between April 2020 and March 2022. Basic characteristics and perioperative indicators, including in-hospital fees, were compared among the RARC, LRC and ORC groups. Propensity score-matched comparisons were performed to assess the differences between RARC and ORC. RESULTS: During the study period, 2931, 1311 and 2435 cases of RARC, LRC and ORC were identified, respectively. The RARC group had the lowest in-hospital fee (median: 2.38 million yen), the shortest hospital stay (26 days) and the lowest blood transfusion rate (29.5%), as well as the lowest complication rate (20.9%), despite having the longest anesthesia time (569 min) among the three groups (all P < 0.01). The outcomes of LRC were comparable with those of RARC, and the differences in these indicators between the RARC and ORC groups were greater than those between the RARC and LRC groups. In propensity score-matched comparisons between the RARC and ORC groups, the differences in the indicators remained significant (all P < 0.01), with an ~50 000 yen difference in in-hospital fees. CONCLUSIONS: RARC and LRC were considered to be more cost-effective surgeries than ORC due to their superior surgical outcomes and comparable surgical fees in Japan. The widespread adoption of RARC and LRC is expected to bring economic benefits to Japanese society.

Incidence and predictors of intraoperative hypotension during transurethral bladder tumor resection with oral 5-aminolevulinic acid.

OBJECTIVES: To analyze the incidence and risk factors of intraoperative hypotension related to photodynamic diagnosis-assisted transurethral resection of bladder tumor (PDD-TURBT) with oral 5-aminolevulinic acid (5-ALA). METHODS: We retrospectively analyzed 487 patients with bladder tumors who underwent PDD-TURBT (n = 184) or conventional TURBT (conv-TURBT) (n = 303) between 2018 and 2021. Intraoperative hypotension was defined as hypotension requiring vasopressors during TURBT, and its incidence was compared between the two groups. Potential risk factors of intraoperative hypotension, including preoperative change in mean arterial pressure (MAP), were further investigated in patients receiving PDD-TURBT. RESULTS: The median age was 72 years, 392 patients (81%) were male, and 203 (42%) had hypertension. TURBT was performed under general and spinal anesthesia in 76 (16%) and 411 (84%) patients, respectively. The incidence of intraoperative hypotension was significantly higher in PDD-TURBT compared to conv-TURBT (43% vs. 17%, respectively). The median change in MAP until the induction of anesthesia was +6.5 mmHg (range: -29.0 to +46.3) in the PDD-TURBT group and +14.7 mmHg (range: -35.3 to +67.7) in the conv-TURBT group, showing a significantly smaller increase in the PDD-TURBT group (p < 0.001). In the multivariable analysis for PDD-TURBT patients, advanced age, general anesthesia, and lower MAP change (<+6.5 mmHg) until anesthesia induction were significantly associated with intraoperative hypotension (p = 0.0104, <0.001, and <0.001, respectively). CONCLUSIONS: Intraoperative hypotension occurred more frequently in patients who underwent PDD-TURBT than in those who underwent conv-TURBT. Using oral 5-ALA decreases preoperative blood pressure elevation and may be responsible for intraoperative hypotension.

Incidence, risk factors, and significance of 20% decrease from new baseline estimated glomerular filtration rate after radical and partial nephrectomy within 2 years.

OBJECTIVES: To evaluate the incidence and risk factors of a 20% decrease from new baseline (NB)-estimated glomerular filtration rate (eGFR) within 2 years after radical nephrectomy (RN) and partial nephrectomy (PN) and to examine the difference in the incidence of end-stage renal disease (ESRD) with or without the 20% decrease. METHODS: This retrospective study included 238 patients undergoing RN and 369 undergoing PN for cT1a-cT3a renal cancer. The incidence of a 20% decrease from NB-eGFR within 2 years after RN/PN was examined and its potential risk factors including surgery type were assessed by multivariate logistic regression analysis. The development of ESRD was analyzed as an endpoint and its incidence was compared according to the presence or absence of the 20% decrease from NB-eGFR within 2 years. RESULTS: Overall, the 20% decrease from NB-eGFR within 2 years was observed in 37 patients (6.1%), including 10 (4.2%) and 27 (7.3%) after RN and PN, respectively (p = 0.117). Diabetes mellitus, proteinuria, and perioperative complications were shown to be independent risk factors for the 20% decrease from NB-eGFR, while surgery type was not. During the median follow-up of 65 months, the ESRD-free survival rate at 6 years was 75.5% and 99.6% in patients with and without the 20% decrease from NB-eGFR, respectively (p < 0.001), while no significant difference was observed between patients undergoing RN and PN (98.1% and 98.7%, p = 0.561). CONCLUSIONS: Because the incidence of ESRD after the 20% decrease from NB-eGFR within 2 years was as high as 24.5% at 6 years, these patients should be followed with utmost care.

Utility of positive core number on MRI-ultrasound fusion targeted biopsy in combination with PI-RADS scores for predicting unexpected extracapsular extension of clinically localized prostate cancer.

OBJECTIVES: To evaluate the utility of magnetic resonance imaging (MRI) and MRI-ultrasound fusion targeted biopsy (TB) for predicting unexpected extracapsular extension (ECE) in clinically localized prostate cancer (CLPC). METHODS: This study enrolled 89 prostate cancer patients with one or more lesions showing a Prostate Imaging-Reporting and Data System (PI-RADS) score ≥3 but without morphological abnormality in the prostatic capsule on pre-biopsy MRI. All patients underwent TB and systematic biopsy followed by radical prostatectomy (RP). Each lesion was examined by 3-core TB, taking cores from each third of the lesion. The preoperative variables predictive of ECE were explored by referring to RP specimens in the lesion-based analysis. RESULTS: Overall, 186 lesions, including 81 (43.5%), 73 (39.2%), and 32 (17.2%) with PI-RADS 3, 4, and 5, respectively, were analyzed. One hundred and twenty-two lesions (65.6%) were diagnosed as cancer on TB, and ECE was identified in 33 (17.7%) on the RP specimens. The positive TB core number was ≤2 in 129 lesions (69.4%) and three in 57 lesions (30.6%). On the multivariate analysis, PI-RADS ≥4 (p = 0.049, odds ratio [OR] = 2.39) and three positive cores on TB (p = 0.005, OR = 3.07) were independent predictors of ECE. Lesions with PI-RADS ≥4 and a positive TB core number of 3 had a significantly higher rate of ECE than those with PI-RADS 3 and a positive TB core number ≤2 (37.5% vs. 7.8%, p < 0.001). CONCLUSIONS: Positive TB core number in combination with PI-RADS scores is helpful to predict unexpected ECE in CLPC.

Stepwise algorithm using computed tomography and magnetic resonance imaging for differential diagnosis of fat-poor angiomyolipoma in small renal masses: A prospective validation study.

OBJECTIVES: To validate the diagnostic accuracy of a stepwise algorithm to differentiate fat-poor angiomyolipoma (fp-AML) from renal cancer in small renal masses (SRMs). METHODS: We prospectively enrolled 223 patients with solid renal masses <4 cm and no visible fat on unenhanced computed tomography (CT). Patients were assessed using an algorithm that utilized the dynamic CT and MRI findings in a stepwise manner. The diagnostic accuracy of the algorithm was evaluated in patients whose histology was confirmed through surgery or biopsy. The clinical course of the patients was further analyzed. RESULTS: The algorithm classified 151 (68%)/42 (19%)/30 (13%) patients into low/intermediate/high AML probability groups, respectively. Pathological diagnosis was made for 183 patients, including 10 (5.5%) with fp-AML. Of these, 135 (74%)/36 (20%)/12 (6.6%) were classified into the low/intermediate/high AML probability groups, and each group included 1 (0.7%)/3 (8.3%)/6 (50%) fp-AMLs, respectively, leading to the area under the curve for predicting AML of 0.889. Surgery was commonly opted in the low and intermediate AML probability groups (84% and 64%, respectively) for initial management, while surveillance was selected in the high AML probability group (63%). During the 56-month follow-up, 36 (82%) of 44 patients initially surveyed, including 13 of 18 (72%), 6 of 7 (86%), and 17 of 19 (89%) in the low/intermediate/high AML probability groups, respectively, continued surveillance without any progression. CONCLUSIONS: This study confirmed the high diagnostic accuracy for differentiating fp-AMLs. These findings may help in the management of patients with SRMs.

Impact of diagnostic ureteral catheterization on intravesical tumour recurrence following radical nephroureterectomy for upper tract urothelial carcinoma.

PURPOSE: To investigate whether even a minimally invasive diagnostic procedure for the upper tract such as ureteral catheterization (UCath) may substantially increase the risk of intravesical recurrence (IVR) in patients with upper tract urothelial carcinoma (UTUC) treated with radical nephroureterectomy (RNU). METHODS: The present, retrospective study enrolled 163 patients undergoing RNU for UTUC between 2010 and 2021 at two, tertiary care hospitals. The primary endpoint was the association between UCath and IVR-free survival (IVRFS). The secondary endpoints were the association of ureterorenoscopy (URS) and URS biopsy (URSBx) with IVRFS. Directed acyclic graph (DAG)-guided multivariable models were used to adjust for potential confounders. RESULTS: Of the 163 patients, 128 (79%), 88 (54%), and 67 (41%) received UCath, URS, and URSBx, respectively. URS was performed concurrently with UCath. During the follow-up period (median: 47 months), IVR developed in 62 patients (5-year IVRFS rate: 52%). A DAG included concurrent bladder cancer, tumour size, hydronephrosis, positive cytology, and multiple UTUCs as potential confounders of the association between UCath and IVR. Both DAG-guided and stepwise multivariable models revealed a significant association between UCath and IVR (hazard ratio: 17.8; P < 0.001). UCath was also associated with shorter IVRFS in a subset of 75 patients who had not received URS (P < 0.001). In contrast, URS and URSBx were not associated with IVR in patients who had received UCath and URS, respectively. CONCLUSION: Any diagnostic manipulations of the upper urinary tract, even a minimally invasive procedure like UCath, could confer a risk of post-RNU IVR in UTUC patients.

Novel utility of Vesical Imaging-Reporting and Data System in multimodal treatment for muscle-invasive bladder cancer.

OBJECTIVES: To examine the clinical significance of the Vesical Imaging-Reporting and Data System (VI-RADS) in predicting outcome of multimodal treatment (MMT) in muscle-invasive bladder cancer (MIBC) patients. METHODS: We reviewed 78 pathologically proven MIBC patients who underwent MMT including transurethral resection and chemoradiotherapy, followed by partial or radical cystectomy. Treatment response was assessed through histologic evaluation of cystectomy specimens. Two radiologists categorized the index lesions of pretherapeutic MRI according to the 5-point VI-RADS score. The associations of VI-RADS score with the therapeutic effect of MMT were analyzed. The diagnostic performance of VI-RADS scores with a cut-off VI-RADS scores ≤ 2 or ≤ 3 for predicting pathologic complete response to MMT (MMT-CR) was evaluated. RESULTS: MMT-CR was achieved in 2 (100%) of VI-RADS score 1 (n = 2), 16 (84%) of score 2 (n = 19), 12 (86%) of score 3 (n = 14), 7 (64%) of score 4 (n = 11), and 14 (44%) of score 5 (n = 32). VI-RADS score was inversely associated with the incidence of MMT-CR (p = 0.00049). The cut-off VI-RADS score ≤ 2 and ≤ 3 could predict the favorable therapeutic outcome of MMT with high specificity (0.89 with 95% confidence interval [CI]: 0.71-0.98 and 0.82 with 95% CI: 0.62-0.94, respectively) and high positive predictive value (0.86 with 95% CI: 0.64-0.97 and 0.86 with 95% CI: 0.70-0.95, respectively). CONCLUSION: VI-RADS score may serve as an imaging marker in MIBC patients for predicting the therapeutic outcome of MMT. CLINICAL RELEVANCE STATEMENT: Muscle-invasive bladder cancer patients with a lower Vesical Imaging-Reporting and Data System score can be a good candidate for bladder-sparing treatment incorporating multimodal treatment. KEY POINTS: • Vesical Imaging-Reporting and Data System (VI-RADS) score was potentially valuable for classifying pathologic tumor response in patients with muscle-invasive bladder cancer. • The likelihood of achieving complete response of multimodal treatment (MMT) decreased with increasing VI-RADS score. • VI-RADS score could serve as an imaging marker that optimizes patient selection for MMT.

Trends of radical cystectomy and comparisons of surgical outcomes among surgical approaches focusing on robot-assisted radical cystectomy: A Japanese nationwide database study.

OBJECTIVE: To clarify the trends in radical cystectomy and to compare surgical outcomes among surgical approaches focusing on robot-assisted radical cystectomy based on a Japanese nationwide database. METHODS: The Diagnosis Procedure Combination database was used to extract data on radical cystectomy cases. Trends in open radical cystectomy, laparoscopic radical cystectomy, minimum incision endoscopic radical cystectomy, and robot-assisted radical cystectomy between April 2012 and March 2021 were evaluated. Basic characteristics and peri-operative indicators were compared among the four groups. Propensity score matching was applied to assess the differences between open radical cystectomy and robot-assisted radical cystectomy. RESULTS: During the study period, a decreasing number of open radical cystectomies and an increasing number of minimally invasive radical cystectomies were shown in the total cohort of 28 345 cases. The number of robot-assisted radical cystectomies rapidly increased after government approval in 2018. Minimally invasive radical cystectomies, including robot-assisted radical cystectomies, had a significantly lower complication rate, a shorter length of stay, and a lower blood transfusion rate, but a longer anesthesia time than open radical cystectomies. In the propensity score matching analysis comparing the surgical outcomes of robot-assisted radical cystectomy and open radical cystectomy, similar results were demonstrated, and blood transfusion rates were equivalent. CONCLUSION: For the past decade, the number of minimally invasive radical cystectomies has steadily increased without compromised surgical outcomes, except for anesthesia time. Robot-assisted radical cystectomies in particular rapidly became widespread in Japan after government approval in 2018 and became a standard surgery within the first 3 years.

Surgical outcomes of robot-assisted radical cystectomy in octogenarian or older patients: A Japanese nationwide study.

OBJECTIVE: To evaluate the surgical outcomes of robot-assisted radical cystectomy (RARC) in octogenarian or older patients based on a Japanese nationwide database. METHODS: The diagnosis procedure combination database was used to extract the data on radical cystectomy cases. Surgical outcomes of RARC in octogenarian or older patients (older group) were initially compared to those of patients younger than 80 years (younger group). Then, the surgical outcomes of RARC in the older group were compared to those of open radical cystectomy (ORC) and laparoscopic radical cystectomy (LRC) in the same age group. RESULTS: Between 2018 and 2021, 478 RARC cases in the older group and 2257 RARC cases in the younger group were identified. In the older group, ileal conduit, neobladder, and other urinary diversions were carried out in 352 (73.6%), 22 (4.6%), and 104 (21.8%) patients, respectively. In the older group, when compared with the younger group, the complication rate (24.9%), blood transfusion rate (41.4%), and in-hospital mortality (1.4%) were equivalent, while significantly shorter anesthesia time and longer length of stay were observed in the older group (521.0 ± 140.4 min vs. 595.1 ± 141.71 min, p < 0.01, and 32.9 ± 16.8 days vs. 30.6 ± 17.8 days, p = 0.01, respectively). In the comparison of the surgical outcomes of older patients receiving RARC to those receiving ORC (n = 746) and LRC (n = 375), the RARC group had the lowest complication rate and the shortest length of stay, while the shortest anesthesia time was noted in the ORC group. CONCLUSION: The feasibility of RARC for octogenarian or older patients was demonstrated by the nationwide database study.

Peritoneal closure and the processus vaginalis transection method to prevent inguinal hernia after robot-assisted radical prostatectomy.

OBJECTIVES: Postoperative inguinal hernia (IH) is one of the most common complications of radical prostatectomy (RP) including robot-assisted RP (RARP). However, a procedure to prevent IH after RARP has not been established. We investigated the impact of processus vaginalis transection (PVT) and PVT with peritoneal closure on IH after RARP. METHODS: A retrospective analysis was performed on data from patients who underwent RARP at two tertiary hospitals in Japan, where PVT with subsequent peritoneal closure was introduced after 2014. The incidence of IH for 2 years after RARP was compared among 79 patients without PVT or peritoneal closure, 232 patients with only PVT, and 325 patients with PVT and peritoneal closure. Multivariable Cox proportional hazard models that adjusted for hospital, age, history of abdominal operation, body mass index, operation time, and prostate weight were used. RESULTS: Postoperative IH was observed in seven (8.9%) patients without PVT or peritoneal closure, 34 (15%) patients with only PVT, and nine (2.8%) patients with PVT and peritoneal closure. Compared with patients without PVT or peritoneal closure, the incidence of IH was not different in patients with only PVT (hazard ratio [HR] 0.89, 95% confidence interval [CI] 0.34, 2.38) and significantly lower in patients with PVT and peritoneal closure (HR 0.22, 95% CI 0.07, 0.70). CONCLUSION: PVT with peritoneal closure may reduce the risk of postoperative IH after RARP. Future randomized controlled trials are required to confirm these findings.

Significance of dorsal bladder neck involvement in predicting the progression of non-muscle-invasive bladder cancer.

OBJECTIVES: Accurately predicting of progression is important for patients with non-muscle-invasive bladder cancer (NMIBC). We previously reported that bladder neck involvement (BNI) was significantly associated with progression of NMIBC. In this study, we evaluated the prognostic significance of the detailed BNI location in NMIBC patients. METHODS: We retrospectively reviewed 651 patients diagnosed with primary NMIBC at a single center between 2000 and 2018. Using the detailed BNI location, patients were divided into the following three groups: dorsal BNI (BNId; 4 to 8 o'clock position), ventral BNI (BNIv; 8 to 4 o'clock but not 4 to 8 o'clock position), and non-BNI group. Both time to progression to muscle-invasive disease and distant metastasis was compared among the three groups. A prognostic model was developed and its discriminative ability was evaluated. RESULTS: Dorsal bladder neck involvement and BNIv were observed in 43 (6.6%) and 36 (5.5%) patients, respectively. During a median follow-up of 61 months, 35 (5.4%) patients progressed. The cumulative incidence at 5 years was 12%, 0%, and 5.0% in BNId, BNIv, and non-BNI groups, respectively. On multivariate analysis, BNId was a significant and independent risk factor for progression, tumor stage pT1, and histologic grade G3. One point was assigned to each factor, and patients were classified into four well-stratified prognostic groups based on the total score. CONCLUSION: Dorsal bladder neck involvement was an independent and significant risk factor for progression in primary NMIBC. Our simple and practical prognostic model including BNId is easy to use and may help selecting the optimal treatment and its timing.

Prognostic impact of the radiological infiltrative feature of primary renal tumor in metastatic renal cell carcinoma.

OBJECTIVES: Recent studies suggest that the radiological infiltrative feature (r-IF) of renal tumors is strongly correlated with poor oncologic outcomes in locally advanced renal cell carcinoma (RCC). This study investigated the prognostic impact of r-IF of primary renal tumors in metastatic RCC (mRCC) in comparison with International Metastatic RCC Database Consortium (IMDC) risk model. METHODS: We retrospectively analyzed 91 patients with previously untreated mRCC. Dynamic computed tomography of the primary renal tumor was reviewed to assess r-IF, defined as a focally/extensively ill-defined tumor interface with normal renal parenchyma. RESULTS: The median age was 67 years, and 69 patients (76%) were men. Prior nephrectomy was performed in 47 patients (52%). The median size of the primary renal tumor was 6.7 cm, and 50 patients (55%) presented with cT3-4 stage. Overall, 25 (28%)/52 (57%)/14 (15%) patients were classified into IMDC favorable/intermediate/poor-risk groups, respectively. An image review identified r-IFs in the primary renal tumor in 40 patients (44%). The incidences of r-IFs were 28%/46%/64% in IMDC favorable/intermediate/poor-risk groups, respectively. During a median follow-up of 2.6 years, 31 patients (34%) died of RCC. On multivariable analysis, r-IF and IMDC intermediate-poor risks were independently associated with poor cancer-specific survival (CSS). Two-year CSS were 64%/87% in patients with/without r-IF, respectively. C-index was improved from 0.73 to 0.81 by adding r-IF to the IMDC risk factors. CONCLUSIONS: R-IF of the primary renal tumor was an independent risk factor for poor CSS in patients with mRCC, which may improve the prognostic accuracy when combined with the IMDC risk model.

Variables measured on three-dimensional computed tomography are preferred for predicting the outcomes of shock wave lithotripsy.

PURPOSE: Shock wave lithotripsy (SWL) is used to treat upper urinary tract stones. Recently, some volume analyzers have enabled preoperative assessment using three-dimensional computed tomography (3D-CT). We evaluated the efficacy of 3D-CT variables for predicting the outcomes of SWL. METHODS: The study population included 193 patients who underwent SWL between November 2014 and August 2020. In addition to conventional two-dimensional computed tomography (2D-CT) assessments, 3D-CT assessments of targeted stones were retrospectively performed, and stone size and stone density (SD) were measured. The successful and unsuccessful treatment groups were compared and risk factors for an unsuccessful first SWL session were investigated. The predictive accuracy of variables measured on 3D-CT was evaluated by receiver operating characteristic curves and multivariate analyses. RESULTS: The success rate of the first SWL session was 73.1%. Stone volume, mean SD and highest SD on 3D-CT were significantly higher in the unsuccessful group than in the successful group. Stone volume showed a higher area under the curve (AUC) than the estimated volumetric stone burden and stone diameter, which were measured on 2D-CT (0.729, 0.683, and 0.672, respectively). The AUCs of the mean SD and highest SD on 3D-CT were higher than those on 2D-CT (0.699, 0.680, 0.617, and 0.627, respectively). Multivariate analyses identified stone volume (≥ 0.29 ml), mean SD on 3D-CT (≥ 421 HU), and absence of hydronephrosis as independent predictive factors for unsuccessful SWL. CONCLUSION: 3D-CT variables were promising predictors of the outcomes of SWL. Preoperative 3D-CT assessment is helpful for selecting favorable patients for SWL.

Risk factors and predictive model for incidence of difficult ureter during retrograde ureteroscopic lithotripsy.

OBJECTIVE: Difficult ureter can be a challenge for accessing upper urinary tract during lithotripsy. In this study, we evaluated the risk factors for the incidence of difficult ureter in retrograde ureteroscopic lithotripsy. Moreover, we aimed to develop a predictive model for the incidence of difficult ureter. METHODS: We retrospectively reviewed consecutive retrograde ureteroscopic lithotripsies performed at our institution between 2009 and 2021. A total of 1010 renal units were evaluated: 449 units with renal stones only and 561 units with ureteral stones, with or without renal stones. RESULTS: The overall incidence of difficult ureter was 5.9%, with a higher incidence in the renal alone stone group than in the ureteral stone group (7.8% vs 4.5%, P = 0.026). Multivariate regression analysis revealed three risk factors for the incidence of difficult ureter: absence of stone history (odds ratio 5.67, 95% confidence interval 2.40-13.4, and P < 0.001), age ≤45 years (odds ratio 3.61, 95% confidence interval 2.05-6.37, and P < 0.001), and renal stone only (odds ratio 2.11, 95% confidence interval 1.22-3.64, and P = 0.008). A simple model using these three risks enabled the stratification of the incidence rate of difficult ureter, with the incidence of high-risk cases being 12.7%. CONCLUSIONS: The greatest risk factor for the incidence of difficult ureter was the absence of stone history, followed by age 45 years or younger, and having only renal stones. In high-risk cases of difficult ureter, the possibility of secondary lithotripsy should be explained to the patients.

Potential of Perfusion Magnetic Resonance Imaging to Predict Residual Renal Function after Radical Nephroureterectomy.

INTRODUCTION: The diffusion-weighted imaging (DWI) technique with intravoxel incoherent motion model enables the estimation of capillary blood volume as a perfusion-related parameter- (PP-) value. Therefore, the PP-value of the kidney theoretically reflects renal capillary blood volume. We analyzed the usefulness of the PP-value in estimating postoperative renal function in upper-tract urothelial carcinoma (UTUC) patients. METHODS: Forty-eight consecutive patients who underwent magnetic resonance imaging before radical nephroureterectomy from 2011 to 2018 were analyzed. A PP-map displaying PP-values on a pixel-by-pixel basis was created from DWI signals (b-values of 0, 500, and 1,000 s/mm2). Two readers independently analyzed the renal PP-value. DWI-based split renal function (SRF) of the intact kidney was calculated by splitting serum Cr-based preoperative estimated glomerular filtration rates (eGFRs). The predictive accuracy of the method was evaluated using renography as the reference standard. RESULTS: Interobserver analysis revealed an excellent correlation value of 0.97. The SRF value showed a good linear correlation with the observed postoperative eGFR (r = 0.76, p < 0.001). The predictive accuracy of the DWI-based method was similar to that of the nuclear-based method. CONCLUSION: This DWI-based evaluation of capillary blood volume provides a noninvasive tool for predicting the postoperative renal function, thereby facilitating the management of UTUC patients.

Usefulness of the inchworm sign on DWI for predicting pT1 bladder cancer progression.

OBJECTIVE: To evaluate the significance of the presence or absence of an "inchworm sign" on DWI for the recurrence and progression of T1 bladder cancer. MATERIALS AND METHODS: We retrospectively analyzed 91 patients with pT1 urothelial carcinoma who underwent DWI prior to transurethral resection between 2007 and 2016. DWI of the dominant tumors was scrutinized for inchworm signs at b = 1000 s/mm2. The association of the presence of the inchworm sign with progression and recurrence was analyzed; progression was defined as recurrence to stage T2 or higher and/or N+, and/or M1. RESULTS: An inchworm sign was seen in 65 cases (71%), while it was absent in 26 cases. Among the 65, 25 (38%) had confirmed tumor recurrence, while in the remaining 26, 14 (54%) had confirmed recurrence (median time post TURB = 7.9 and 10.1 months for each). At the time of recurrence, the tumor had progressed in one (2%) inchworm-sign-positive and seven (27%) inchworm-sign-negative cases. The progression rate of inchworm-sign-negative cases was significantly higher than that of inchworm-sign-positive cases (hazard ratio = 17.2, p = 0.0017), whereas there was no significant difference in the recurrence rate between two groups. The absence of an inchworm sign and histological grade 3 were independent risk factors for progression (p < 0.001 and 0.010, respectively). CONCLUSIONS: The absence of an inchworm sign on DWI was a significant prognostic factor for progression of T1 bladder cancer. Morphological evaluation of DWI signals may therefore be a useful adjunct to preoperative assessment of biological aggressiveness. KEY POINTS: • An inchworm sign is a simple diagnostic criterion that characterizes only the shape of the tumor signal on DWI, and potentially serves as an imaging biomarker to predict clinical aggressiveness. • The absence of an inchworm sign on DWI is a significant indicator of progression of T1 bladder cancer.

Predictive ability of renal cortex enhancement in dynamic computed tomography for residual renal function after nephroureterectomy: Comparison with 99m Tc-diethylenetriaminopentacetic acid renography and validation study.

OBJECTIVE: To estimate postoperative residual renal function after radical nephroureterectomy for upper tract urothelial carcinoma using the preoperative dynamic computed tomography renal cortex enhancement ratio in comparison with the split kidney glomerular filtration rate measured by 99m Tc-diethylenetriaminopentacetic acid renography. METHODS: A total of 47 patients who received radical nephroureterectomy and underwent both preoperative dynamic computed tomography and renography were the model-development cohort; and 109 patients who underwent dynamic computed tomography alone were the validation cohort. Postoperative renal function of the unremoved kidney was estimated using the following formulas: preoperative estimated glomerular filtration rate × the percentage of total renal cortex radiodensity for the intact kidney in Hounsfield units obtained from corticomedullary phase images in the computed tomography-based model, or the percentage of the total glomerular filtration rate measured by renography in the nuclear model. The correlation between observed and estimated postoperative renal function was determined. The computed tomography-based prediction model derived from linear regression analysis was validated externally. RESULTS: The correlation of computed tomography-based split renal function with the observed postoperative estimated glomerular filtration rate (r = 0.80) was equivalent to that of nuclear split renal function (r = 0.78). In the validation cohort, the computed tomography-based prediction model showed an equivalently strong correlation (r = 0.78). CONCLUSIONS: The present study showed that the percentage of total renal cortex radiodensity for the intact kidney is a useful tool for predicting unremoved kidney function in upper tract urothelial carcinoma patients, thereby allowing appropriate patient selection for perioperative cisplatin-based combination chemotherapy.

Incidence and predictive factors of hypoglycemia after pheochromocytoma resection.

OBJECTIVES: To determine the incidence and preoperative risk factors of post-excisional hypoglycemia in patients undergoing pheochromocytoma resection. METHODS: Patients who underwent surgical resection of pheochromocytoma at a single institution were retrospectively enrolled in the present study. The primary end-point was the development of post-excisional hypoglycemia; that is, a serum glucose level <70 mg/dL. The serum levels of immunoreactive insulin and glucose levels during the preoperative oral glucose-tolerance test and surgery were analyzed to elucidate the mechanism of hypoglycemia. RESULTS: A total of 49 patients underwent surgical resection of pheochromocytoma, of which 21 patients (43%) developed post-excisional hypoglycemia. The incidence of hypoglycemia was not statistically different between patients with adrenal tumors and those with extra-adrenal tumors (18/41 [44%] vs 3/8 [38%], respectively, P = 0.73). There was no difference in the immunoreactive insulin/glucose ratio during the preoperative oral glucose-tolerance test between patients with and those without post-excisional hypoglycemia. The intraoperative immunoreactive insulin/glucose ratio was significantly higher in patients with hypoglycemia than in those without hypoglycemia. A higher 24-h urinary epinephrine level, but not norepinephrine level, was a predictive factor for post-excisional hypoglycemia. CONCLUSIONS: Post-excisional hypoglycemia is a frequent complication of pheochromocytoma resection, irrespective of the tumor location, and might be common in patients with epinephrine-predominant tumors. All patients undergoing resection of adrenal and extra-adrenal pheochromocytoma require intensive monitoring of serum glucose levels during and after surgery.

Utility of computed diffusion-weighted MRI for predicting aggressiveness of prostate cancer.

PURPOSE: To investigate the value of computed (c) diffusion-weighted imaging (DWI) in assessing prostate cancer aggressiveness. MATERIALS AND METHODS: Fifty-five patients with peripheral zone prostate cancer who underwent prebiopsy 1.5T magnetic resonance imaging (including native DWI at b-values of 0 and 1000 s/mm2 ) were included. cDWI signal intensities of peripheral zone prostate cancer and nonmalignant prostate tissue were measured. Association between changes in monoexponentially calculated cDWI signals according to different b-values and primary Gleason grades were assessed. RESULTS: The cDWI signal intensity of prostate cancer was lower at b = 0 s/mm2 and higher at b = 1000 s/mm2 compared to nonmalignant prostate tissue. The b-value at which the signal intensities of prostate cancer and nonmalignant prostate tissue were equal was defined as the "iso-b-value." On multivariate analysis, only the iso-b-value was a significant predictor of primary Gleason grade 4/5 cancer (P = 0.001). The area under the curve (AUC) of the iso-b-value for diagnosing primary Gleason grade 4/5 cancer was 0.94, and significantly higher than that of the tumor apparent diffusion coefficient (ADC) value with an AUC of 0.68 (P < 0.001). CONCLUSION: cDWI with iso-b-value-based semiquantitative analysis was found to be useful for predicting the aggressiveness of prostate cancer and may potentially outperform tumor ADC measurements in this setting. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:490-496.

DWI as an Imaging Biomarker for Bladder Cancer.

OBJECTIVE: DWI has been increasingly applied in the management of bladder cancer. In this article, we discuss the role of DWI as an imaging biomarker for bladder cancer. CONCLUSION: The DWI signal is derived from the motion of water molecules, which represents the physiologic characteristics of the tissue of interest. The emerging evidence highlights the utility of DWI for bladder cancer detection and characterization. DWI is a potentially useful tool to individualize treatment strategies.