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Purpose: We investigated whether the standardized apparent diffusion coefficient (ADC) value reflects bladder cancer characteristics across different centers., Methods: Ninety-eight bladder cancer patients underwent MRI at two institutions. Standardized tumor ADC (sT-ADC) was calculated by dividing absolute tumor ADC (aT-ADC) by that of gluteus maximus. We compared ADCs between MRI protocols according to grade and T-stage., Results: The differences in aT-ADC between MRI protocols were negated by sT-ADC. The best sT-ADC cut-offs to predict cancer aggressiveness in the development cohort worked in the validation cohort compared to the development cohort., Conclusion: Standardized ADC overcomes the incompatibility between different MRI protocols., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Objectives: To identify prostatic quadrants that could be preserved without intervention, using diffusion-weighted magnetic resonance imaging (DWI) and extended core biopsy, as a step toward implementation of quadrant-based focal ablation with potential preservation of erectile and ejaculatory functions, based on comparisons with unilateral hemi-gland ablation., Patients and Methods: We conducted a prebiopsy DWI study including 648 quadrants in 162 men who underwent 14-core biopsy including anterior sampling and radical prostatectomy (RP) for localised cancer. Imaging and pathology were analysed on a quadrant basis. Each quadrant was assessed through four-core sampling. Predictive performance of DWI and biopsy for quadrant status was analysed., Results: On RP specimens, 170 anterior (52.5%) and 172 posterior quadrants (53.1%) harboured significant cancer. Negative predictive values of DWI, biopsy, and their combination for significant cancer were 79.7%, 70.6%, and 91.1%, respectively, in anterior quadrants, and 78.5%, 81.3%, and 91.7%, respectively, in posterior quadrants. DWI incrementally improved the negative predictive values of biopsy in anterior (P < 0.001) and posterior quadrants (P = 0.025), without untoward impacts on positive predictive values. Negative findings on both DWI and biopsy were identified in posterior quadrants of 109 sides (33.6%), but in entire hemi-glands of 54 sides (16.7%)., Conclusions: The combination of DWI and 14-core biopsy including anterior sampling efficiently identifies quadrants without significant cancer in men with localised prostate cancer; the remaining quadrants, therefore, could be potential candidate areas for focal ablation. Focal therapy designed based on quadrant-based assessment could be superior to unilateral hemi-gland ablation for preservation of posterior quadrants and retaining of sexual function in more sides., (© 2014 The Authors BJU International © 2014 BJU International Published by John Wiley & Sons Ltd.)

Diffusion-weighted magnetic resonance imaging is a type of functional imaging that is increasingly being applied in the management of upper tract urothelial carcinoma and bladder cancer. The image contrast is derived from differences in the Brownian motion of water molecules in tissues. The homogenous high signal intensity of upper tract urothelial carcinoma and bladder cancer on diffusion-weighted magnetic resonance imaging provides helpful diagnostic information for the presence of cancerous lesions in a non-invasive manner. Recently, growing evidence has emerged showing that diffusion-weighted magnetic resonance imaging can serve as an imaging biomarker for characterizing cancer pathophysiology, because the signal reflects biophysical information about the tissues. Quantitative analysis by evaluating the apparent diffusion coefficient values potentially reflects the histological grade and the biological aggressiveness of urothelial carcinoma. The apparent diffusion coefficient value could be a biomarker predicting the clinical course of upper tract urothelial carcinoma and bladder cancer. In addition, in chemoradiotherapy-based bladder-sparing approaches against muscle-invasive bladder cancer, the role of diffusion-weighted magnetic resonance imaging for predicting the chemoradiosensitivity and for monitoring therapeutic response has been shown. Diffusion-weighted magnetic resonance imaging is expected to improve the diagnostic accuracy, and this qualitative information might allow individualized treatment strategies for patients with urothelial carcinoma., (© 2014 The Japanese Urological Association.)

Purpose: To assess whether there is an association between the apparent diffusion coefficient (ADC) value and the pathological characteristics of prostate cancer., Methods: The study cohort consisted of 29 consecutive patients with prostate cancer treated with radical prostatectomy. All patients underwent diffusion-weighted MRI before the prostate biopsy. In 42 tumor foci, the associations of the ADC values with the clinicopathological characteristics and Ki-67 labeling index (LI) were analyzed., Results: High-grade cancers (Gleason score [GS] ≥ 4 + 3), larger cancers (maximum diameter (MD) ≥ 16 mm), and highly proliferating cancers (Ki-67 LI ≥ 4.43 %) had significantly lower ADC values, respectively (P < .001, P = .008, and P = .044, respectively). There was no significant difference in ADC value according to age, prostate-specific antigen, presence of extra-prostatic extension, and intra-tumoral stroma proportion. Multivariate analysis showed that GS, Ki-67 LI, and MD had independent and significant correlations with ADC value (P < .001, P = .006, and P = .002, respectively). Low ADC tumors (<0.52 × 10(-3) mm(2)/s) are likely to be high-grade cancer foci compared with high ADC tumors (relative risk: 65.2). The sensitivity and specificity of the ADC value to predict high-grade cancer foci are 81.8 and 93.5 %, respectively., Conclusions: A low ADC value reflects the morphological and biological features of prostate cancer. Analyzing the ADC value may make it possible to more precisely predict the cancer aggressiveness of each focus before treatment.

Purpose: To elucidate a role of apparent diffusion coefficient (ADC) value as a biomarker of bladder cancer, we investigated its associations with Ki-67 labeling index (LI) along with classical clinicopathological prognosticators., Materials and Methods: Diffusion-weighted MRI (DW-MRI) at 1.5 Tesla using b-values of 0, 500, 1000, and 2000 s/mm(2) was prospectively taken before transurethral resection by 132 bladder cancer patients. ADC value of index tumors was measured and compared with clinicopathological prognosticators including Ki-67 LI., Results: ADC value was significantly lower in tumors with higher Ki-67 LIs, sessile tumors (versus papillary), larger tumors, higher grade disease, and higher T stage disease. ADC value inversely correlated with Ki-67 LI (ρ = -0.57; P < 0.0001). On multiple regression analysis, T stage and Ki-67 LI significantly correlated with ADC value. The Akaike information criterion confirms these two parameters constitute the best model for determining ADC value. Similarly, T stage and ADC value significantly correlated with Ki-67 LI and these two parameters composed the best model for predicting Ki-67 LI., Conclusion: ADC value would reflect T stage and Ki-67 LI, representing invasive and proliferative potential, respectively. ADC value is likely to serve as a biomarker reflecting aggressiveness of bladder cancer., (Copyright © 2013 Wiley Periodicals, Inc.)

Background: Significant cancer in contralateral sides of the prostate that was missed on prostate biopsy (PBx) is a concern in hemiablative focal therapy (FT) of prostate cancer (PCa). However, extended PBx, a common diagnostic procedure, has a limited predictive ability for lobes without significant cancer., Objective: To identify prostate lobes without significant cancer using extended PBx combined with diffusion-weighted imaging (DWI), which has the potential to provide pathophysiologic information on pretreatment assessment., Design, Setting, and Participants: We conducted a prebiopsy DWI study between 2007 and 2012 that included 270 prostate lobes in 135 patients who underwent radical prostatectomy (RP) for clinically localized PCa., Intervention: Participants underwent DWI and 14-core PBx; those with PBx-proven PCa and who were treated with RP were analyzed., Outcome Measurements and Statistical Analysis: Imaging and pathology were assessed in each side. Based on RP pathology, lobes were classified into lobes with no cancer (LNC), lobes with indolent cancer (LIC), and lobes with significant cancer (LSC). Predictive performance of DWI, PBx, and their combination in identifying lobes without significant cancer was examined., Results and Limitations: LNC, LIC, and LSC were identified in 23 (8.5%), 64 (23.7%), and 183 sides (67.8%), respectively. The negative predictive values (NPV) of DWI, PBx, and their combination were 22.1%, 27.8%, and 43.5%, respectively, for lobes with any cancer (ie, either LIC or LSC), and 68.4%, 72.2%, and 95.7%, respectively, for LSC. The NPV of PBx for LSC was improved by the addition of DWI findings (p=0.001), with no adverse influence on the positive predictive value. Limitations included a possible selection bias under which the decision to perform PBx might be affected by DWI findings., Conclusions: The combination of DWI and extended PBx efficiently predicts lobes without significant cancer. This procedure is applicable to patient selection for hemiablative FT., (Copyright © 2012 European Association of Urology. Published by Elsevier B.V. All rights reserved.)

Objective: To clarify the clinical significance of incidentally found diffusion-weighted MRI (DW-MRI)-positive findings on pre-biopsy MRI in patients with suspected prostate cancer., Patients and Methods: 754 consecutive patients with suspected prostate cancer underwent pelvic MRI including DW-MRI. 43 DW-MRI-positive bone lesions were found in 27 patients. Imaging findings of these lesions were compared with the clinical diagnosis., Results: Of the 43 DW-MRI-positive bone lesions, 21 (48.8%) were diagnosed as metastatic prostate cancer. The remaining 22 (51.2%) were diagnosed as red bone marrow in 17, enchondroma in 1, ganglion in 1, osteoma in 1, fibrous dysplasia in 1 and bone infarction in 1. Enchondroma, ganglion, osteoma and fibrous dysplasia all showed T1-weighted imaging (T1WI) low and T2-weighted imaging (T2WI) high signals, while others, including prostate cancer metastases, showed T1WI and T2WI low signals. Of the 40 lesions with T1WI and T2WI low signals, metastatic prostate cancer had higher apparent diffusion coefficient values (median 0.42 × 10(-3) mm(2)/s) than other lesions (0.26 × 10(-3) mm(2)/s; p < 0.0001)., Conclusions: DW-MRI-positive bone lesions represent various coexisting types of bone lesions, including metastatic cancer in patients with suspected prostate cancer. T2WI findings and apparent diffusion coefficient values can be helpful in diagnosing metastatic cancer., (2014 S. Karger AG, Basel.)

A 66-year-old woman was referred to our department for thickening bladder wall incidentally found during postoperative follow-up of transverse colon cancer. Cystoscopy showed edematous tumor with a diameter of 5 cm on the right wall. Deep portion of the tumor showed high intensity on diffusion-weighted magnetic resonance imaging (DW-MRI). Transurethral resection and transvaginal needle biopsy was performed, and pathological examination revealed granulation tissues mainly consisted of inflammatory cells and fibrosis. DW-MRI is a functional imaging constructed by quantifying the diffusion of water molecules. Recently, the feasibility of this imaging in the diagnosis of bladder cancer has been reported. However, we should keep in mind that granulation tissues consisted of inflammatory cells and fibrosis is also possible to be positive for DW-MRI.

Purpose: In chemoradiation (CRT)-based bladder-sparing approaches for muscle invasive bladder cancer (MIBC), patients who respond favorably to induction CRT enjoy the benefits of bladder preservation, whereas nonresponders do not. Thus, accurate prediction of CRT sensitivity would optimize patient selection for bladder-sparing protocols. Diffusion-weighted MRI (DW-MRI) is a functional imaging technique that quantifies the diffusion of water molecules in a noninvasive manner. We investigated whether DW-MRI predicts CRT sensitivity of MIBC., Methods and Materials: The study cohort consisted of 23 MIBC patients (cT2/T3 = 7/16) who underwent induction CRT consisting of radiotherapy to the small pelvis (40 Gy) with two cycles of cisplatin (20 mg/day for 5 days), followed by partial or radical cystectomy. All patients underwent DW-MRI before the initiation of treatment. Associations of apparent diffusion coefficient (ADC) values with CRT sensitivity were analyzed. The proliferative potential of MIBC was also assessed by analyzing the Ki-67 labeling index (LI) in pretherapeutic biopsy specimens., Results: Thirteen patients (57%) achieved pathologic complete response (pCR) to CRT. These CRT-sensitive MIBCs showed significantly lower ADC values (median, 0.63 × 10(-3) mm(2)/s; range, 0.43-0.77) than CRT-resistant (no pCR) MIBCs (median, 0.84 × 10(-3) mm(2)/s; range, 0.69-1.09; p = 0.0003). Multivariate analysis identified ADC value as the only significant and independent predictor of CRT sensitivity (p < 0.0001; odds ratio per 0.001 ×10(-3) mm(2)/s increase, 1.03; 95% confidence interval, 1.01-1.08). With a cutoff ADC value at 0.74 × 10(-3) mm(2)/s, sensitivity/specificity/accuracy in predicting CRT sensitivity was 92/90/91%. Ki-67 LI was significantly higher in CRT-sensitive MIBCs (p = 0.0005) and significantly and inversely correlated with ADC values (ρ = -0.67, p = 0.0007)., Conclusions: DW-MRI is a potential biomarker for predicting CRT sensitivity in MIBC. DW-MRI may be useful to optimize patient selection for CRT-based bladder-sparing approaches., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Objectives: The diagnostic performance of diffusion-weighted magnetic resonance imaging (DW-MRI) in bladder cancer and the potential role of apparent diffusion coefficient (ADC) values in predicting pathological bladder cancer phenotypes associated with clinical aggressiveness were investigated., Methods: One hundred and four bladder cancer patients underwent DW-MRI and T2-weighted magnetic resonance imaging (T2W-MRI) before transurethral resection. The image sets were reviewed by two independent radiologists. ADC values were measured in 121 eligible tumours., Results: In detecting patients with bladder cancer, DW-MRI exhibited high sensitivity equivalent to that of T2W-MRI (>90%). Interobserver agreement was excellent for DW-MRI (κ score, 0.88) though moderate for T2W-MRI (0.67). ADC values were significantly lower in high-grade (vs. low-grade, P < 0.0001) and high-stage (T2 vs. T1 vs. Ta, P < 0.0001) tumours. At a cut-off ADC value determined by partition analysis, clinically aggressive phenotypes including muscle-invasive bladder cancer (MIBC) and high-grade T1 disease were differentiated from less aggressive phenotypes with a sensitivity of 88%, a specificity of 85% and an accuracy of 87%., Conclusion: DW-MRI exhibits high diagnostic performance in bladder cancer with excellent objectivity. The ADC value could potentially serve as a biomarker to predict clinical aggressiveness in bladder cancer.

The aim of the present study was to evaluate diffusion-weighted (DW) magnetic resonance imaging (MRI) in differentiating between minimal fat angiomyolipoma (MFAML) and clear cell renal cell carcinoma (CCRCC). Forty-one solid renal tumors without visible macroscopic fat on unenhanced computed tomography images were evaluated by MRI, including DW-MRI, and were diagnosed pathologically as CCRCC (n = 36) or MFAML (n = 5). To evaluate the heterogeneity of diffusion in each tumor, the signals of the tumors on DW-MRI were analyzed subjectively and the apparent diffusion coefficient (ADC) values and histograms assessed objectively. Thirty-three of 36 CCRCC (92%) exhibited a heterogeneous signal on DW-MRI and several peaks in the ADC value histogram, whereas four of five MFAML exhibited a homogeneous signal on DW-MRI and a single prominent peak in the histogram. The standard deviations of the ADC values were significantly smaller for MFAML than for CCRCC (P = 0.0015). In conclusion, DW-MRI can be considered a useful and noninvasive addition to the preoperative differentiation of CCRCC and MFAML., (© 2011 The Japanese Urological Association.)

Objectives: To investigate the feasibility of diffusion-weighted magnetic resonance imaging (DWI) in predicting therapeutic response to low-dose chemoradiotherapy (LCRT) against muscle-invasive bladder cancer (MIBC). Accurate assessment of response to induction therapy is an essential part of bladder-sparing therapeutic protocols against MIBC. However, conventional imaging studies are not useful in evaluating therapeutic response because of their inability to distinguish residual cancer from changes secondary to the treatment., Methods: Twenty patients with clinical T2-4aN0M0 bladder urothelial carcinoma (T2/T3/T4a: n = 10/8/2) who underwent induction LCRT comprising external beam radiotherapy to the bladder (40 Gy) concomitant with 2 cycles of cisplatin administration (20 mg/d for 5 days) followed by partial (n = 13) or radical cystectomy (n = 7) were prospectively enrolled. The patients underwent magnetic resonance imaging examinations with T2-weighted imaging (T2W), dynamic contrast-enhanced T1-weighted imaging (DCE), and DWI after LCRT. A finding of each protocol was compared with a pathologic finding of cystectomy specimen., Results: Pathologic examination of cystectomy specimens revealed pathologic complete response in 13 (65%) of the 20 patients. The sensitivity/specificity/accuracy of T2W, DCE, and DWI in predicting pathologic response was 43/45/44%, 57/18/33%, and 57/92/80%, respectively. Despite comparable sensitivity, DWI was significantly superior in specificity and accuracy to T2W (P = .03 and .02, respectively) and DCE (P = .002 for both)., Conclusions: This is the first study to show the feasibility of DWI over T2W and DCE for assessing therapeutic response to induction chemoradiotherapy against MIBC. The high specificity of DWI indicates that DWI is useful to accurately predict pathologic complete response, allowing more optimal patient selection in bladder-sparing protocols., (2010 Elsevier Inc. All rights reserved.)

Diffusion-weighted MRI (DW-MRI) is a functional imaging to assess molecular diffusion. We report a case in which treatment response to lymph node metastatic bladder cancer was monitored by DW-MRI. A 67-year-old man had paraaortic lymph node metastasis from bladder cancer; the paraaortic lymph node showed high signal intensity on DW-MRI. After four course treatment of gemcitabine and cisplatin, the lesion showed reduction of signal intensity on DW-MRI and increase of the apparent diffusion coefficient value. These signal changes were consistent with the change of morphological images (CT, MRI (T1-W, T2-W)), 18F-FDG PET and tumor markers. This case suggests that DW-MRI is useful in monitoring treatment response of metastatic bladder cancer.

Diffusion-weighted (DW) magnetic resonance imaging (MRI) is a functional imaging to assess molecular diffusion. We report a first case of female urethral diverticular abscess examined by DW MRI. A 49-year-old woman presented with perineal pain, pyuria and inflammatory reaction. Conventional MRI revealed urethral diverticulum with the content of slightly lower-signal-intensity than urine on T2-weighted contrast. On DW MRI, the diverticulum was shown as a marked hyperintense lesion with restrained signal background of the surrounding tissue. The low apparent diffusion coefficient value of the diverticulum indicated high viscosity restricting water diffusion. DW MRI could depict urethral diverticular abscess clearly and easily in a non-invasive manner.

Background: Several studies have investigated the potential role of the apparent diffusion coefficient (ADC) value of diffusion-weighted magnetic resonance imaging as a biomarker of high-grade and invasive bladder cancer. Methods: PubMed and the Cochrane Library were systematically searched in September 2021 to extract studies that evaluated the associations between ADC values, pathological T stage, and histological grade bladder cancers. The diagnostic performance of ADC values in detecting muscle-invasive bladder cancer (MIBC) and high-grade disease was systematically reviewed. Results: Six studies were included in this systematic review. MIBC showed significantly lower ADC values than non-muscle-invasive bladder cancer (NMIBC) in all six studies. The median (range) sensitivity, specificity, and area under the curve (AUC) of ADC values to detect MIBC among the four eligible studies were 73.5% (68.8–90.0%), 79.9% (66.7–84.4%), and 0.762 (0.730–0.884), respectively. Similarly, high-grade disease showed significantly lower ADC values than did low-grade disease in all four eligible studies. The median (range) sensitivity, specificity, and AUC of ADC values for detecting high-grade disease among the three eligible studies were 75.0% (73.0–76.5%), 95.8% (76.2–100%), and 0.902 (0.804–0.906), respectively. Conclusions: The ADC value is a non-invasive diagnostic biomarker for discriminating muscle-invasive and high-grade bladder cancer. [ABSTRACT FROM AUTHOR]