Inguinal lymph node metastases from prostate cancer: clinical, pathology, and multimodality imaging considerations.

Objective: To investigate clinical, pathology, and imaging findings associated with inguinal lymph node (LN) metastases in patients with prostate cancer (PCa). Materials and Methods: This was a retrospective single-center study of patients with PCa who underwent imaging and inguinal LN biopsy between 2000 and 2023. We assessed the following aspects on multimodality imaging: inguinal LN morphology; extrainguinal lymphadenopathy; the extent of primary and recurrent tumors; and non-nodal metastases. Imaging, clinical, and pathology features were compared between patients with and without metastatic inguinal LNs. Results: We evaluated 79 patients, of whom 38 (48.1%) had pathology-proven inguinal LN metastasis. Certain imaging aspects- short-axis diameter, prostate-specific membrane antigen uptake on positron-emission tomography, membranous urethra involvement by the tumor, extra-inguinal lymphadenopathy, and distant metastases-were associated with pathology-proven inguinal LN metastases (p < 0.01 for all). Associations with long-axis diameter, fatty hilum, laterality, and uptake of other tracers on positronemission tomography were not significant (p = 0.09-1.00). The patients with metastatic inguinal LNs had higher prostate-specific antigen levels and more commonly had castration-resistant PCa (p < 0.01), whereas age, histological grade, and treatment type were not significant factors (p = 0.07-0.37). None of the patients had inguinal LN metastasis in the absence of locally advanced disease with membranous urethra involvement or distant metastasis. Conclusion: Several imaging, clinical, and pathology features are associated with inguinal LN metastases in patients with PCa. Isolated metastasis to inguinal LNs is extremely rare and unlikely to occur in the absence of high-risk imaging, clinical, or pathology features.

Objetivo: Investigar achados clinicopatológicos e de imagem associados a metástases linfonodais inguinais em pacientes com câncer de próstata (CaP). Materiais e Métodos: Estudo retrospectivo de uma única instituição de pacientes com CaP submetidos a exames de imagem e biópsia inguinal de linfonodos em 2000­2023. A imagem multimodalidade foi avaliada para morfologia inguinal do linfonodo, linfadenopatia fora da região inguinal, extensão do CaP primário/recorrente e sítios metastáticos não nodais. Características de imagem e clinicopatológicas foram comparadas entre pacientes com e sem linfonodos inguinais metastáticos pela patologia. Resultados: Entre 79 pacientes estudados, 38 (48,1%) apresentaram metástase inguinal de linfonodo comprovada patologicamente. Certos achados de imagem ­ diâmetro do eixo curto, captação do antígeno de membrana prostático específico na tomografia por emissão de pósitrons, envolvimento da uretra membranosa pelo tumor, linfadenopatia fora da região inguinal e metástases a distância ­ foram associados com metástases inguinais no linfonodo pela patologia (p < 0,01). Diâmetro de eixo longo, hilo gorduroso, lateralidade, captação em outros traçadores de tomografia por emissão de pósitrons não foram significativos (p = 0,09­1,00). Clinicopatologicamente, os pacientes com linfonodos inguinais metastáticos apresentaram maior antígeno prostático específico e foram mais resistentes à castração (p < 0,01); idade, grau histológico e tipo de tratamento não foram estatisticamente significantes (p = 0,07­0,37). Nenhum paciente apresentou metástase inguinal isolada no linfonodo na ausência de doença localmente avançada com envolvimento da uretra membranosa ou metástase a distância. Conclusão: Várias características de imagem e clinicopatológicas foram associadas a metástases em LNs inguinais em pacientes com CaP. A metástase isolada para os LNs inguinais é extremamente rara e é improvável que ocorra na ausência de características de imagem e clinicopatológicas de alto risco.

Pictorial review of multiparametric MRI in bladder urothelial carcinoma with variant histology: pearls and pitfalls.

Bladder cancer (BC), predominantly comprising urothelial carcinomas (UCs), ranks as the tenth most common cancer worldwide. UCs with variant histology (variant UC), including squamous differentiation, glandular differentiation, plasmacytoid variant, micropapillary variant, sarcomatoid variant, and nested variant, accounting for 5-10% of cases, exhibit more aggressive and advanced tumor characteristics compared to pure UC. The Vesical Imaging-Reporting and Data System (VI-RADS), established in 2018, provides guidelines for the preoperative evaluation of muscle-invasive bladder cancer (MIBC) using multiparametric magnetic resonance imaging (mpMRI). This technique integrates T2-weighted imaging (T2WI), dynamic contrast-enhanced (DCE)-MRI, and diffusion-weighted imaging (DWI) to distinguish MIBC from non-muscle-invasive bladder cancer (NMIBC). VI-RADS has demonstrated high diagnostic performance in differentiating these two categories for pure UC. However, its accuracy in detecting muscle invasion in variant UCs is currently under investigation. These variant UCs are associated with a higher likelihood of disease recurrence and require precise preoperative assessment and immediate surgical intervention. This review highlights the potential value of mpMRI for different variant UCs and explores the clinical implications and prospects of VI-RADS in managing these patients, emphasizing the need for careful interpretation of mpMRI examinations including DCE-MRI, particularly given the heterogeneity and aggressive nature of variant UCs. Additionally, the review addresses the fundamental MRI reading procedures, discusses potential causes of diagnostic errors, and considers future directions in the use of artificial intelligence and radiomics to further optimize the bladder MRI protocol.

Profiling Fibroblast Growth Factor Receptor 3 Expression Based on the Immune Microenvironment in Upper Tract Urothelial Carcinoma.

BACKGROUND: Although several studies have shown favorable outcomes in upper tract urothelial carcinoma (UTUC) with fibroblast growth factor receptor 3 (FGFR3) mutations and/or expression, the relationship between immune cell markers and FGFR3 expression remains unknown. OBJECTIVE: To clarify the FGFR3-based immune microenvironment and investigate biomarkers to predict the treatment response to pembrolizumab (Pem) in patients with UTUC. DESIGN, SETTING, AND PARTICIPANTS: We conducted immunohistochemical staining in 214 patients with UTUC. The expression levels of FGFR3, CD4, CD8, CD68, CD163, CD204, and programmed cell death ligand 1 (PD-L1) were examined. INTERVENTION: All UTUC patients underwent radical nephroureterectomy. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We assessed the relationship between these immune markers and patient prognosis. RESULTS AND LIMITATIONS: A total of 109 (50.9%) patients showed high FGFR3 expressions and a favorable prognosis compared with the remaining patients. Among the six immune markers, CD8 high expression was an independent favorable factor, whereas CD204 expression was an independent prognostic factor for cancer death. From the FGFR3-based immune clustering, three immune clusters were identified. Cluster A showed low FGFR3 with tumor-associated macrophage-rich components (CD204+) followed by a poor prognosis due to a poor response to Pem. Cluster B showed low FGFR3 with an immune hot component (CD8+), followed by the most favorable prognosis owing to a good response to Pem. Cluster C showed high FGFR3 expression but an immune cold component, followed by a favorable prognosis due to the high FGFR3 expression, but a poor response was confirmed with Pem. CONCLUSIONS: Although most patients exhibit a poor response to Pem, individuals with low FGFR3 expression and immune hot status may benefit clinically from Pem treatment. PATIENT SUMMARY: We conducted immunohistochemical staining to evaluate fibroblast growth factor receptor 3 (FGFR3)-related immune microenvironment by evaluating the expressions of CD4, CD8, CD68, CD163, CD204, and PD-L1 in 214 upper tract urothelial carcinoma patients. We identified three distinct immune clusters based on FGFR3 expressions and found that patients with a low FGFR3 expression but immune hot status received the maximum benefit from an immune checkpoint inhibitor.

Biparametric versus Multiparametric Magnetic Resonance Imaging for Assessing Muscle Invasion in Bladder Urothelial Carcinoma with Variant Histology Using the Vesical Imaging-Reporting and Data System.

BACKGROUND: The diagnostic performance of contrast medium-free biparametric magnetic resonance imaging (bpMRI; combining T2-weighted imaging [T2WI] and diffusion-weighted imaging [DWI]) for evaluating variant-histology urothelial carcinoma (VUC) remains unknown. OBJECTIVE: To compare the diagnostic performance of bpMRI and multiparametric MRI (mpMRI; combining T2WI, DWI, and dynamic contrast-enhanced MRI]) for assessing muscle invasion of VUC. DESIGN, SETTING, AND PARTICIPANTS: This multi-institution retrospective analysis included 118 patients with pathologically verified VUC who underwent bladder mpMRI before transurethral bladder tumor resection between 2010 and 2019. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Three board-certified radiologists separately evaluated two sets of images, set 1 (bpMRI) and set 2 (mpMRI), in accordance with the Vesical Imaging Reporting and Data System (VI-RADS). The histopathology results were utilized as a reference standard. Receiver operating characteristic curve analysis, Z test, and Wald test were used to assess diagnostic abilities. RESULTS AND LIMITATIONS: Sixty-six (55.9%) and 52 (44.1%) of the 118 patients with VUC included in the analysis (mean age, 71 ± 10 yr; 88 men) had muscle-invasive bladder cancer (MIBC) and non-MIBC, respectively. For the diagnosis of MIBC, the areas under the curve for bpMRI were significantly smaller than those for mpMRI (0.870-0.884 vs 0.902-0.923, p < 0.05). The sensitivity of bpMRI was significantly lower than that of mpMRI for all readers with a VI-RADS cutoff score of 4 (65.2-66.7% vs 77.3-80.3%, p < 0.05). The specificity of bpMRI and mpMRI did not differ significantly for all readers (88.5-90.4 vs 88.5-92.3, p > 0.05). A limitation of the study is the limited sample size because of the rarity of VUC. CONCLUSIONS: In patients with VUC, on applying VI-RADS, the diagnostic results of bpMRI were inferior to those of mpMRI for evaluating muscle invasion. Therefore, mpMRI-based methods are recommended for evaluating muscle invasiveness of VUC. PATIENT SUMMARY: Contrast medium-free biparametric magnetic resonance imaging (bpMRI)-based Vesical Imaging Reporting and Data System (VI-RADS) can accurately diagnose pure urothelial carcinomas, similar to conventional multiparametric magnetic resonance imaging-based VI-RADS. However, bpMRI-based VI-RADS may misdiagnose muscle invasiveness of urothelial carcinoma with variant histology, particularly when its cutoff score is 4.

Evaluation of the clinical behavior of unclassified renal cell carcinoma and its imaging findings on computed tomography and magnetic resonance imaging based on World Health Organization (WHO) 2022.

OBJECTIVES: To ascertain the clinical behaviors of unclassified renal cell carcinoma (RCC) and its characteristic imaging findings on CT and MRI. METHODS: Subjects in this retrospective study were 10 patients who had received a histological diagnosis of unclassified RCC based on World Health Organization (WHO) 2022 and who had undergone CT and/or MRI prior to surgery. In terms of clinical behaviors, TNM classification, stage, postoperative recurrence, time to recurrence, and postoperative survival were evaluated. In terms of imaging findings, tumor size, growth pattern, CT density, dynamic contrast-enhancement (DCE) pattern, internal appearance, presence of a pseudocapsule, and signal intensity on MRI were evaluated. We compared clinical behaviors and imaging findings, and investigated associations between them. RESULTS: One patient could not be followed-up due to death from other causes. Postoperative recurrence was observed in 4 patients, all of whom had Stage 3 RCC. In the remaining 5 patients without recurrence, all 5 patients showed Stage 2 or below. On imaging, unclassified RCC tended to be large (58.7 mm) and solid (100%), and heterogeneous interiors (80%), cystic degeneration (80%) and high intensity on diffusion-weighted imaging (DWI) (71.4%) were common. Comparing patients with and without recurrence, the following findings tended to differ between recurrence and recurrence-free groups: tumor size (73.4 ± 33.9 mm vs. 50.2 ± 33.9 mm, P = 0.286), growth pattern (invasive: 100% vs. 0%, expansive: 0% vs. 100%, P = 0.008 each), DCE pattern (progressive enhancement pattern, 66.7% vs. 0%, washout pattern, 0% vs. 66.7%, P = 0.135 each) and presence of a pseudocapsule (25% vs. 80%, P = 0.167). CONCLUSION: The clinical behavior of unclassified RCC varies widely. Although imaging findings are also variable, findings of large, heterogeneous tumors with cystic degeneration and high intensity on DWI were common. Several imaging findings such as large size, invasive growth, progressive enhancement pattern and no pseudocapsule may enable prediction of prognosis in unclassified RCC.

Evaluating residual tumor after neoadjuvant chemotherapy for muscle-invasive urothelial bladder cancer: diagnostic performance and outcomes using biparametric vs. multiparametric MRI.

BACKGROUND: Neoadjuvant chemotherapy (NAC) before radical cystectomy is standard of care in patients with muscle-invasive bladder cancer (MIBC). Response assessment after NAC is important but suboptimal using CT. We assessed MRI without vs. with intravenous contrast (biparametric [BP] vs. multiparametric [MP]) for identifying residual disease on cystectomy and explored its prognostic role. METHODS: Consecutive MIBC patients that underwent NAC, MRI, and cystectomy between January 2000-November 2022 were identified. Two radiologists reviewed BP-MRI (T2 + DWI) and MP-MRI (T2 + DWI + DCE) for residual tumor. Diagnostic performances were compared using receiver operating characteristic curve analysis. Kaplan-Meier curves and Cox proportional-hazards models were used to evaluate association with disease-free survival (DFS). RESULTS: 61 patients (36 men and 25 women; median age 65 years, interquartile range 59-72) were included. After NAC, no residual disease was detected on pathology in 19 (31.1%) patients. BP-MRI was more accurate than MP-MRI for detecting residual disease after NAC: area under the curve = 0.75 (95% confidence interval (CI), 0.62-0.85) vs. 0.58 (95% CI, 0.45-0.70; p = 0.043). Sensitivity were identical (65.1%; 95% CI, 49.1-79.0) but specificity was higher in BP-MRI compared with MP-MRI for determining residual disease: 77.8% (95% CI, 52.4-93.6) vs. 38.9% (95% CI, 17.3-64.3), respectively. Positive BP-MRI and residual disease on pathology were both associated with worse DFS: hazard ratio (HR) = 4.01 (95% CI, 1.70-9.46; p = 0.002) and HR = 5.13 (95% CI, 2.66-17.13; p = 0.008), respectively. Concordance between MRI and pathology results was significantly associated with DFS. Concordant positive (MRI+/pathology+) patients showed worse DFS than concordant negative (MRI-/pathology-) patients (HR = 8.75, 95% CI, 2.02-37.82; p = 0.004) and compared to the discordant group (MRI+/pathology- or MRI-/pathology+) with HR = 3.48 (95% CI, 1.39-8.71; p = 0.014). CONCLUSION: BP-MRI was more accurate than MP-MRI for identifying residual disease after NAC. A negative BP-MRI was associated with better outcomes, providing complementary information to pathological assessment of cystectomy specimens.

A phase II randomized trial of metastasis-directed therapy with alpha emitter radium-223 in men with oligometastatic castration-resistant prostate cancer (MEDAL).

BACKGROUND: The significance of metastasis-directed therapy for oligometastatic prostate cancer has been widely discussed, and targeted therapy for progressive sites is a feasible option as a multidisciplinary treatment for castration-resistant prostate cancer (CRPC). When oligometastatic CRPC with only bone metastases progresses after targeted therapy, it tends to progress as multiple bone metastases. The progression of oligometastatic CRPC after targeted therapy may be due in part to the presence of micrometastatic lesions that, though undetected on imaging, were present prior to targeted therapy. Thus the systemic treatment of micrometastases in combination with targeted therapy for progressive sites is expected to enhance the therapeutic effect. Radium-223 dichloride (radium-223) is a radiopharmaceutical that selectively binds to sites of increased bone turnover and inhibits the growth of adjacent tumor cells by emitting alpha rays. Therefore, for oligometastatic CRPC with only bone metastases, radium-223 may enhance the therapeutic effect of radiotherapy for active metastases. METHODS: This phase II, randomized trial of Metastasis-Directed therapy with ALpha emitter radium-223 in men with oligometastatic CRPC (MEDAL) is designed to assess the utility of radium-223 in combination with metastasis-directed radiotherapy in patients with oligometastatic CRPC confined to bone. In this trial, patients with oligometastatic CRPC with three or fewer bone metastases on whole-body MRI with diffusion-weighted MRI (WB-DWI) will be randomized in a 1:1 ratio to receive radiotherapy for active metastases plus radium-223 or radiotherapy for active metastases alone. The prior use of androgen receptor axis-targeted therapy and prostate-specific antigen doubling time will be used as allocation factors. The primary endpoint will be radiological progression-free survival against progression of bone metastases on WB-DWI. DISCUSSION: This will be the first randomized trial to evaluate the effect of radium-223 in combination with targeted therapy in oligometastatic CRPC patients. The combination of targeted therapy for macroscopic metastases with radiopharmaceuticals targeting micrometastasis is expected to be a promising new therapeutic strategy for patients with oligometastatic CRPC confined to bone. Trial registration Japan Registry of Clinical Trials (jRCT) (jRCTs031200358); Registered on March 1, 2021, https://jrct.niph.go.jp/latest-detail/jRCTs031200358.

Diagnostic Value of the Vesical Imaging-Reporting and Data System in Bladder Urothelial Carcinoma with Variant Histology.

The value of the Vesicle Imaging-Reporting and Data System (VI-RADS) in the diagnosis of muscle-invasive bladder cancer (MIBC) for urothelial carcinoma with variant histology (VUC) remains unknown. We retrospectively evaluated 360 consecutive patients with bladder cancer (255 pure urothelial carcinoma [PUC] and 69 VUC) who underwent multiparametric magnetic resonance imaging between 2011 and 2019. VI-RADS scores assigned by four readers were significantly higher for the VUC group than for the PUC group (p < 0.05). In the cohort of 122 pair-matched patients, there was no significant difference in VI-RADS score distribution between the PUC and VUC groups for all readers (p > 0.05). The area under the receiver operating characteristic curve for MIBC diagnosis via overall VI-RADS score was 0.93-0.94 for PUC and 0.89-0.92 for VUC, with no significant difference between the PUC and VUC groups (p = 0.32-0.60). These data suggests that VI-RADS scores achieved high diagnostic performance for detection of muscle invasion in both PUC and VUC. PATIENT SUMMARY: The Vesical Imaging-Reporting and Data System (VI-RADS) is a standardized system for reporting on detection of muscle-invasive bladder cancer via magnetic resonance imaging (MRI) scans. Our study shows that VI-RADS is also highly accurate for diagnosis for different variants of muscle-invasive bladder cancer, with good inter-reader agreement.

Patterns of recurrence in genuine and induced oligometastatic castration-resistant prostate cancer treated with progressive site-directed therapy.

OBJECTIVES: To describe oncological outcomes after progressive site-directed therapy (PSDT) in genuine and induced oligometasatic (OM)-castration-resistant prostate cancer (CRPC). METHODS: Thirty-seven patients with OM-CRPC treated with PSDT were retrospectively analyzed, and oncological outcomes and recurrence patterns on whole-body diffusion-weighted MRI (WB-DWI) were evaluated. RESULTS: Twenty-two (59%) were classified as genuine OM-CRPC and 15 (41%) as induced OM-CRPC. A 50% decline in PSA after PSDT was observed in 21 (95%) genuine OM-CRPCs and 7 (47%) induced OM-CRPCs (p = 0.0005). At a median observation period of 7.3 months, median PSA progression-free survival were 10.9 months in the genuine OM-CRPCs and 4.8 months in the induced OM-CRPCs (p = 0.015). Among the patients who developed PSA progression after PSDT, 11 of 15 in the genuine OM-CRPCs (73%) and 11 of 14 in the induced OM-CRPCs (79%) underwent WB-DWI at PSA progression. The median numbers of newly detected metastases were 2 (range: 1-5) in the genuine OM-CRPCs and 4 (range: 1-40) in the induced OM-CRPCs (p = 0.049). Only one new metastasis appeared in 5 patients from the genuine OM-CRPCs (46%) and 1 from the induced OM-CRPCs (9.1%, p = 0.048). In 7 of 9 patients from the genuine OM-CRPCs (78%) and 7 of 8 patients from the induced OM-CRPCs (88%) who had bone metastases alone, the newly detected metastasis limited to the bone. CONCLUSIONS: Genuine OM-CRPC had better oncological outcomes after PSDT than induced OM-CRPC, and the number of lesions detected at recurrence was limited. Induced OM-CRPC might be a disseminated condition with micrometastases at OM diagnosis.

Advances in MRI-Based Assessment of Rectal Cancer Post-Neoadjuvant Therapy: A Comprehensive Review.

Rectal cancer presents significant diagnostic and therapeutic challenges, with neoadjuvant therapy playing a pivotal role in improving resectability and patient outcomes. MRI serves as a critical tool in assessing treatment response. However, differentiating viable tumor tissue from therapy-induced changes on MRI remains a complex task. In this comprehensive review, we explore treatment options for rectal cancer based on resectability status, focusing on the role of MRI in guiding therapeutic decisions. We delve into the nuances of MRI-based evaluation of treatment response following neoadjuvant therapy, paying particular attention to emerging techniques like radiomics. Drawing from our insights based on the literature, we provide essential recommendations for post-neoadjuvant therapy management of rectal cancer, all within the context of MRI-based findings.

Apparent Diffusion Coefficient Map-Based Texture Analysis for the Differentiation of Chromophobe Renal Cell Carcinoma from Renal Oncocytoma.

Preoperative imaging differentiation between ChRCC and RO is difficult with conventional subjective evaluation, and the development of quantitative analysis is a clinical challenge. Forty-nine patients underwent partial or radical nephrectomy preceded by MRI and followed by pathological diagnosis with ChRCC or RO (ChRCC: n = 41, RO: n = 8). The whole-lesion volume of interest was set on apparent diffusion coefficient (ADC) maps of 1.5T-MRI. The importance of selected texture features (TFs) was evaluated, and diagnostic models were created using random forest (RF) analysis. The Mean Decrease Gini as calculated through RF analysis was the highest for mean_ADC_value. ChRCC had a significantly lower mean_ADC_value than RO (1.26 vs. 1.79 × 10−3 mm2/s, p < 0.0001). Feature selection by the Boruta method identified the first-quartile ADC value and GLZLM_HGZE as important features. ROC curve analysis showed that there was no significant difference in the classification performances between the mean_ADC_value-only model and the Boruta model (AUC: 0.954 vs. 0.969, p = 0.236). The mean ADC value had good predictive ability for the distinction between ChRCC and RO, comparable to that of the combination of TFs optimized for the evaluated cohort. The mean ADC value may be useful in distinguishing between ChRCC and RO.

Utility of radiomics features of diffusion-weighted magnetic resonance imaging for differentiation of fat-poor angiomyolipoma from clear cell renal cell carcinoma: model development and external validation.

PURPOSE: To investigate the utility of radiomics features of diffusion-weighted magnetic resonance imaging (DW-MRI) to differentiate fat-poor angiomyolipoma (fpAML) from clear cell renal cell carcinoma (ccRCC). MATERIALS AND METHODS: This multi-institutional study included two cohorts with pathologically confirmed renal tumors: 65 patients with ccRCC and 18 with fpAML in the model development cohort, and 17 with ccRCC and 13 with fpAML in the external validation cohort. All patients underwent magnetic resonance imaging (MRI) including DW-MRI. Radiomics analysis was used to extract 39 imaging features from the apparent diffusion coefficient (ADC) map. The radiomics features were analyzed with unsupervised hierarchical cluster analysis. A random forest (RF) model was used to identify radiomics features important for differentiating fpAML from ccRCC in the development cohort. The diagnostic performance of the RF model was evaluated in the development and validation cohorts. RESULTS: The cases in the developmental cohort were classified into three groups with different frequencies of fpAML by cluster analysis of radiomics features. RF analysis of the development cohort showed that the mean ADC value was important for differentiating fpAML from ccRCC, as well as higher-texture features including gray-level run length matrix (GLRLM)_long-run low gray-level enhancement (LRLGE), and GLRLM_low gray-level run emphasis (LGRE). The area under the curve values of the development [0.90, 95% confidence interval (CI) 0.80-1.00] and validation cohorts (0.87, 95% CI 0.74-1.00) were similar (P = 0.91). CONCLUSION: The radiomics features of ADC maps are useful for differentiating fpAML from ccRCC.

Synthetic magnetic resonance imaging for primary prostate cancer evaluation: Diagnostic potential of a non-contrast-enhanced bi-parametric approach enhanced with relaxometry measurements.

PURPOSE: Bi-parametric magnetic resonance imaging (bpMRI) with diffusion-weighted images has wide utility in diagnosing clinically significant prostate cancer (csPCa). However, bpMRI yields more false-negatives for PI-RADS category 3 lesions than multiparametric (mp)MRI with dynamic-contrast-enhanced (DCE)-MRI. We investigated the utility of synthetic MRI with relaxometry maps for bpMRI-based diagnosis of csPCa. METHODS: One hundred and five treatment-naïve patients who underwent mpMRI and synthetic MRI before prostate biopsy for suspected PCa between August 2019 and December 2020 were prospectively included. Three experts and three basic prostate radiologists evaluated the diagnostic performance of conventional bpMRI and synthetic bpMRI for csPCa. PI-RADS version 2.1 category 3 lesions were identified by consensus, and relaxometry measurements (T1-value, T2-value, and proton density [PD]) were performed. The diagnostic performance of relaxometry measurements for PI-RADS category 3 lesions in peripheral zone was compared with that of DCE-MRI. Histopathological evaluation results were used as the reference standard. Statistical analysis was performed using the areas under the receiver operating characteristic curve (AUC) and McNemar test. RESULTS: In 102 patients without significant MRI artefacts, the diagnostic performance of conventional bpMRI was not significantly different from that of synthetic bpMRI for all readers (p = 0.11-0.79). The AUCs of the combination of T1-value, T2-value, and PD (T1 + T2 + PD) for csPCa in peripheral zone for PI-RADS category 3 lesions were 0.85 for expert and 0.86 for basic radiologists, with no significant difference between T1 + T2 + PD and DCE-MRI for both expert and basic radiologists (p = 0.29-0.45). CONCLUSION: Synthetic MRI with relaxometry maps shows promise for contrast media-free evaluation of csPCa.

Impact of Progressive Site-Directed Therapy in Oligometastatic Castration-Resistant Prostate Cancer on Subsequent Treatment Response.

The purpose of this study was to evaluate the impact of progressive site-directed therapy (PSDT) for oligometastatic castration-resistant prostate cancer (OM-CRPC) on the efficacy of subsequent androgen receptor axis-targeted (ARAT) drugs, and to demonstrate the possibility of prolonging overall survival (OS). We performed a retrospective analysis of 15 OM-CRPC patients who underwent PSDT and subsequently received first-line ARAT drugs (PSDT group) and 13 OM-CRPC patients who were treated with first-line ARAT drugs without PSDT (non-PSDT group). PSDT was performed with the intention of treating all progressing sites detected by whole-body diffusion-weighted MRI with radiotherapy. Thirteen patients (86.7%) treated with PSDT had a decrease in PSA levels, which was at least 50% in 10 (66.7%) patients. The median PSA progression-free survival (PFS) for PSDT was 7.4 months. The median PSA-PFS for ARAT was 27.2 months in patients in the PSDT group and 11.7 months in the non-PSDT group, with a significant difference between the two groups (hazard ratio [HR], 0.28; p = 0.010). The median OS was not reached in the PSDT group and was significantly longer than 44.5 months in the non-PSDT group (HR, 0.11; p = 0.014). In OM-CRPC, PSDT may improve the efficacy of subsequent ARAT and OS.

Clinical utility of the Bosniak classification version 2019: Diagnostic value of adding magnetic resonance imaging to computed tomography examination.

PURPOSE: To assess the impact of the updated Bosniak classification (BC2019) for cystic renal masses (CRMs) on interobserver agreement between radiologists and urologists and the diagnostic value of adding MRI to CT examination (combined CT/MRI). METHOD: This study included 103 CRMs from 83 consecutive patients assessed using contrast-enhanced CT and MRI between 2010 and 2016. Nine readers in three groups (three radiologists, three radiology residents, and three urologists) reviewed CT alone and the combined CT/MRI using BC2019. Bosniak category was determined by consensus in each group for diagnosing malignancy, with a cut-off category of ≧III. Interobserver agreement was assessed using Fleiss' kappa values. The effect of CT or combined CT/MRI on the diagnosis of malignancy was assessed using McNemar's test. RESULTS: Interobserver agreement of BC2019 for CT alone was substantial for radiologists and residents, moderate for urologists (0.77, 0.63, and 0.58, respectively). Interobserver agreement of BC2019 for combined CT/MRI was substantial for all three groups (radiologists: 0.78; residents: 0.65; and urologists: 0.61). Among residents, the sensitivity/specificity/accuracy rates of combined CT/MRI vs. CT alone were 82.1/74.7/76.7% vs. 75.0/66.7/68.9%, and specificity and accuracy were significantly higher for combined CT/MRI than that for CT alone (p = 0.03 and 0.008, respectively). Similarly, sensitivity/specificity/accuracy values were significantly higher for combined CT/MRI among urologists (78.6/73.3/74.8% vs. 64.3/64.0/64.1%, p = 0.04/0.04/0.008). However, sensitivity/specificity/accuracy did not significantly differ between the two among radiologists (89.3/74.7/78.6% vs. 85.7/73.3/76.7%, p = 0.32/0.56/0.32). CONCLUSIONS: Combined CT/MRI is useful for diagnosing malignancy in patients with CRMs using BC2019, especially for non-expert readers.

A novel technique for automating stiffness measurement and emphasizing the main wave: Coherent-wave auto-selection (CHASE).

This study aims to develop and assess a new automated processing technique in MR elastography (MRE), namely coherent-wave auto-selection (CHASE). CHASE enables automatic selection of the region of interest (ROI) for stiffness measurement by extraction of the coherent wave region (CHASE ROI), and it improves the reconstruction of stiffness by a directional filter oriented along the main wave in each pixel (CHASE filtering). In this study, MRE of a phantom and of the liver of four healthy volunteers was performed. To investigate the potential of CHASE, this study assessed the CHASE according to three indices through the phantom study: 1) agreement on the ROI settings between CHASE and expert observers, 2) noise dependency, and 3) effect of the CHASE on stiffness variability within the CHASE ROI. The agreements on the ROI settings were analyzed by Cohen's kappa coefficient (κ). The noise dependency was analyzed by the mean absolute percentage errors (MAPEs) within the ROI between low (20%-80% amplitudes) and high vibration amplitudes (100% amplitude). The stiffness variability was assessed by standard deviation (SD) within the ROI. In the volunteer study, agreements on the ROI settings (or stiffness value) and stiffness variability within the CHASE ROI were assessed using κ-value (or intraclass correlation coefficient: ICC) and coefficient of variation, respectively. The results showed close agreement on the ROI settings and stiffness (κ-value: greater than 0.61 in both the phantom and volunteer studies, ICC: 0.97 in the volunteer study). The MAPEs within the CHASE ROI were much smaller than those in the whole region of the phantom (CHASE ROI vs. the whole region at 20% amplitude: 10.3% vs. 50.8%). Moreover, in both the phantom and volunteer studies, the stiffness variation within the CHASE ROI was smaller in the elastogram processed with CHASE filtering than in the unprocessed one. Our results demonstrated that the CHASE has high robustness against noise and the potential to provide ROI settings for stiffness measurement comparable to expert observers, as well as improve the reconstruction of stiffness.

Diagnostic performance of the vesical imaging-reporting and data system for detecting muscle-invasive bladder cancer in real clinical settings: Comparison with diagnostic cystoscopy.

PURPOSE: We herein compared the diagnostic performance of Vesical Imaging-Reporting and Data System (VI-RADS) scoring with diagnostic cystoscopy and evaluated diagnostic accuracies based on tumor locations. MATERIALS AND METHODS: Among 112 bladder cancer patients who underwent multiparametric magnetic resonance imaging and diagnostic cystoscopy preoperatively to detect bladder cancer, 61 were analyzed. VI-RADS was categorized into 5 stages by 2 radiologists (R1 and R2). Cut-off values ≥3 indicated muscle-invasive bladder cancer (MIBC). Muscle invasion (MI) was visually evaluated using diagnostic cystoscopy by 2 urologists (U1 and U2). The sensitivity and specificity of VI-RADS scores and diagnostic cystoscopy for diagnosing MI were compared. RESULTS: 16 patients (26.2%) were pathologically diagnosed with MIBC. Regarding MI diagnostic accuracy, the sensitivity/specificity of VI-RADS scores were 93.8/88.9% by R1 and 87.5/86.7% by R2, while those of diagnostic cystoscopy were 56.3/68.9% by U1 and 68.8/84.4% by U2. Therefore, the diagnostic accuracy of VI-RADS was significantly higher than that of cystoscopy, particularly for tumors located on the bladder neck, trigone, dome, and posterior and anterior walls. Over- and under-diagnosis rates were higher with VI-RADS than with diagnostic cystoscopy (25.9% vs. 14.8%) for tumors located on the lateral wall or ureteral orifice. CONCLUSION: VI-RADS had superior diagnostic performance for detecting MI, especially in tumors located at the bladder neck/trigone/dome/posterior and anterior wall. However, VI-RADS was inferior to cystoscopy in terms of MI detection for tumors located on the lateral wall or ureteral orifice. Therefore, a combination of diagnostic tools is recommended for the accurate staging of these tumors.

Does neoadjuvant chemotherapy have therapeutic benefit for node-positive upper tract urothelial carcinoma? Results of a multi-center cohort study.

OBJECTIVE: The indications of neoadjuvant chemotherapy (NAC) for lymph node-positive upper tract urothelial carcinoma (UTUC) have not been investigated regarding improved survival outcomes. Our specific aim was to compare the clinical outcomes of clinically node-positive UTUC patients who were treated by NAC followed by radical nephroureterectomy (RNU) or upfront RNU followed by adjuvant chemotherapy (AC). MATERIALS AND METHODS: Among 966 UTUC patients, we identified 89 with clinical nodal involvement who received either NAC before RNU nor AC after upfront RNU. Cox proportional hazard models were employed to evaluate the impact of chemotherapy modality on the oncological outcomes. RESULTS: Of the patient cohort, 36 (40.4%) received NAC followed by RNU, whereas 53 (59.6%) underwent RNU followed by AC. Multivariate analysis revealed that tumor size ≥3 cm, clinical T4, and gemcitabine and cisplatin regimen were independent risk factors for disease recurrence, whereas NAC followed by RNU was an independent factor for favorable RFS. Furthermore, regarding cancer-specific survival (CSS), NAC followed by RNU remained an independent factor for favorable CSS. According to Kaplan-Meier analysis, the 1-year and 2-year RFS were 67.9% and 47.0%, respectively, in the NAC+RNU group, which were significantly higher than those in the RNU+AC group (43.9% and 24.6%, respectively, P = 0.006). Moreover, the 1-year and 2-year CSS were 80.5% and 64.2%, respectively, in the NAC+RNU group, which were higher than those in the RNU+AC group (68.6% and 48.2%, respectively, P = 0.016). CONCLUSION: For node-positive UTUC patients, NAC followed by RNU was more clinically beneficial than RNU followed by AC.

Deep Learning Algorithm for Fully Automated Detection of Small (≤4 cm) Renal Cell Carcinoma in Contrast-Enhanced Computed Tomography Using a Multicenter Database.

OBJECTIVES: Renal cell carcinoma (RCC) is often found incidentally in asymptomatic individuals undergoing abdominal computed tomography (CT) examinations. The purpose of our study is to develop a deep learning-based algorithm for fully automated detection of small (≤4 cm) RCCs in contrast-enhanced CT images using a multicenter database and to evaluate its performance. MATERIALS AND METHODS: For the algorithmic detection of RCC, we retrospectively selected contrast-enhanced CT images of patients with histologically confirmed single RCC with a tumor diameter of 4 cm or less between January 2005 and May 2020 from 7 centers in the Japan Medical Image Database. A total of 453 patients from 6 centers were selected as dataset A, and 132 patients from 1 center were selected as dataset B. Dataset A was used for training and internal validation. Dataset B was used only for external validation. Nephrogenic phase images of multiphase CT or single-phase postcontrast CT images were used. Our algorithm consisted of 2-step segmentation models, kidney segmentation and tumor segmentation. For internal validation with dataset A, 10-fold cross-validation was applied. For external validation, the models trained with dataset A were tested on dataset B. The detection performance of the models was evaluated using accuracy, sensitivity, specificity, and the area under the curve (AUC). RESULTS: The mean ± SD diameters of RCCs in dataset A and dataset B were 2.67 ± 0.77 cm and 2.64 ± 0.78 cm, respectively. Our algorithm yielded an accuracy, sensitivity, and specificity of 88.3%, 84.3%, and 92.3%, respectively, with dataset A and 87.5%, 84.8%, and 90.2%, respectively, with dataset B. The AUC of the algorithm with dataset A and dataset B was 0.930 and 0.933, respectively. CONCLUSIONS: The proposed deep learning-based algorithm achieved high accuracy, sensitivity, specificity, and AUC for the detection of small RCCs with both internal and external validations, suggesting that this algorithm could contribute to the early detection of small RCCs.