Prospective Assessment of Vesical Imaging Reporting and Data System (VI-RADS) and Its Clinical Impact on the Management of High-risk Non–muscle-invasive Bladder Cancer Patients Candidate for Repeated Transurethral Resection

Combining Multiparametric MRI Radiomics Signature With the Vesical Imaging-Reporting and Data System (VI-RADS) Score to Preoperatively Differentiate Muscle Invasion of Bladder Cancer

Background

The treatment and prognosis for muscle-invasive bladder cancer (MIBC) and non-muscle-invasive bladder cancer (NMIBC) are different. We aimed to construct a nomogram based on the multiparametric MRI (mpMRI) radiomics signature and the Vesical Imaging-Reporting and Data System (VI-RADS) score for the preoperative differentiation of MIBC from NMIBC.

Method

The retrospective study involved 185 pathologically confirmed bladder cancer (BCa) patients (training set: 129 patients, validation set: 56 patients) who received mpMRI before surgery between August 2014 to April 2020. A total of 2,436 radiomics features were quantitatively extracted from the largest lesion located on the axial T2WI and from dynamic contrast-enhancement images. The minimum redundancy maximum relevance (mRMR) algorithm was used for feature screening. The selected features were introduced to construct radiomics signatures using three classifiers, including least absolute shrinkage and selection operator (LASSO), support vector machines (SVM) and random forest (RF) in the training set. The differentiation performances of the three classifiers were evaluated using the area under the curve (AUC) and accuracy. Univariable and multivariable logistic regression were used to develop a nomogram based on the optimal radiomics signature and clinical characteristics. The performance of the radiomics signatures and the nomogram was assessed and validated in the validation set.

Results

Compared to the RF and SVM classifiers, the LASSO classifier had the best capacity for muscle invasive status differentiation in both the training (accuracy: 90.7%, AUC: 0.934) and validation sets (accuracy: 87.5%, AUC: 0.906). Incorporating the radiomics signature and VI-RADS score, the nomogram demonstrated better discrimination and calibration both in the training set (accuracy: 93.0%, AUC: 0.970) and validation set (accuracy: 89.3%, AUC: 0.943). Decision curve analysis showed the clinical usefulness of the nomogram.

Conclusions

The mpMRI radiomics signature may be useful for the preoperative differentiation of muscle-invasive status in BCa. The proposed nomogram integrating the radiomics signature with the VI-RADS score may further increase the differentiation power and improve clinical decision making.

State of the art in abdominal MRI structured reporting: a review

In the management of several abdominal disorders, magnetic resonance imaging (MRI) has the potential to significantly improve patient's outcome due to its diagnostic accuracy leading to more appropriate treatment choice. However, its clinical value heavily relies on the quality and quantity of diagnostic information that radiologists manage to convey through their reports. To solve issues such as ambiguity and lack of comprehensiveness that can occur with conventional narrative reports, the adoption of structured reporting has been proposed. Using a checklist and standardized lexicon, structured reports are designed to increase clarity while assuring that all key imaging findings related to a specific disorder are included. Unfortunately, structured reports have their limitations too, such as risk of undue report simplification and poor template plasticity. Their adoption is also far from widespread, and probably the ideal balance between radiologist autonomy and report consistency of has yet to be found. In this article, we aimed to provide an overview of structured reporting proposals for abdominal MRI and of works assessing its value in comparison to conventional free-text reporting. While for several abdominal disorders there are structured templates that have been endorsed by scientific societies and their adoption might be beneficial, stronger evidence confirming their imperativeness and added value in terms of clinical practice is needed, especially regarding the improvement of patient outcome.

The validity, reliability, and reviewer acceptance of VI-RADS in assessing muscle invasion by bladder cancer: a multicenter prospective study

OBJECTIVE

To assess diagnostic validity and reliability of VI-RADS in predicting muscle invasion by bladder cancer (BCa) and evaluate reviewer acceptance of VI-RADS for clinical routine.

METHODS

A prospective multicenter study enrolled 331 patients with suspected/untreated BCa who underwent preoperative multiparametric MRI examination (mp-MRI) of the urinary bladder. Four experienced radiologists independently evaluated all mp-MRI using VI-RADS. The diagnostic validity of VI-RADS for predicting muscle invasion by BCa was calculated using histopathology of the first transurethral resection bladder tumor (TURBT) and second TURBT as the reference standards. The kappa statistics (κ) were applied to assess the interreader agreement (IRA). Reviewer acceptance was evaluated with questionnaires.

RESULTS

The risk of muscle invasion in VI-RADS 2, 3, 4, and 5 after the first and second TURBT was 21.8%, 45.8%, 69.6%, and 96.4% and 24.4%, 58.3%, 87%, and 99.2%, respectively. The overall diagnostic validity of VI-RADS was high. The optimal cut-off value for predicting muscle invasion after first TURBT was > VI-RADS 3 (sensitivity = 84.1% and specificity = 92.3%), and after second TURBT was > VI-RADS 2 (sensitivity = 89.9% and specificity = 90.1%). VI-RADS categorization showed a very good IRA (κ = 0.93). Reviewers fully agreed with the statement, "The application of structured reporting of bladder tumor should be encouraged" (score = 20).

CONCLUSIONS

VI-RADS showed high diagnostic validity and reliability for predicting muscle invasion by BCa, especially VI-RADS 4 and 5. However, VI-RADS 2 and 3 require further modifications to enhance their diagnostic validity. VI-RADS is highly encouraged to be used in daily practice.

KEY POINTS

• VI-RADS showed high diagnostic validity and reliability in predicting BCa muscle invasion, especially VI-RADS 4 and 5. • In VI-RADS 2 and 3, we observed a notable percentage of BCa with muscle invasion and this would require further modifications to enhance the diagnostic validity for these scores. • Overall VI-RADS is well-accepted by radiologists who recommend it for daily practice.

Attention to detail and a permissive set-up: crucial for an effective TURBT

An effective transurethral resection of bladder tumour (TURBT) is essential to achieve safe tumour clearance and to determine the biological potential of the cancer. Attention to surgical detail within a set-up that embraces evidence-based practice, training, quality standards, prospective audit and feedback will facilitate these objectives.

Multiparametric magnetic resonance imaging for bladder cancer: a comprehensive systematic review of the Vesical Imaging-Reporting and Data System (VI-RADS) performance and potential clinical applications

BACKGROUND

The Vesical Imaging-Reporting and Data System (VI-RADS) score is a novel standardized approach to image and report bladder cancer (BC) with multiparametric MRI (mpMRI).

OBJECTIVES

To describe and evaluate the performance of the VI-RADS score using mpMRI and assess its potential clinical applications and limitations.

METHODS

A systematic review was conducted using the MEDLINE and EMBASE electronic bibliographic databases between June 2020 and December 2020. All reports deemed relevant to describe the VI-RADS score and assess its performance and applications were retrieved. Results presentation stands as narrative, purely descriptive synthesis based on aggregate studies data.

RESULTS

A total of 20 relevant studies were retrieved: three meta-analyses, five prospective studies, and twelve retrospective studies. The retrospective studies covered 1676 patients, while the prospective studies included a total number of 468 patients. Pooled sensitivity, specificity to differentiate muscle-invasive from non-muscle-invasive bladder cancer, ranged from 74.1% to 97.3%, and 77% to 100%, respectively. The chosen VI-RADS score thresholds for this discrimination varied across studies. The interreader agreement ranged from 0.73 to 0.95. Currently, the potential clinical applications of VI-RADS consist of initial BC risk stratification, assessment of neoadjuvant therapies response, and bladder sparing approaches, although further validation is required.

CONCLUSIONS

The VI-RADS score helps to discriminate muscle invasive from non-muscle invasive BC with good performance and reproducibility. A simple algorithm based on four basic questions may enhance its popularization. Further studies are required to validate the clinical applications.

Utilization of imaging for staging in bladder cancer: is there a role for MRI or PET-computed tomography?

PURPOSE OF REVIEW

Accurate staging of bladder cancer is essential to guide appropriate management. In this review, we discuss the principles, applications and performance of multiparametric MRI (mpMRI) and PET-computer tomography (PET-CT) for local and distant staging of bladder cancer.

RECENT FINDINGS

Bladder mpMRI has a high diagnostic performance in local staging of bladder cancer, superior to other imaging modalities. It can accurately differentiate muscle invasive bladder cancer (MIBC) from non-MIBC (NMIBC), as well as ≤T2 from ≥T3 stages. mpMRI can be used to assess pelvic lymph nodes, although its sensitivity is relatively low. For the assessment of the upper urinary tract, CT urography is the imaging modality of choice. magnetic resonance urography is a viable alternative to CT in selected cases. Although PET-CT is accurate for nodal and distant staging of bladder cancer, there is no clear evidence on its superior diagnostic performance compared with contrast-enhanced CT.

SUMMARY

mpMRI is the most accurate imaging modality for local staging of bladder cancer, capable to accurately distinguish MIBC from NMIBC. Nodal and distant staging relies primarily on contrast-enhanced CT.

Transurethral resection of bladder tumor and the need for re-transurethral resection of bladder tumor: time to change our practice?

PURPOSE OF REVIEW

To summarize the current knowledge on the role of repeated transurethral resection of the bladder (re-TURBT) at the light of recently published trials that indicate the possibility to safely avoid it in well selected patients.

RECENT FINDINGS

Recently published trials tried to predict the histology of re-TURBT with the aim of improving patients' selection for this procedure. The en bloc resection technique seems to improve the quality of the resection, thereby diminishing and even eliminating the risk of upstaging and the residual disease rate after TURBT. Moreover, the introduction of multiparametric MRI (mpMRI) in bladder cancer showed initial promising results and aims, in the next future, to play a role in the selection of patients for re-TURBT.

SUMMARY

International guidelines agree to recommend re-TURBT in case of incomplete first resection and in T1 tumors. Conversely, the performance of re-TURBT in case of high-grade/high-risk Ta or in case of absence of detrusor muscle in TURBT specimen remains a matter of debate. Re-TURBT aims to reduce the risk of understaging the disease and to remove residual disease in case of persistent nonmuscle invasive bladder cancer. Actually, upstaging at re-TURBT is not a negligible event in T1 tumors (8-15%), while is quite uncommon in case of Ta tumors (0.4%). Residual disease at re-TURBT is usually found in the majority of patients (55-60%) and seems to impact oncological outcomes, even if recent evidence mitigated its relevance as prognostic factor.

Systematic Review and Meta-Analysis of Vesical Imaging-Reporting and Data System (VI-RADS) Inter-Observer Reliability: An Added Value for Muscle Invasive Bladder Cancer Detection

Simple Summary

In our systematic review and meta-analysis of eight observational studies including a total of 1016 patients, we demonstrated excellent pooled inter-observer agreement among Genito-Urinary radiologists when adopting the novel Vesical Imaging-Reporting and Data System (VI-RADS) criteria in the pre-trans-urethral resection of bladder tumor (TURBT) assessment for non-muscle (NMIBC) vs. muscle-invasive bladder cancer (MIBC) detection.

Abstract

The Vesical Imaging-Reporting and Data System (VI-RADS) has been introduced to provide preoperative bladder cancer staging and has proved to be reliable in assessing the presence of muscle invasion in the pre-TURBT (trans-urethral resection of bladder tumor). We aimed to assess through a systematic review and meta-analysis the inter-reader variability of VI-RADS criteria for discriminating non-muscle vs. muscle invasive bladder cancer (NMIBC, MIBC). PubMed, Web of Science, Cochrane, and Embase were searched up until 30 July 2020. The Quality Appraisal of Diagnostic Reliability (QAREL) checklist was utilized to assess the quality of included studies and a pooled measure of inter-rater reliability (Cohen’s Kappa [κ] and/or Intraclass correlation coefficients (ICCs)) was calculated. Further sensitivity analysis, subgroup analysis, and meta-regression were conducted to investigate the contribution of moderators to heterogeneity. In total, eight studies between 2018 and 2020, which evaluated a total of 1016 patients via 21 interpreting genitourinary (GU) radiologists, met inclusion criteria and were critically examined. No study was considered to be significantly flawed with publication bias. The pooled weighted mean κ estimate was 0.83 (95%CI: 0.78–0.88). Heterogeneity was present among the studies (Q = 185.92, d.f. = 7, p < 0.001; I2 = 92.7%). Meta-regression analyses showed that the relative % of MIBC diagnosis and cumulative reader’s experience to influence the estimated outcome (Coeff: 0.019, SE: 0.007; p= 0.003 and 0.036, SE: 0.009; p = 0.001). In the present study, we confirm excellent pooled inter-reader agreement of VI-RADS to discriminate NMIBC from MIBC underlying the importance that standardization and reproducibility of VI-RADS may confer to multiparametric magnetic resonance (mpMRI) for preoperative BCa staging.

VI-RADS for Bladder Cancer: Current Applications and Future Developments

Bladder cancer (BCa) is among the ten most frequent cancers globally. It is the tumor with the highest lifetime treatment-associated costs, and among the tumors with the heaviest impacts on postoperative quality of life. The purpose of this article is to review the current applications and future perspectives of the Vesical Imaging Reporting and Data System (VI-RADS). VI-RADS is a newly developed scoring system aimed at standardization of MRI acquisition, interpretation, and reporting for BCa. An insight will be given on the BCa natural history, current MRI applications for local BCa staging with assessment of muscle invasiveness, and clinical implications of the score for disease management. Future applications include risk stratification of nonmuscle invasive BCa, surveillance, and prediction and monitoring of therapy response. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 2.

Quantitation of bladder cancer for the prediction of muscle layer invasion as a complement to the vesical imaging-reporting and data system

OBJECTIVES

To examine the diagnostic performance of Vesical Imaging-Reporting and Data System (VIRADS) and to find a quantitative indicator for predicting muscle layer invasion of bladder cancer.

METHODS

3-T MRI of 82 patients performed before transurethral resection of bladder tumors or radical cystectomy between July 2018 and June 2019 were retrospectively analyzed. For one index lesion of each patient, two radiologists independently assigned VIRADS score and measured tumor-wall interface (contact length between tumor and bladder wall) on T2-weighted, diffusion-weighted, and dynamic contrast-enhanced MRI. Inter-reader agreement was assessed, and logistic regression analysis was performed to find indicators of muscle layer invasion. Comparison of indicators' diagnostic performance was done with receiver operating characteristic (ROC) curve and generalized linear model analyses. Optimal cutoff point was determined by the Youden index J.

RESULTS

Inter-reader agreement was at least substantial for VIRADS categorization (κ 0.77-0.81), and almost perfect for tumor-wall interface (intraclass correlation coefficient 0.88-0.90). Tumor-wall interface (odds ratio [OR] 1.90-2.00) and VIRADS score (OR 8.59-8.89) were independently associated with muscle layer invasion (p ≤ 0.02). For VIRADS, area under the ROC curve (AUROC) was 0.94, and the accuracy was 0.93 at score 3, the optimal threshold for predicting muscle layer invasion. Depending on the MRI sequence, tumor-wall interface showed AUROCs of 0.90-0.92 and accuracy of 0.84-0.90 at suggested thresholds (3 ± 0.3 cm). Tumor-wall interface showed insignificant differences in accuracy compared with VIRADS (p > 0.10), except as measured on diffusion-weighted images (p = 0.01).

CONCLUSIONS

VIRADS is a good predictor of muscle layer invasion. As an independent quantitative indicator, tumor-wall interface may complement VIRADS to enhance prediction.

KEY POINTS

• Vesical Imaging-Reporting and Data System (VIRADS) is a promising predictor of muscle invasion of bladder cancer with good reproducibility, as suggested by previous studies. • VIRADS score and the tumor-wall interface (curvilinear contact length between the tumor and the bladder wall) are independent predictors of muscle layer invasion. • As an easy-to-use quantitative indicator, tumor-wall interface is expected to be used as an indicator complementary to VIRADS, a qualitative indicator.

Clinical utility of the Vesical Imaging-Reporting and Data System for muscle-invasive bladder cancer between radiologists and urologists based on multiparametric MRI including 3D FSE T2-weighted acquisitions

OBJECTIVES

To investigate the clinical utility of the Vesical Imaging-Reporting and Data System (VI-RADS) by comparing its diagnostic performance for muscle-invasive bladder cancer (MIBC) between radiologists and urologists based on multiparametric MRI, including three-dimensional (3D) fast spin-echo (FSE) T2-weighted acquisitions.

METHODS

This study included 66 treatment-naïve patients (60 men, 6 women; mean age 74.0 years) with pathologically proven bladder cancer who underwent multiparametric MRI, including 3D FSE T2-weighted imaging, before transurethral bladder tumour resection between January 2010 and November 2018. The MRI scans were categorised according to the five-point VI-RADS score by four independent readers (two board-certified radiologists and board-certified urologists each), blinded to the histopathological findings. The VI-RADS scores were compared with the postoperative histopathological diagnosis. Interobserver agreement was assessed using weighted kappa coefficients. ROC analysis and generalised estimating equations were used to evaluate the diagnostic performance.

RESULTS

Forty-nine (74.2%) and 17 (25.8%) tumours were confirmed to be non-MIBC and MIBC, respectively, based on pathological examination. The interobserver agreement was good-to-excellent between all pairs of readers (range, 0.73-0.91). The urologists' sensitivity/specificity values for DCE-MRI VI-RADS scores were significantly lower than those of radiologists. No significant differences were observed for the overall VI-RADS score. The AUC for the overall VI-RADS score was 0.94, 0.92, 0.89, and 0.87 for radiologists 1 and 2 and urologists 1 and 2, respectively.

CONCLUSIONS

The VI-RADS score, based on multiparametric MRI including 3D FSE T2-weighted acquisitions, can be useful for radiologists and urologists to determine the bladder cancer muscle invasion status preoperatively.

KEY POINTS

• VI-RADS (using multiparametric MRI including 3D FSE T2-weighted acquisitions) achieves good to excellent interobserver agreement and has similar diagnostic performance for detecting muscle invasion by both radiologists and urologists. • The diagnostic performance of the overall VI-RADS score is high for both radiologists and urologists, particularly due to the dominant effect of diffusion-weighted imaging on the overall VI-RADS score. • The sensitivity and specificity values of the T2WI VI-RADS scores for four readers in our study (using 3D FSE T2-weighted acquisitions) were similar (with slightly higher specificity values) to previously published results (using 2D FSE T2-weighted acquisitions).

Preoperative detection of Vesical Imaging-Reporting and Data System (VI-RADS) score 5 reliably identifies extravesical extension of urothelial carcinoma of the urinary bladder and predicts significant delayed time to cystectomy: time to reconsider the need for primary deep transurethral resection of bladder tumour in cases of locally advanced disease?

OBJECTIVES

(I) To determine Vesical Imaging-Reporting and Data System (VI-RADS) score 5 accuracy in predicting locally advanced bladder cancer (BCa), so as to potentially identify those patients who could avoid the morbidity of deep transurethral resection of bladder tumour (TURBT) in favour of histological sampling-TUR prior to radical cystectomy (RC). (II) To explore the predictive value of VI-RADS score 5 on time-to-cystectomy (TTC) outcomes.

PATIENTS AND METHODS

We retrospectively reviewed patients' ineligible or refusing cisplatin-based combination neoadjuvant chemotherapy who underwent multiparametric magnetic resonance imaging (mpMRI) of the bladder prior to staging TURBT followed by RC for muscle-invasive BCa. Sensitivity, specificity, positive and negative predictive values (PPV, NPV) were calculated for VI-RADS score 5 vs. score 2-4 cases to assess the accuracy of mpMRI for extravesical BCa detection (≥pT3). VI-RADS score performance was assessed by receiver operating characteristics curve analysis. A Κ statistic was calculated to estimate mpMRI and pathological diagnostic agreement. The risk of delayed TTC (i.e. time from initial BCa diagnosis of >3 months) was assessed using multivariable logistic regression model.

RESULTS

A total of 149 T2-T4a, cN0-M0 patients (VI-RADS score 5, n = 39 vs VI-RADS score 2-4, n = 110) were examined. VI-RADS score 5 demonstrated sensitivity, specificity, PPV and NPV, in detecting extravesical disease of 90.2% (95% confidence interval [CI] 84-94.3), 98.1% (95% CI 94-99.6), 94.9% (95% CI 89.6-97.6) and 96.4% (95% CI 91.6-98.6), respectively. The area under the curve was 94.2% (95% CI 88.7-99.7) and inter-reader agreement was excellent (Κ_inter 0.89). The mean (SD) TTC was 4.2 (2.3) and 2.8 (1.1) months for score 5 vs 2-4, respectively (P < 0.001). VI-RADS score 5 was found to independently increase risk of delayed TTC (odds ratio 2.81, 95% CI 1.20-6.62).

CONCLUSION

The VI-RADS is valid and reliable in differentiating patients with extravesical disease from those with muscle-confined BCa before TURBT. Detection of VI-RADS score 5 was found to predict significant delay in TTC independently from other clinicopathological features. In the future, higher VI-RADS scores could potentially avoid the morbidity of extensive primary resections in favour of sampling-TUR for histology. Further prospective, larger, and multi-institutional trials are required to validate clinical applicability of our findings.

Impact of tumor size on the oncological outcome of high-grade nonmuscle invasive bladder cancer - examining the utility of classifying Ta bladder cancer based on size

PURPOSE

To examine survival rates and to calculate the risk of disease recurrence, progression, overall, and cancer-specific mortality in patients diagnosed with high-risk NMIBC using a multi-institutional dataset to evaluate differences between the guidelines of the European Association of Urology and the guidelines of the National Comprehensive Cancer Network (NCCN) with regard to tumor size in risk stratification.

METHODS AND MATERIAL

In total 1,116 individuals diagnosed with high-risk NMIBC between 2001 and 2013 were included in the analysis. Patients were stratified to NCCN guideline recommendations (high-grade T1, high-grade Ta ≤ 3 cm, and high-grade Ta > 3 cm). Recurrence and progression rates were calculated. Kaplan-Meier curves were fitted to examine differences in recurrence-free (RFS) and progression-free survival (PFS). Multivariable Cox proportional hazards regression models were employed to calculate differences in the RFS, PFS, overall, and cancer-specific survival (CSS).

RESULTS

The majority of patients were diagnosed with high-grade T1 disease (N = 576, 51.6%), while 34.2% and 14.2% of patients were diagnosed with high-grade Ta ≤ 3 cm and Ta > 3 cm NMIBC, respectively. The 1- and 5-year RFS (1-year: 80.5% vs. 64.9%; 5-year: 58.6% vs. 48.3%, P = 0.048) and PFS (1-year: 99.1% vs. 98.6%; 5-year: 97.7% vs. 92.4%, P = 0.054) rates were higher in patients with Ta ≤ 3 cm. Patients diagnosed with high-grade Ta > 3 cm experienced unfavorable progression-free, and cancer-specific survival compared to high-grade Ta ≤ 3 cm, respectively (PFS: 2.41, 95% confidence interval [CI] 1.05-5.56, P = 0.038; CSS: hazard ratios [HR] 2.22, 95% CI 1.02-4.89, P = 0.048).

CONCLUSION

Patients diagnosed with high-grade Ta NMIBC ≤3 cm demonstrated a favorable progression-free, and cancer-specific survival compared to patients diagnosed with high-grade Ta > 3 cm and high-grade T1 NMIBC.

Staging of bladder cancer with multiparametric MRI

The distinction of non-muscle-invasive bladder cancer and muscle-invasive bladder cancer is important for the selection of the optimal treatment. Multiparametric MRI (mp-MRI) has been an useful modality for the T staging of bladder cancer, and a systematic evaluation of mp-MRI is needed. The Vesical Imaging Reporting and Data System was designed to standardize the scanning and reporting criteria based on mp-MRI for clinical and research applications. This review briefly describes the method, interpretation, and timing of mp-MRI examinations in the clinical settings. Validation studies of Vesical Imaging Reporting and Data System and future perspectives are also considered.

Overview of VI-RADS in Bladder Cancer

OBJECTIVE. The purpose of this article is to review the natural history and management of bladder cancer, with insight into MRI applications for the assessment of muscle invasiveness of bladder cancer using the newly developed Vesical Imaging Reporting and Data System (VI-RADS) score. CONCLUSION. Multiparametric MRI and the VI-RADS score have been consistently validated across several different institutions as appropriate tools for local staging of bladder cancer and have been proven to contribute to the diagnostic workup and management of urinary bladder cancer.

Use of Vesical Imaging-Reporting and Data System (VI-RADS) for detecting the muscle invasion of bladder cancer: a diagnostic meta-analysis

OBJECTIVES

To comprehensively assess the diagnostic performance of Vesical Imaging-Reporting and Data System (VI-RADS) score for detecting the muscle invasion of bladder cancer.

METHODS

PubMed, Web of Science, and Embase were searched up to November 20, 2019. QUADAS-2 tool assessed the quality of included studies. The diagnostic estimates including sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and the area under the curve (AUC) of hierarchical summary receiver operating characteristic (HSROC) were calculated. Further subgroup analysis, meta-regression and sensitivity analysis were conducted.

RESULTS

Six studies with 1064 patients were finally included. The pooled sensitivity, specificity, and AUC value were 0.90 (95% CI 0.86-0.94), 0.86 (95% CI 0.71-0.94), and 0.93 (95% CI 0.91-0.95) for VI-RADS 3 as the cutoff value. The corresponding estimates were 0.77 (95% CI 0.65-0.86), 0.97 (95% CI 0.88-0.99), and 0.92 (95% CI 0.89-0.94) for VI-RADS 4 as the cutoff value. Meta-regression analysis revealed that study design (p value 0.01) and surgical pattern of reference standard (p value 0.02) were source of the heterogeneity of pooled sensitivity. No publication bias was observed.

CONCLUSIONS

The VI-RADS score can provide a good predictive ability for detecting the muscle invasiveness of primary bladder cancer with VI-RADS 3 or VI-RADS 4 as the cutoff value.

KEY POINTS

• VI-RADS score has high sensitivity and specificity for predicting muscle invasion. • The diagnostic efficiencies of VI-RADS 3 and VI-RADS 4 as the cutoff value are similar. • VI-RADS score could be used for detecting muscle invasion of bladder cancer in clinical practice.

Diagnostic Performance of Vesical Imaging Reporting and Data System for the Prediction of Muscle-invasive Bladder Cancer: A Systematic Review and Meta-analysis

CONTEXT

A noninvasive multiparametric magnetic resonance imaging (MRI)-based scoring system for predicting muscle-invasive bladder cancer (MIBC), the "Vesical Imaging Reporting and Data System" (VI-RADS), was recently developed by an international multidisciplinary panel. Since then, a few studies evaluating the value of VI-RADS for predicting MIBC have been published.

OBJECTIVE

To review the diagnostic performance of VI-RADS for the prediction of MIBC.

EVIDENCE ACQUISITION

PubMed and EMBASE databases were searched up to November 10, 2019. We included diagnostic accuracy studies using VI-RADS to predict MIBC using cystectomy or transurethral resection as the reference standard. Methodological quality was evaluated with Quality Assessment of Diagnostic Accuracy Studies-2. Sensitivity and specificity were pooled and plotted using hierarchical summary receiver operating characteristics (HSROC) modeling. Meta-regression analyses were done to explore heterogeneity.

EVIDENCE SYNTHESIS

Six studies (1770 patients) were included. Pooled sensitivity and specificity were 0.83 (95% confidence interval [CI] 0.70-0.90) and 0.90 (95% CI 0.83-0.95), and the area under the HSROC curve was 0.94 (95% CI 0.91-0.95). Heterogeneity was present among the studies (Q = 29.442, p <  0.01; I² = 87.93%, and 90.99% for sensitivity and specificity). Meta-regression analyses showed that the number of patients (>205 vs ≤205), magnetic field strength (3 vs 1.5 T), T2-weighted image slice thickness (3 vs 4 mm), and VI-RADS cutoff score (≥3 vs ≥4) were significant factors affecting heterogeneity (p ≤  0.03).

CONCLUSIONS

VI-RADS shows good sensitivity and specificity for determining MIBC. Technical factors associated with MRI acquisition and cutoff scores need to be taken into consideration as they may affect performance.

PATIENT SUMMARY

A recently established noninvasive magnetic resonance imaging-based scoring system shows good diagnostic performance in detecting muscle-invasive bladder cancer.

The effectiveness of multiparametric magnetic resonance imaging in bladder cancer (Vesical Imaging-Reporting and Data System): A systematic review

Objective

To evaluate the role of the Vesical Imaging-Reporting and Data System (VI-RADS) score in the diagnostic pathway of bladder cancer.

Methods

A systemic search of the contemporary literature was performed in December 2019 using the Medical Literature Analysis and Retrieval System Online (MEDLINE), the Excerpta Medica dataBASE (EMBASE), and Web of Science databases focussing on all available articles on VI-RADS.

Results

Overall, six of 15 articles were included. All the available articles evaluated the ability of radiologists to use the VI-RADS score for discriminating non-muscle-invasive bladder cancer (NMIBC) from muscle-invasive bladder cancer (MIBC). Considering a cut-off VI-RADS score of >2, the sensitivity, specificity, positive (PPV) and negative predictive value (NPV) were 78-91.9%, 85-91%.1, 69-78%, and 88-97.1%, respectively. Considering a VI-RADS score cut-off of >3, the sensitivity, specificity, PPV and NPV were 77-94.6%, 43.9-96.5%, 51.6-86%, and 63.7-93%, respectively. Good interobserver agreement was demonstrated in the evaluated studies with a κ score of 0.73-0.89. Only one study evaluated the utility of VI-RADS in determining the presence of MIBC in patients treated with transurethral resection of the bladder diagnosed with high-grade T1 before the second transurethral resection using a VI-RADS score cut-off of >2; the sensitivity, specificity, PPV and NPV were 85%, 93.6%, 74.5%, and 96.6%, respectively.

Conclusion

The VI-RADS score, using multiparametric magnetic resonance imaging, showed excellent results in discriminating MIBC from NMIBC. Preliminary results have been reported for its use in patients with high-grade T1 bladder cancer. These results need to be validated in high-quality real-world settings.

Abbreviations

DCE: dynamic contrast enhancement; DWI: diffusion-weighted imaging; (N)MIBC: (non-)muscle-invasive bladder cancer; mpMRI: multiparametric MRI; TURBT: transurethral resection of bladder tumour; (N)(P)PV: (negative) (positive) predictive value; SC: structural category; T2W: T2-weighted; VI-RADS: vesical imaging-reporting and data system.

MRI of Bladder Cancer: Local and Nodal Staging

Accurate staging of bladder cancer (BC) is critical, with local tumor staging directly influencing management decisions and affecting prognosis. However, clinical staging based on clinical examination, including cystoscopy and transurethral resection of bladder tumor (TURBT), often understages patients compared to final pathology at radical cystectomy and lymph node (LN) dissection, mainly due to underestimation of the depth of local invasion and the presence of LN metastasis. MRI has now become established as the modality of choice for the local staging of BC and can be additionally utilized for the assessment of regional LN involvement and tumor spread to the pelvic bones and upper urinary tract (UUT). The recent development of the Vesical Imaging-Reporting and Data System (VI-RADS) recommendations has led to further improvements in bladder MRI, enabling standardization of image acquisition and reporting. Multiparametric magnetic resonance imaging (mpMRI) incorporating morphological and functional imaging has been proven to further improve the accuracy of primary and recurrent tumor detection and local staging, and has shown promise in predicting tumor aggressiveness and monitoring response to therapy. These sequences can also be utilized to perform radiomics, which has shown encouraging initial results in predicting BC grade and local stage. In this article, the current state of evidence supporting MRI in local, regional, and distant staging in patients with BC is reviewed. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 2 J. Magn. Reson. Imaging 2020;52:649-667.