Prediction of chemotherapeutic response in bladder cancer using K-means clustering of dynamic contrast-enhanced (DCE)-MRI pharmacokinetic parameters

Multiparametric Characterization of the DSL-6A/C1 Pancreatic Cancer Model in Rats

The DSL-6A/C1 murine pancreatic ductal adenocarcinoma (PDAC) tumor model was established in Lewis rats and characterized through a comprehensive multiparametric analysis to compare it to other preclinical tumor models and explore potential diagnostic and therapeutical targets. DSL-6A/C1 tumors were histologically analyzed to elucidate PDAC features. The tumor microenvironment was studied for immune cell prevalence. Multiparametric MRI and PET imaging were utilized to characterize tumors, and 68Ga-FAPI-46-targeting cancer-associated fibroblasts (CAFs), were used to validate the histological findings. The histology confirmed typical PDAC characteristics, such as malformed pancreatic ductal malignant cells and CAFs. Distinct immune landscapes were identified, revealing an increased presence of CD8+ T cells and a decreased CD4+ T cell fraction within the tumor microenvironment. PET imaging with 68Ga-FAPI tracers exhibited strong tracer uptake in tumor tissues. The MRI parameters indicated increasing intralesional necrosis over time and elevated contrast media uptake in vital tumor areas. We have demonstrated that the DSL-6A/C1 tumor model, particularly due to its high tumorigenicity, tumor size, and 68Ga-FAPI-46 sensitivity, is a suitable alternative to established small animal models for many forms of preclinical analyses and therapeutic studies of PDAC.

Clinical application of bladder MRI and the Vesical Imaging-Reporting and Data System

Diagnostic work-up and risk stratification in patients with bladder cancer before and after treatment must be refined to optimize management and improve outcomes. MRI has been suggested as a non-invasive technique for bladder cancer staging and assessment of response to systemic therapy. The Vesical Imaging-Reporting And Data System (VI-RADS) was developed to standardize bladder MRI image acquisition, interpretation and reporting and enables accurate prediction of muscle-wall invasion of bladder cancer. MRI is available in many centres but is not yet recommended as a first-line test for bladder cancer owing to a lack of high-quality evidence. Consensus-based evidence on the use of MRI-VI-RADS for bladder cancer care is needed to serve as a benchmark for formulating guidelines and research agendas until further evidence from randomized trials becomes available.

Multiparametric MRI in Era of Artificial Intelligence for Bladder Cancer Therapies

This review focuses on the principles, applications, and performance of mpMRI for bladder imaging. Quantitative imaging biomarkers (QIBs) derived from mpMRI are increasingly used in oncological applications, including tumor staging, prognosis, and assessment of treatment response. To standardize mpMRI acquisition and interpretation, an expert panel developed the Vesical Imaging-Reporting and Data System (VI-RADS). Many studies confirm the standardization and high degree of inter-reader agreement to discriminate muscle invasiveness in bladder cancer, supporting VI-RADS implementation in routine clinical practice. The standard MRI sequences for VI-RADS scoring are anatomical imaging, including T2w images, and physiological imaging with diffusion-weighted MRI (DW-MRI) and dynamic contrast-enhanced MRI (DCE-MRI). Physiological QIBs derived from analysis of DW- and DCE-MRI data and radiomic image features extracted from mpMRI images play an important role in bladder cancer. The current development of AI tools for analyzing mpMRI data and their potential impact on bladder imaging are surveyed. AI architectures are often implemented based on convolutional neural networks (CNNs), focusing on narrow/specific tasks. The application of AI can substantially impact bladder imaging clinical workflows; for example, manual tumor segmentation, which demands high time commitment and has inter-reader variability, can be replaced by an autosegmentation tool. The use of mpMRI and AI is projected to drive the field toward the personalized management of bladder cancer patients.

The assessment of pathological response to neoadjuvant chemotherapy in muscle-invasive bladder cancer patients with DCE-MRI and DWI: a systematic review and meta-analysis

OBJECTIVE

The purpose of this meta-analysis was to determine the value of dynamic contrast-enhanced-MRI (DCE-MRI) and diffusion-weighted imaging (DWI) in evaluating the pathological response of muscle invasive bladder cancer (MIBC) to neoadjuvant chemotherapy (NAC), and further indirectly compare the diagnostic performance of DCE-MRI and DWI.

METHODS

Literatures associated to DCE-MRI and DWI in the evaluation of pathological response of MIBC to NAC were searched from PubMed, Cochrane Library, web of science, and EMBASE databases. The quality assessment of diagnostic accuracy studies 2 tool was used to assess the quality of studies. Pooled sensitivity (SE), specificity (SP), positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and the area under the receiver operating characteristic curves (AUC) with their 95% confidence intervals (CIs) were calculated to evaluate the diagnostic performance of DCE-MRI and DWI in predicting the pathological response to NAC in patients with MIBC.

RESULTS

There were 11 studies involved, 6 of which only underwent DCE- MRI examination, 4 of which only underwent DWI examination, and 1 of which underwent both DCE- MRI and DWI examination. The pooled SE, SP, PLR, NLR, DOR of DCE-MRI were 0.88 (95% CI: 0.78-0.93), 0.88 (95% CI: 0.67-0.96), 7.4 (95% CI: 2.3-24.2), 0.14 (95% CI: 0.07-0.27), and 53 (95% CI: 10-288), respectively. The pooled SE, SP, PLR, NLR, DOR of DWI were 0.83 (95% CI: 0.75-0.88), 0.88 (95% CI: 0.81-0.93), 7.1 (95% CI: 4.3-11.7), 0.20 (95% CI: 0.14-0.28), and 36 (95% CI:18-73), respectively. The AUCs of SROC curve for DCE-MRI and DWI were 0.93 (95% CI: 0.91-0.95) and 0.92 (95% CI: 0.89-0.94), respectively. There were no significant differences between DWI and DCE-MRI for SE, SP, and AUC.

CONCLUSION

This meta-analysis demonstrated high diagnostic performance of both DCE-MRI and DWI in predicting the pathological response to NAC in MIBC. DWI might be a potential substitute for DCE-MRI, with no significant difference in diagnostic performance between the two. However, caution should be taken when applying our results, as our results were based on indirect comparison.

ADVANCES IN KNOWLEDGE

No previous studies have comprehensively analysed the value of DCE-MRI and DWI in evaluating the pathological response to NAC in MIBC. According to the current study, both DCE-MRI and DWI yielded high diagnostic performance, with the AUCs of 0.93 and 0.92, respectively. Indirect comparison no significant difference in the diagnostic performanceof DCE-MRI and DWI.

Bladder preservation after neoadjuvant therapy - 2021 IBCN updates part 1

The morbidity associated with radical cystectomy (RC) for muscle-invasive bladder cancer (MIBC) has fueled investigations into the feasibility of bladder preservation strategies after a favorable clinical response to neoadjuvant therapy (NAT). Identifying optimal candidates for bladder preservation is predicated on our ability to identify tumors with inherent cisplatin sensitivity and accurately stage patients before and after NAT. In the present review, we evaluate the accuracy and limitations of contemporary staging modalities and investigate clinical outcomes in patients with MIBC who were managed with bladder preservation after NAT. Lastly, we discuss the predictive role of cisplatin-sensitizing DNA damage response (DDR) gene alterations as a foundational component to current prospective clinical trials evaluating bladder preservation in the setting of MIBC.

Biparametric magnetic resonance imaging assessment for detection of muscle-invasive bladder cancer: a systematic review and meta-analysis

OBJECTIVES

To investigate if removing DCE from the Vesical Imaging Reporting and Data System (VI-RADS) influences the diagnostic accuracy of muscle-invasive bladder cancer (MIBC). We also explored using different reference standards on the MRI diagnostic performance.

METHODS

We searched the Cochrane Library, Embase, and PubMed databases to June 26, 2021. Pooled biparametric MRI (bpMRI, T2WI+DWI) and multiparametric MRI (mpMRI, T2WI+DWI+DCE) sensitivities and specificities and the diagnostic performances of these methods for MIBC were compared using different reference standards.

RESULTS

Seventeen studies with 2344 patients were finally included, of which 7 studies, including 1041 patients, reported the diagnostic performance of bpMRI. VI-RADS showed sensitivities and specificities of 0.91 (95% CI 0.87-0.94) and 0.86 (95% CI 0.77-0.91) at cutoff scores of 3, and 0.85 (95% CI 0.77-0.90) and 0.93 (95% CI 0.89-0.96) at cutoff scores of 4. BpMRI showed sensitivities and specificities of 0.90 (95% CI 0.69-0.97) and 0.90 (95% CI 0.81-0.95), and 0.84 (95% CI 0.78-0.88) and 0.97 (95% CI 0.87-0.99), respectively, for cutoff scores of 3 and 4. The sensitivities of bpMRI vs mpMRI for MIBC were not significantly different, but bpMRI was more specific than mpMRI at cutoff scores of 3 (p = 0.02) and 4 (p = 0.02). The VI-RADS studies using primary transurethral resection of bladder tumors (TURBT) as the reference standard had significantly higher sensitivities (p < 0.001) than those using secondary TURBT or radical cystectomy as the reference.

DATA CONCLUSION

BpMRI and conventional VI-RADS had similar diagnostic efficacies for MIBC. Since MRI overestimated MIBC diagnoses using primary TURBT as the reference standard, we recommend using secondary TURBT as the reference standard.

KEY POINTS

• Biparametric MRI without DCE had similar diagnostic efficacies for MIBC compared with conventional VI-RADS. • The sensitivity of VI-RADS was overestimated when referring to the primary TURBT results. • Biparametric MRI comprised of T2WI and DWI could be used for detecting MIBC in clinical practice.

Novel Therapeutic Opportunities in Neoadjuvant Setting in Urothelial Cancers: A New Horizon Opened by Molecular Classification and Immune Checkpoint Inhibitors

Muscle invasive bladder cancer (MIBC) is a widespread malignancy with a worse prognosis often related to a late diagnosis. For early-stage MIBC pts, a multidisciplinary approach is mandatory to evaluate the timing of neoadjuvant chemotherapy (NAC) and surgery. The current standard therapy is platinum-based NAC (MVAC-methotrexate, vinblastine, doxorubicin, and cisplatin or Platinum–Gemcitabine regimens) followed by radical cystectomy (RC) with lymphadenectomy. However, preliminary data from Vesper trial highlighted that dose-dense NAC MVAC is endowed with a good pathological response but shows low tolerability. In the last few years, translational-based research approaches have identified several candidate biomarkers of NAC esponsiveness, such as ERCC2, ERBB2, or DNA damage response (DDR) gene alterations. Moreover, the recent consensus MIBC molecular classification identified six molecular subtypes, characterized by different sensitivity to chemo- or targeted or immunotherapy, that could open a novel procedure for patient selection and also for neoadjuvant therapies. The Italian PURE-01 phase II Trial extended data on efficacy and resistance to Immune Checkpoint Inhibitors (ICIs) in this setting. In this review, we summarize the most relevant literature data supporting NAC use in MIBC, focusing on novel therapeutic strategies such as immunotherapy, considering the better patient stratification and selection emerging from novel molecular classification.

[French ccAFU guidelines - update 2020-2022: bladder cancer]

OBJECTIVE

- To update French guidelines for the management of bladder cancer specifically non-muscle invasive (NMIBC) and muscle-invasive bladder cancers (MIBC).

METHODS

- A Medline search was achieved between 2018 and 2020, notably regarding diagnosis, options of treatment and follow-up of bladder cancer, to evaluate different references with levels of evidence.

RESULTS

- Diagnosis of NMIBC (Ta, T1, CIS) is based on a complete deep resection of the tumor. The use of fluorescence and a second-look indication are essential to improve initial diagnosis. Risks of both recurrence and progression can be estimated using the EORTC score. A stratification of patients into low, intermediate and high risk groups is pivotal for recommending adjuvant treatment: instillation of chemotherapy (immediate post-operative, standard schedule) or intravesical BCG (standard schedule and maintenance). Cystectomy is recommended in BCG-refractory patients. Extension evaluation of MIBC is based on contrast-enhanced pelvic-abdominal and thoracic CT-scan. Multiparametric MRI can be an alternative. Cystectomy associated with extended lymph nodes dissection is considered the gold standard for non-metastatic MIBC. It should be preceded by cisplatin-based neoadjuvant chemotherapy in eligible patients. An orthotopic bladder substitution should be proposed to both male and female patients with no contraindication and in cases of negative frozen urethral samples; otherwise transileal ureterostomy is recommended as urinary diversion. All patients should be included in an Early Recovery After Surgery (ERAS) protocol. For metastatic MIBC, first-line chemotherapy using platin is recommended (GC or MVAC), when performans status (PS <1) and renal function (creatinine clearance >60 mL/min) allow it (only in 50% of cases). In second line treatment, immunotherapy with pembrolizumab demonstrated a significant improvement in overall survival.

CONCLUSION

- These updated French guidelines will contribute to increase the level of urological care for the diagnosis and treatment of patients diagnosed with NMIBC and MIBC.

Diagnostic performance of contrast-enhanced dynamic and diffusion-weighted MR imaging in the assessment of tumor response to neoadjuvant therapy in muscle-invasive bladder cancer

OBJECTIVES

To evaluate the diagnostic performance of DCE MRI and DWI in the assessment of pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) in patients with muscle-invasive bladder cancer (MIBC).

METHODS

This prospective study included 90 patients with MIBC who finished NAC. Two radiologists independently assessed MRI for the determination of semi-quantitative parameters (wash-in rate and wash-out rate) and apparent diffusion coefficient (ADC) value. The correlation between pCR and wash-in rate, wash-out rate, ADC value were analyzed. The area under the ROC curve (AUC) was used to evaluate the diagnostic performance for detecting pCR. Inter-reader agreement was assessed using the ICC statistics.

RESULTS

On cystectomy specimens, pCR was confirmed in (43.3%, 39/90). pCR is negatively correlated with wash-out rate (r = - 0.701, p = 0.01) and ADC value (r = - 0.621, p = 0.01). ADC value is positively correlated with wash-out rate (r = 0.631, p = 0.001). The diagnostic accuracy of ADC value (cut-off value: 0.911 × 10^-3mm²/s) and wash-out rate (cut-off value: 0.677 min^-1) in the identification of pCR was (92% for reader 1, 91% for reader 2), and (90% for reader 1, 88% for reader 2), respectively. The sensitivity, specificity for predicting pCR using ADC value + washout rate cut off values were 95.4%, 97.7% for reader 1, and 96%, 97% for reader 2, respectively. AUC was 0.981 for reader 1, 0.971 for reader 2. The overall reproducibility of the mean ADC value and wash out rate was excellent (ICC = 0.83-0.90). The ICC values for the mean ADC value, washout rate was 0.89 (95% CI 0.84-0.89) and 0.87 (95% CI 0.86-0.91), respectively.

CONCLUSION

Semi-quantitative parameter (wash-out) derived from DCE-MRI and ADC has the potential to assess the tumor's complete pathologic response. The two parameters using together can offer the best possibility to identify complete response to NAC in MIBC.

MR-Guided Adaptive Radiotherapy for Bladder Cancer

Radiotherapy has an important role in the curative and palliative treatment settings for bladder cancer. As a target for radiotherapy the bladder presents a number of technical challenges. These include poor tumor visualization and the variability in bladder size and position both between and during treatment delivery. Evidence favors the use of magnetic resonance imaging (MRI) as an important means of tumor visualization and local staging. The availability of hybrid systems incorporating both MRI scanning capabilities with the linear accelerator (MR-Linac) offers opportunity for in-room and real-time MRI scanning with ability of plan adaption at each fraction while the patient is on the treatment couch. This has a number of potential advantages for bladder cancer patients. In this article, we examine the technical challenges of bladder radiotherapy and explore how magnetic resonance (MR) guided radiotherapy (MRgRT) could be leveraged with the aim of improving bladder cancer patient outcomes. However, before routine clinical implementation robust evidence base to establish whether MRgRT translates into improved patient outcomes should be ascertained.

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.

French ccAFU guidelines – Update 2018–2020: Bladder cancer

Objective

To propose updated French guidelines for non-muscle invasive (NMIBC) and muscle-invasive (MIBC) bladder cancers.

Methods

A Medline search was achieved between 2015 and 2018, as regards diagnosis, options of treatment and follow-up of bladder cancer, to evaluate different references with levels of evidence.

Results

Diagnosis of NMIBC (Ta, T1, CIS) is based on a complete deep resection of the tumor. The use of fluorescence and a second-look indication are essential to improve initial diagnosis. Risks of both recurrence and progression can be estimated using the EORTC score. A stratification of patients into low, intermediate and high risk groups is pivotal for recommending adjuvant treatment: instillation of chemotherapy (immediate post-operative, standard schedule) or intravesical BCG (standard schedule and maintenance). Cystectomy is recommended in BCG-refractory patients. Extension evaluation of MIBC is based on contrast-enhanced pelvic-abdominal and thoracic CT-scan. Multiparametric MRI can be an alternative. Cystectomy associated with extended lymph nodes dissection is considered the gold standard for non-metastatic MIBC. It should be preceded by cisplatin-based neoadjuvant chemotherapy in eligible patients. An orthotopic bladder substitution should be proposed to both male and female patients with no contraindication and in cases of negative frozen urethral samples; otherwise transileal ureterostomy is recommended as urinary diversion. All patients should be included in an Early Recovery After Surgery (ERAS) protocol. For metastatic MIBC, first-line chemotherapy using platin is recommended (GC or MVAC), when performans status (PS < 1) and renal function (creatinine clearance > 60 mL/min) allow it (only in 50 % of cases). In second line treatment, immunotherapy with pembrolizumab demonstrated a significant improvement in overall survival.

Conclusion

These updated French guidelines will contribute to increase the level of urological care for the diagnosis and treatment for NMIBC and MIBC.

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.

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.

RETRACTED: Recommandations françaises du Comité de Cancérologie de l’AFU — Actualisation 2018—2020 : tumeurs de la vessie French ccAFU guidelines — Update 2018—2020: Bladder cancer

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). Cet article est retiré de la publication à la demande des auteurs car ils ont apporté des modifications significatives sur des points scientifiques après la publication de la première version des recommandations. Le nouvel article est disponible à cette adresse: doi:10.1016/j.purol.2019.01.006. C’est cette nouvelle version qui doit être utilisée pour citer l’article. This article has been retracted at the request of the authors, as it is not based on the definitive version of the text because some scientific data has been corrected since the first issue was published. The replacement has been published at the doi:10.1016/j.purol.2019.01.006. That newer version of the text should be used when citing the article.

Multiparametric Magnetic Resonance Imaging for Bladder Cancer: Development of VI-RADS (Vesical Imaging-Reporting And Data System)

CONTEXT

Management of bladder cancer (BC) is primarily driven by stage, grade, and biological potential. Knowledge of each is derived using clinical, histopathological, and radiological investigations. This multimodal approach reduces the risk of error from one particular test, but may present a staging dilemma when results conflict. Multiparametric magnetic resonance imaging (mpMRI) may improve patient care through imaging of the bladder with better resolution of the tissue planes than computed tomography and without radiation exposure.

OBJECTIVE

To define a standardized approach to imaging and reporting mpMRI for BC, by developing a VI-RADS score.

EVIDENCE ACQUISITION

We created VI-RADS (Vesical Imaging-Reporting And Data System) through consensus using existing literature.

EVIDENCE SYNTHESIS

We describe standard imaging protocols and reporting criteria (including size, location, multiplicity, and morphology) for bladder mpMRI. We propose a five-point VI-RADS score, derived using T2-weighted MRI, diffusion-weighted imaging, and dynamic contrast enhancement, which suggests the risks of muscle invasion. We include sample images used to understand VI-RADS.

CONCLUSIONS

We hope that VI-RADS will standardize reporting, facilitate comparisons between patients, and in future years, will be tested and refined if necessary. While we do not advocate mpMRI for all patients with BC, this imaging may compliment pathology or reduce radiation-based imaging. Bladder mpMRI may be most useful in patients with non-muscle-invasive cancers, in expediting radical treatment or for determining response to bladder-sparing approaches.

PATIENT SUMMARY

Magnetic resonance imaging (MRI) scans for bladder cancer are becoming more common and may provide accurate information that helps improve patient care. Here, we describe a standardized reporting criterion for bladder MRI. This should improve communication between doctors and allow better comparisons between patients.

A glance at imaging bladder cancer

Purpose

Early and accurate diagnosis of Bladder cancer (BCa) will contribute extensively to the management of the disease. The purpose of this review was to briefly describe the conventional imaging methods and other novel imaging modalities used for early detection of BCa and outline their pros and cons.

Methods

Literature search was performed on Pubmed, PMC, and Google scholar for the period of January 2014 to February 2018 and using such words as "bladder cancer, bladder tumor, bladder cancer detection, diagnosis and imaging".

Results

A total of 81 published papers were retrieved and are included in the review. For patients with hematuria and suspected of BCa, cystoscopy and CT are most commonly recommended. Ultrasonography, MRI, PET/CT using ¹⁸F-FDG or ¹¹C-choline and recently PET/MRI using ¹⁸F-FDG also play a prominent role in detection of BCa.

Conclusion

For initial diagnosis of BCa, cystoscopy is generally performed. However, cystoscopy can not accurately detect carcinoma insitu (CIS) and can not distinguish benign masses from malignant lesions. CT is used in two modes, CT and computed tomographic urography (CTU), both for dignosis and staging of BCa. However, they cannot differentiate T1 and T2 BCa. MRI is performed to diagnose invasive BCa and can differentiate muscle invasive bladder carcinoma (MIBC) from non-muscle invasive bladder carcinoma (NMIBC). However, CT and MRI have low sensitivity for nodal staging. For nodal staging PET/CT is preferred. PET/MRI provides better differentiation of normal and pathologic structures as compared with PET/CT. Nonetheless none of the approaches can address all issues related for the management of BCa. Novel imaging methods that target specific biomarkers, image BCa early and accurately, and stage the disease are warranted.

Radiomics-guided therapy for bladder cancer: Using an optimal biomarker approach to determine extent of bladder cancer invasion from t2-weighted magnetic resonance images

Background

Current clinical staging methods are unable to accurately define the extent of invasion of localized bladder cancer, which affects the proper use of systemic therapy, surgery, and radiation. Our purpose was to test a novel radiomics approach to identify optimal imaging biomarkers from T2-weighted magnetic resonance imaging (MRI) scans that accurately classify localized bladder cancer into 2 tumor stage groups (≤T2 vs >T2) at both the patient level and within bladder subsectors.

Method and Materials

Preoperative T2-weighted MRI scans of 65 consecutive patients followed by radical cystectomy were identified. A 3-layer, shell-like volume of interest (VOI) was defined on each MRI slice: Inner (lumen), middle (bladder wall), and outer (perivesical tissue). An optimal biomarker method was used to identify features from 15,834 intensity and texture properties that maximized the classification of patients into ≤T2 versus >T2 groups. A leave-one-out strategy was used to cross-validate the performance of the identified biomarker feature set at the patient level. The performance of the feature set was then evaluated at the subsector level of the bladder by dividing the VOIs into 8 radial sectors.

Results

A total of 9 optimal biomarker features were derived and demonstrated a sensitivity, specificity, accuracy of prediction, and area under a receiver operating characteristic curve of 0.742, 0.824, 0.785, and 0.806, respectively, at the patient level and 0.681, 0.788, 0.763, and 0.813, respectively, at the radial sector level. All 9 selected features were extracted from the middle shell of the VOI and based on texture properties.

Conclusions

An approach to select a small, highly independent feature set that is derived from T2-weighted MRI scans that separate patients with bladder cancer into ≤T2 versus >T2 groups at both the patient level and within subsectors of the bladder has been developed and tested. With external validation, this radiomics approach could improve the clinical staging of bladder cancer and optimize therapeutic management.

Quantitative Assessment of Heterogeneity in Bladder Tumor MRI Diffusivity: Can Response be Predicted Prior to Neoadjuvant Chemotherapy?

Background:

It is a critical unmet need to predict chemosensitivity in muscle-invasive bladder cancer patients who receive neoadjuvant chemotherapy (NAC). Quantification of tumor heterogeneity has been shown to be useful in the assessment of therapeutic response. Apparent diffusion coefficient (ADC) is derived from diffusion weighted MRI (DWI) to quantify the water diffusivity which characterizes micro-cellularity in tumor tissues.

Objective:

The aim of this study is to assess if a quantitative measurement of ADC heterogeneity in bladder tumors can be a predictor of therapeutic response to NAC.

Materials and Methods:

Twenty patients with pT2 bladder cancer have been included in this study. Patient MRI was performed on a 3T system with DWI prior to NAC. Regions of interest (ROIs) were placed over the whole tumor volume on ADC maps to acquire a data matrix of voxel-wise ADC values for each patient. We performed histogram analysis on each ADC data matrix to calculate uniformity (U) and entropy (E). These quantities were subsequently correlated with the patient’s response to chemotherapy. Statistical significance was found with P < 0.05.

Results:

Fifteen patients were categorized as responders, and five as non-responders. The data showed that tumors of responders were significantly higher in U (P = 0.01) and lower in E (P < 0.01) than non-responders. This finding indicates that resistant tumors were more heterogeneous in their spatial distribution of ADC values. While this difference in ADC heterogeneity was not always visually recognizable, it could be quantified by the data analytics.

Conclusions:

This study demonstrates that the quantitative readout of tumor heterogeneity in micro-cellularity is associated with the patient’s defined response to chemotherapy. Quantification of tumor ADC heterogeneity may provide useful information to enable the prediction of chemotherapeutic response prior to the treatment to improve patient outcomes.

Preoperative Imaging for Clinical Staging Prior to Radical Cystectomy

The importance of patient selection for quality outcomes following radical cystectomy is critical. Clinical staging is one of the key elements necessary for patient selection, and staging relies on accurate preoperative imaging. Many imaging modalities are available and have been utilized for preoperative staging with published operating characteristics. In this update, we review recently published literature for advances in preoperative imaging prior to radical cystectomy.

Usefulness of dynamic contrast-enhanced magnetic resonance imaging for predicting treatment response to vinorelbine-cisplatin with or without recombinant human endostatin in bone metastasis of non-small cell lung cancer

Metastatic bone disease is a frequent complication of advanced non-small cell lung cancer (NSCLC) and causes skeletal-related events, which result in a poor prognosis. Currently, no standard method has been developed to precisely assess the therapeutic response of bone metastases (BM) and the early efficacy of anti-angiogenic therapy, which does not conform to the concept of precision medicine. This study aimed to investigate the usefulness of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for precise evaluation of the response to chemotherapy with anti-angiogenic agents in NSCLC patients with BM. Patients were randomly assigned to a treatment group (vinorelbine + cisplatin [NP] + recombinant human endostatin [rh-endostatin]) or a control group (NP + placebo). All patients were evaluated before treatment and after 2 cycles of treatment using DCE-MRI quantitative analysis technology for BM lesions and chest computed tomography (CT). Correlations between changes in the DCE-MRI quantitative parameters and treatment effect were analyzed. We enrolled 33 patients, of whom 28 were evaluable (20 in the treatment group and 8 in the control group). The results suggested a higher objective response rate (30% vs. 0%), better overall survival (21.44 ± 17.28 months vs. 7.71 ± 4.68 months), and a greater decrease in the transport constant (Ktrans) value (60% vs. 4.4%) in the treatment group than in the control group (P < 0.05). The Ktrans values in the "partial remission plus stable disease (PR + SD)" group were significantly lower after treatment (P < 0.05). Patients with a decrease of > 50% in the Ktrans value showed a significantly better overall survival than those with a decrease of ≤ 50% (13.2 vs. 9.8 months, P < 0.05). Ktrans as a DEC-MRI quantitative parameter could be used for the precise evaluation of BM lesions after anti-angiogenic therapy and as a predictor of survival. In addition, we reconfirmed the anti-angiogenic effect of rh-endostatin in NSCLC patients with BM.

Non-invasive quantification of tumour heterogeneity in water diffusivity to differentiate malignant from benign tissues of urinary bladder: a phase I study

OBJECTIVES

To quantify the heterogeneity of the tumour apparent diffusion coefficient (ADC) using voxel-based analysis to differentiate malignancy from benign wall thickening of the urinary bladder.

METHODS

Nineteen patients with histopathological findings of their cystectomy specimen were included. A data set of voxel-based ADC values was acquired for each patient's lesion. Histogram analysis was performed on each data set to calculate uniformity (U) and entropy (E). The k-means clustering of the voxel-wised ADC data set was implemented to measure mean intra-cluster distance (MICD) and largest inter-cluster distance (LICD). Subsequently, U, E, MICD, and LICD for malignant tumours were compared with those for benign lesions using a two-sample t-test.

RESULTS

Eleven patients had pathological confirmation of malignancy and eight with benign wall thickening. Histogram analysis showed that malignant tumours had a significantly higher degree of ADC heterogeneity with lower U (P = 0.016) and higher E (P = 0.005) than benign lesions. In agreement with these findings, k-means clustering of voxel-wise ADC indicated that bladder malignancy presented with significantly higher MICD (P < 0.001) and higher LICD (P = 0.002) than benign wall thickening.

CONCLUSIONS

The quantitative assessment of tumour diffusion heterogeneity using voxel-based ADC analysis has the potential to become a non-invasive tool to distinguish malignant from benign tissues of urinary bladder cancer.

KEY POINTS

• Heterogeneity is an intrinsic characteristic of tumoral tissue. • Non-invasive quantification of tumour heterogeneity can provide adjunctive information to improve cancer diagnosis accuracy. • Histogram analysis and k-means clustering can quantify tumour diffusion heterogeneity. • The quantification helps differentiate malignant from benign urinary bladder tissue.

Improving Staging in Bladder Cancer: The Increasing Role of Multiparametric Magnetic Resonance Imaging

CONTEXT

In bladder cancer (BCa) patients, accurate local and regional tumor staging is required when planning treatment. Clinical understaging frequently occurs and leads to undertreatment of the disease, with a negative impact on survival. An improvement in staging accuracy could be attained by advances in imaging. Magnetic resonance imaging (MRI) is currently the best imaging technique for locoregional staging for several malignancies because of its superior soft tissue contrast resolution with the advantage of avoiding exposure to ionizing radiation. Important improvements in MRI technology have led to the introduction of multiparametric MRI (mpMRI), which combines anatomic and functional evaluation.

OBJECTIVE

To review the fundamentals of mpMRI in BCa and to provide a contemporary overview of the available data on the role of this emerging imaging technology.

EVIDENCE ACQUISITION

A nonsystematic literature search using the Medline and Cochrane Library databases was performed up to March 2016. Additional articles were retrieved by cross-matching references of selected articles. Only articles reporting complete data with regard to image acquisition protocols, locoregional staging, monitoring response to therapy, and detection of locoregional recurrence after primary treatment in BCa patients were selected.

EVIDENCE SYNTHESIS

Standardization of acquisition and reporting protocols for bladder mpMRI is paramount. Combining anatomic and functional sequences improves the accuracy of local tumor staging compared with conventional imaging alone. Diffusion-weighted imaging may distinguish BCa type and grade. Functional sequences are capable of monitoring response to chemotherapy and radiation therapy. Diffusion-weighted imaging enhanced by lymphotropic nanoparticles showed high accuracy in pelvic lymph node staging compared with conventional cross-sectional imaging.

CONCLUSIONS

In BCa patients, mpMRI appears a promising tool for accurate locoregional staging, predicting tumor aggressiveness and monitoring response to therapy. Further large-scale studies are needed to confirm these findings.

PATIENT SUMMARY

Better imaging through improved technology will improve outcomes in bladder cancer patients. We reviewed the emerging use of multiparametric magnetic resonance imaging for staging and monitoring bladder cancer. Multiparametric magnetic resonance imaging appears more accurate than current methods for local and nodal staging and monitoring tumor response to treatment, but requires further investigation.

Can Dynamic Contrast-Enhanced MRI (DCE-MRI) and Diffusion-Weighted MRI (DW-MRI) Evaluate Inflammation Disease: A Preliminary Study of Crohn's Disease

The aim of the study was to investigate diagnosis efficacy of dynamic contrast-enhanced MRI (DCE-MRI) and diffusion-weighted MRI (DW-MRI) in Crohn's disease (CD). To find out the correlations between functional MRI parameters including K, Kep, Ve, Vp, and apparent diffusion coefficient (ADC) with a serologic biomarker. The relationships between pharmacokinetic parameters and ADC were also studied.Thirty-two patients with CD (22 men, 10 women; mean age: 30.5 years) and 18 healthy volunteers without any inflammatory disease (10 men, 8 women; mean age, 34.11 years) were enrolled into this approved prospective study. Pearson analysis was used to evaluate the correlation between K, Kep, Ve, Vp, and C-reactive protein (CRP), ADC, and CRP respectively. The diagnostic efficacy of the functional MRI parameters in terms of sensitivity and specificity were analyzed by receiver operating characteristic (ROC) curve analyses. Optimal cut-off values of each functional MRI parameters for differentiation of inflammatory from normal bowel were determined according to the Youden criterion.Mean value of K in the CD group was significantly higher than that of normal control group. Similar results were observed for Kep and Ve. On the contrary, the ADC value was lower in the CD group than that in the control group. K and Ve were shown to be correlated with CRP (r = 0.725, P < 0.001; r = 0.533, P = 0.002), meanwhile ADC showed negative correlation with CRP (r = -0.630, P < 0.001). There were negative correlations between the pharmacokinetic parameters and ADC, such as K to ADC (r = -0.856, P < 0.001), and Ve to ADC (r = -0.451, P = 0.01). The area under the curve (AUC) was 0.994 for K (P < 0.001), 0.905 for ADC (P < 0.001), 0.806 for Ve (P < 0.001), and 0.764 for Kep (P = 0.002). The cut-off point of the K was found to be 0.931 min. This value provided the best trade-off between sensitivity (93.8%) and specificity (100%). The best cut-off point of ADC was 1.11 × 10 mm/s. At this level, sensitivity was 100% and specificity was 68.8%.DCE-MRI and DW-MRI were helpful in the diagnosis of CD. Quantitative MRI parameters could be used to assess the severity of inflammation. The relationships between pharmacokinetic parameters (K and Ve) and ADC reflected microstructure and microcirculation of CD to some extent.

Performance of simultaneous high temporal resolution quantitative perfusion imaging of bladder tumors and conventional multi-phase urography using a novel free-breathing continuously acquired radial compressed-sensing MRI sequence

PURPOSE

To investigate the feasibility of high temporal resolution quantitative perfusion imaging of bladder tumors performed simultaneously with conventional multi-phase MR urography (MRU) using a novel free-breathing continuously acquired radial MRI sequence with compressed-sensing reconstruction.

METHODS

22 patients with bladder lesions underwent MRU using GRASP (Golden-angle RAdial Sparse Parallel) acquisition. Multi-phase contrast-enhanced abdominopelvic GRASP was performed during free-breathing (1.4×1.4×3.0mm(3) voxel size; 3:44min acquisition). Two dynamic datasets were retrospectively reconstructed by combining different numbers of sequentially acquired spokes into each dynamic frame: 110 spokes per frame for 25-s temporal resolution (serving as conventional MRU for clinical interpretation) and 8 spokes per frame for 1.7-s resolution. Using 1.7-s resolution images, ROIs were placed within bladder lesions and normal bladder wall, a femoral artery arterial input function was generated, and the Generalized Kinetic Model was applied.

RESULTS

Biopsy/cystectomy demonstrated 16 bladder tumors (13 stage≥T2, 3 stage≤T1) and 6 benign lesions. All lesions were well visualized using 25-s clinical multi-phase images. Using 1.7-s resolution images, K(trans) was significantly higher in tumors (0.38±0.24) than normal bladder (0.12±0.02=8, p<0.001) or benign lesions (0.15±0.04, p=0.033). Ratio between K(trans) of lesions and normal bladder was nearly double for tumors than benign lesions (4.3±3.4 vs. 2.2±1.6), and K(trans) was nearly double in stage≥T2 than stage≤T1 tumors (0.44±0.24 vs. 0.24±0.24), although these did not approach significance (p=0.180-0.209), possibly related to small sample size.

CONCLUSION

GRASP allows simultaneous quantitative high temporal resolution perfusion of bladder lesions during clinical MRU examinations using only one contrast injection and without additional scan time.

Contemporary role of advanced imaging for bladder cancer staging

Optimized pretreatment staging of bladder urothelial carcinoma is essential in guiding appropriate treatment. This staging process relies heavily on tissue pathology from transurethral resection of bladder tumor as well as imaging for diagnosis of local, regional, nodal, or distant visceral spread. Accurate preoperative staging is critical for appropriate treatment decision making and patient counseling as these are based on the extent of disease involvement, largely classifying the cancer as having local, regional, or distant spread. Currently, the gold standard of transurethral resection of bladder tumor followed by computed tomography imaging with intravenous contrast provides excellent staging specificity in cases of more advanced bladder cancers with suspicion of spread; however, this often under stages patients that can lead to adverse oncologic outcomes in these patients undergoing radical cystectomy. Incorporation of novel imaging modalities including multiparametric magnetic resonance imaging and positron emission tomography imaging have shown promise in improving accuracy of staging for both local and distant disease in patients with bladder urothelial carcinoma.

Optimal acquisition and modeling parameters for accurate assessment of low Ktrans blood-brain barrier permeability using dynamic contrast-enhanced MRI

PURPOSE

To determine optimal parameters for acquisition and processing of dynamic contrast-enhanced MRI (DCE-MRI) to detect small changes in near normal low blood-brain barrier (BBB) permeability.

METHODS

Using a contrast-to-noise ratio metric (K-CNR) for Ktrans precision and accuracy, the effects of kinetic model selection, scan duration, temporal resolution, signal drift, and length of baseline on the estimation of low permeability values was evaluated with simulations.

RESULTS

The Patlak model was shown to give the highest K-CNR at low Ktrans . The Ktrans transition point, above which other models yielded superior results, was highly dependent on scan duration and tissue extravascular extracellular volume fraction (ve ). The highest K-CNR for low Ktrans was obtained when Patlak model analysis was combined with long scan times (10-30 min), modest temporal resolution (<60 s/image), and long baseline scans (1-4 min). Signal drift as low as 3% was shown to affect the accuracy of Ktrans estimation with Patlak analysis.

CONCLUSION

DCE acquisition and modeling parameters are interdependent and should be optimized together for the tissue being imaged. Appropriately optimized protocols can detect even the subtlest changes in BBB integrity and may be used to probe the earliest changes in neurodegenerative diseases such as Alzheimer's disease and multiple sclerosis.

Dynamic contrast enhanced magnetic resonance imaging of an orthotopic pancreatic cancer mouse model

Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) has been limitedly used for orthotopic pancreatic tumor xenografts due to severe respiratory motion artifact in the abdominal area. Orthotopic tumor models offer advantages over subcutaneous ones, because those can reflect the primary tumor microenvironment affecting blood supply, neovascularization, and tumor cell invasion. We have recently established a protocol of DCE-MRI of orthotopic pancreatic tumor xenografts in mouse models by securing tumors with an orthogonally bent plastic board to prevent motion transfer from the chest region during imaging. The pressure by this board was localized on the abdominal area, and has not resulted in respiratory difficulty of the animals. This article demonstrates the detailed procedure of orthotopic pancreatic tumor modeling using small animals and DCE-MRI of the tumor xenografts. Quantification method of pharmacokinetic parameters in DCE-MRI is also introduced. The procedure described in this article will assist investigators to apply DCE-MRI for orthotopic gastrointestinal cancer mouse models.

Breath analysis as a potential and non-invasive frontier in disease diagnosis: an overview

Currently, a small number of diseases, particularly cardiovascular (CVDs), oncologic (ODs), neurodegenerative (NDDs), chronic respiratory diseases, as well as diabetes, form a severe burden to most of the countries worldwide. Hence, there is an urgent need for development of efficient diagnostic tools, particularly those enabling reliable detection of diseases, at their early stages, preferably using non-invasive approaches. Breath analysis is a non-invasive approach relying only on the characterisation of volatile composition of the exhaled breath (EB) that in turn reflects the volatile composition of the bloodstream and airways and therefore the status and condition of the whole organism metabolism. Advanced sampling procedures (solid-phase and needle traps microextraction) coupled with modern analytical technologies (proton transfer reaction mass spectrometry, selected ion flow tube mass spectrometry, ion mobility spectrometry, e-noses, etc.) allow the characterisation of EB composition to an unprecedented level. However, a key challenge in EB analysis is the proper statistical analysis and interpretation of the large and heterogeneous datasets obtained from EB research. There is no standard statistical framework/protocol yet available in literature that can be used for EB data analysis towards discovery of biomarkers for use in a typical clinical setup. Nevertheless, EB analysis has immense potential towards development of biomarkers for the early disease diagnosis of diseases.