Role of magnetic resonance imaging in bladder cancer: current status and emerging techniques

Management of patients with muscle-invasive bladder cancer with clinical evidence of pelvic lymph node metastases

Identification of clinically positive pelvic lymph node metastases (cN+) in patients with muscle-invasive bladder cancer is currently challenging, as the diagnostic accuracy of available imaging modalities is limited. Conventional CT is still considered the gold-standard approach to diagnose lymph node metastases in these patients. The development of innovative diagnostic methods including radiomics, artificial intelligence-based models and molecular biomarkers might offer new perspectives for the diagnosis of cN+ disease. With regard to the treatment of these patients, multimodal strategies are likely to provide the best oncological outcomes, especially using induction chemotherapy followed by radical cystectomy and pelvic lymph node dissection in responders to chemotherapy. Additionally, the use of adjuvant nivolumab has been shown to decrease the risk of recurrence in patients who still harbour ypT2-T4a and/or ypN+ disease after surgery. Alternatively, the use of avelumab maintenance therapy can be offered to patients with unresectable cN+ tumours who have at least stable disease after induction chemotherapy alone. Lastly, patients with cN+ tumours who are not responding to induction chemotherapy are potential candidates for receiving second-line treatment with pembrolizumab.

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.

Deep Learning for Medical Image-Based Cancer Diagnosis

(1) Background: The application of deep learning technology to realize cancer diagnosis based on medical images is one of the research hotspots in the field of artificial intelligence and computer vision. Due to the rapid development of deep learning methods, cancer diagnosis requires very high accuracy and timeliness as well as the inherent particularity and complexity of medical imaging. A comprehensive review of relevant studies is necessary to help readers better understand the current research status and ideas. (2) Methods: Five radiological images, including X-ray, ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI), positron emission computed tomography (PET), and histopathological images, are reviewed in this paper. The basic architecture of deep learning and classical pretrained models are comprehensively reviewed. In particular, advanced neural networks emerging in recent years, including transfer learning, ensemble learning (EL), graph neural network, and vision transformer (ViT), are introduced. Five overfitting prevention methods are summarized: batch normalization, dropout, weight initialization, and data augmentation. The application of deep learning technology in medical image-based cancer analysis is sorted out. (3) Results: Deep learning has achieved great success in medical image-based cancer diagnosis, showing good results in image classification, image reconstruction, image detection, image segmentation, image registration, and image synthesis. However, the lack of high-quality labeled datasets limits the role of deep learning and faces challenges in rare cancer diagnosis, multi-modal image fusion, model explainability, and generalization. (4) Conclusions: There is a need for more public standard databases for cancer. The pre-training model based on deep neural networks has the potential to be improved, and special attention should be paid to the research of multimodal data fusion and supervised paradigm. Technologies such as ViT, ensemble learning, and few-shot learning will bring surprises to cancer diagnosis based on medical images.

Multidisciplinary Management and Radiotherapy Recommendations for Clinically and Pathologically Node-positive Bladder Cancer

There are limited data regarding the optimal management of patients with pelvic node-positive, but non-metastatic, bladder cancer. Increasing data demonstrate that this is a distinct clinical entity with outcomes bridging between bladder-confined muscle-invasive bladder cancer and metastatic advanced bladder cancer. Guidelines and staging systems have formalized the need to incorporate the unique considerations of management of pelvic node-positive bladder cancer. However, there remains an absence of a definite standard of care. Treatment options include systemic therapy alone, neoadjuvant chemotherapy followed by radical cystectomy, or bladder-preserving trimodality therapy. Furthermore, ongoing studies aim to determine the benefit of incorporating immunotherapy into these treatment paradigms. In this review article, we will discuss the key considerations for management of patients with pelvic node-positive bladder cancer.

The comparison between contrast-enhanced ultrasound and contrast-enhanced magnetic resonance imaging in diagnosing bladder urothelial carcinoma

PURPOSE

The surgical treatment of bladder urothelial carcinoma depends on whether the tumor has invaded the bladder muscular layer. Normal ultrasound and contrast-enhanced magnetic resonance imaging (contrast-enhanced MRI) are widely used in patients bear bladder tumors; the latter is also widely used in estimating the muscularis invasion of bladder cancer (BC). However, contrast-enhanced ultrasound (CEUS) is rarely used in this aspect. As the gold standard in diagnosing muscularis invasion remains being pathological examination, this study was set to find out whether there are differences between CEUS and contrast-enhanced MRI in diagnosing bladder malignant tumors and in diagnosing the muscularis invasion of the bladder urothelial carcinoma under the guide of the pathological results.

METHODS

160 patients from Yongchuan Hospital of Chongqing Medical University and The Second Affiliated Hospital of Chongqing Medical University were recruited from July 1st, 2021, to June 30th, 2022. Patients are arranged to undergo CEUS, contrast-enhanced MRI and then take a surgery. After surgery, we compare the results of CEUS, MRI and the pathological results, using software to run the statistical examinations.

RESULTS

The accuracies of CEUS and contrast-enhanced MRI in diagnosing malignant bladder tumors were 85.90 and 84.62%, and they had no differences (P > 0.05). While the accuracies of CEUS and contrast-enhanced MRI in diagnosing the muscularis invasion were 84.62 and 76.92%, in which CEUS had a better sensitivity (P < 0.05).

CONCLUSIONS

We found that CEUS and contrast-enhanced MRI had no differences in diagnosing the different pathological types (benign or malignant) of BC, but CEUS holds a better sensitivity in diagnosing muscularis invasions of bladder urothelial carcinoma than the contrast-enhanced MRI.

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.

Study Progress of Noninvasive Imaging and Radiomics for Decoding the Phenotypes and Recurrence Risk of Bladder Cancer

Urinary bladder cancer (BCa) is a highly prevalent disease among aged males. Precise diagnosis of tumor phenotypes and recurrence risk is of vital importance in the clinical management of BCa. Although imaging modalities such as CT and multiparametric MRI have played an essential role in the noninvasive diagnosis and prognosis of BCa, radiomics has also shown great potential in the precise diagnosis of BCa and preoperative prediction of the recurrence risk. Radiomics-empowered image interpretation can amplify the differences in tumor heterogeneity between different phenotypes, i.e., high-grade vs. low-grade, early-stage vs. advanced-stage, and nonmuscle-invasive vs. muscle-invasive. With a multimodal radiomics strategy, the recurrence risk of BCa can be preoperatively predicted, providing critical information for the clinical decision making. We thus reviewed the rapid progress in the field of medical imaging empowered by the radiomics for decoding the phenotype and recurrence risk of BCa during the past 20 years, summarizing the entire pipeline of the radiomics strategy for the definition of BCa phenotype and recurrence risk including region of interest definition, radiomics feature extraction, tumor phenotype prediction and recurrence risk stratification. We particularly focus on current pitfalls, challenges and opportunities to promote massive clinical applications of radiomics pipeline in the near future.

The Role of Molecular Imaging in a Muscle-Invasive Bladder Cancer Patient: A Narrative Review in the Era of Multimodality Treatment

Diagnostic imaging in bladder cancer plays an important role since it is needed from pretreatment staging to follow-up, but a morphological evaluation performed with both CT and MRI showed low sensitivities and specificities in detecting pathologic lymph nodes, due to the occurrence of false positive results. Implementation of functional information provided by PET/CT could be a determinant in the management of patients with muscle-invasive bladder cancer. A focus on the role of ¹⁸F-FDG PET/CT and alternative tracers in patients with muscle-invasive bladder cancer is provided in this analysis in order to outline its potential applications in staging settings and response evaluation after neoadjuvant chemotherapy.

The value of MR-based radiomics in identifying residual disease in patients with carcinoma in situ after cervical conization

Carcinoma in situ (CIS) of the uterine cervix is a precursor to cervical carcinoma. However, hysterectomy can be avoided in patients who can be treated by cone biopsy. Previous studies have shown that imaging-based approaches allow for the noninvasive visualization of cervical cancer, and radiomics has high accuracy in classifying cancer and predicting treatment outcome for different cancer types. To develop a magnetic resonance (MR)-based radiomics model for identifying residual disease in patients with CIS after cervical conization. Patients who had CIS after conization and finally underwent hysterectomy were collected to comprise a database to establish an imaging model for predicting the residual status after conization. Then, patients who opted for uterine preservation were classified as high-risk or low-risk patients according to the model. The disease-free survival was compared between the different risk groups using the Kaplan–Meier curve. The model built with the Boruta features outperformed the random forest model. Further validation with patients with uterine preservation showed that the patients classified as high risk were more likely to have tumor recurrence/residual disease in the follow-up period. In conclusion, radiomics can be used to identify residual disease in patients with CIS after cervical conization and could have the potential to predict recurrence in patients who opt for uterine preservation.

Use of transrectal ultrasonography for assessment of the size and location of prostatic carcinoma in dogs

OBJECTIVE

To evaluate the use of transrectal ultrasonography (TRUS) for the assessment of prostatic tumors in dogs and to compare results for TRUS with results for other imaging modalities.

ANIMALS

10 client-owned male dogs.

PROCEDURES

Client-owned dogs identified with prostatic carcinoma were enrolled. Fluoroscopy, transabdominal ultrasonography (TAUS), TRUS, and MRI were performed on all dogs. Tumor measurements, urethral penetration (identification of abnormal tissue within the urethral lumen), and tumor extension into the urinary tract were recorded for all imaging modalities. Agreement between results for MRI (considered the criterion-referenced standard) and results for other modalities were compared.

RESULTS

Median body weight of the 10 dogs was 26.3 kg (range, 9.4 to 49.5 kg). No complications were encountered during or after TRUS. Significant moderate to good agreements (intraclass correlation coefficients, 0.60 to 0.86) among TAUS, TRUS, fluoroscopy, and MRI were identified for tumor length and height. Assessments of urethral penetration and tumor extension into the bladder with TRUS did not differ significantly from those made with MRI and were superior in terms of absolute agreement with MRI when compared with those for TAUS.

CONCLUSIONS AND CLINICAL RELEVANCE

TRUS was successfully and safely used to evaluate prostatic carcinoma in dogs. There was moderate to good agreement with MRI results for tumor height and length measurements, and TRUS was found to be superior to TAUS for some assessments. Transrectal ultrasonography can be considered an adjunctive imaging modality for the performance of prostatic interventional procedures or assessment of response to treatment.

Assessment of Intrafraction Motion of the Urinary Bladder Using Magnetic Resonance Imaging (cineMRI)

AIM

To assess the intrafraction motion of the urinary bladder and delineate the appropriate margin size for radiotherapy planning, for both the full and empty bladder.

MATERIALS AND METHODS

This was a single-site, single-arm study of 20 patients planned to undergo radical cystectomy for histologically confirmed muscle-invasive bladder cancer. Patients underwent magnetic resonance imaging (cineMRI) of the entire pelvis using a 3-Tesla system, prior to cystectomy. Patients first underwent a cineMRI with a full bladder, then voided and underwent a second MRI with an empty bladder. All MRI sequences were acquired over 18 min. We assessed the differences in bladder filling and subsequent bladder wall displacement, between the empty and full bladder, during a time period consistent with radiotherapy treatment delivery.

RESULTS

Twenty patients underwent cineMRI of the entire pelvis. The maximum mean directional displacements of the bladder walls over the 18 min duration of the scan for the empty bladders were 9.8 mm superiorly, 1.1 mm inferiorly, 2.39 mm anteriorly, 3.73 mm posteriorly, 2.74 mm to the left and 2.48 mm to the right. The maximal mean displacements for the full bladders were 9.2 mm superiorly, 1.1 mm inferiorly, 2.28 mm anteriorly, 1.08 mm posteriorly, 1.85 mm to the left and 1.73 mm to the right. Statistically significant differences were seen in the posterior, left and right displacements but were quantitatively small.

CONCLUSIONS

Intrafractional motion secondary to bladder filling showed minimal variation between the full and empty bladder. Similar clinical target volume to planning target volume margins can be applied for the delivery of radiotherapy for a full and empty bladder.

A Potential Application of Dynamic Contrast-Enhanced Magnetic Resonance Imaging Combined with Photodynamic Diagnosis for the Detection of Bladder Carcinoma in Situ: Toward the Future 'MRI-PDD Fusion TURBT'

The detection of carcinoma in situ (CIS) is essential for the management of high-risk non-muscle invasive bladder cancers. Here, we focused on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) combined with photodynamic diagnosis (PDD) for the detection of CIS. A total of 45 patients undergoing pre-surgical DCE-MRI and PDD-assisted endoscopic surgery accompanied by biopsies of the eight segmentations were analyzed. Immunohistochemical analysis of the biopsies revealed hypervascularity of CIS lesions, a cause of strong submucosal contrast-enhancement. It was found that 56 (16.2%) of 344 biopsies had pathologically proven CIS. In the DCE-MRI, the overall sensitivity and specificity for detecting CIS were 48.2% and 81.9%, respectively. We set out two different combinations of PDD and DCE-MRI for detecting CIS. Combination 1 was positive when either the PDD or DCE-MRI were test-positive. Combination 2 was positive only when both PDD and DCE-MRI were test-positive. The overall sensitivity of combinations 1 and 2 were 75.0% and 37.5%, respectively (McNemar test, vs PDD alone; p = 0.041 and p < 0.001, respectively). However, the specificity was 74.0% and 91.7%, respectively (vs PDD alone; both p < 0.001). Our future goal is to establish 'MRI-PDD fusion transurethral resction of the bladder tumor (TURBT), which could be an effective therapeutic and diagnostic approach in the clinical management of high-risk disease.

Evaluation of lymph node status in patients with urothelial carcinoma-still in search of the perfect imaging modality: a systematic review

While accurate lymph node status evaluation in urothelial carcinoma patients is essential for the correct disease staging and, hence, establishing the most beneficial treatment strategy, the diagnostic performance of routine imaging in regards to this issue is not satisfactory. For the purpose of this article, we systematically reviewed the contemporary literature on the sensitivity and specificity of particular imaging modalities which have been studied for detecting lymph node metastases in patients diagnosed with urothelial carcinoma. The evidence reviewed shows that computed tomography (CT), although recognized as the imaging modality of choice, is associated with marked limitations, resulting in its low sensitivity for lymph node involvement detection in urothelial carcinoma patients, with no study reporting a value higher than 46% using standard cut-off values. Markedly higher sensitivity rates may be achieved with magnetic resonance imaging (MRI), especially when using ultrasmall superparamagnetic iron oxide as the contrast agent, however, no uniform protocol has been systematically studied up to date. The vast majority of recent evidence concerns positron emission tomography (PET), which is being reported to improve the diagnostic performance of CT alone, as has been demonstrated in multiple articles, which investigated the accuracy of PET/CT at primary or post-treatment staging of urothelial carcinoma patients. However, there has been substantial heterogeneity in terms of methodology and results between those studies, making it premature to draw any definitive conclusions. The results of this review lead to a conclusion, that while CT, despite being not fully satisfactory, still remains the gold-standard method of imaging for staging purposes in urothelial carcinoma, other imaging modalities are under investigation, with promising results.

11C-acetate PET/MRI in bladder cancer staging and treatment response evaluation to neoadjuvant chemotherapy: a prospective multicenter study (ACEBIB trial)

Background

To evaluate the accuracy of ¹¹C-acetate Positron Emission Tomography/Magnetic Resonance Imaging (PET/MRI) in bladder cancer (BC) staging and monitoring response to neoadjuvant chemotherapy (NAC).

Methods

Eighteen patients were prospectively enrolled. Fifteen treatment naive patients underwent ¹¹C-acetate PET/MRI before transurethral resection of bladder tumor (TUR-BT) for primary tumor evaluation. Five patients with muscle invasive BC were imaged after NAC and prior to radical cystectomy (RC) with extended pelvic lymph node dissection (ePLND) for NAC treatment response evaluation. Two patients were part of both cohorts. ¹¹C-acetate PET/MRI findings were correlated with histopathology. Accuracy for lymph node detection was evaluated on patient and the ePLND template (10 regions) levels.

Results

The sensitivity, specificity and accuracy of ¹¹C-acetate PET/MRI for the detection of muscle invasive BC was 1.00, 0.69 and 0.73 while the area under the receiver operating characteristic curve (95% confidence interval) was 0.85 (0.55–1.0), respectively. All five NAC patients underwent chemotherapy as planned and ¹¹C-acetate PET/MRI correctly staged three patients, overstaged one and understaged one patient compared with RC and ePLND findings. A total of 175 lymph node were removed, median of 35 (range, 27–43) per patient in five patients who had RC and ePLND while 12 (7%) harboured metastases. Sensitivity, specificity, accuracy and AUC for N-staging were 0.20, 0.96, 0.80 and 0.58 on the ePLND template (10 regions) level.

Conclusions

¹¹C-acetate PET/MRI is feasible for staging of BC although sensitivity for the detection of nodal metastases is low. Monitoring response to NAC shows promise and warrants evaluation in larger studies.

Trial registration

ClinicalTrials.gov Identifier: NCT01918592, registered August 8 2013

[OUTCOME OF BLADDER PRESERVATION USING LOW DOSE CHEMORADIATION THERAPY IN PATIENTS WITH LOCALLY INVASIVE BLADDER CANCER]

(Purpose) We investigated the outcome of selective organ preservation in invasive bladder cancer using chemoradiation therapy. (Patients and method) We examined locally invasive bladder cancer in 60 patients (51 men, 9 women; mean age at treatment 66.1 years) who underwent chemoradiation therapy for bladder preservation in the Department of Urology at Sumitomo Hospital between 2000 and 2015. The clinical stage was T1, T2, T3 and T4 in 4, 24, 17, 4 patients. Our protocol includes transurethral resection of the bladder tumor (TURBT) and 46 Gy radiation (2 Gy/fraction) to the bladder with concurrent cisplatin chemotherapy (20 mg/body/day, 10 days, intravenously). The initial evaluation included urine cytology and transurethral bladder biopsy. If patients developed superficial residual or recurrent cancer, they were treated with TURBT and/or intravesical Bacillus Calmette-Guerin (BCG), while patients with invasive residual or recurrent cancer were advised to undergo a salvage cystectomy. The mean follow-up was 55 months. (Results) The first assessment after the chemoradiation therapy showed that the complete remission rate for evaluable cases was 72% (38/53) and bladder preservation was achieved in 56 patients (93%). The 1-, 3-, and 5-year overall survival rate was 95, 86, and 78%, respectively. The 1-, 3-, and 5-year cancer-specific survival rate was 97, 90, and 85%, respectively. The 5-year patient survival rate with an intact bladder was 68%. Hydronephrosis and cisplatin dose (<200 mg) were independent adverse factors of overall survival in a Cox model (HR 4.5 and 4.1, respectively). (Conclusions) Chemoradiation therapy for invasive bladder cancer can achieve similar survival rate to those in patients treated with radical cystectomy, and enable the majority of patients to preserve the bladder.

Advancements in optical techniques and imaging in the diagnosis and management of bladder cancer

Accurate detection and staging is critical to the appropriate management of urothelial cancer (UC). The use of advanced optical techniques during cystoscopy is becoming more widespread to prevent recurrent nonmuscle invasive bladder cancer. Standard of care for muscle-invasive UC includes the use of computed tomography and/or magnetic resonance imaging, but staging accuracy of these tests remains imperfect. Novel imaging modalities are being developed to improve current test performance. Positron emission tomography/computed tomography has a role in the initial evaluation of select patients with muscle-invasive bladder cancer and in disease recurrence in some cases. Several novel immuno-positron emission tomography tracers are currently in development to address the inadequacy of current imaging modalities for monitoring of tumor response to newer immune-based treatments. This review summaries the current standards and recent advances in optical techniques and imaging modalities in localized and metastatic UC.

Magnetic nanoformulations for prostate cancer

Magnetic nanoparticles (MNPs) play a vital role for improved imaging applications. Recently, a number of studies demonstrate MNPs can be applied for targeted delivery, sustained release of therapeutics, and hyperthermia. Based on stable particle size and shape, biocompatibility, and inherent contrast enhancement characteristics, MNPs have been encouraged for pre-clinical studies and human use. As a theranostic platform development, MNPs need to balance both delivery and imaging aspects. Thus, this review provides significant insight and advances in the theranostic role of MNPs through the documentation of unique magnetic nanoparticles used in prostate cancer, their interaction with prostate cancer cells, in vivo fate, targeting, and biodistribution. Specific and custom-made applications of various novel nanoformulations in prostate cancer are discussed.

Prospective Pilot Study to Evaluate the Incremental Value of PET Information in Patients With Bladder Cancer Undergoing 18F-FDG Simultaneous PET/MRI

PURPOSE

The aim of this study was to conduct a prospective pilot study comparing the diagnostic performance of MRI alone and F-FDG simultaneous PET/MRI using a diuresis protocol in bladder cancer patients.

METHODS

Twenty-two bladder cancer patients underwent F-FDG PET/MRI, using intravenous furosemide and oral hydration for bladder clearance. A radiologist scored probability of tumor in 3 locations (urinary bladder, pelvic lymph nodes, nonnodal pelvis) using 1- to 3-point scale (1 = negative, 2 = equivocal, 3 = definite tumor). A nuclear medicine physician reviewed fused PET/MRI images, after which scores were reassigned based on combined findings. Follow-up pathologic and imaging data served as reference. Performances of MRI alone and PET/MRI were compared.

RESULTS

Of these patients, 82%, 38%, and 18% were positive for bladder, pelvic nodal, and nonnodal pelvic tumor, respectively. At a score of 3, PET/MRI exhibited greater accuracy for detection of bladder tumor (86% vs 77%), metastatic pelvic lymph nodes (95% vs 76%), and nonnodal pelvic malignancy (100% vs 91%). In the bladder, PET changed the level of suspicion in 36% of patients (50% increased suspicion, 50% decreased suspicion), with 75% of these changes deemed correct based on reference standard. For pelvic lymph nodes, PET changed suspicion in 52% (36% increase, 64% decrease), with 95% of changes deemed correct. For nonnodal pelvis, PET changed suspicion in 9% (100% increase), with 100% deemed correct.

CONCLUSIONS

Additional PET information helped to appropriately determine level of suspicion in multiple anatomic sites for otherwise equivocal findings on MRI alone. Although requiring larger studies, findings suggest a possible role for simultaneous PET/MRI to assist bladder cancer management.

The surgical management of patients with clinical stage T4 bladder cancer: A single institution experience

INTRODUCTION

Patients with clinical T4 (cT4) bladder cancer (BCa) infrequently undergo radical cystectomy (RC). We investigated the reliability of preoperative clinical staging, perioperative and survival outcomes in patients treated with RC due to cT4a-b BCa disease at a single tertiary care institution.

METHODS

The study relied on 917 BCa patients treated with RC and pelvic lymph node dissection (PLND) at a single institution between January 1995 and December 2012. We compared the accuracy of the clinical assessment with final pathology results. Moreover, we evaluated perioperative outcomes, complication rates and survival after surgery.

RESULTS

The median follow-up was 62 months. Overall, 74 (8.1%) patients presented cT4 stage at preoperative evaluation. Conversely, a pathological T4 disease was confirmed only in 68.9% patients staged initially as cT4. No differences were recorded in complications, 30 days readmission or 30 days death rates between cT1-T3 vs. cT4a vs. cT4b (p > 0.1). At multivariable Cox regression analyses predicting cancer specific mortality, clinical T4 stage vs. clinical T1-2, clinical T3 stage vs. clinical T1-2 and age were predictors of worst survival after RC (all p < 0.04).

CONCLUSIONS

We recorded poor concordance between preoperative imaging and pathology in cT4 patients. No differences in major perioperative outcomes and acceptable survival expectancies were reported in patients treated for cT4 disease.

Essential content of evidence-based clinical practice guidelines for bladder cancer: The Japanese Urological Association 2015 update

The Japanese Urological Association revised the clinical practice guidelines for bladder cancer in April 2015. This was the first update carried out in the 6 years since the development of the initial clinical practice guidelines for bladder cancer in 2009. The descriptive content was revised, and additions were made with a focus on new-found evidence and advances in the latest medical practices, and on the basis of the increasingly aging population observed in the underlying social context in Japan. An algorithm for the treatment of bladder cancer has been presented as a new trial. In the present article, we will introduce the essential contents and clinical questions that address the present revisions.

Urovision 2020: The future of urology

Urology, as a specialty, has always been at the forefront of innovation and research. Newer technologies have been rapidly embraced and, in many cases, improved upon in order to achieve better patient outcomes. This review addresses the possible future directions that technological advances in urology may take. The role of further miniaturization of urolithiasis treatment, robotic surgery and other minimally invasive techniques is addressed. The potential for enhanced imaging and diagnostic techniques like magnetic resonance imaging and ultrasonography modifications, as well as the potential applications of nanotechnology and tissue engineering, are reviewed.

This article is based on the Dr. Sitharaman Best Essay award of the Urological Society of India for 2013.

Development of Magnetic Nanoparticles for Cancer Gene Therapy: A Comprehensive Review

Since they were first proposed as nonviral transfection agents for their gene-carrying capacity, magnetic nanoparticles have been studied thoroughly, both in vitro and in vivo. Great effort has been made to manufacture biocompatible magnetic nanoparticles for use in the theragnosis of cancer and other diseases. Here we survey recent advances in the study of magnetic nanoparticles, as well as the polymers and other coating layers currently available for gene therapy, their synthesis, and bioconjugation processes. In addition, we review several gene therapy models based on magnetic nanoparticles.

Magnetic resonance and computed tomography in pediatric urology: an imaging overview for current and future daily practice

The main imaging modality of the urinary tract in children is ultrasound. When further cross-sectional morphologic examination and/or functional evaluation is required, magnetic resonance (MR) imaging is the logical and optimal second step, particularly in pediatric patients. There are two main exceptions to this. The first one is when after an ultrasound, additional diagnostic imaging for urolithiasis is needed. The second one involves severe polytrauma, including blunt abdominal trauma. In this review, an overview of the MR imaging and computed tomography examinations important for current and future daily pediatric uroradiologic practice is presented.

Current role of PET, CT, MR for invasive bladder cancer

Imaging for urothelial cancer, particularly that located in the bladder, has generally been based on computed tomography (CT). However in more recent times the role of positron emission tomography-CT (PET-CT) has emerged and increasingly magnetic resonance (MR) imaging has become utilised. This concise review will outline the role of these modalities when dealing with muscle-invasive bladder cancer (MIBC).

Dynamic contrast-enhanced MRI in patients with muscle-invasive transitional cell carcinoma of the bladder can distinguish between residual tumour and post-chemotherapy effect

INTRODUCTION

Treatment of muscle-invasive bladder cancer with chemotherapy results in haemorrhagic inflammation, mimicking residual tumour on conventional MR images and making interpretation difficult. The aim of this study was to use dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to estimate descriptive and tracer kinetic parameters post-neoadjuvant chemotherapy and to investigate whether parameters differed in areas of residual tumour and chemotherapy-induced haemorrhagic inflammation (treatment effect, Tr-Eff).

METHODS AND MATERIALS

Twenty-one patients underwent DCE-MRI scans with 2.5s temporal resolution before and following neoadjuvant chemotherapy. Regions-of-interest (ROIs) were defined in areas suspicious of residual tumour on T2-weighted MRI scans. Data were analysed semi-quantitatively and with a two-compartment exchange model to obtain parameters including relative signal intensity (rSI80s) and plasma perfusion (Fp) respectively. The bladder was subsequently examined histologically after cystectomy for evidence of residual tumour and/or Tr-Eff. Differences in parameters measured in areas of residual tumour and Tr-Eff were examined using Student's t-test.

RESULTS

Twenty-four abnormal sites were defined after neoadjuvant chemotherapy. On pathology, 10 and 14 areas were identified as residual tumour and Tr-Eff respectively. Median rSI80s and Fp were significantly higher in areas of residual tumour than Tr-Eff (rSI80s = 2.9 vs 1.7, p < 0.001; Fp = 20.7 vs 9.1 ml/100ml/min, p = 0.03). The sensitivity and specificity for differentiating residual tumour from Tr-Eff were 70% and 100% (rSI80s), 60% and 86% (Fp), and 75% and 100% when combined.

CONCLUSION

DCE-MRI parameters obtained post-treatment are capable of distinguishing between residual tumour and treatment effect in patients treated for bladder cancer with neoadjuvant chemotherapy.

Evaluation of risk of muscle invasion, perivesical and/or lymph node affectation by diffusion-weighted magnetic nuclear resonance in the patient who is a candidate for radical cystectomy

INTRODUCTION

Preoperative staging of bladder cancer using imaging methods has serious limitations. The accuracy of the abdominal diffusion-weighted magnetic resonance (DW-MRI) to predict residual muscle invasion, perivesical and/or lymph node affectation in the cystectomy specimen is evaluated.

MATERIAL AND METHODS

A prospective study was performed on 20 patients with high grade muscle invasive bladder cancer who received transurethral resection of the bladder (TURB) in a period of <1 month. The DW-MRI was performed before the radical cystectomy and the radiologist predicted muscle invasion, extravesical affectation and lymph node affectation, being blind to the histopathological study. Sensitivity (S), specificity (sp), positive predictive value (PPV), negative predictive value (NPV) and accuracy (Ac) of the test were analyzed. The medians of the apparent diffusion coefficient (ADC) value (Mann-Whitney) were compared and the ROC curves study for DW-MRI and ADC was carried out.

RESULTS

Distribution by categories was: pT0 1(5%), pT1 6(30%), pT2 2(10%), pT3 8(40%) and pT4 3(15%). There was agreement in the T-pT assignment in 17(85%). In 7(35%) there was lymph node affectation (pN1-2). Consistency of the DW-MRI for muscle affectation was k=.89 (CI .67-1; S=1.0, Sp=,86, PPV=.93, NPV=1.0, Ac=.95), for perivesical fat affectation k=.6 (CI .25-.95; S=.8, Sp=.8, PPV=.8, NPV=.8, Ac=.8) and for lymph node affectation k=.89 (CI .67-1; S=.86, Sp=1.0, PPV=1.0, NPV=.93, Ac=.95). Mean value of ADC was greater in G2 tumors (OMS1987) compared to G3 (p=.08). Evaluation of DW-MRI imaging and ADC numerical value showed equivalent areas under the curve for muscle (.93 and .9; Z=.7), fat (.8 and .91; Z=.31) and lymph node (.93 and .97; Z=.36) affectation, respectively.

CONCLUSIONS

DW-MRI allows for good pre-operative evaluation of the patient who is a candidate for cystectomy, especially for the prediction of muscle (<pT2 vs ≥pT2) and/or lymph node (N0 vs N1-2) affectation. Both are key points to choice the therapeutic attitude after the bladder TURB. Furthermore, the ADC coefficient also predicts tumor differentiation grade.

Current Staging Procedures in Urinary Bladder Cancer

Currently computed tomography (CT) represents the most widely used standard imaging modality in muscle-invasive urinary bladder cancer. Visualization of local tumor or depth of invasion as well as lymph node staging, however, is often impaired. Magnetic resonance imaging (MRI) with diffusion-weighted sequences, determination of apparent diffusion coefficient (ADC) values or utilization of superparamagnetic iron nanoparticles potentially exhibits advantages in the assessment of local tumor or lymph node involvement and therefore might play a role in routine staging of urinary bladder cancer in the future. Likewise, positron emission tomography (PET) with the currently utilized tracers ¹⁸F-FDG, ¹¹C-choline and ¹¹C-acetate is investigated in bladder cancer patients—mostly in combination with diagnostic CT. Although promising results could be obtained for these PET/CT examinations in smaller series, their true value cannot be determined at present.

[Functional imaging in bladder cancer]

Computed tomography (CT) represents the current standard imaging modality in muscle invasive bladder cancer; however, local tumor and lymph node staging is often impaired. Magnetic resonance imaging (MRI) with diffusion-weighted sequences, determination of apparent diffusion coefficient (ADC) values or utilization of supraparamagnetic iron nanoparticles potentially exhibits advantages in the assessment of local tumor and lymph node involvement and therefore might play a role in the staging of bladder tumor in the future. Likewise, positron emission tomography (PET) with the currently used tracers (18)F fluorodeoxyglucose ((18)F-FDG), (11)C-choline and (11)C-acetate is being investigated in bladder cancer patients, mostly in combination with diagnostic CT. Although promising results could be obtained for PET/CT investigations to some extent, the true value cannot be determined at present.