Imaging of Bladder Cancer: Standard Applications and Future Trends

Abstract

The evolution in imaging has had an increasing role in the diagnosis, staging and follow up of bladder cancer. Conventional cystoscopy is crucial in the diagnosis of bladder cancer. However, a cystoscopic procedure cannot always depict carcinoma in situ (CIS) or differentiate benign from malignant tumors prior to biopsy. This review will discuss the standard application, novel imaging modalities and their additive role in patients with bladder cancer. Staging can be performed with CT, but distinguishing between T1 and T2 BCa (bladder cancer) cannot be assessed. MRI can distinguish muscle-invasive from non-muscle-invasive tumors with accurate local staging. Vesical Imaging-Reporting and Data System (VI-RADS) score is a new diagnostic modality used for the prediction of tumor aggressiveness and therapeutic response. Bone scintigraphy is recommended in patients with muscle-invasive BCa with suspected bony metastases. CT shows low sensitivity for nodal staging; however, PET (Positron Emission Tomography)/CT is superior and highly recommended for restaging and determining therapeutic effect. PET/MRI is a new imaging technique in bladder cancer imaging and its role is promising. Texture analysis has shown significant steps in discriminating low-grade from high-grade bladder cancer. Radiomics could be a reliable method for quantitative assessment of the muscle invasion of bladder cancer.

The role of radiomics with machine learning in the prediction of muscle-invasive bladder cancer: A mini review

“…Diffusion Weighted Imaging(DWI) and Apparent Diffusion Coefficient(ADC) have a good ability to reflect signal intensity differences between muscle, peritumoral inflammation and fibrosis ( 23 , 24 ). The significance of dynamic contrast enhanced MRI(DCE-MRI) in assessing tumor aggressiveness depends on the neoangiogenesis of the tumor, which is an important factor in tumor growth; the more neovascularization there is, the higher the tumor stage and grade ( 25 ). In studies on dynamic enhancement sequences, the tumor, bladder mucosa and submucosa show early enhancement, but the bladder wall muscle maintains its low signal and delays enhancement.…”

Optimization of Preoperative Lymph Node Staging in Patients with Muscle-Invasive Bladder Cancer Using Radiomics on Computed Tomography

“…In addition, irregular border contour [ 60 ] and signal intensity heterogeneity [ 60 , 61 ] on MRI have been shown to differentiate metastatic lymph nodes. Therefore, further research is needed to investigate the use of various MRI protocols (e.g., T2-weighted, dynamic-contrast-enhanced and diffusion-weighted MRI [ 62 ],) for the detection of lymph nodes in patients with MIBC, as well as the relatively novel PET/MRI approach [ 63 ]. Since our radiomics approach has previously been proven successful for MRI [ 35 , 36 ], the same approach could be evaluated to differentiate pN+ and pN0 disease based on MRI.…”

A Case of Incidental Detection of Asymptomatic Bladder Cancer by Transvaginal Ultrasound

“…To detect bladder cancer by ultrasound, it is easier to diagnose when the size of the tumor is 0.5 cm or larger. An ultrasound finding suggestive of bladder cancer is an echogenic soft-tissue lesion protruding from the bladder mucosa, which contains internal blood flow on Doppler ultrasonography [ 10 ]. However, when observing the bladder, it must be filled with urine to reduce the likelihood of a false positive [ 11 ].…”