PET/CT and MRI in Bladder Cancer

Abstract

Bladder Cancer (BCa) is the most common malignancy arising from the urinary tract. One of the mainstays of diagnosis, staging, and therapeutic decision-making for BCa is accurate and appropriate imaging. The ability to identify metastatic disease preoperatively is of utmost importance in determining treatment. Advances in standard cross sectional imaging techniques like Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) have improved imaging of bladder cancer. Over the last decade, 18F-fluorodeoxyglucose (FDG) Positron Emission Tomography (PET) in combination with CT (18F-FDG PET/CT) has become an important non-invasive imaging modality for the preoperative staging of various malignancies. 18F-FDG PET/CT is useful for detection of metastatic disease in BCa, but the ability to detect primary bladder wall lesions remains to be elucidated. To overcome the problem with urinary excretion of 18F-FDG, new PET tracers are being tested. MRI is an accurate technique for the local staging of BCa due to its superior spatial and contrast resolution. Anatomical MRI has a modest utility in NM-staging of BCa. However, incorporation of functional MR techniques, such as diffusion weighted MRI can improve the results for lesion detection and staging and multi-parametric MRI`s role is yet to be explored widely. The aim of this review is to present the recent advances in PET/CT and MRI in BCa, with particular focus on improvements in staging.

Advances in medical imaging for the diagnosis and management of common genitourinary cancers

“…The mpMRI bladder/pelvis and lumbosacral sequences can be accomplished in a single session without moving the patient [73]. …”

“…Further studies are required to determine whether simultaneous acquisition of MRI and PET provide more accurate imaging than subsequent sequencing (Figure 9). In addition, PET/MRI's diagnostic accuracy, influence on therapeutic management, and related economic factors need to be carefully considered and evidenced by larger prospective clinical studies [73]. We found that PET/MRI allowed us to detect malignant lesions more accurately and confidently, potentially allowing physicians to improve treatment planning and disease monitoring (Figure 10) [97].…”

PET/Computed Tomography in Renal, Bladder, and Testicular Cancer

“…For local tumor assessment, MRI is reported to be more accurate than CT 18 . MRI is superior to CT for determining depth of bladder wall infiltration 20 . Both CT and MRI have limited capability for detecting microscopic invasion of the perivesical fat, but they may be used to find T3b disease or higher with good diagnostic accuracy 21 .…”

Positron Emission Tomography-Magnetic Resonance Imaging in Oncologic Diseases of the Male and Female Pelvis

“…The most common histopathologic subtype is transitional cell carcinoma (490%), and much less frequent are squamous cell (5%) and adenocarcinoma (2%) subtypes. 47 Overall, 70% of bladder cancers are superficial and poorly detected with noninvasive imaging techniques such as radiography, CT, or even MRI. They are successfully managed with diagnostic and therapeutic endoscopic procedures such as cystoscopy.…”

“…Only 30% of all bladder cancers develop into high-risk malignancies with tendency to metastasize and risk of death. 47 If these tumors are addressed with CT, the sensitivity and specificity are limited to 85% and 94%, respectively. 48 This is mainly because of the limited soft tissue resolution of CT, which does not allow distinguishing the muscular layers of the bladder.…”