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

Abstract

Medical imaging of the 3 most common genitourinary (GU) cancers-prostate adenocarcinoma, renal cell carcinoma, and urothelial carcinoma of the bladder-has evolved significantly during the last decades. The most commonly used imaging modalities for the diagnosis, staging, and follow-up of GU cancers are computed tomography, magnetic resonance imaging (MRI), and positron emission tomography (PET). Multiplanar multidetector computed tomography and multiparametric MRI with diffusion-weighted imaging are the main imaging modalities for renal cell carcinoma and urothelial carcinoma, and although multiparametric MRI is rapidly becoming the main imaging tool in the evaluation of prostate adenocarcinoma, biopsy is still required for diagnosis. Functional and molecular imaging using 18-fluorodeoxyglucose-PET and sodium fluoride-PET are essential for the diagnosis, and especially follow-up, of metastatic GU tumors. This review provides an overview of the latest advances in the imaging of these 3 major GU cancers.

Keywords: Bladder urothelial carcinoma; CT; MRI; PET; Prostate adenocarcinoma; Renal cell carcinoma.

Figure 1

Dynamic contrast-enhanced MRI in a 27-year-old female with a large, enhancing high-grade RCC within the left kidney, with extension into the left renal vein and IVC on axial (A) and coronal (B) delayed post-contrast images. Patient underwent left nephrectomy in addition to IVC thrombectomy.

Figure 2

MRI in a 19-year-old male with a large, locally advanced high-grade RCC with papillary features in the setting of hereditary leiomyomatosis and RCC syndrome within the lower pole of the right kidney. The mass demonstrates heterogeneous signal intensity on T2-weighted images (two panels on left) and heterogeneous enhancement on post-contrast image (second from the right) and restricted diffusion on DWI image (right panel). There is extension of the mass into the mesonephric fat beyond the capsule and involvement of Gerota's fascia and right psoas muscle.

Figure 3

Pre- (left) and post-treatment (right) maximum-intensity FDG-PET projections of the whole body of a patient with RCC. The extent of the new sites of lung metastases are clearly observed, in addition to new sites of osseous metastatic disease (white arrows) in the right iliac wing and left femur, which were not detected on CT.

Figure 4

FDG-PET/CT of a patient with RCC. From left to right, maximum-intensity projection PET, coronal PET, CT, and PET/CT fusion are shown. Clearly visualized by PET, the left supraclavicular cluster of nodal metastasis was not detected on CT.

Figure 5

CT urogram multiplanar volume-rendered (MPVR) coronal reformation showing ureters in white, with normal peristalsis, hence incompletely seen the moment this CT was acquired. This was a 10-min delay for a hematuria workup.

Figure 6

Demonstration of viable tumor volume (VTV) where a metastatic urothelial carcinoma lesion became less dense (less IV contrast enhancement) visually; however, the left shift of the histogram objectively represents likely tumor necrosis from an antiangiogenic treatment.

Figure 7

A 62-year-old female with metastatic urothelial carcinoma. Focal abnormal FDG metabolism in supraclavicular, mediastinal, hepatic, retroperitoneal, and osseous metastases.

Figure 8

mpMRI of the bladder combined with targeted PET imaging. Moderately distended urinary bladder activity. Adequate image magnification during the interpretation, and diluted radioactive urine by adequate hydration of the patient during and prior to image acquisition are simple factors that improve our ability to properly evaluate the wall of the urinary bladder. A moderately distended urinary bladder is more optimally imaged compared to a non-distended or excessively distended bladder, both of which may hinder accurate visualization of a bladder wall tumor.

Figure 9

Urothelial carcinoma FDG-PET/MRI. Focal wall thickening and increased FDG activity of the posterior inferior bladder wall in its neck and within the superior portion of the prostate are present.

Figure 10

Urothelial carcinoma FDG-PET/MRI. A 59-year-old male with high-grade non-muscle-invasive bladder cancer post-TURBT and intravesical chemotherapy. PET/MRI showed activity at or near the expected segment of intraprostatic urethra and retroperitoneal lymph nodes, upgrading the stage.

Figure 11

A 68-year-old man with serum PSA of 4.88 ng/mL and history of 2 prior negative TRUS-guided biopsies. Axial T2W MRI shows a hypointense lesion in the left apical anterior transition zone (arrow) with capsular bulge (A). The lesion shows restricted diffusion on ADC maps (B) and b2000 DW-MRI (C) (arrows) and hypervascularity on DCE-MRI (D) (arrow). This PI-RADS 5 lesion underwent TRUS/MRI fusion-guided biopsy, which revealed Gleason 4+5 prostate adenocarcinoma.

Figure 12

A 72-year-old man with serum PSA of 4.03 ng/mL with no prior biopsy. Axial T2W MRI shows a hypointense lesion in the left apical peripheral zone (arrow) (A). The lesion shows restricted diffusion on ADC maps (B) and b2000 DW-MRI (C) (arrows) and hypervascularity on DCE-MRI (D) (arrow). This PI-RADS 4 lesion underwent TRUS/MRI fusion-guided biopsy, which revealed Gleason 3+4 prostate adenocarcinoma.

Figure 13

A 53-year-old man with history of prostate adenocarcinoma. NaF-PET/CT demonstrates focal abnormal uptake in multiple bone metastases throughout the skeleton.