■ Distinguishing between an adrenal adenoma and adrenal metastases can prove more difficult
■ Bilateral adrenal masses are more suggestive of secondaries or lymphoma
■ Masses >2 cm are likely to be malignant
Traditionally, CT scanning has been the primary imaging modality in the staging of bladder and prostate cancer, but recent evidence suggests that magnetic resonance imaging (MRI) provides superior resolution and therefore may be more accurate. In addition, metastatic disease within the pelvis is easily demonstrated on CT.
On CT, normal lymph nodes are up to 10 mm in maximum transverse diameter in the para-aortic and iliac chains, and 6 mm in the retrocrural region. While this size criteria is reasonably accurate, CT cannot differentiate between lymphadenopathy secondary to tumor or inflammation. It is also well recognized that tumor infiltration may be present in smaller nodes considered insignificant on the basis of size criteria.
• Bladder cancer
■ Bladder tumors may be seen as mass lesions, filling defects, or bladder wall thickenings on CT
■ CT is reasonably accurate (70-88%) at detecting locally advanced tumor (stage T3b and above)
■ CT is unable to distinguish between tumors of a lower stage and over-staging is a distinct possibility
■ Accuracy of CT for lymph node detection lies between 70% and 92%
■ CT is primarily utilized for patients with advanced disease or those at risk of metastatic spread
• Prostate cancer
■ MRI scanning is now the principal imaging technique for CAP
■ CT cannot distinguish between the various grades of organ-confined disease
■ CT able to detect local invasion into bladder or seminal vesi-cals and the presence of gross lymphadenopathy
■ overall accuracy of CT in the staging of prostate cancer varies between 50% and 80%
■ CT unable to differentiate confidently between malignant and benign conditions involving the prostate
• Bladder trauma
As an alternative to conventional retrograde contrast cystogram in patients with suspected bladder trauma, up to 400 mL of diluted iodinated contrast (4%) can be inserted into the bladder via a urethral or suprapubic catheter prior to performing a CT scan (CT cystography). Bladder rupture may be intra- (involving the dome of bladder) or extra-peritoneal.
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