CMS requires that the CT scan be reasonable and necessary based on the literature and opinion. Reasonableness and opinion is expressed by guidelines,
After radical cystectomy, NCCN recommends:
Urine cytology, liver function tests, creatinine, and electrolytes every 3 to 6 mo for 2 y and then as clinically indicated
Imaging of the chest, upper tracts, abdomen, and pelvis every 3 to 6 mo for 2 y based on risk of recurrence and then as clinically indicated
Urethral wash cytology every 6 to 12 mo, particularly if Tis was found within the bladder or prostatic urethra
If a continent diversion was created, monitor for vitamin B12 deficiency annually.
ACR has similar recommendations: CT is recommended at 6, 12, and 24 months for follow-up of patients with minimal muscle invasion (T2) who elect either cystectomy or other types of therapy without cystectomy, since most recurrences become evident within the first 2 years after surgery.
NCCN, BLadder Cancer, BL-E, 2013
CMS Guidelines National Coverage Determination (NCD) Computed Tomography (220.1)
Leyendecker JR, Francis IR, Casalino DD, Arellano RS, Baumgarten DA, Curry NS, Dighe M, Fulgham P, Israel GM, Papanicolaou N, Prasad S, Ramchandani P, Remer EM, Sheth S, Expert Panel on Urologic Imaging. ACR Appropriateness Criteria follow-up imaging of bladder carcinoma. [online publication]. Reston (VA): American College of Radiology (ACR); 2009. 10 p. [80 references]