Indications for CT Chest, Abdomen, and Pelvis

Primary Indications for CT CAP

The American College of Radiology recommends CT CAP for patients with biopsy-proven cancer to detect distant metastases and guide treatment planning 1, 2, 3
For gastric cancer, contrast-enhanced CT CAP with neutral oral contrast is essential for staging, detecting nodular wall thickening, lymphadenopathy, and distant metastases 1, 2, 3
In lung cancer (NSCLC), CT CAP is required to detect occult extrathoracic metastatic disease, which occurs in up to 37% of patients 4, 5
For breast cancer, CT CAP identifies metastatic disease in 15-36% of patients depending on stage, particularly for tumors >2 cm (T2) or node-positive disease 6
In endometrial cancer, CT CAP is useful when distant metastases are clinically suspected in high-risk disease 7

The American College of Radiology suggests that in septic patients without localizing symptoms or after nondiagnostic chest radiography, CT abdomen and pelvis with IV contrast is the appropriate next step 8, 9
Chest radiography should be performed first for all septic patients, and if the chest X-ray is normal/equivocal and no localizing symptoms exist, proceed to CT abdomen and pelvis with IV contrast 8, 9

IV contrast is essential for most indications, as omitting it significantly reduces sensitivity 1, 2, 5
Detection of solid organ metastases depends on contrast enhancement 5
Non-contrast CT CAP has limited utility except in specific scenarios, such as renal insufficiency or suspected perforation 8, 9
Routine multiphase CT CAP provides limited additional value for most indications, and single-phase contrast-enhanced studies answer most clinical questions 1, 2, 6

The American College of Radiology notes that CT CAP should not be used for surveillance when guidelines don't support it, as most cancer recurrences are detected clinically, not by imaging 7
Negative imaging does not exclude disease, and CT sensitivity for lymph node metastases is only 50-70%, requiring tissue diagnosis when suspicion is high 5