Diagnostic performance and clinical outcomes of computed tomography colonography in a sick inpatient population

Purpose: Though prior studies have proven CTC's efficacy in outpatients, its utility in the inpatient setting has not been studied. We evaluated the efficacy of a modified CTC protocol in the inpatient setting, primarily for patients awaiting organ transplantation.

Methods: This retrospective study compared a group of inpatient CTCs from 2019 to 2021 and a randomly selected, age-matched 2:1 control group of outpatient CTCs. Both groups were assessed based on established criteria from literature.

Results: 10 % (63/652) of CTCs were performed in the inpatient setting, of which 29 were excluded, yielding 34 inpatient cases. 90 % (589/652) of CTCs were performed in the outpatient setting, from which 68 randomly selected, age-matched patients were selected as controls. Significantly more (24 %, 8/34) inpatients expired due to extracolonic causes (vs. 1 %, 1/68 outpatients, p < 0.05). 62 % (21/34) of inpatient CTCs were reported as diagnostic (vs. 74 %, 50/68 outpatient, p = 0.22). Significantly more inpatients (12 %, 4/34) than outpatients (1 %, 1/68) were unable to tolerate two imaging positions (p = 0.02). Subsequent colonoscopy was performed in 24 % (8/34) of inpatients, revealing pathologies including colonic polyps and non-bleeding ulcers. Inpatient CTCs had lower average quality scores, significant for one reviewer (p = 0.009-0.054). Inpatients had a larger number of segments with: >25 % residual fluid (1.22-1.28 inpatients vs. 0.60-0.73 outpatients, p = 0.003-0.026) and inadequate fluid tagging (1.10 inpatients vs. 0.49 outpatients, p = 0.046-0.0501). Distention was not significantly different between groups (p = 0.317-0.410).

Conclusion: Quality of inpatient CTC was inferior to outpatient CTCs across several metrics. 24 % undergoing inpatient CTC died of extracolonic causes within 22 months, and most did not have findings warranting intervention, questioning the value of this difficult exam in this patient population. Routine CT may be sufficient to exclude large or metastatic colonic lesions precluding transplant.