Multi-detector CT enterography in active inflammatory bowel disease: Image quality and diagnostic efficacy of a low-radiation high contrast protocol

Purpose: To prospectively evaluate image quality and diagnostic efficacy of a low radiation-high contrast (LR-HC) CT Enterography (CTE) in active Inflammatory Bowel Disease (IBD). Materials and Methods: Eighty-five (36M;49F; 17-75 yrs) patients with active IBD underwent contrast-enhanced CTE and were stratified in two groups according to age (< or ≥ 45 yrs): Group A (N=45; 32 ± 9 yrs; 58 ± 10 Kg) and Group B (N=40; 58 ± 10 yrs; 61 ± 13 Kg). Each group received a different amount of radiation (Noise Index, NI) and non ionic iodinated contrast media (LOCM) as follows: Group A (NI = 15; 2.5 mL/Kg) and Group B (NI = 12.5; 2 mL/Kg). Thyroid functional tests were performed in all patients of group A at 4-6 wks. Signal- and contrast-to-noise ratios were calculated for liver (L) and abdominal aorta (A). Statistical analysis was performed by Student's t- or Chi-square test for continuous and categorical data, respectively. Results: No patient of Group A developed signs of thyrotoxicosis. SNRL, CNRL and diagnostic accuracy of CTE were 8.4 ± 1.7 vs 8.9 ± 2.1 (p = 0.256), 5.4 ± 1.5 vs 5.6 ±1.7 (p = 0.486) and 91.1 vs 92.5 % (p = 0.764) whereas the effective dose and the LOCM administered were 6.7 ± 2.2 vs 13.9 ± 6.0 mSv (p < 0.001) and 144 ± 25 vs 122 ± 25 ml (p < 0.001) for Group A and B, respectively. Conclusion: LR-HC CTE is a dose-effective protocol in the evaluation of active IBD in young patients.