Fat Fraction and Iodine Density in Bowel Inflammation: A DECTE VMI Cross-Sectional Study

Abstract

Background:
Accurate differentiation between inflamed and normal bowel segments is critical in managing inflammatory bowel disease (IBD). Dual-energy computed tomography enterography (DECTE) offers quantitative biomarkers such as Fat fraction and iodine density, which may enhance diagnostic accuracy.

Aim:
To evaluate the utility of DECTE-derived Fat fraction and iodine density in distinguishing inflamed from normal bowel segments at various virtual monochromatic imaging (VMI) energy levels.

Methods:
A cross-sectional study was conducted at multicenter in Ahsa , Saudi Arabia, involving 160 adult patients diagnosed with Crohn’s disease or ulcerative colitis. DECTE scans were analyzed to quantify Fat fraction and iodine density in inflamed and adjacent normal bowel segments. Receiver operating characteristic (ROC) analysis was performed to assess diagnostic accuracy across different VMI energy levels. Interobserver reliability was calculated using intraclass correlation coefficients (ICCs).

Results:
Inflamed segments had significantly lower Fat fraction (6.3±2.4%) and higher iodine density (3.7±0.9 mg/mL) compared to normal segments (12.7±3.8% and 1.8±0.6 mg/mL, respectively; p<0.001). Optimal diagnostic performance was observed at 50 keV for Fat fraction (AUC=0.92) and at 40 keV for iodine density (AUC=0.95). Interobserver reliability was excellent (ICC >0.90).

Conclusion:
Fat fraction and iodine density derived from DECTE provide reliable, non-invasive biomarkers for distinguishing inflamed from normal bowel tissue. These findings support the integration of DECTE into clinical workflows for IBD assessment and monitoring.