Creeping fat in patients with ileo‐colonic Crohn's disease correlates with disease activity and severity of inflammation: A preliminary study using energy spectral computed tomography

OBJECTIVE To investigate the relationship between creeping fat and inflammatory activity as well as the prognosis of ileo‐colonic Crohn's disease (CD), based on a quantitative analysis of energy spectral computed tomography (CT). METHODS A total of 40 patients with CD and 40 with other gastrointestinal diseases who underwent an energy spectral CT scanning between March 2014 and March 2015 were retrospectively enrolled. The endoscopic severity of CD was evaluated by the simple endoscopic score for Crohn's disease (SES‐CD). The slope of the Hounsfield unit (HU) curve (λ HU ) was measured and calculated on energy spectral CT images. Visceral and subcutaneous fat areas were also measured. The relationship between the quantitative data of creeping fat as well as the fat area and CD inflammation were analyzed. RESULTS The λ HU of creeping fat in patients with CD increased with the severity of intestinal inflammation (moderate/severe vs mild: −0.17 ± −0.68 vs −0.49 ± −0.61, P < 0.01). Moreover, the λ HU of creeping fat around the intestinal segments without lesions in CD was significantly larger than that in the controls (−1.19 ± −0.56 vs − 1.42 ± −0.45, P < 0.01). The λ HU was more accurate for detecting inflammatory lesions in CD than for calculating visceral fat. It was significantly correlated with SES‐CD ( r = 0.66, P < 0.01) and moderately correlated with the Harvey–Bradshaw index ( r = 0.414, P < 0.01). CONCLUSION The quantitative analysis of creeping fat using energy spectral CT is an effective method in inflammatory evaluation in patients with CD.