Submucosal fat accumulation in Crohn's disease: evaluation with sonography

Area of Science:

• Gastroenterology
• Medical Imaging
• Radiology

Background:

• Crohn's disease (CD) is a chronic inflammatory bowel disease.
• Submucosal fat deposition, termed the fat halo sign (FHS), is associated with CD.
• Accurate identification of FHS is crucial for disease assessment.

Purpose of the Study:

• To investigate ultrasound features for suspecting the fat halo sign (FHS) in the intestinal wall of Crohn's disease patients.
• To correlate ultrasound findings with CT-confirmed FHS.
• To establish ultrasound criteria for predicting FHS in CD.

Main Methods:

• Retrospective review of 68 patients' CT and ultrasound examinations.
• CT used to identify FHS with a threshold of -10 Hounsfield units.
• Ultrasound measured submucosal and wall thickness; ROC curve analysis determined optimal cutoff for FHS prediction.

Main Results:

• FHS was identified in 31% of patients via CT.
• Significantly greater submucosal thickness in patients with FHS (4.19 mm) versus those without (2.41 mm).
• A submucosal thickness cutoff of 3.1 mm demonstrated high sensitivity (95.5%) and specificity (89.1%) for suspecting FHS.

Conclusions:

• Ultrasound can suggest FHS in Crohn's disease with marked submucosal thickening.
• Ultrasound-detected FHS warrants further assessment of disease activity using methods like color Doppler.
• Ultrasound offers a valuable, non-invasive tool for suspecting FHS in CD patients.