If the folds are thin, the mnemonic MISS can be used to recall the common diagnoses:
|M||Mechanical obstruction||Due to intraluminal impaction (high fiber foods), adhesions post-operatively, or a mass|
Systemic sclerosis due to deposition of collagen
Sacculations of anti-mesenteric border
Hidebound bowel (unchanging on dynamic studies)
|S||Sprue||Villous atrophy and crypt hypertrophy → chronic fluid overload → ‘congestive gut overload’ → featureless mucosal pattern proximally in small bowel = reversal of jejunal / ileal fold pattern|
Moulage sign: moulage means casted or molded structure; the jejunum appears a cast of itself due to featureless appearance because of lack of mucosal folds
|Small Bowel Obstruction|
Source: Radiology Assistant
If there is segmental thickening of the folds, think of the three Is: ischemia, infection, or idiopathic. Diffuse fold thickening is usually due to systemic processes such as venous congestion or cirrhosis.
Nodular fold thickening is usually due to infiltrative processes of the bowel wall. Common etiologies include Crohn disease, infection, lymphoma, metastases, and Whipple disease.
If the dilatation is thick walled, check out the differential diagnosis for small bowel aneurysmal dilatation.
If you want to learn more about GI imaging, specifically fluoroscopy, the Mayo Clinic Gastrointestinal Imaging book is a wonderful reference with over 500 images: