Eye Spy with My Little i
Ashley Davidoff MD TheCommonVein.net (139827cEyeSpy)
CT of body part in the coronal projection with a focus on the pelvis
Number the findings
1) loop in the RLQ exhibits a thick wall with a narrowed lumen (yellow arrowhead)
2) loop in the RLQ alternating layers of enhanced and relatively non-enhanced wall. (yellow arrowhead
3) small bowel loop in the LLQ, “target sign” (red arrowhead)
4) small bowel loop in LLQ causes mass effect on the bladder.
5) small bowel loop abutting the left pelvic wall shows mild dilatation and dilution of contrast. (pink arrowhead
6) evidence of creeping fat in the mesentery subtending the affected loops is characterized by vascular and lymphatic congestion and mild induration. (looped in white ring)
7) small focus of loculated fluid along the right iliac vessels.(teal blue arrowhead}
8) Incidental finding of bilateral hip DJD
Comment
These findings are almost pathognomonic of acute Crohn’s ileitis. Included in the differential diagnosis, though less likely, are infectious enteritis and ischemic enteritis
Ashley Davidoff MD TheCommonVein.net (139827cLEye Spy)
The CT scan findings described are indicative of acute on chronic Crohn’s disease. The presence of a thick-walled loop with a narrowed lumen in the right lower quadrant (RLQ), alternating layers of enhanced and non-enhanced wall, and the “target sign” in the left lower quadrant (LLQ) are classic signs of active inflammation superimposed on chronic changes.
1. Thickened Wall and Narrowed Lumen: These findings suggest chronic inflammation and fibrosis, leading to stricture formation, which is a common complication in long-standing Crohn’s disease.[1-2]
2. Alternating Layers of Enhancement: This pattern, also known as mural stratification, is indicative of active inflammation. The American College of Radiology notes that mural stratification is a hallmark of acute exacerbation in Crohn’s disease.[1]
3. Target Sign: The target sign, characterized by concentric rings of varying attenuation, is associated with active transmural inflammation and is commonly seen in acute flares of Crohn’s disease.[3-4]
4. Creeping Fat: The presence of creeping fat, characterized by mesenteric fat wrapping around the bowel, is indicative of chronic inflammation and fibrosis. This finding is associated with a more complicated disease course and is often seen in chronic Crohn’s disease.[3]
5. Mass Effect and Loculated Fluid: The mass effect on the bladder and the presence of loculated fluid suggest complications such as abscess formation or phlegmon, which are common in chronic Crohn’s disease with acute exacerbations.[1-2]
In summary, the CT findings of thickened bowel wall, mural stratification, target sign, creeping fat, and strictures, along with the presence of loculated fluid, are consistent with acute on chronic Crohn’s disease. These findings highlight the ongoing cycle of inflammation, healing, and fibrosis characteristic of this condition.
References
1. ACR Appropriateness Criteria® Crohn Disease.
Kim DH, Chang KJ, Fowler KJ, et al. Journal of the American College of Radiology : JACR. 2020;17(5S):S81-S99.
2. ACG Clinical Guideline: Management of Crohn’s Disease in Adults.
Lichtenstein GR, Loftus EV, Isaacs KL, et al. The American Journal of Gastroenterology. 2018;113(4):481-517.
3. Small Bowel Crohn Disease at CT and MR Enterography: Imaging Atlas and Glossary of Terms. Guglielmo FF, Anupindi SA, Fletcher JG, et al. Radiographics : A Review Publication of the Radiological Society of North America, Inc. 2020 Mar-Apr;40(2):354-375.
4. Bowel Wall Thickening in Patients With Crohn’s Disease: CT Patterns and Correlation With Inflammatory Activity. Choi D, Jin Lee S, Ah Cho Y, et al. Clinical Radiology. 2003;58(1):68-74.