Whirl sign

 Q: What is 'CT whirl sign' in 'closed-loop bowel obstruction'? 

Answer: As the name implies closed-loop bowel obstruction is a segment of the bowel with no proximal or distal outlet due to obstruction at two places. Although sounds simple, it is a surgical emergency, which requires early intervention, as necrosis due to ischemia and perforation can occur very quickly. Restoration of perfusion is urgently needed. Sometimes it needs full abdominal exploration. Another caveat is its difficult diagnosis via imaging. 

CT whirl sign: A closed-loop obstruction should be suspected if a C or U-shaped distended, fluid-filled bowel segment with prominent mesenteric vessels converging on a point of torsion or incarceration is seen. 

Other clues in imaging are the presence of a triangular bowel loop, the beak sign (gradual narrowing of the bowel), and the two collapsed bowel loops adjacent to the obstruction site.

#surgical-critical-care

References:

1. Mbengue, A., Ndiaye, A., Soko, T. O., Sahnoun, M., Fall, A., Diouf, C. T., Régent, D., & Diakhaté, I. C. (2015). Closed loop obstruction: pictorial essay. Diagnostic and interventional imaging, 96(2), 213–220. https://doi.org/10.1016/j.diii.2013.10.011 

2. Ho YC. "Venous cut-off sign" as an adjunct to the "whirl sign" in recognizing acute small bowel volvulus via CT scan. J Gastrointest Surg 2012; 16:2005. 

3. Elsayes, K. M., Menias, C. O., Smullen, T. L., & Platt, J. F. (2007). Closed-loop small-bowel obstruction: diagnostic patterns by multidetector computed tomography. Journal of computer assisted tomography, 31(5), 697–701. https://doi.org/10.1097/RCT.0b013e318031f516. 

4. Edwards, M. K., Kuppler, C. S., Croft, C. A., & Eason-Bates, H. M. (2018). Adhesive Closed-loop Small Bowel Obstruction. Clinical practice and cases in emergency medicine, 2(1), 31–34. https://doi.org/10.5811/cpcem.2017.10.35927