The "whirl sign". Diagnostic accuracy for intestinal volvulus. Poster No.: C-0670 Congress: ECR 2014 Type: Scientific Exhibit Authors: M. Pire, M. Marti, A. Borobia, A. Verón; Madrid/ES Keywords: Abdomen, Emergency, CT, Diagnostic procedure, Volvulus DOI: 10.1594/ecr2014/C-0670 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.myesr.org Page 1 of 10
Aims and objectives To determine the utility of the "whirl sign", an uncommon finding in the emergency TC, for the diagnosis of small and large bowel volvulus. Methods and materials We have reviewed all patients studied at our institution between 2008 and 2013 with a clinical diagnosis of bowel obstruction. They underwent a CT of abdomen and pelvis with obtaining of the images during the portal-venous phase after the administration of iodinated contrast material. We have selected those patients in whose CT images was identified the "whirl sign", stablishing a prior radiological diagnosis of bowel volvulus. It was previously necessary to fix the definition and CT imaging features of the "whirl sign": wrapped bowel loops encircling mesenteric vessels, which act as an axis of rotation and determine cranio-caudally the direction of the twist (clockwise or counterclockwise). Exclusively vascular or bowel twist were excluded from the definition. Page 2 of 10
Fig. 1: Axial contrast-enhanced CT image shows the "whirl sign" (yellow arrow): twisted bowel loops encircling mesenteric vessels. Page 3 of 10
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Fig. 2: Axial contrast-enhanced CT scan. Example of vascular "whirl" (red arrow), not included in the definition of "whirl sign". Thin yellow arrows are pointing bowel loops with thickened and poorly enhanced walls, findings suggestive of ischemia. The utility of the "whirl sign" for the diagnosis of bowel volvulus is been statitically evaluated taking the outcome of surgery and endoscopic treatment as the "gold standard". 95% confidence intervals (CIs) were calculated for sensitivity, specificity and predictive values. Results From the reviewed cases, we have selected 15 patients in whose radiological study was identified the "whirl sign". 7 patients were male and 8 were female. Patients ranged ages from 31 to 95 years (mean age was 74 years). After treatment 13 volvulus were confirmed (86,7%): 6 patients presented small bowel volvulus (46,2%). They all were surgically treated. One case was due to internal hernia. The rest five cases were secondary to closed-loop obstructions due to adhesive bands. Fig. 3: Axial contrast-enhanced CT images show the whirl sign (red arrow) in a patient with ileal volvulus due to internal hernia. Thin yellow arrows point collapsed terminal ileum entering the "whirl". Page 5 of 10
Fig. 4: Axial contrast-enhanced CT images show the "whirl sign" (blue arrows) in a patient with ileal volvulus. 6 patients had sigmoid volvulus, all of them confirmed endoscopically. Most of them had no specific predisposing factors, except from one 35 year-old patient with Chagas disease and recurrent sigmoid volvulus. Page 6 of 10
Fig. 5: Axial contrast-enhanced CT image shows dilated sigmoid colon (red star) in a patient with large bowel obstruction. Thin yellow arrow marks the point of obstruction. Page 7 of 10
Fig. 6: Coronal CT scan of the same patient (fig 5). The "whirl sign" (green arrow) is best appreciated when the scanning plane is perpendicular to the axis of the twist, as it happens in this case. Note the presence of free intraperitoneal fluid (yellow spot). 1 patient had a cecal volvulus (7,6%). The patient underwent surgery. It was a type I volvulus, that is an axial torsion of the cecum. Page 8 of 10
Fig. 7: Cecal volvulus. Axial contrast-enhanced CT images show the whirl sign (green arrows). Red star marks dilated cecum in the right lower abdomen. In 2 cases, surgery could not prove the existence of volvulus, one of them was a patient with intestinal malrotation and suspected midgut volvulus. No bowel obstruction or volvulation was present at surgery. During our review process, we also found one patient with a small bowel volvulus confirmed at surgery in whose imaging study there wasn't the "whirl sign". Instead, a twist of mesenteric vessels was found on coronal CT images. Given all these data and our statistical analysis establishes that the whirl sign has a sensitivity of 93% (95%CI: 79-100) and a positive predictive value of 87% (95%CI: 69-100). Page 9 of 10
Conclusion The "whirl sign" has high sensitivity for the diagnosis of bowel volvulus in cases of intestinal obstruction, which can be a life-threatening surgical emergency due to impairment of the vascular support and intestinal ischemia. Given the potential catastrophic consequences of misdiagnosis, the radiologist must be aware and keep in mind that there are cases in which the existence of volvulus doesn't associate the radiological presence of this sign. Personal information References 1. Suárez Vega VM, Martí de Gracia M, Verón Sanchez A et al (2010).Trapped on the "whirl": diagnostic sign on emergency CT. Emerg Radiol 17: 139-147. 2. Loh YH, Dunn GD (2000). Computed tomography features of small vowel volvulus. Australas Radiol 44: 464-467. 3. Peterson CM, Anderson JS, Hara AK et al (2009). Volvulus of the gastrointestinal tract: appearences at multimodality imaging. Radiographics 29: 1281-1293. Page 10 of 10