ª Springer Science+Business Media New York 2015
Abdom Imaging (2015) DOI: 10.1007/s00261-015-0402-3
Coffee bean sign Amit Chakraborty,1 Andres Ayoob,2 David DiSantis2 1 2
University of Kentucky College of Medicine, 138 Leader Ave, Lexington, KY 40506, USA Department of Radiology, University of Kentucky College of Medicine, 800 Rose St, Lexington, KY 40536, USA
The coffee bean sign is a metaphor describing the classic radiographic appearance of a closed loop obstruction, most notably associated with sigmoid volvulus [1, 2]. Twisting of the sigmoid colon about its mesenteric axis creates an inverted, U-shaped, and a gas-filled segment of dilated bowel originating in the pelvis and extending cephalad. A central linear opacity bisects the dilated loop (Fig. 1a), mimicking the cleft of a coffee bean (Fig. 1b). This central line represents the ‘‘double’’ thickness of apposed bowel walls  (Fig. 2).
Correspondence to: Amit Chakraborty; email: [email protected]
Failure to recognize this ﬁnding may lead to delayed diagnosis with increased risk of ischemia, infarction, and perforation. Emergent operation for sigmoid volvulus has been associated with 24% mortality, compared with 6% in an elective setting .
A. Chakraborty et al.: Coffee bean sign
Fig. 2. Sigmoid volvulus. CT scout view reveals the typical inverted U-shaped sigmoid colon with the coffee bean configuration (red arrows). Note the dilation of the more proximal colon, and extension of the distended sigmoid loop cephalad to the transverse colon (northern exposure sign) .
References 1. Feldman D (2000) The coffee bean sign. Radiology 216(1):178–179 2. Mellins HZ, Rigler LG (1954) The roentgen findings in strangulating obstructions of the small intestine. Am J Roentgenol Radium Ther Nucl Med 71(3):404–415 3. Burgener FA, Kormano M, Pudas T (2011) Differential diagnosis in conventional radiology. New York: Thieme 4. Grossmann E, Longo W, Stratton M, et al. (2000) Sigmoid volvulus in Department of Veterans Affairs Medical Centers. Dis Colon Rectum 43:414–418 5. Javors BR, Baker SR, Miller JA (1999) The northern exposure sign: a newly described finding in sigmoid volvulus. AJR Am J Roentgenol 173(3):571–574
Fig. 1. A Sigmoid volvulus. Supine frontal radiograph showing the inverted U-shaped sigmoid colon which resembles a coffee bean. The thick inner wall (‘‘cleft’’) represents the ‘‘double’’ thickness of apposed bowel walls (red arrows). B Photograph of a roasted coffee bean. Note the central cleft (red arrow).