Citation, DOI, disclosures and article data
Citation:
Amini B, Ismail M, Sharma R, et al. Sentinel loop. Reference article, Radiopaedia.org (Accessed on 24 Mar 2025) https://doi.org/10.53347/rID-2031
A sentinel loop is a short segment of adynamic ileus close to an intra-abdominal inflammatory process. It is usually identified on abdominal radiography 4 and CT 3.
The sentinel loop sign may aid in localising the source of inflammation, although non-specific. For example, a sentinel loop in the upper abdomen may indicate pancreatitis or cholecystitis, whilst one in the right lower quadrant may be due to appendicitis or renal infarction 2,5. Patients usually will have localised pain at the region of the involved organ, followed by vomiting and/or abdominal distension few hours later.
History and etymology
In 1946, Levita first reported on sentinel loop on supine abdominal radiographs in cases of acute gallbladder disease, acute appendicitis, and subhepatic abscess. In 1950, Grollman applied the sentinel loop as a sign of acute pancreatitis 3.
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1. Pickhardt PJ. The colon cutoff sign. Radiology. 2000;215 (2): 387-9. Radiology (full text) - Pubmed citation
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2. Frauenfelder T, Wildermuth S, Marincek B et-al. Nontraumatic emergent abdominal vascular conditions: advantages of multi-detector row CT and three-dimensional imaging. Radiographics. 24 (2): 481-96. doi:10.1148/rg.242025714 - Pubmed citation
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3. Ali N, Leshchinskiy S, Johnson M, D’Agostino R. The Sentinel Loop Sign. Abdom Radiol. 2018;43(11):3192-4. doi:10.1007/s00261-018-1582-4 - Pubmed
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4. Essential Radiology Review. SpringerLink. 2019. doi:10.1007/978-3-030-26044-6
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5. Mori K, Hayashi K, Oe K, Aburao T, Yagi M, Yamagishi M. Acute Renal Infarction Complicated by a Sentinel Loop in a Patient with Atrial Fibrillation. J Xiangya Med. 2017;2(4):35. doi:10.21037/jxym.2017.03.14
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