Misty mesentery sign

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The misty mesentery sign was described by Mindelzun et al in 1996 In the American Journal of Roentgenology and represents a non-specific radiological finding characterized by increased attenuation within the mesenteric fat on computed tomography (CT) imaging. It reflects pathological processes that result in infiltration, edema, or increased cellularity within the mesentery, often in association with inflammation and adjacent lymphadenopathy. [1] The term "misty" is descriptive of the hazy appearance of the mesenteric fat, which typically has a lower attenuation on CT in healthy individuals. [2]

Contents

Pathophysiology

The misty mesentery sign results from abnormal accumulation of fluid, cells, or fibrotic material within the mesentery. The causes can be classified into inflammatory, neoplastic, or vascular categories. [3] The attenuation changes are measured in Hounsfield Units (HU), with affected mesenteric fat demonstrating values higher than normal fatty tissue (typically less than -100 HU). [4]

Radiological features

The misty mesentery sign is typically identified on contrast-enhanced CT scans, particularly in the portal venous phase. Key imaging characteristics include hazy attenuation of mesenteric fat, with loss of the normal fat density and co-oexisting findings such as lymphadenopathy, ascites, or thickening of mesenteric vessels or bowel loops. The distribution of the mesenteric changes may help narrow the differential diagnosis. [2]

References

Mindelzun R, Jeffrey R, Lane M, Silverman P. The Misty Mesentery on CT: Differential Diagnosis. AJR Am J Roentgenol. 1996;167(1):61-5. doi:10.2214/ajr.167.1.8659422 - Pubmed

  1. Yudin, Andrey (2014). "Misty Mesentery Sign and Fat Halo Sign" . Metaphorical Signs in Computed Tomography of Chest and Abdomen. Springer International Publishing. p. 167. doi:10.1007/978-3-319-04013-4_84. ISBN   978-3-319-04012-7 . Retrieved 16 January 2025.
  2. 1 2 McLaughlin, Patrick D.; Filippone, Antonella; Maher, Michael M. (February 2013). "The "Misty Mesentery": Mesenteric Panniculitis and Its Mimics" . American Journal of Roentgenology. 200 (2): W116 –W123. doi:10.2214/AJR.12.8493. ISSN   0361-803X. PMID   23345375 . Retrieved 16 January 2025.
  3. Lal, Hira; Yadav, Priyank (1 March 2017). "Misty mesentery: a CT sign of mesenteric infiltration" . Abdominal Radiology. 42 (3): 977–978. doi:10.1007/s00261-016-0934-1. ISSN   2366-0058. PMID   27714418 . Retrieved 16 January 2025.
  4. Danti, Ginevra; Morelli, Noemi; Addeo, Gloria; Cozzi, Diletta; Lanzetta, Monica; Frezzetti, Gianluca; Masserelli, Antonella; Miele, Vittorio (2019). "The sign of misty mesentery: Differential diagnosis on multi-detector computed tomography". Journal of Radiological Review. 6 (1): 71–83. doi:10.23736/S2283-8376.19.00161-X.