title: PREVALENCE AND SIGNIFICANCE OF AN ULTRASONOGRAPHIC COLONIC MUSCULARIS HYPERECHOIC BAND PARALLELING THE SEROSAL LAYER IN DOGS.
abstract: The muscularis layer of the canine colon has been reported to appear homogeneously hypoechoic on ultrasonography. A hyperechoic band in the muscularis layer paralleling the serosal surface has been observed by authors in routine canine abdominal ultrasound examinations. The purpose of this prospective and retrospective cross-sectional study was to determine the prevalence of this lesion, characterize its ultrasonographic and postmortem histologic features, and correlate its presence with clinical signs of gastrointestinal disease. In the prospective study, all dogs that underwent routine abdominal ultrasonography by one of two observers during a 4-week period were included without any exclusion criteria. One observer reviewed ultrasound images and recorded the presence or absence of this lesion and its distribution, e.g. focal (< 2 cm long) or diffuse (> 2 cm long). In the retrospective study, all dogs that had both abdominal ultrasonography and necropsy from January 2011 to December 2013 were included without any exclusion criteria. Histologic examinations were performed by two observers and Masson's trichrome stain was used to identify fibrous collagen. Prevalence for the hyperechoic band was 32% in the prospective and 4.8% in the retrospective sample populations, respectively. The hyperechoic band appeared as diffuse, focal, or a combination of both. Histologic sections were available for six dogs. In a few cases, the lesion corresponded to the presence of fibrous tissue in the myenteric plexus or in the tunica muscularis. None of the dogs had a history of diarrhea. Findings supported the hypothesis that a colonic muscularis hyperechoic band paralleling the serosal layer in dogs could be a normal variant rather than a marker of disease.
authors.affiliation: Department of Veterinary Clinical Sciences, Purdue University, West Lafayette, IN, 47907.
authors.forename: Hock Gan
authors.initials: HG
authors.lastname: Heng
authors.affiliation: Department of Veterinary Clinical Sciences, Purdue University, West Lafayette, IN, 47907.
authors.forename: Chee Kin
authors.initials: CK
authors.lastname: Lim
authors.affiliation: Department of Comparative Pathobiology, Purdue University, West Lafayette, IN, 47907.
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Miller
authors.affiliation: Department of Comparative Pathobiology, Purdue University, West Lafayette, IN, 47907.
authors.forename: Meaghan M
authors.initials: MM
authors.lastname: Broman
mesh_terms: D063405:Anatomic Variation; D000818:Animals; D003094:Collagen / Q000032:analysis / Q000648:ultrastructure; D003106:Colon / Q000000981:diagnostic imaging*; D003108:Colonic Diseases / Q000000981:diagnostic imaging / Q000473:pathology / Q000662:veterinary; D003430:Cross-Sectional Studies; D004283:Dog Diseases / Q000000981:diagnostic imaging / Q000473:pathology; D004285:Dogs / Q000033:anatomy & histology*; D007413:Intestinal Mucosa / Q000000981:diagnostic imaging; D009130:Muscle, Smooth / Q000000981:diagnostic imaging; D011446:Prospective Studies; D012189:Retrospective Studies; D012704:Serous Membrane / Q000000981:diagnostic imaging*; D014463:Ultrasonography
chemical_list: D003094:Collagen
keywords: colon; dogs; muscularis layer; ultrasound