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Title:Comparative imaging of surgical small intestinal disease in dogs: evaluation of pre-operative contrast-enhanced ultrasound, intra-operative contrast-enhanced ultrasound, and triple-phase contrast-enhanced computed tomography
Author(s):Goodall, Elisabeth Frieda Peters
Department / Program:Vet Clinical Medicine
Discipline:VMS-Veterinary Clinical Medicine
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:M.S.
Genre:Thesis
Subject(s):contrast-enhanced ultrasound
Abstract:Surgical small intestinal diseases occur commonly in canine patients seen in veterinary practices. Failure to identify ischemic tissue intra-operatively can result in surgical dehiscence, require surgical revision, and lead to sepsis or death. Currently contrast-enhanced computed tomography (CT) is the standard of care for evaluating ischemic lesions of the bowel in humans. Contrast-enhanced ultrasound (CEUS) is an alternative method for evaluating tissue perfusion whose utility for evaluation of canine small intestinal lesions remains to be fully tested. Thirteen client-owned dogs were prospectively recruited after presenting with surgical diseases within the small intestine. Presenting conditions included discrete foreign bodies, linear foreign bodies, intestinal abscess, and neoplasia. Patients underwent pre-operative CEUS, triple-phase contrast-enhanced CT, and intra-operative CEUS. Surgical specimens obtained from each patient included resected intestinal segments or biopsy. Both CT and CEUS data were compared to histopathology findings. All patients that required a resection (n=4) received an ischemia score of 4 or 5. A higher ischemia score was correlated with an increased chance of necrosis (p=0.003) and thrombosis (p=0.024). The presence of a visual perfusion deficit on CT was correlated with a higher ischemia grade (p=0.048) and higher chance of necrosis (p=0.024); however, observers only detected a perfusion deficit in 3/4 (75%) of patients requiring a resection. Ischemia was correlated with lower Hounsfield (HU) values aborad to the lesion in the pre-contrast CT (p=0.049). Necrosis was correlated with increased HU values at normal intestine in the arterial phase (p=0.017) and orad to the lesion in the venous phase of CT (p=0.014). Thrombosis was correlated with lower HU values aborad to the lesion in the pre-contrast CT (p=0.025) and higher HU values at normal intestine in the arterial phase (p=0.037) and orad to the lesion in the venous phase CT (p=0.041). Edema was correlated with lower HU values aborad to the lesion in the arterial phase (p=0.03) and higher HU values at normal intestine in the venous phase CT (p=0.038). Ulceration and erosion were correlated with higher HU values orad to the lesion in both the arterial (p=0.028) and venous phases of CT (p=0.044). No significant correlations were found at the site of the lesion in any phase of CT. For pre-operative CEUS, edema was correlated with higher peak intensity (p=0.014) while necrosis (p=0.046) and thrombosis (p=0.04) were correlated with a faster time to peak. For intra-operative CEUS, ulceration and erosion were correlated with a greater inflow slope (p=0.045), hemorrhage was correlated with a longer time to initial rise (p=0.028), thrombosis was correlated with a faster time to peak (p=0.014), and necrosis was correlated with increased baseline pixel intensity (p=0.046). Observers were able to detect a perfusion deficit on CEUS exam in 4/4 (100%) of patients requiring a resection. No advantage to the intra-operative CEUS versus a pre-operative CEUS exam was appreciated. Lower HU values obtained from the pre-contrast CT aborad to the lesion site (p=0.036) and at normal intestine (p=0.036) were correlated with a higher chance of patient mortality. The presence of a visual perfusion deficit on CEUS was also correlated with a higher chance of patient mortality (p=0.014). Findings from our study indicate that a variety of CT and CEUS findings were correlated with various histopathologic features, with no single imaging modality found to be superior. The clinical application of these findings warrants further investigation.
Issue Date:2016-04-20
Type:Thesis
URI:http://hdl.handle.net/2142/90791
Rights Information:Copyright 2016 Elisabeth Goodall
Date Available in IDEALS:2016-07-07
Date Deposited:2016-05


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