Comparative imaging of the canine acute abdomen: survey radiography, contrast-enhanced ultrasound and contrast-enhanced multi-detector helical computed tomography

Shanaman, Miriam

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https://hdl.handle.net/2142/44190 Copy

Description

Title

Comparative imaging of the canine acute abdomen: survey radiography, contrast-enhanced ultrasound and contrast-enhanced multi-detector helical computed tomography

Author(s)

Shanaman, Miriam

Issue Date

2013-05-24T21:53:47Z

Director of Research (if dissertation) or Advisor (if thesis)

O'Brien, Robert T.

Department of Study

Vet Clinical Medicine

Discipline

VMS-Veterinary Clinical Medcne

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• computed tomography (CT)
• Contrast
• Acute Abdomen
• Dog

Abstract

Canine patients with acute abdominal signs are often clinically unstable and need a rapid and accurate diagnosis. Contrast-enhanced multi-detector computed tomography (CE-MDCT) is the current modality of choice for evaluating acute abdominal pain in people. In phase one of this study we hypothesized that CE-MDCT would be a feasible and safe technique for use in awake and lightly sedated dogs with acute abdominal signs. Eighteen client-owned dogs were enrolled, all presenting with acute abdominal signs. Dogs were scanned using a dual-phase protocol that included pre-contrast, arterial and portal venous phases. Eight dogs were scanned awake and 10 were given light sedation as chosen by the primary care clinician. Two observers who were unaware of clinical findings and sedation status scored image quality for each scan by consensus opinion. Mean serum creatinine in the sedated group was significantly higher than in the awake group but was within the normal reference range for dogs. Other laboratory and physiologic measures did not differ between awake and sedated groups. No intravenous contrast-related adverse reactions were seen in any of the dogs. Median scan time for all patients was less than 10 minutes. Sixteen of 18 CE-MDCT scans were scored fair to excellent in diagnostic quality, with no statistical difference in diagnostic quality for awake versus sedated patients. The two poor quality diagnostic scans were attributed to severe beam hardening from previously administered barium contrast agent and severe motion artifacts. The results of this study suggest that dual-phase CE-MDCT is a feasible and safe technique for evaluating awake and minimally sedated dogs presenting with acute abdominal signs. Unlike CE-MDCT, contrast-enhanced ultrasound (CEUS) continues to be in its infancy as it relates to evaluation of the acute abdomen. The primary purpose of phase two of this study, therefore, was to determine the level of agreement between survey radiography, combined B-Mode/CEUS, and CE-MDCT in the same population of canine patients; particularly the ability of these modalities to differentiate surgical from non-surgical conditions. Nineteen dogs (18 from phase 1 plus one additional case) with acute abdominal signs were prospectively enrolled. Inclusion required the cytologic, radiographic or sonographic detection of an underlying surgical condition or alternatively a source of acute abdominal disease that would necessitate medical management. Agreement for the majority of imaging features assessed was at least moderate. There was poor agreement in the identification of pneumoperitoneum and in the comparison of pancreatic lesion dimensions on B-mode vs. CEUS. The CT feature of fat stranding was noted in a variety of disease processes including gastric neoplasia with perforation, pancreatitis, and small intestinal foreign body. Ultrasound underestimated both the size and number of specific lesions when compared with CE-MDCT. CEUS was successful in the detection of bowel and pancreatic perfusion deficits that CE-MDCT failed to identify. Accuracy for the differentiation of surgical from non-surgical conditions was high for all modalities; 100%, 94% and 94% for CE-MDCT, US and survey radiography, respectively. CE-MDCT is an effective screening test of choice in the differentiation of surgical vs. non-surgical acute abdominal conditions. Focused CEUS may be beneficial following preliminary CE-MDCT or B-mode US given the potential for identifying clinically significant hypoperfused lesions.

Graduation Semester

2013-05

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http://hdl.handle.net/2142/44190

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Copyright 2013 Miriam Shanaman

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