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Abdominal computed radiography for the diagnosis of enterolithiasis in horses: 142 cases (2003–2007)

Omar MaherWilliam R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.

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Sarah M. PuchalskiDepartment of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.

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Christiana DrakeDepartment of Statistics, University of California-Davis, Davis, CA 95616.

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Sarah S. le JeuneDepartment of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.

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Abstract

Objective—To evaluate the sensitivity and specificity of abdominal computed radiography (CR) for the diagnosis of enterolithiasis in horses and to examine how these parameters are affected by the number and anatomic location of enteroliths and by gas distension of the gastrointestinal tract.

Design—Retrospective case series.

Animals—Horses ≥ 1 year old that underwent abdominal CR and subsequent exploratory laparotomy or postmortem examination.

Procedures—3 reviewers blinded to signalment, history, clinical signs, and diagnoses separately evaluated abdominal computed radiographs of horses included in the study. Each set of radiographs was evaluated for the presence or absence of enteroliths, the amount of gas distention, and the image quality. Signalment, definitive diagnosis on the basis of findings on exploratory laparotomy or postmortem examination, and the number and location of enteroliths were obtained from medical records.

Results—Of the 142 cases reviewed, 58.4% (83/142) had confirmed enterolithiasis. For the 3 reviewers, overall sensitivity was 85% and specificity was 93%. Sensitivity was lower for small colon enteroliths than for large colon enteroliths (50% and 94.5%, respectively) and was significantly affected by gas distention. Sensitivity was not significantly affected by the number of enteroliths.

Conclusions and Clinical Relevance—Computed radiography provided high sensitivity and high specificity for the diagnosis of enterolithiasis in horses. Caution should be exercised when the radiographic results are negative, as the sensitivity for small colon enterolithiasis was relatively low and gas distension negatively affected detection of enteroliths. Abdominal CR is indicated as a diagnostic test in horses examined for colic in geographic regions in which enterolithiasis is endemic.

Abstract

Objective—To evaluate the sensitivity and specificity of abdominal computed radiography (CR) for the diagnosis of enterolithiasis in horses and to examine how these parameters are affected by the number and anatomic location of enteroliths and by gas distension of the gastrointestinal tract.

Design—Retrospective case series.

Animals—Horses ≥ 1 year old that underwent abdominal CR and subsequent exploratory laparotomy or postmortem examination.

Procedures—3 reviewers blinded to signalment, history, clinical signs, and diagnoses separately evaluated abdominal computed radiographs of horses included in the study. Each set of radiographs was evaluated for the presence or absence of enteroliths, the amount of gas distention, and the image quality. Signalment, definitive diagnosis on the basis of findings on exploratory laparotomy or postmortem examination, and the number and location of enteroliths were obtained from medical records.

Results—Of the 142 cases reviewed, 58.4% (83/142) had confirmed enterolithiasis. For the 3 reviewers, overall sensitivity was 85% and specificity was 93%. Sensitivity was lower for small colon enteroliths than for large colon enteroliths (50% and 94.5%, respectively) and was significantly affected by gas distention. Sensitivity was not significantly affected by the number of enteroliths.

Conclusions and Clinical Relevance—Computed radiography provided high sensitivity and high specificity for the diagnosis of enterolithiasis in horses. Caution should be exercised when the radiographic results are negative, as the sensitivity for small colon enterolithiasis was relatively low and gas distension negatively affected detection of enteroliths. Abdominal CR is indicated as a diagnostic test in horses examined for colic in geographic regions in which enterolithiasis is endemic.

Contributor Notes

Dr. Maher's present address is New England Equine Medical and Surgical Center, 15 Members Way, Dover, NH 03820.

Address correspondence to Dr. le Jeune (sslejeune@ucdavis.edu.