# Accuracy of Plain Digital Radiography for the Detection of Gastrointestinal Masses in Dogs and Cats

## TL;DR

Digital abdominal radiography in dogs and cats has higher accuracy than previously thought for detecting gastrointestinal masses, though it's still less effective than advanced imaging.

## Contribution

The study provides updated, statistically validated accuracy rates for detecting GI masses in dogs and cats using digital radiography.

## Key findings

- Digital radiography detected gastrointestinal masses in 75% of dogs and 81% of cats.
- Cats showed higher detection accuracy than dogs, with no significant difference based on reviewer experience.
- Radiography has high specificity, making it useful for ruling out GI masses despite lower sensitivity.

## Abstract

Abdominal radiographs are commonly performed in cats and dogs when presenting with gastrointestinal signs; however, the detection of gastrointestinal masses is anecdotally unreliable. To further evaluate the efficacy of abdominal radiographs in detecting gastrointestinal masses, radiographs of 222 dogs and cats were reviewed. 85 had a gastrointestinal mass, 100 were normal, and 40 had gastrointestinal disease, but no masses. Statistical comparisons were conducted between species and between reviewers with varying levels of experience. The accuracy of radiography for the detection of gastrointestinal masses was significantly higher than previously reported. Cats had a more accurate detection rate than dogs, and there were no significant differences in accuracy between reviewers of varying experience. Although advanced imaging such as ultrasound or computed tomography remain superior, abdominal radiographs are clinically useful as a screening tool in ruling out gastrointestinal masses.

Abdominal radiography is commonly used as an initial diagnostic tool in dogs and cats with gastrointestinal (GI) signs. Historically, abdominal radiographs were considered unreliable for detecting GI masses, with detection rates below 50%. The purpose of this retrospective, case–control study was to determine the accuracy of abdominal radiographs in identifying the presence and location of GI masses and to assess the influence of the reviewer experience. Radiographs from 114 dogs and 111 cats were reviewed by two board-certified radiologists, one first year radiology resident, and one rotating intern. Patients were categorized into three groups: animals with a GI mass greater than 2 cm (dogs n = 44; cats n = 41), animals with a normal abdomen (both n = 50), and animals with abdominal disease but no GI mass (both n = 20). Reviewers demonstrated high specificity but low sensitivity for both detection and localization of GI masses. Sensitivity for detecting a mass ranged from 34 to 64% in dogs and 36 to 71% in cats; specificity exceeded 87% in dogs and 92% in cats. Sensitivity for location identification ranged from 9 to 58% in dogs and 21 to 68% in cats; specificity exceeded 76% in dogs and 81% in cats. No statistically significant differences in detection rates were found among reviewers. The accuracy of plain digital radiography for the detection of gastrointestinal masses in dogs (75%) and cats (81%) is better than previously reported film radiography but remains inferior to other imaging modalities. However, its high specificity supports its clinical utility in ruling out gastrointestinal masses.