# Ultrasonographic evaluation of the normal gastrointestinal wall in dogs and cats: a systematic review on study design and imaging outcomes

## TL;DR

This paper reviews ultrasonographic studies on the gastrointestinal tract in dogs and cats to create standardized reference values for wall thickness and layers.

## Contribution

The study compiles a consensus-based reference table for ultrasonographic GI wall measurements in dogs and cats.

## Key findings

- Reference values for GI wall thickness and layers were reported in both dogs and cats.
- Discrepancies in weight-based classifications and limited data on adult dog stomachs were identified.
- Standardized ultrasonographic parameters could improve diagnostic accuracy in veterinary practice.

## Abstract

Diagnostic ultrasound (US) is a noninvasive, cost-effective imaging modality widely used for evaluating the gastrointestinal (GI) tract in companion animals. It provides information on wall thickness and layer differentiation, allowing assessment of normal anatomy and pathological changes. Despite its diagnostic relevance, ultrasonographic reference values for the GI tract in dogs and cats remain inconsistent across publications. This study reviewed ultrasonographic characteristics of the normal GI wall in dogs and cats and compiled a consensus-based reference table for overall wall thickness and individual layer proportions to enhance clinical interpretation. A literature search of PubMed and Scopus identified studies assessing the ultrasonographic features of normal GI segments, from stomach to colon, in healthy dogs and cats. Twelve studies met the inclusion criteria: six focused on dogs and six on cats. Reference values for GI wall thickness and its layers were reported in both species. However, discrepancies were noted in weight-based classifications for dogs, and the stomach of adult dogs remains poorly studied. Moreover, evaluation of gastric rugal and inter-rugal folds remains limited in this species. US is valuable for GI assessment, but dispersion of reference values across studies may hinder accessibility. Establishing standardized ultrasonographic parameters could improve diagnostic accuracy and clinical decision-making.