Intra‐rater and inter‐rater reliability of ultrasonographic intestinal wall thickness measurements in healthy horses

BACKGROUND: Abdominal ultrasound is widely used to evaluate the intestinal tract of horses. Despite being a routine examination, there is limited data on the reliability of this diagnostic procedure. OBJECTIVES: To investigate intra- and inter-rater reliability of ultrasonographic intestinal wall thickness measurements in healthy horses. A second aim was to assess variance within repeated measurements to determine threshold values that distinguish whether differences between repeated examinations are true findings versus solely due to measurement variation. STUDY DESIGN: In vivo reliability study. METHOD: Eight healthy horses (7 Standardbreds, 1 Warmblood) were ultrasonographically examined in six intestinal regions: duodenum, right dorsal colon (RDC), right ventral colon (RVC), caecum, jejunum and left ventral colon (LVC). In each horse, triplicate measurements of intestinal wall thickness were performed by three sonographers on three consecutive days. Intra-class correlation coefficient (ICC) was calculated to assess intra- and inter-rater reliability. RESULTS: Intra-rater ICC was