Intra- And Interobserver Variability of Ultrasonographic Measurements of the Adrenal Glands in Healthy Beagles

Abstract

The aim of the present study was to establish which adrenal gland measurement was characterized by the least variations. To do this, we quantified the variability of seven different size measurements of the canine adrenal gland (maximal length, maximal height at the cranial and caudal poles on longitudinal and transverse images, and maximal width of the cranial and caudal poles) within observer, between observer, and between dogs based on three different measurements made by each of the three observers in six healthy Beagle dogs. The height of the caudal pole of both adrenal glands measured on longitudinal images had the lowest intra- and interobserver variability, while measurements of the length had the highest intra- and interobserver variability. Other measurements that were characterized by low intra- and interobserver variability were: height and width of the caudal pole on transverse images and height of the cranial pole on longitudinal images only. These results provide a basis for further study of the changes in adrenal gland size in dogs with pituitary-dependent hyperadrenocorticism.

Ultrasonographic Evaluation of Adrenal Gland Size Compared to Body Weight in Normal Dogs

“…Fourth, both observers were always able to easily and reliably visualize the caudal pole of the adrenal gland in the sagittal plane; the caudal pole is often more clearly visually defined and consistently has a similar shape than the cranial pole and the adrenal glands are typically evaluated in a sagittal plane rather than a transverse plane ultrasonographically. Similarly, previous studies found that the thickness of the caudal pole of the adrenal gland measured in the sagittal plane best correlated with grossly measured adrenal glands and had the least intraobserver and interobserver variability …”

“…A wide range of values have been documented by previous studies with regard to normal ultrasonographic size (length, width, and thickness) of the adrenal glands in healthy dogs. Adrenal gland measurements in normal dogs have been reported to vary from 0.91 to 5.02 cm for length, from 0.19 to 1.74 cm for width, and from 0.17 to 1.07 cm for thickness/height . Additionally, although dogs with hyperadrenocorticism have adrenal gland measurements significantly greater than those of normal dogs and dogs with hypoadrenocorticism have adrenal gland measurements significantly less than those of normal dogs, an overlap in the range of measurements of dogs with either disease and normal dogs is present.…”

“…Grooters et al determined that ultrasonographically measured adrenal gland thickness, but not adrenal gland length or width, accurately represents gross measurements while independently, Barberet et al noted that measurements of adrenal gland thickness at the caudal pole in a sagittal plane have the least intraobserver and interobserver variability . Therefore, since dogs have great variability in body weight and previous studies have not consistently identified a single best measurement for distinguishing normal from enlarged adrenal glands, further research is needed to determine if a relationship exists between adrenal gland size (length, width, and thickness) in small, medium, and large breed dogs.…”

Ultrasonographical examination of feline adrenal glands: intra- and inter-observer variability

“…These findings are similar to what is described in dogs and most likely due to the similar echogenicity and the close contact of the right adrenal gland, particularly the cranial pole, with the caudate lobe of the liver and the caudal vena cava. 5 The agreement on the descriptive ultrasonographical features of the feline adrenal gland is satisfactory to very good, except for the assessment of the shape between observers. Despite a consensual scanning protocol, the descriptive features are very subjective.…”

Adrenal Glands

“…[30][31][32] The right adrenal gland is best imaged from the ventral or right lateral abdomen just caudal to the last rib or through the right 11th or 12th intercostal space in deep-chested dogs. It is deeper and more cranial than the left adrenal gland, where overlying ribs and bowel gas can compromise visualization.…”