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25

Adrenal Gland
Merrilee Holland

Department of Clinical Sciences, College of Veterinary Medicine, Auburn, AL, USA

25.1 Adrenal Gland Anatomy imaging plane. By sliding the probe cranial to the kidney
and fanning dorsally toward the vessels, the right adrenal
The location of the adrenal glands in cats, unlike in dogs, is gland can be located. Alternatively, after finding the right
typically slightly cranial to the kidneys. The right adrenal kidney, slide dorsally toward the caudal vena cava; the
gland lies cranial to the right kidney along the caudal vena right adrenal gland will be located slightly cranial to the
cava (CVC) (Figure 25.1). The left adrenal gland can be kidney. The normal mean height (width) and length of
found cranial to the left kidney adjacent to the aorta the adrenal glands in healthy cats should be <4.8 and
(Figure 25.1). The normal adrenal gland is ovoid or “jelly‐ <12.7 mm, respectively [2].
bean” shaped. The phrenicoabdominal vessels can be seen
associated with the dorsal and ventral surface of the adre-
nal gland. The adrenal gland is composed of an inner 25.4 Normal Ultrasound Appearance
medulla and an outer cortex. The outer cortex has three
layers which secrete aldosterone, glucocorticoids, and sex The normal adrenal gland is ovoid or “jelly‐bean” shaped.
hormones. The inner medulla can produce catecholamine The appearance has been reported to be hypoechoic with a
when mediated by acetylcholine [1]. hyperechoic outer rim. Focal hyperechoic foci with or
without shadowing have been associated with dystrophic
mineralization, fat deposition, or focal hemorrhage and are
25.2 Normal Radiographic considered an incidental finding in up to 30% of normal
Appearance cats (Figures 25.3 and 25.4) [2].
Contrast‐enhanced ultrasound of the adrenal glands has
Normal adrenal glands are not visualized on radiographs not been reported in cats. However, there was two times
unless mineralization is present. Mineralization in the greater perfusion in the adrenal glands in 18 dogs with
adrenal glands can be seen as an incidental finding on radi- pituitary‐dependent hyperadrenocorticism than in four
ographic imaging (Figure 25.2). control dogs [3].

25.3 Ultrasound Scanning Tips 25.5 Adrenal Gland Diseases

With the patient in right lateral recumbency, find the left Hyperadrenocorticism (HAC) is a rare disease in feline
kidney in a sagittal imaging plane. Slide slightly cranial to patients. It occurs most commonly in middle‐aged and
the kidney, and fan dorsally until the abdominal aorta is older cats with a slightly higher incidence in female cats. In
visualized. The left adrenal gland will be found in close cats with HAC, the adrenal glands secrete excess cortisol.
proximity to the aorta cranial to the left kidney. The right Common physical examination findings include abdomi-
adrenal gland can be found by placing the patient in left nal distension, bilaterally symmetric alopecia, hepatomeg-
lateral recumbency. The right kidney is located in a sagittal aly, and open sores. The clinical signs appear similar to

Feline Diagnostic Imaging, First Edition. Edited by Merrilee Holland and Judith Hudson.
© 2020 John Wiley & Sons, Inc. Published 2020 by John Wiley & Sons, Inc.