18, 19 Obesity, deep-chested conformation, and bowel gas were cited as the most common reasons for nonvisualization. 2 Later studies, one with 50 dogs and another with 100 dogs of varying size, found that an experienced sonographer could visualize the left and right adrenal glands in 91% to 100% and 83% to 86% of cases, respectively. In one early investigation of 10 dogs, the normal left and right adrenal glands were visualized in 70% and 50% of the dogs, respectively. The right adrenal gland is more difficult to visualize than the left because of its deeper, more cranial location under the ribs. The right adrenal gland is best evaluated from the right craniolateral abdomen or through the 11th or 12th intercostal space, depending on body conformation.

The left adrenal gland is best seen from the left lateral abdomen or, less commonly, the left 12th intercostal space in deep-chested animals. The small size of the adrenals, deep-chested conformation, large body size, obesity, overlying gas-filled viscera, or lack of the patient compliance may contribute to nonvisualization. Nevertheless, one or both adrenal glands may not be visualized in every animal. In lateral recumbency, the uppermost adrenal can be imaged. A combination of views and positions may be required to avoid bowel gas.

Hair must be removed from the lateral aspects of the abdomen to obtain optimal visualization of the adrenal glands in most cases. Transverse, sagittal, and dorsal scans, like those used for the kidney, are made from the ventral or lateral abdomen with the animal restrained in dorsal, left, or right lateral recumbency (see Chapter 4, Fig. It is not uncommon to use a lower frequency convex or microconvex transducer to initially locate the adrenal gland and then use a higher frequency linear-array transducer for further examination. The highest frequency that will penetrate to the adrenal region should be used, and a 10- to 18-MHz transducer can often be used on small dogs and cats. The adrenal glands are usually evaluated with a 7.5-MHz transducer or higher frequency, depending on the animal’s body size. Sellon, in Small Animal Diagnostic Ultrasound (Fourth Edition), 2021 Examination technique

Hormones produced by adrenal gland