Normal Thickness of the Adrenal Gland in Computed Tomography in the Iranian Adult Population

Abstract

Background: The morphology and size of the adrenal glands are influenced by various pathological and physiological conditions. Establishing normal gland dimensions is therefore clinically important. Objectives: This study aimed to determine the normal thickness of the adrenal glands using computed tomography (CT) in an Iranian adult population. Method: This cross-sectional analytical study was conducted at Imam Khomeini Hospital, Tehran, Iran, in 2020. A total of 500 adult patients undergoing non-contrast abdominal CT scans over the course of one year were included, excluding those with clinical or radiological evidence of adrenal pathology. Measurements included maximum adrenal thickness, lateral and medial limb thickness, and long-axis thickness. An independent samples t-test was used to compare measurements between the left and right adrenal glands. Results: Among the 500 evaluated cases, the mean ± standard deviation (SD) thickness of the right adrenal gland was 6.40 ± 1.05 mm, and that of the left adrenal gland was 6.21 ± 1.12 mm (P = 0.001), indicating that the right gland was significantly larger. The mean thickness of the right lateral limb was 4.23 ± 0.87 mm, compared to 3.61 ± 0.83 mm on the left (P = 0.001). Similarly, the mean thickness of the right medial limb was 3.91 ± 0.85 mm, greater than the left at 3.68 ± 0.89 mm (P = 0.001). All measurements were also significantly greater in males than in females. Conclusions: This study provides reference values for the normal thickness of the right and left adrenal glands in an adult Iranian population. These measurements may serve as a useful comparative standard in the assessment of adrenal abnormalities in clinical practice.