A serious article analyzing the prevalence of left-sided vs. right-sided adrenal tumors. Prior observations have consistently shown that left-sided adenomas are more common than right-sided ones, in 2:1 ratio.
Although a reason could be embryological, leading to a greater left adrenal vascularity, innervation, volume and mass; authors suggest that asymmetry could also be due to anatomical locations of the glands.
The left adrenal gland is surrounded by the hypo-attenuated visceral fat, making it easier to be seen by imaging, versus the right gland which is somewhat compressed by the relatively hyper-attenuated liver and kidney.
Authors' argument is compelling enough that clinicians should be aware of possibly missing right-sided adrenal tumors, especially in the context of hyper-functionality; elevated catecholamines, cortisol, aldosterone and DHEAs.