"The majority (~95%) of adrenal adenomas are non-functioning, in which case they are asymptomatic. If found incidentally, please refer to the Management of incidental adrenal masses: American College of Radiology white paper."
"attenuation measurements should have an ROI covering two-thirds of the lesion and excluding calcifications and the periphery of the lesion to avoid volume averaging 18"
"be aware that HCC and RCC may contain intracellular fat and, therefore, their metastasis may mimic adenoma 12"
"be aware that HCC and RCC may contain intracellular fat and, therefore, their metastasis may mimic adenoma 12"
Expected headings
"Associations"
"General"
"External links"
"macroscopic fat: rare; seen in lipomatous metaplasia 22"
"Chemical shift imaging is the most reliable for diagnosis, especially when CT findings are equivocal. Because of the high sensitivity of chemical shift, MR imaging to minute amounts of intravoxel (i.e. intracellular) fat, MR imaging demonstrates signal dropout on opposed-phase images in the majority of adenomas, and a drop in signal intensity of >16.5% is considered diagnostic for an adenoma 17,18. Rather than measuring the signal, one can compare the adenoma in and out of phase, with images windowed identically; a visible loss of signal is diagnostic of an adenoma 17,18. Do not use the liver as a reference, as it can change in signal between in- and out-of-phase imaging, depending on the presence of haemochromatosis or hepatic steatosis 4."
"Surgical resection is recommended if an adrenal lesion increased in size by ≥5 mm and ≥20% in maximum diameter, or if there is growth not meeting this threshold; ongoing imaging surveillance is recommended 24."
"For lipid-poor lesions, the contrast washout rate can be calculated using CT adrenals. Adenomas typically have rapid contrast washout, whereas non-adenomas tend to wash out more slowly. There are different protocols, and some controversy exists as to which protocol is the best. A 5 or 10-minute protocol may be more suitable for busy CT lists. However, there is evidence that a 15-minute post-contrast protocol has better diagnostic accuracy 11."