Adrenal adenomas appear as small (<3 cm), well-defined homogeneous masses that are typically hypoattenuating relative to the liver.
At an attenuation value of less than 0 HU at unenhanced<unk> , the diagnosis of an<unk> n be made with 100% confidence; however, this threshold has only 47% sensitivity.
At cutoff of 18 HU, a diagnosis of adenoma was made with 100% specificity and 85% sensitivity, compared to the specificity:sensitivity ratio of 68%:100% with a more conservative cutoff of 10 HU.
A rational approach advocated by some authorities is to choose the<unk>  number threshold on the basis of the patient’s risk for metastatic disease. For example, a threshold of 10 HU could be applied to older patients or to those with known primary malignancies. A threshold of 18 HU could be applied to younger patients without underlying cancer.
Lipid-poor adenomas are more difficult to diagnose because the<unk>  numbers increase and approach those of soft tissue.
Contrast-enhanced imaging with 10-minute-delayed<unk>  scans may be helpful in these cases.
By using a threshold of 30 HU, the sensitivity and specificity for delayed contrast-enhanced<unk>  in the characterization of benign disease are 80% and 100%, respectively.
A relative percentage washout of more than 50% in the delayed study represents a sensitivity and specificity of 98% and 100%, respectively, for the detection of adenoma.
By using a threshold of 30 HU, the sensitivity and specificity for delayed contrast-enhanced<unk>  in the characterization of benign disease are 80% and 100%, respectively.
A relative percentage washout of more than 50% in the delayed study represents a sensitivity and specificity of 98% and 100%, respectively, for the detection of adenoma.
Adenoma CT
Fibroadenoma CT
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Fibroadenoma physical examination
Breast lumps MRI
Fibroadenoma MRI
Acinic cell carcinoma CT
Oral cancer MRI