Algorithm of Brady et al for Identifying an Adrenal Metastasis in a Patient with Lung Cancer Based on PET/CT Findings

 

Patient selection: adrenal nodules with in a patient with suspected lung cancer

 

Exclusions: adrenal myelolipoma (based on fat content) or size < 7 mm

 

Parameters:

(1) mean CT attenuation in Hounsfield units (HU)

(2) maximum standardized uptake value (SUV) in the adrenal nodule

(3) average SUV in the liver

 

SUV ratio =

= (maximum SUV in the adrenal nodule) / (average SUV in the liver)

Attenuation	Maximum SUV	SUV Ratio	Percent Malignant
< 10 HU	NA	NA	0%
>= 10 HU	<= 3.1	NA	6%
>= 10 HU	> 3.1	<= 2.5	36%
>= 10 HU	> 3.1	> 2.5	100%

 

where:

• A maximum SUV > 9 indicates a malignant tumor.

 

Followup of an indeterminate nodule:

(1) monitoring change in size over time

(2) fine needle aspirate or biopsy