Scintigraphic evaluation of clinically silent adrenal masses.
We studied 229 patients with abnormal adrenal anatomy depicted by CT who were without biochemical evidence of endocrine dysfunction using the presence of 131I-6 beta-iodomethyl-nor-cholesterol (NP-59) adrenal gland uptake as an index of differential adrenal function in the evaluation of the clinically "silent" adrenal mass lesion.


METHODS
NP-59 (1 mCi) was injected intravenously with posterior and lateral abdominal images obtained 5-7 days postinjection.


RESULTS
One-hundred and fifty-nine of 185 patients with unilateral adrenal enlargement on CT had scintigraphic evidence that the mass represented a functioning (NP-59 avid) but not hypersecretory, (biochemically normal) adrenal cortical adenoma (concordant imaging pattern). Forty-one of 44 patients with intra-adrenal neoplasms were depicted on scintigraphy as decreased or absent NP-59 accumulation on the side of the adrenal mass (discordant imaging pattern). In this study, sensitivity was 71% (41 of 58 patients; 95% confidence interval (CI), 58% to 88%); specificity was 100% (171 of 171 patients; 95% CI, 95% to 100%) and accuracy was 93% (212 of 229 patients; 95% CI, 88% to 96%).


CONCLUSIONS
These data confirm our earlier observations that the functional information depicted by scintigraphy complements the morphological evaluation by CT and in the absence of hormonal dysfunction, the presence of concordant CT and 131I-NP-59 scans are characteristic of functioning, but not hypersecretory, benign adrenocortical adenomas. Conversely, discordant CT and 131I-NP-59 scans are suggestive of nonfunctioning, space-occupying, adrenal lesions.
Department of Internal Medicine, University of Michigan, Ann Arbor.
M D
MD
Gross
B
B
Shapiro
I R
IR
Francis
G M
GM
Glazer
R L
RL
Bree
M A
MA
Arcomano
D E
DE
Schteingart
M K
MK
McLeod
J A
JA
Sanfield
N W
NW
Thompson
D000236:Adenoma / Q000000981:diagnostic imaging; D000293:Adolescent; D000301:Adosterol; D000310:Adrenal Gland Neoplasms / Q000000981:diagnostic imaging*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed
D000301:Adosterol