Quantitative CT evaluation of adrenal gland masses: a step forward in the differentiation between adenomas and nonadenomas?
OBJECTIVE
To assess the attenuation of the adrenal gland with computed tomography (CT) before and after multiple phases of contrast enhancement in both control subjects and patients with adenomas and nonadenomas.


METHODS
Seventy-two patients with 78 adrenal masses (41 adenomas, 37 nonadenomas) underwent helical CT. Forty subjects served as controls. Unenhanced CT was performed followed by enhanced CT at 30, 60, 90, and 180 seconds and 30 minutes.


RESULTS
At unenhanced CT, mean attenuation was 4 HU +/- 16 for adenomas compared with 37 HU +/- 12 for the nonadenomas (P < .001) and 24 HU +/- 3 for normal glands. Although the mean attenuation of nonademonas was significantly greater than that of adenomas on 60- and 90-second scans (P < .001), there was greater overlap in attenuation of the adenomas and nonadenomas than on unenhanced images. At 180 seconds, nonadenomas had higher attenuation than adenomas (73 HU +/- 17 vs 41 HU +/- 18; P < .001). At 30 minutes, all adenomas had attenuation less than 37 HU, whereas all nonadenomas had attenuation greater than 41 HU.


CONCLUSIONS
Delayed-enhanced CT scans obtained 30 minutes after administration of contrast material can enable differentiation of adenomas and nonadenomas.
Szolar
D H
DH
Department of Radiology, Karl-Franzens Medical School, Graz, Austria.
Kammerhuber
F
F
D000236:Adenoma / Q000000981:diagnostic imaging*; D000293:Adolescent; D000310:Adrenal Gland Neoplasms / Q000000981:diagnostic imaging*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed