Adrenal adenomas: characteristic hyperintense rim sign on fat-saturated spin-echo MR images.
OBJECTIVE
To determine whether adrenal adenomas can be differentiated from metastases on fat-saturated magnetic resonance (MR) images.


METHODS
Twenty-eight adrenal adenomas and 20 metastatic lesions were imaged at 1.5 T by means of fat-saturated T1- and T2-weighted and gadolinium-enhanced T1-weighted sequences. The authors evaluated visually whether structures of high signal intensity (hyperintense rim sign) could be observed in the outer margin of the adrenal masses.


RESULTS
Twenty-six of 28 adrenal adenomas revealed the hyperintense rim sign on at least one kind of fat-saturated image, compared with only one of 20 metastases. The sensitivity of the hyperintense rim sign as suggestive of adrenal adenoma was 92%, specificity was 95%, and overall accuracy was 94%.


CONCLUSIONS
The hyperintense rim sign is characteristic of adrenal adenomas. Thus, adrenal adenomas can be differentiated from metastases by means of this new imaging sign on fat-saturated MR images.
Ichikawa
T
T
Department of Radiology, Yamanashi Medical College, Japan.
Ohtomo
K
K
Uchiyama
G
G
Koizumi
K
K
Monzawa
S
S
Oba
H
H
Nogata
Y
Y
Kachi
K
K
Toyama
K
K
Yamaguchi
M
M
D000306:Adrenal Cortex Neoplasms / Q000175:diagnosis* / Q000453:epidemiology; D000310:Adrenal Gland Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000556:secondary*; D000311:Adrenal Glands / Q000473:pathology*; D018246:Adrenocortical Adenoma / Q000175:diagnosis* / Q000453:epidemiology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012680:Sensitivity and Specificity