Distinction between benign and malignant adrenal masses: value of T1-weighted chemical-shift MR imaging.
OBJECTIVE
Accuracy of T1-weighted chemical-shift MR imaging for the differentiation between benign and malignant adrenal masses was blindly assessed among three radiologists.


METHODS
MR imaging was performed at 1.5 T in 50 patients with 58 adrenal masses, proved benign (n = 38) or malignant (n = 20) based on surgery or growth (malignant) or stable size (benign) for at least 1 year. In-phase spin-echo sequences or in-phase breath-hold fast multiplanar spoiled gradient-recalled echo (FMPSPGR) sequences with a TE of 4.2 msec were compared with opposed-phase breath-hold FMPSPGR sequences with a TR/TE of 35-155/2.2-2.9 and a 90 degrees flip angle for the detection of lipid in adrenal masses. Three radiologists who were blinded to diagnosis and clinical data independently rated the likelihood of a benign adrenal lesion on a five-point scale of confidence.


RESULTS
Mean sensitivity, specificity, and positive predictive value for a definite or probable diagnosis of a benign lesion by the three readers were 87%, 92%, and 95%, respectively. At the highest (definite) confidence of a benign lesion, the mean positive predictive value was 99%, with lower sensitivity (54%). Areas under receiver operating characteristic curves for the three radiologists were .98 (95% confidence interval [CI] = .94-1.00), .96 (CI = .91-1.00), and .95 (CI = .89-1.00). Interobserver variation for the diagnosis of a benign mass was low (kappa = .79).


CONCLUSIONS
Chemical-shift imaging using breath-hold opposed-phase T1-weighted MR images is a reliable and reproducible technique for the diagnosis of most benign adrenal masses at the highest threshold of confidence.
Outwater
E K
EK
Department of Radiology, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA.
Siegelman
E S
ES
Radecki
P D
PD
Piccoli
C W
CW
Mitchell
D G
DG
D000310:Adrenal Gland Neoplasms / Q000175:diagnosis*; D000328:Adult; D000368:Aged; D016001:Confidence Intervals; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012680:Sensitivity and Specificity