ECHOPLANAR MR-IMAGING FOR CHARACTERIZATION OF ADRENAL MASSES IN PATIENTS WITH MALIGNANT NEOPLASMS - PRELIMINARY EVALUATION OF CALCULATED T2RELAXATION VALUES

OBJECTIVE. We undertook this study to assess the utility of echoplanar MR imaging for distinguishing benign from malignant adrenal masses in patients with known malignant neoplasms. MATERIALS AND METHODS. Thirt y consecutive patients with 31 adrenal masses and a known malignant ne oplasm underwent breath-hold echoplanar MR imaging with a repetition t ime of 6000 msec and four echo times (40, 80, 120, 160 msec) on a 1.5- T unit before biopsy. Subsequently, 10 masses were shown to be maligna nt at histologic examination, 12 masses were benign at histologic exam ination, and nine were thought to be benign because they had not chang ed in size at follow-up imaging, Mean lesion size was 2.4 +/- 2.1 cm, T2 calculations using regions of interest in the liver and adrenal mas s were performed in each patient. RESULTS. The mean calculated 12 valu e of benign adrenal masses was 70.3 msec (SD, 11.6 msec) versus 104.6 msec (SD, 35.2 msec) for malignant adrenal masses (p = .013), Using a cutoff T2 value of 84 msec, 19 (90%) of 21 benign masses and nine (90% ) of 10 malignant masses were correctly classified, The mean adrenal/l iver T2 ratio was 1.4 (SD, 0.25) for benign lesions, and 2.1 (SD, 0.78 ) for malignant lesions (p = .017). Using a cutoff ratio of 1.60, 19 ( 90%) of 21 benign lesions and eight (80%) of 10 malignant lesions woul d have been correctly classified. CONCLUSION. This preliminary work su ggests that obtaining T2 calculations from echoplanar MR images of adr enal masses is a useful technique for distinguishing benign from malig nant adrenal masses in patients at risk for adrenal metastasis.