Adrenal lesions with heterogeneous suppression on chemical shift imaging: Clinical implications

Purpose To investigate the frequency and significance of adrenal lesions that demonstrate heterogeneous suppression on chemical shift magnetic resonance imaging (MRI). Materials and Methods A retrospective search of adrenal lesions identified on MR from November 1997–July 2001 was performed. The adrenal lesions were classified as having suppression typical for an adenoma, nonsuppression, or atypical heterogeneous suppression. Lesions with heterogeneous suppression were further reviewed. Follow‐up for the heterogeneous lesions consisted of imaging studies or pathology from surgical excision. Results Adrenal lesions were identified in 242 patients. Heterogeneously suppressing lesions were seen in 34 (14%) patients. Several different patterns of heterogeneous suppression were identified. Imaging or pathologic follow‐up was available for 18 of the heterogeneously suppressing lesions (one patient had both). Fifteen patients with follow‐up imaging showed stability of the lesion over a significant interval, suggesting a benign lesion. Pathology was available for four patients revealing two patients with adenomas and two patients with nodular hyperplasia. Thus, all 18 patients with heterogeneous suppression had a benign lesion. Conclusion Adrenal lesions that have a heterogeneous pattern of suppression on out‐of‐phase chemical shift MR images are a common finding. Our small series suggest that these lesions are probably benign. J. Magn. Reson. Imaging 2004;19:308–316. © 2004 Wiley‐Liss, Inc.