Diffusion-weighted MR imaging in assessment of primary adrenal tumors at 3.0 T

Objective:To evaluate the value of diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC) at 3.0 T MR in primary adrenal tumors.Materials and Methods:DWI images of 48 patients with primary adrenal tumors proved by surgical pathology were retrospectively reviewed.ADC values of tumors were statistically analyzed.Results:The mean ADC value of neoplasms were listed below:ganglioneuromas (n=5), 1.948±0.357×10-3 mm2/s; benign pheochromocytomas (n=7, including 1 case with bilateral tumor), 1.666±0.547×10-3 mm2/s; cortical adenomas (n=21), 1.434±0.430×10-3 mm2/s; primary adrenal malignant tumors(n=8, including 7 adrenal cortical carcinomas and 1 malignant pheochromocytoma), 0.951±0.144×10-3 mm2/s; myelolipomas (n=7), 0.764±0.209×10-3 mm2/s.Except myelolipomas, given ADC value of 1.08×10-3 mm2/s as a threshold for diagnosing primary adrenal malignant tumor, the sensitivity, specificity and accuracy were 87.50%, 85.29% and 85.71%, respectively.There were significant differences between primary adrenal tumors and ganglioneuromas, benign pheochromocytomas and cortical adenomas (P=0.003, 0.006 and 0.001, respectively).However, no statistic difference was found between primary adrenal malignant tumors and myelolipomas.Conclusion:3.0 T MR DWI could be used in diagnosis of primary adrenal tumors, and ADC value might be helpful in differentiating the adrenal pathology.