The Value of Diffusion Weighted Magnetic Resonance Imaging in Differentiation of Benign and Malignant Adrenal Lesions

Purpose: Diffusion weighted imaging (DWI) is a functional magnetic resonance imaging (MRI) technique that explores the random motion of water molecules in the body. Although DWI has been widely applied in the evaluation of intracranial disorders, there is growing interest for its use in detection and characterization of abdominal masses. In this study, the efficiency of DWI in distinguishing benign adrenal focal lesions from malignant ones is investigated. Material and Methods: Sixty six adrenal focal lesions in 56 patients were included in the study. The lesions were characterized with dynamic adrenal computed tomography and/or adrenal MRI if there was not a histopathological result or radiological follow up. DWI was performed for these lesions and apparent diffusion coefficient (ADC) values were measured by using three different b values (b=500 sec/mm, b=750 sec/mm, b=1000 sec/mm). Results: The mean ADC values of 39 benign lesions were 1.54 x 10 mm/sec for b=500 sec/mm, 1.01x 10 mm/sec for b=750 sec/mm and 0.77 x 10 mm/sec for b=1000 sec/mm. The mean ADC values of 27 malignant lesions were found to be 1.69x 10 mm/sec, 1.14 x 10 mm/sec and 0.86 x 10 mm/sec for b=500 sec/mm, b=750 sec/mm, b=1000 sec/mm, respectively. There was not any statistically significant difference between ADC values of benign and malignant lesions for all three b values (p<0.05). Conclusion: According to this study, DWI did not seem to be an effective radiological method for differentiating benign and malignant adrenal lesions; but for a more accurate decision, studies with improved and high resolution images, standard technical parameters and larger number of lesions may be needed.