Characterization of orbital masses by diffusion-weighted Magnetic Resonance Imaging (DWI) and Apparent Diffusion Coefficient (ADC) value

Abstract

ObjectiveTo assess DWI and ADC value in characterization of orbital masses (differentiation of benign, inflammatory and malignant orbital masses). Patients & methodsCross-sectional study included 38 patients, and diagnosed histopathologically, clinically and radiologically 26 with benign and inflammatory masses and 12 with malignant masses. Their ages ranged from 15 to 63 years. They were examined using 1.5T MR machine. ResultsThere was a significant difference in ADC value of malignant and benign orbital masses. Malignant masses have a lower ADC values and restricted diffusion, compared with benign masses. Using 0.93×10−3mm2/s as a cutoff value, in differentiating malignant from benign lesions, resulted in a total of 80% sensitivity, 83.3% specificity and 82% accuracy. Lesions with ADC values less than 0.87×10−3mm2/s, had 90% likely to be of malignant nature. Lesions with ADC greater than 1.1×10−3mm2/s, had 90% likely to be of benign nature. In between these two values, lesions are indeterminate. ConclusionDiffusion weighted imaging with ADC value, can help in differentiating malignant from benign orbital masses. Malignant orbital masses have a significant lower ADC value than benign masses. We can use ADC cutoff value between malignant and benign masses.