Quantitative characterization of extraocular orbital lesions in children using diffusion-weighted imaging

Background Diffusion-weighted imaging (DWI) has been shown to be helpful in providing information about cellular density and also predicting the histological features of aggressive tumors. Several studies have evaluated this technique for orbital tumors. However, very few articles have focused exclusively on evaluating pediatric orbital masses and, within those, only a small number of patients were included in the study. Objective This study aimed to evaluate the use of DWI and apparent diffusion coefficient (ADC) values to differentiate between benign and malignant extraocular orbital lesions in children. Materials and methods This retrospective study included 73 patients under the age of 18 seen in our hospital between October 2016 and February 2019. The extraocular orbital lesions were evaluated clinically and radiologically using DWI. The diagnosis was confirmed by either histological examination (after biopsy or surgery) or based on clinical and radiologic evaluation. Results The malignant lesions were found to have increased diffusion restriction in comparison to the benign lesions. The ADC values of the malignant lesions were significantly lower (P<0.0001). The use of a cutoff value of 0.99x10(-3) mm(2)/s allowed for the differentiation of the benign lesions and malignant lesions with a sensitivity of 75% and a specificity of 100% while the cutoff point of 1.26x10(-3) mm(2)/s had a sensitivity of 100% and a specificity of 73%. Conclusion Measurement of ADC in extraocular orbital lesions in children may help differentiate malignant lesions from benign lesions.