Value of MRI in the differential diagnosis of uveal melanoma and other intraocular masses in adults

Objective To compare MRI findings of uveal melanomas and other intraocular masses in adults and to evaluate the optimal MRI features for the differential diagnosis. Methods The MRI data of 254 patients with intraocular masses confirmed by histopathologic or clinical follow-up results from March 2005 to December 2015 in Beijing Tongren Hospital, Capital Medical University was analyzed retrospectively. A total of 128 patients with uveal melanoma and 126 patients with other intraocular masses were enrolled. MRI findings of the masses including the location, shape, margin, signal intensity on T1WI and T2WI compared to the gray matter and vitreous body, homogeneity and degree of enhancement of the mass, secondary retinal detachment, height, and ratio of basal diameter to height were compared between uveal melanoma and other intraocular masses by χ2 test or independent t test. The logistic regression analysis was performed to identify the most discriminating MRI features. The diagnostic performance of different predictive models was analyzed by receiver operating characteristic (ROC) curve. The model of multiple parameters was established by logistic analysis, and the diagnostic efficacy was evaluated. Results The location, shape, margin, signal intensity on T1WI and T2WI compared to the gray matter and vitreous body, homogeneity and degree of enhancement of the mass, secondary retinal detachment, height and ratio of basal diameter to height were significantly different between the uveal melanoma and other intraocular masses (all P<0.05). The results of logistic regression analysis showed that the signal intensity on T1WI and T2WI compared to the gray matter, height, shape, location, degree of enhancement of the mass, and secondary retinal detachment were associated with higher likelihood of uveal melanoma. The mass with hypointense on T2WI (compared with gray matter) was the best MRI feature in the differential diagnosis of uveal melanoma and other intraocular masses (odds ratio 12.237), with the accuracy of 86.2%. The diagnostic accuracy of low signal on T2WI and high signal on T1WI (compared with gray matter) was significantly higher than those of vitreous (Delong test, P<0.001). The sensitivity, specificity and accuracy of the combination of height, degree of enhancement, T1WI and T2WI signal compared to the gray matter were 90.6%, 92.1% and 96.1%, respectively. The diagnostic performance of combination features was higher than that of each single sign (P<0.001). Conclusion MRI features including the signal intensity on T1WI and T2WI compared to the gray matter, height, shape, degree of enhancement of the mass, and secondary retinal detachment are helpful in the differential diagnosis between uveal melanoma and other intraocular masses. In addition, the gray matter as the reference is superior to the vitreous body in the evaluation of the signal intensity of intraocular masses. Key words: Melanoma; Eye neoplasms; Magnetic resonance imaging; Diagnosis, differential