Role of New Magnetic Resonance Imaging Modalities in Diagnosis of Orbital Masses: A Clinicopathologic Correlation

PURPOSE: To evaluate the role of diffusion-weighted magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (MRS) in the diagnosis of different orbital masses and their advantages over conventional MRI. MATERIALS AND METHODS: The study included 20 patients presenting with proptosis. Every patient was subjected to thorough clinical examination, conventional MRI “T1 weighted, T2 weighted, and postcontrast T1 weighted if needed,” diffusion-weighted MRI, and proton MRS. Orbitotomy was performed, the orbital mass was excised, and histopathological examination was performed. RESULTS: Diffusion-weighted MRI could differentiate between benign lesions and malignant tumors in 70% of cases; however, overlap occurred in 30% of cases with benign tumors showing restricted diffusion whereas proton MRS could differentiate between benign and malignant tumors in 90% of cases. CONCLUSION: Diffusion-weighted MRI and proton MRS can potentially increase the accuracy of diagnosis of orbital masses through in vivo tissue characterization. Magnetic resonance spectroscopy seems to be the more accurate modality.