Role of new magnetic resonance imaging modalities in diagnosis of orbital masses: a clinicopathologic correlation

ABSTRACT

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. The study included 20 patients presenting with proptosis. Every patient was subjected to thorough clinical examination, conventional MRI [Tl weighted, T2 weighted, and postcontrast Tl weighted if needed,] diffusion-weighted MRI, and proton MRS. Orbitotomy was performed, the orbital mass was excised, and histopathological examination was performed. 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. 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