MR Microscopy of the Human Eye at 7.1 T and Correlation with Histopathology – Proof of Principle

Abstract

Objective: Magnetic resonance imaging (MRI) at 1.5 and 3.0 Tesla with small surface coils is a well-established procedure in the diagnosis of masses of the eye and orbital cavity. Until now histological examination has been required to obtain definitive information on tumor extent or possible infiltration of surrounding structures. With ultra-high-field MRI, however, it is possible to evaluate tumor morphology as well as possible extension into surrounding structures with submillimeter spatial resolution.

Materials and Methods: We present a female patient with a uveal melanoma who underwent a preoperative MRI at 1.5 T (spatial resolution = 0.9 x 0.9 x 4 mm/voxel). Postoperatively, the enucleated specimen was examined in a 7.1 Tesla high-field MRI scanner (slice thickness = 500 µm, matrix size = 512 x 512 pixels, spatial resolution = 78 x 78 x 500 µm/voxel, acquisition time = 8:20 min per plane). Finally, the specimen was examined histologically, and the histological and MRI results were correlated.

Results: Ultra-high-field MRI at 7.1 Tesla visualized the uveal melanoma and anatomical structures of the bulb with high resolution, enabling definitive assessment of tumor morphology and extent. Subsequent histological examination confirmed the MRI findings regarding origin, internal structure, and extent of the tumor.

Conclusion: MR microscopy correlates strongly with histology, suggesting that this new imaging modality has the potential for noninvasively assessing tumor morphology, extent, and infiltration of surrounding structures. The examination was performed ex vivo and demonstrates that diagnostic assessment of malignant masses is feasible using high-resolution MR microscopy.

KEYWORDS::

• MRI
• MR-Microscopy
• Eye
• Orbit
• Melanoma

ACKNOWLEDGMENTS

The study was supported by the German Federal Ministry of Education and Research (BMBF; Grant No. 0314107 and REMEDIS) as well as in part by the German Science Foundation (DFG; Transregio 37, Micro- and Nanosystems in Medicine − Reconstruction of Biological Functions).

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.