Pathways Linked to Internuclear Ophthalmoplegia on Diffusion-Tensor Imaging in a Case with Midbrain Infarction

Background: Midbrain infarction shows diverse patterns of ophthalmoplegia; however, the association of ophthalmoplegia with a precise microanatomy has not been fully studied. Here, we report a patient with characteristic ophthalmoplegia and explore the associated pathologic fiber tracts using diffusion-tensor imaging (DTI). Methods: A 21-year-old woman with an 11-year history of mixed connective tissue disease (MCTD) abruptly developed bilateral internuclear ophthalmoplegia (INO) with upward gaze and convergence palsies. Plasma levels of U1-ribonucleoprotein, double-stranded-DNA antibodies, and cerebrospinal fluid interleukin-6 were all increased. Diffusion-weighted imaging showed an acute ischemic lesion in the periaqueductal gray matter. Results: DTI exhibited a reduction of fractional anisotropy and an increase of apparent diffusion coefficient values in the tract involving the left medial longitudinal fasciculus (MLF) in the midbrain to the posterior commissure (PC) when compared to the right-sided tract in the midbrain and to the bilateral MLF in the upper pontine levels. Antiplatelet and immunosuppressant therapies dramatically improved her symptoms. Conclusions: We believe this is the first case of a patient with juvenile MCTD presenting with bilateral INO with an upward gaze and convergence palsies caused by midbrain infarction associated with vasculitis. It is suggested that DTI might identify the pathologic fiber tract connecting the left MLF in the midbrain to the PC.