Abstract
Introduction Although myelin oligodendrocyte glycoprotein associated disease (MOGAD) has well described spinal cord MRI features, the utility of diffusion-weighted imaging in acute MOGAD is not clear. Here we describe a case of MOGAD with true restricted diffusion on spinal cord MRI and consider therapeutic and prognostic implications.
Case A 45-year-old man presented with acute urinary retention and over several days developed predominantly complete paraplegia and anaesthesia below T4 level with acute and severe sphincter dysfunction. Two weeks prior he had upper respiratory tract infection symptoms. An admission MRI spine demonstrated longitudinally extensive transverse myelitis from C3-C7 and T1-T10. Serum MOG antibodies were confirmed using a live cell-based assay. He was treated with pulsed intravenous methylprednisolone followed by a slow oral steroid taper, plasma exchange, IVIg, and rituximab. A repeat scan 4 weeks from onset, whilst our patient remained paraplegic, showed patchy foci of true diffusion restriction (hyperintense on diffusion-weighted imaging and hypointense apparent diffusion coefficient) from T6-T8 without contrast enhancement. Six months later he has no clinical or radiological evidence of disease relapse and can walk short distances independently, although has residual sphincter dysfunction.
Conclusions Restriction on diffusion-weighted imaging may reflect a greater degree of acute inflammation, and thus potentially be useful as a prognostic marker in MOGAD. We review the scant literature on diffusion restriction in longitudinally extensive traverse myelitis, and in neuroinflammatory conditions more broadly, and consider implications for guiding proactive immunotherapy regimes at disease onset.
