PMC4589868_01
MRI Findings. (A) Baseline: left, transversal FLAIR image; right, transverse T1-weighted image. A 1.1x0.9x1.0-cm gadolinium-enhancing lesion in the right upper cerebral peduncle with perifocal edema is shown. (B) Follow-up MRI after 4 months: left, only a slightly smaller right red nucleus compared to the left, and a small hyperintensity in the area of the right substantia nigra indicating discrete residual changes on T2-weighted imaging; right, complete remission on contrast-enhanced T1-weighted MRI. (C) DaT-SPECT 5 months after symptom onset shows nearly absent DaT binding in the right striatum. Abbreviations: DaT-SPECT, Dopamine Transporter Single-photon Emission Computed Tomography; FLAIR, Fluid-attenuated Inversion Recovery; MRI, Magnetic Resonance Imaging.
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Magnetic resonance imaging (MRI) of the brain revealed a single gadolinium-enhancing lesion in the right upper cerebral peduncle extending rostrally to the thalamus, which led to an inflammatory demyelinating process being suspected (Figure 1A). Follow-up MRI taken 1 month earlier (Figure 1B) had shown almost complete remission of the lesion; a slightly smaller red nucleus on the right side and a small hyperintense area in the right substantia nigra were the only discrete residual changes on T2-weighted imaging. To further explore the discrepancy between her persistent clinical symptoms and nearly normal MRI, we performed dopamine transporter single-photon emission computed tomography (DaT-SPECT) with 123I-ioflupane and found nearly absent DaT binding in the right striatum compatible with ipsilateral nigrostriatal pathway disconnection (Figure 1C).