Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Transient global amnesia (TGA) is a rare clinical entity with a sudden onset of anterograde amnesia that recovers within 24 hours. The underlying pathophysiology is uncertain. Imaging studies are controversial, but diffusion-weighted images often show small diffusion-restricted lesions in the hippocampus, which may suggest ischemic damage. Thus, we conducted the first clinical study using neurite orientation dispersion and density imaging (NODDI) and arterial spin labeling (ASL) to examine whether the microstructure and perfusion status of the hippocampus are influenced by the presence of diffusion-restricted lesions. ⋯ The first NODDI and ASL study in patients after TGA demonstrated no obvious microstructural or perfusion abnormalities in the hippocampus with typical DWI-positive lesions, which may indicate that TGA does not cause destructive damage or involve baseline microstructure or perfusion abnormalities in the hippocampus in relation to diffusion-restricted lesions.
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Although transcranial Doppler detects microembolic signals (MES) in numerous settings, the practical significance of such findings remains unclear. ⋯ MES may help to risk stratify patients as their presence is associated with ischemic recurrence and worse outcomes.
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Susceptibility-Weighted 3T MRI of the Swallow Tail Sign in Multiple Sclerosis: A Case Control Study.
The swallow tail sign describes the physiological appearance of nigrosome-1 within the substantia nigra on high-resolution transverse susceptibility-weighted imaging (SWI). Previous studies demonstrated its absence in Parkinson's disease due to increasing iron content. In multiple sclerosis (MS), increased iron accumulation can be found in the brain tissue including the substantia nigra. ⋯ The finding of an abnormal swallow tail sign in MS patients may provide an additional imaging marker even in early MS development.
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Cerebrovascular disease is a common comorbidity in older adults, typically assessed in terms of white matter hyperintensities (WMHs) on MRI. While it is well known that WMHs exacerbate cognitive symptoms, the exact relation of WMHs with cognitive performance and other degenerative diseases is unknown. Furthermore, based on location, WMHs are often classified into periventricular and deep WMHs and are believed to have different pathological origins. ⋯ Of note, more associations were detected between cognitive performance and deep WMHs than between cognitive performance and periventricular WMHs. Mechanistically, both deep and periventricular WMHs were associated with increased MD. Both deep and periventricular WMHs were also associated with reduced CBF in the gray matter.
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Blood-derived monocytes/macrophages can be labeled with ultrasmall superparamagnetic iron oxides (USPIO) at periphery and subsequently migrate into areas of inflammation in the brain. We investigated temporal pattern of migration of peripheral immune cells in Theiler's murine encephalomyelitis virus (TMEV) model of chronic demyelination by USPIO-enhanced imaging. ⋯ Serial USPIO imaging is a promising biomarker for investigating the effect of therapeutic interventions on monocytes/macrophages and microglia activation and neurodegeneration in TMEV-infected animals.