Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Vascular aspects like global cerebral hypoperfusion are frequently reported in patients with multiple sclerosis (MS). Although mechanistic question remains unanswered, this hemodynamic impairment may be caused by a widespread endothelial dysfunction. Furthermore, impaired cerebrovascular reactivity (CVR) has been described in patients with MS by means of hypercapnic perfusion magnetic resonance imaging (MRI). We sought to further evaluate potential hemodynamic restriction in patients with MS using functional sonographic methods. ⋯ These preliminary sonographic findings appear to independently corroborate the previously reported observation of impaired CVR on brain MRI in patients with MS. However, the underlying pathophysiological mechanisms as well as the clinical impact of this observation remain elusive.
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We hypothesized that vessel wall MR imaging (VWI) with 3D-time-of-flight magnetic resonance imaging (3D-TOF-MRA) together increases the ability to detect abnormal intracranial vessel segments compared to 3D-TOF-MRA alone. ⋯ 3D-TOF-MRA and VWI together identifies a higher number of abnormal vessel segments than 3D-TOF-MRA alone and may provide a more accurate assessment of disease burden.
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In vivo detection of β-amyloid (Aβ) plaques in Alzheimer's disease (AD) is now possible with 11 C-PiB positron emission tomography (PET). Conventionally, a cortical:cerebellar PiB uptake ratio threshold of 1.4-1.5 has been used to categorize at-risk subjects as "amyloid-positive" and "amyloid-negative." It has been suggested that this threshold is too conservative and may miss early amyloid pathology. We investigated the relationship between conventional and lower baseline 11 C-PiB PET thresholds for raised amyloid load and the subsequent clinical and radiological progression of mild cognitive impairment (MCI) cases longitudinally. ⋯ Use of a PiB SUVR threshold of >1.5 for raised amyloid missed 14.3% of MCI cases who likely had Thal stage 1 or 2 pathology and showed a progressive amyloid increase over 2 years. Lowering the threshold for abnormality to 1.3 abolished all false negatives but resulted in 75% of HCs being falsely diagnosed as raised amyloid subjects.
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Tuberous sclerosis complex (TSC) is a rare, genetic disease that is associated with multiple manifestations including epilepsy and autism. Self-injurious behaviors (SIBs) also occur in a subset of patients. This study used diffusion tensor imaging (DTI) in children with TSC for quantitative and volumetric analysis of brain regions that have been associated with SIB in other genetic conditions. ⋯ These data support a correlation between lower volumes of the globus pallidus and caudate with SIB in children with TSC.
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Periventricular nodular heterotopias (PNHs) are frequently associated with drug-resistant epilepsy (DRE). Although magnetic resonance imaging (MRI) can define the morphological features of PNHs, still there is a need to assess their metabolic activity in order to provide useful information on epileptogenicity and long-term outcome. To that end, we investigated the ability of 18 F-FDG PET to identify seizure onset zone in order to assess the metabolic activity of the ectopic neurons and to provide prognostic information on the postsurgical outcome. ⋯ In PNHs-related epilepsy, FDG-PET more accurately identifies epileptogenic foci, which aids surgical planning and in postoperative seizure control.