Journal of neuroimaging : official journal of the American Society of Neuroimaging
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To determine the sensitivity and specificity of the hyperdense artery sign (HAS) on thin-slice non-contrast computed tomography (NCCT), combined with brief clinical history, as an indicator for large vessel occlusion (LVO) in the setting of acute ischemic stroke. ⋯ The HAS on thin-slice NCCT has a reasonably high sensitivity and specificity for identifying LVO in acute ischemic stroke patients presenting with an NIHSS > 10 and suspected MCA M1 or basilar artery occlusion.
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Human immunodeficiency virus (HIV)-infected patients commonly have abnormalities in cerebral white matter that are visible on magnetic resonance imaging (MRI) as hyperintensities (WMHs). Visual rating scales (VRSs) have been used to quantify WMH in other diseases such as cerebral small vessel disease (CSVD), but not in HIV. Such scales are advantageous because they are applicable to routinely acquired MRIs and so are suitable for large-scale studies and clinical care. We sought to establish the utility of three VRSs (the Fazekas, Scheltens, and van Sweiten scales) in HIV. ⋯ VRSs reliably quantify WMH in HIV-infected individuals and correlate with cognitive impairment. Future studies may find routinely acquired brain MRI quantified by VRS to be an accessible and meaningful neurologic outcome measure in HIV.
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Acetazolamide reactivity on 123 I-IMP SPECT is used to detect misery perfusion due to intracranial atherosclerosis. Noninvasive fractional flow assessed by signal intensity ratio (SIR) on time of flight-magnetic resonance angiography (TOF-MRA) might offer a feasible alternative to identify high-risk intracranial stenosis. ⋯ In patients with unilateral MCA stenosis, decreased SIR was correlated with misery perfusion, providing a simpler, widely available predictor of high-risk intracranial stenosis.
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Perivascular spaces (PVSs), also known as Virchow-Robin spaces, are pial-lined, fluid-filled structures found in characteristic locations throughout the brain. They can become abnormally enlarged or dilated and in rare cases can cause hydrocephalus. ⋯ In addition, various pathologic processes, including cryptococcosis and chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids, can spread into the brain via PVSs, resulting in characteristic magnetic resonance imaging appearances. This review aims to describe the key imaging characteristics of normal and dilated PVSs, as well as cystic mimics and pathologic processes that directly involve PVSs.
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Fluid-attenuated inversion recovery (FLAIR) imaging at 3 Tesla (T) field strength is the most sensitive modality for detecting white matter lesions in multiple sclerosis. While 7T FLAIR is effective in detecting cortical lesions, it has not been fully optimized for visualization of white matter lesions and thus has not been used for delineating lesions in quantitative magnetic resonance imaging (MRI) studies of the normal appearing white matter in multiple sclerosis. Therefore, we aimed to evaluate the sensitivity of 7T magnetization-transfer-weighted (MTw ) images in the detection of white matter lesions compared with 3T-FLAIR. ⋯ Seven-Tesla MTw sequences detected most of the white matter lesions identified by FLAIR at 3T. This suggests that 7T-MTw imaging is a robust alternative for detecting demyelinating lesions in addition to 3T-FLAIR. Future studies need to compare the roles of optimized 7T-FLAIR and of 7T-MTw imaging.