Journal of neuroimaging : official journal of the American Society of Neuroimaging
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We investigated the effects of aging, white matter hyperintensities (WMH), and cognitive impairment on brain iron levels and cerebral oxygen metabolism, known to be altered in Alzheimer's disease (AD), using quantitative susceptibility mapping and MR-based cerebral oxygen extraction fraction (OEF). ⋯ Higher brain OEF and χn in cognitively impaired older individuals may reflect altered oxygen metabolism and iron in areas with underlying AD pathology. Both age and WMH have associations with OEF and χn but are modified by the presence of cognitive impairment.
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This study aims to investigate the feasibility of a "real-time" estimate of the optimal CT perfusion (CTP) acquisition time (Top ) in ischemic stroke patients. ⋯ The linear correlation between Top and the VOF time to peak is well suited to implement a new technique to automatically customize the patient's CTP acquisition time. The method does not require an additional dose of contrast medium and does not increase the overall study time, so its use would be desirable to decrease the average radiation dose.
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Magnetic resonance elastography to study the effect of amyloid plaque accumulation in a mouse model.
Biomechanical changes in the brain have not been fully elucidated in Alzheimer's disease (AD). We aimed to investigate the effect of β-amyloid accumulation on mouse brain viscoelasticity. ⋯ Aging had region-specific effects on cerebral viscoelasticity, namely, WB softening and hippocampal stiffening. Amyloid plaque deposition may have sex-specific effects, which require further scrutiny.
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Objective diagnosis and prognosis in major depressive disorder (MDD) remains a challenge due to the absence of biomarkers based on physiological parameters or medical tests. Numerous studies have been conducted to identify functional magnetic resonance imaging-based biomarkers of depression that either objectively differentiate patients with depression from healthy subjects, predict personalized treatment outcome, or characterize biological subtypes of depression. While there are some findings of consistent functional biomarkers, there is still lack of robust data acquisition and analysis methodology. ⋯ Novel acquisition techniques, such as multiband and multiecho imaging, and neural network-based cleaning approaches can enhance the signal quality in limbic and frontal regions. More comprehensive analyses, such as directed or dynamic functional features or the identification of biological depression subtypes, can improve objective diagnosis or treatment outcome prediction and mitigate the heterogeneity of MDD. Overall, these improvements in functional MRI imaging techniques, processing, and analysis could advance the search for biomarkers and ultimately aid patients with MDD and their treatment course.
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Review Case Reports
Hirayama disease: Nosological classification and neuroimaging clues for diagnosis.
Hirayama disease (HD) is a rare, benign, and nonprogressive motor neuron disease (MND) affecting the upper limbs. It usually presents with weakness and amyotrophy in a single upper extremity with an insidious onset between adolescence and the third decade of life. Since its description in 1959, HD has been known under several names and eponyms in Europe and in Asian countries probably due to its heterogeneous clinical features. ⋯ Also, we report a case of a 18-year-old boy who presented to our Clinic complaining of muscle weakness of the left distal upper limb without other neurological signs. The cervical MRI, in the neutral position, revealed a high T2 signal intensity in the C5-C7 cervical myelomeres as well as the loss of cervical lordosis, whereas, during neck flexion, it showed the anterior displacement of the posterior dura ad the post-gadolinium T1-weighted imaging enhancement of the posterior epidural plexus. These findings are typical for HD allowing the diagnosis as well as the differential diagnosis from other neuromuscular diseases.