Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Recent studies in rodents suggest that somatosensory stimulation could provide neuroprotection during ischemic stroke by inducing plasticity in the cortex-vasculature relationship. While functional magnetic resonance imaging (fMRI) has shown that somatosensory stimulation increases cerebral blood flow (CBF) over several seconds, subsecond changes in CBF in the basal cerebral arteries have rarely been studied due to temporal resolution limitations. This study characterized hemodynamic changes in the middle cerebral arteries (MCAs) during somatosensory stimulation with high temporal resolution (100 samples/s) using functional transcranial Doppler ultrasound (fTCD). ⋯ Pneumotactile somatosensory stimulation is a potent stimulus that can evoke large, rapid hemodynamic changes, with adaptation between successive stimulus applications. Due to its high temporal resolution, fTCD is useful for identifying quickly evolving hemodynamic responses, and for correlating changes in hemodynamic parameters such as pulsatility index (PI) and CBFV.
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Endovascular therapy (ET) has become the standard of care for selected patients with acute ischemic stroke (AIS) due to large vessel occlusion (LVO). However, many LVO or medium vessel occlusion (MVO) patients are ineligible for ET, including some who harbor salvageable tissues. To develop complementary therapies for these patients, it is important to delineate their prevalence, clinical features, and outcomes. ⋯ Even in the modern stent retriever era, 1 in 6 AIS patients presents with substantial penumbra judged not appropriate for ET. This population may benefit from the development of alternative therapies, including collateral enhancement, neuroprotection, and thrombectomy devices deployable in distal arteries.
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Somatoform pain disorder is characterized by chronic pain and various psychological symptoms including increased attention to mental and physical processes. Given that the medial prefrontal cortex (mPFC) of the default mode network (DMN) and the anterior insula of the salience network are critically involved in intrinsic and attentional processes, we investigated the involvement of these networks during the distraction from physical pain in somatoform pain patients. ⋯ Modulating the FC between the mPFC and the insula may be highly relevant for shifting the attention away from external stimuli, including nociceptive input. The observed alterations in somatoform pain patients may foster new strategies in cognitive behavioral training tools for these patients.
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Computer-based analysis of Dopamine transporter imaging (DaTscan) can aid in image interpretation. In this study, we examined the distribution of putamen-to-caudate ratios (PCRs) obtained by using a clinically available semiquantification method. ⋯ Although PCR can intrinsically be a useful indication of disease, this ratio obtained in our analysis by using one of the clinically available automatic semiquantitative methods has large variability and might not be a reliable numeric marker in interpretation of [I-123]ioflupane studies. This may be due to difficulty in separating caudate from putamen on SPECT images, as well as the nonuniform decreased Ioflupane uptake in both putamen and caudate.
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Previous cross-sectional studies have reported the involvement of thalamus, pallidum, superior cerebellar peduncle, temporal cortex, and fronto-parietal white matter in multiple sclerosis (MS)-related fatigue. However, the longitudinal imaging correlates of fatigue severity variation in MS remain unclear. ⋯ The pallidal volume and the FA-RTC may be used to evaluate longitudinal fatigue severity variation. Our study proposes new biomarkers to monitor fatigue severity in MS patients.