Journal of neuroimaging : official journal of the American Society of Neuroimaging
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With conventional magnetic resonance imaging (MRI), 20-30% of patients with temporal lobe epilepsy (TLE) have negative pathological MRI findings. Further investigations of the role of magnetic resonance spectroscopy (MRS) in the pre-surgical evaluation of patients with MRI-negative TLE are important to avoid intracranial EEG recording and to better understand the mechanism of the epileptogenic process. This study aimed to compare the measurements of N-acetylaspartate (NAA), creatine (Cr), and choline (Cho) in the hippocampi of MRI-negative TLE patients and normal subjects. ⋯ In MRI-negative TLE, significant reductions in the NAA/Cr and NAA/(Cr+Cho) ratios ipsilateral to the seizure side may help lateralize and localize the epileptogenic zone.
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The phenomenon known as neural flow coupling (NFC) occurs at the capillary level where there are no known pressure controlling structures. Recent developments in advanced magnetic resonance imaging technologies have made possible in vivo direct investigations of water physiology that have shed new insight on the water dynamics of the cortical pericapillary space and their complex functionality in relation to NFC. Neural activities initiate a chain of events that ultimately affect NFC. ⋯ Reduction of pericapillary water pressure results in a negative balance between pericapillary and intraluminal capillary pressure, allowing for capillary caliber expansion. Proton permeability through the tight junctions of the blood brain barrier is significantly high owing to the Grotthuss proton "tunneling" mechanism and, therefore, carbonic anhydrase (CA) type IV (CA-IV) anchored to the luminal surface of brain capillaries functions as scavenger of extracellular protons. CA-IV inhibition by acetazolamide or carbon dioxide results in the accumulation of extracellular protons, causing AQP-4 inhibition and a secondary increase in rCBF.
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Though still debated, early reperfusion is increasingly used as a biomarker for clinical outcome. However, the lack of a standard definition hinders the assessment of reperfusion therapies and study comparisons. The objective was to determine the optimal early reperfusion criteria that predicts clinical outcome in ischemic stroke. ⋯ TTP and Tmax should be preferred to MTT in defining early reperfusion. GBTM provided a clinically relevant reperfusion classification that does not require prespecified delay thresholds or clinical outcomes.
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Susceptibility weighted imaging and assessment of intratumoral susceptibility signal (ITSS) morphology is used to identify high-grade glioma (HGG) in patients with suspected brain neoplasm. ⋯ Our findings indicate that ITSS-morphology is not a random phenomenon. Location of GB, as well as tumor volume, appear to be factors contributing to ITSS morphology.
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To determine if patients with relapsing-remitting multiple sclerosis (RRMS) have a reduced brain stem cross-sectional area (CSA) compared to age- and sex-matched controls. The brain stem is a common site of involvement in MS. However, relatively few imaging studies have investigated brain stem atrophy. ⋯ A significantly reduced, normalized brain stem CSA was detected in all areas of the brain stem of the RRMS patients, when compared to age- and gender-matched controls. Lack of detectable upper cervical cord atrophy in the same patients suggests some independence of the MS pathology in these regions.