Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Headache after cerebral angiography is frequent but has received little attention. The purpose of this study was to evaluate the incidence and risk factors of headache after cerebral angiography. This study also addressed the predisposing factors that facilitate headache recovery. ⋯ The incidence of headache after DSA was 55.6%. Patients with a previous history of headaches, cerebrovascular disease, or a college education may have a higher risk of developing post-DSA headaches than do those without such history. Headache recovery may be associated with a patient history of diabetes or cerebrovascular disease.
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The aim of this study was to evaluate the differences in dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) perfusion estimates of high-grade brain gliomas (HGG) due to the use of an input function (IF) obtained respectively from arterial (AIF) and venous (VIF) approaches by two different commercially available software applications. ⋯ Direct comparison of DCE-MRI measurements with IF generated by means of arterial or venous waveform led to no statistical difference in quantitative metrics for evaluating HGG. However, additional research involving DCE-MRI acquisition protocols and post-processing would be beneficial to further substantiate the effectiveness of venous approach as the IF method compared with arterial-based IF measurement.
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Brain masking of MRI images separates brain from surrounding tissue and its accuracy is important for further imaging analyses. We implemented a new brain masking technique based on multi-atlas brain segmentation (MABS) and compared MABS to masks generated using FreeSurfer (FS; version 5.3), Brain Extraction Tool (BET), and Brainwash, using manually defined masks (MM) as the gold standard. We further determined the effect of different masking techniques on cortical and subcortical volumes generated by FreeSurfer. ⋯ Brain masks generated using FreeSurfer, BET, and Brainwash are rapidly obtained, but are less accurate than manually defined masks. Masks generated using MABS, in contrast, resemble more closely the gold standard of manual masking, thereby offering a rapid and viable alternative.
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The aim of this study was to investigate the characteristic pattern of age-related cortical thinning in patients with Down Syndrome (DS), as assessed by MRI and automatic cortical thickness measurements. ⋯ Our findings showed that Down Syndrome subjects are affected by a diffuse cortical thinning. The involvement of cortical structures can be observed at an earlier age than previous studies have reported.
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Meta Analysis
A Meta-Analysis of fMRI Activation Differences during Episodic Memory in Alzheimer's Disease and Mild Cognitive Impairment.
Functional MRI (fMRI) has the potential to be used as a tool to detect biomarkers related to classifying Alzheimer's disease (AD) and its prodromal stage, mild cognitive impairment (MCI). Previous meta-analyses suggest that during episodic memory tasks, MCI patients exhibit hyperactivation in the medial temporal lobe (MTL) while AD patients exhibit hypoactivation, compared to healthy older adults (HOAs). However, these previous studies have methodological weaknesses that limit the generalizability of the results. ⋯ Additionally, the HOA sample showed more activation in the right hippocampus compared to the AD sample. The MCI studies showed greater activation in the cerebellum compared to the HOA sample, potentially indicating a compensatory mechanism for verbal encoding. MTL hypoactivation in the AD sample is consistent with previous studies, but more evidence of MCI hyperactivation is needed before considering MTL activation as an early biomarker for the AD disease process.