Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Comparative Study
Relative FLAIR Signal Intensities over Time in Acute Ischemic Stroke: Comparison of Two Methods.
Visibility of lesions on fluid attenuated inversion recovery (FLAIR) images appears indicative of the time window in acute ischemic stroke. We compared two published methods for calculation of relative FLAIR signal intensities (rSI) regarding their association with time from symptom onset in a longitudinal fashion. ⋯ Both methods show a similar performance, and might be a suitable help for the visual assessment of FLAIR lesion visibility.
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Diffusion tensor imaging (DTI) tractography reconstruction of white matter pathways can help guide brain tumor resection. However, DTI tracts are complex mathematical objects and the validity of tractography-derived information in clinical settings has yet to be fully established. To address this issue, we initiated the DTI Challenge, an international working group of clinicians and scientists whose goal was to provide standardized evaluation of tractography methods for neurosurgery. The purpose of this empirical study was to evaluate different tractography techniques in the first DTI Challenge workshop. ⋯ The DTI Challenge provides a benchmark for the standardized evaluation of tractography methods on neurosurgical data. This study suggests that there are still limitations to the clinical use of tractography for neurosurgical decision making.
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This study assesses whether magnetization transfer (MT) imaging provides additive information to conventional MRI in brain tumors. ⋯ MTR and qMT imaging enables a better differentiation between brain tumors and provides additive information to MRI.
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Ultrasonographic measurement of optic nerve sheath diameter (ONSD) can successfully be used to estimate intracranial pressure (ICP) elevation. Its utility in corroboration of brain death (BD) was herein studied. ⋯ ONSD is significantly greater in subjects with BD. However, quantification of ONSD cannot discriminate BD subjects from comatose ones with raised ICP with 100% certainty.
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Eddy current distortion is an important issue that may influence the quantitative measurements of diffusion tensor imaging (DTI). The corrections of eddy current artifacts could be performed using bipolar diffusion gradients or unipolar gradients with affine registration. Whether the diffusion pulse sequence affects the quantification of DTI indices and the technique that produces more reliable DTI indices in terms of reproducibility both remain unclear. ⋯ The results revealed that the reproducibility and mean values of DTI indices were significantly affected by the pulse sequence. Unipolar DTI exhibited significantly higher reproducibility than bipolar DTI even at the same TE, and the mean values of DTI indices were significantly different between them. Therefore, we concluded that the reproducibility and mean values of DTI indices were significantly influenced by diffusion pulse sequences.