No abstract available.
Brain*

PURPOSE: To develop a novel approach to calculate the sensitivity profiles of the phased array coil for use in non-uniform intensity correction. MATERIALS AND METHODS: The proposed intensity correction method estimates the sensitivity profile of the coil to extract intensity variations that represent the scanned image. The sensitivity profile is estimated by fitting a non-linear curve to various angles of projections through the imaged object in order to eliminate the high-frequency image content. Filtered back projection is then used to compute the estimates of the sensitivity profile of each coil. The method was applied both to phantom and brain images from 8-channel phased-array coil and 4-channel phased-array coil, respectively. RESULTS: Intensity-corrected images from the proposed method have more uniform intensity than those from the commonly used `sum-of-squares' approach. By using the proposed correction method, the intensity variation was reduced to 6.1% from 13.1%, acquired from the `sum-of-squares'. CONCLUSION: The proposed method is more effective at correcting the intensity non-uniformity of the phased-array surface-coil images than the conventional`sum-of-squares' method.
Brain

PURPOSE: To develop a novel approach to calculate the sensitivity profiles of the phased array coil for use in non-uniform intensity correction. MATERIALS AND METHODS: The proposed intensity correction method estimates the sensitivity profile of the coil to extract intensity variations that represent the scanned image. The sensitivity profile is estimated by fitting a non-linear curve to various angles of projections through the imaged object in order to eliminate the high-frequency image content. Filtered back projection is then used to compute the estimates of the sensitivity profile of each coil. The method was applied both to phantom and brain images from 8-channel phased-array coil and 4-channel phased-array coil, respectively. RESULTS: Intensity-corrected images from the proposed method have more uniform intensity than those from the commonly used `sum-of-squares' approach. By using the proposed correction method, the intensity variation was reduced to 6.1% from 13.1%, acquired from the `sum-of-squares'. CONCLUSION: The proposed method is more effective at correcting the intensity non-uniformity of the phased-array surface-coil images than the conventional`sum-of-squares' method.
Brain

No abstract available.
Brain*

No abstract available.
Brain*

No abstract available.
Brain*

No abstract available.
Brain

No abstract available.
Brain

Introduction: Mitragyna speciosa (Korth.) or kratom is a native medicinal plant of Southeast Asia. Commonly used by hard labours in harsh working environment, the ingestion of brewed kratom decoction is reported to produce dose-dependent stimulant and opioid-like effects. Kratom is also regularly consumed as a pain killer and as traditional cure for common maladies such as fever and cough. However, it remains unknown whether regular consumption of kratom decoction is associated with brain abnormalities in regular users in traditional settings. Methods: A total of 14 subjects (7 regular kratom users and 7 non-kratom users) voluntarily participated in this cross-sectional study. Face-to-face interviews were conducted with kratom users to determine history of kratom use and later these respondents underwent brain magnetic resonance imaging (MRI). Results: There were no significant differences (p>0.05) in the intracranial volume (ICV), cortical volumes (frontal, parietal, temporal, occipital, or cingulate lobe), or subcortical volumes (striatum, hippocampus, or amygdala), as well as in the diffusion tensor imaging (DTI) metrics, fractional anisotropy (FA) and mean diffusivity (MD) between kratom users and the controls. Conclusion: This preliminary study showed long-term consumption of kratom decoction is not significantly associated with altered brain structures in regular kratom users in traditional settings. However, further study is needed to establish more data for kratom use and its effects.
brain

No abstract available.
Brain*