Simultaneous correction of ghost and geometric distortion artifacts in EPI using a multiecho reference scan

Schmithorst, Vince; Dardzinski, Bernard J.; Holland, Scott K.

doi:10.1109/42.929619

Cited by 188 publications

(159 citation statements)

References 10 publications

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“…Any residual distortion due to gradient eddy currents was corrected for by co-registering the diffusion-weighted images to the FLAIR-EPI scan with no diffusion weighting using a Levenberg-Marquardt iterative least-squares algorithm. Geometric distortion due to B 0 inhomogeneity was corrected for using a multi-echo reference scan (Schmithorst, et al 2001). …”

Section: Methodsmentioning

confidence: 99%

Cognitive functions correlate with white matter architecture in a normal pediatric population: A diffusion tensor MRI study

Schmithorst¹,

Wilke²,

Dardzinski³

et al. 2005

Human Brain Mapping

364

233

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A possible relationship between cognitive abilities and white matter structure as assessed by magnetic resonance diffusion tensor imaging (DTI) was investigated in the pediatric population. DTI was performed on 47 normal children ages 5–18. Using a voxelwise analysis technique, the fractional anisotropy (FA) and mean diffusivity (MD) were tested for significant correlations with Wechsler full‐scale IQ scores, with subject age and gender used as covariates. Regions displaying significant positive correlations of IQ scores with FA were found bilaterally in white matter association areas, including frontal and occipito‐parietal areas. No regions were found exhibiting correlations of IQ with MD except for one frontal area significantly overlapping a region containing a significant correlation with FA. The positive direction of the correlation with FA is the same as that found previously with age, and indicates a positive relationship between fiber organization and/or density with cognitive function. The results are consistent with the hypothesis that regionally specific increased fiber organization is a mechanism responsible for the normal development of white matter tracts. Hum Brain Mapp, 2005. © 2005 Wiley‐Liss, Inc.

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Section: Methodsmentioning

confidence: 99%

Cognitive functions correlate with white matter architecture in a normal pediatric population: A diffusion tensor MRI study

Schmithorst¹,

Wilke²,

Dardzinski³

et al. 2005

Human Brain Mapping

364

233

View full text Add to dashboard Cite

show abstract

“…Finally, a high-resolution T1-weighted threedimensional anatomical scan was obtained using a modified driven equilibrium For all data, the fMRI image postprocessing was performed using software developed in the IRC in the IDL software environment (IDL 6.3; Research Systems Inc., Boulder, CO, USA). Geometric distortion due to B0 field inhomogeneity was corrected for during reconstruction using a multi-echo reference scan [45]. Next, data were first co-registered and motion corrected using a pyramid iterative algorithm [46].…”

Section: Functional Mrimentioning

confidence: 99%

Comprehensive presurgical functional MRI language evaluation in adult patients with epilepsy

Szaflarski

Holland

Jacola

et al. 2008

Epilepsy & Behavior

112

137

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Functional magnetic resonance imaging (fMRI) has the potential to replace the intracarotid amobarbital procedure (IAP) in presurgical evaluation of patients with epilepsy patients. In this study, we compared fMRI verb generation (VG) and semantic decision/tone decision (SDTD) tasks and the IAP in their ability to localize language functions in patients with epilepsy undergoing presurgical evaluation. We enrolled 50 healthy controls to establish normal language activation patterns for VG and SDTD tasks at 3 or 4 T, and to design language regions of interest (ROIs) that were later applied to 38 patients with epilepsy (28 of 38 also underwent the IAP). We calculated laterality indices (LIs) for each task for each subject based on the ROIs, and we used general linear modeling to analyze the fMRI data. All healthy and epileptic subjects activated language areas with both fMRI tasks. We found significant correlations in language lateralization between the fMRI tasks (r = 0.495, P ≤ 0.001) and between VG and IAP (r = 0.652, P < 0.001) and SDTD and IAP (r = 0.735, P < 0.001). The differences in LIs between SDTD and VG tasks were small and not affected by age, gender, epilepsy status, handedness, or performance. SDTD and VG tasks combined explained approximately 58.4% in the variability of the IAP/language. In the general linear modeling, only the SDTD task significantly contributed to the determination of language lateralization in patients with epilepsy undergoing presurgical evaluation. Results indicate a moderate convergent validity between both fMRI language tasks and between IAP and fMRI tasks. The results of this study indicate that either of these fMRI tasks can be used for language lateralization in patients with epilepsy undergoing presurgical evaluation, but that the SDTD task is likely to provide more information regarding language lateralization than the VG task.

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“…The EPI images were corrected for geometrical distortion and Nyquist ghost artifacts using the multi-echo reference method (Schmithorst et al, 2001). The reconstructed EPI data were corrected for drift using quadratic baseline correction on a pixel-by-pixel basis (Hu et al, 1995;Le & Hu, 1996), co-registered to further reduce the effects of motion artifacts (Thevenaz & Unser, 1998), and transformed into Talairach coordinates (Talairach & Tournoux, 1988) using a linear affine transformation shown previously to be valid for individuals 5 to 18 years of age (Muzik & Chugani, 2000;Wilke et al, 2002).…”

Section: Fmri Data Acquisition and Analysesmentioning

confidence: 99%

Long-term neural processing of attention following early childhood traumatic brain injury: fMRI and neurobehavioral outcomes

Kramer

Chiu

Walz

et al. 2008

J Inter Neuropsych Soc

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Attentional deficits are common and significant sequelae of pediatric traumatic brain injury (TBI). However, little is known about how the underlying neural processes that support different components of attention are affected. The present study examined brain activation patterns using f MRI in a group of young children who sustained a TBI in early childhood (n 5 5; mean age 5 9.4), and a group of age-matched control children with orthopedic injuries (OI) (n 5 8) during a continuous performance task (CPT). Four children in the TBI group had moderate injuries, and one had a severe injury. Performance on the CPT task did not differ between groups. Both TBI and OI children activated similar networks of brain regions relevant to sustained attention processing, but the TBI group demonstrated several areas of significantly greater activation relative to controls, including frontal and parietal regions. These findings of over-activation of the relevant attention network in the TBI group contrast with those obtained in imaging studies of Attention-Deficit0Hyperactivity Disorder where under-activation of the attention network has been documented. This study provides evidence that young children's brains function differently following a traumatic brain injury, and that these differences persist for years after the injury. (JINS, 2008, 14, 424-435.)

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Simultaneous correction of ghost and geometric distortion artifacts in EPI using a multiecho reference scan

Cited by 188 publications

References 10 publications

Cognitive functions correlate with white matter architecture in a normal pediatric population: A diffusion tensor MRI study

Cognitive functions correlate with white matter architecture in a normal pediatric population: A diffusion tensor MRI study

Comprehensive presurgical functional MRI language evaluation in adult patients with epilepsy

Long-term neural processing of attention following early childhood traumatic brain injury: fMRI and neurobehavioral outcomes

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