Parallel Magnetic Resonance Imaging

Katscher, Ulrich; Börnert, Peter

doi:10.1016/j.nurt.2007.04.011

Cited by 16 publications

(10 citation statements)

References 93 publications

(136 reference statements)

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“…However, it is doubtful that chemical shift or artifacts from trabecular bone substantially alter lesion detectability in the spinal cord. Parallel imaging has been proposed to reduce scan time and address SAR concerns when there is ample SNR 27. At the time of initiating our study, parallel imaging was unavailable.…”

Section: Discussionmentioning

confidence: 99%

Spinal cord lesions and clinical status in multiple sclerosis: A 1.5 T and 3 T MRI study

Stankiewicz

Neema

Alsop³

et al. 2009

Journal of the Neurological Sciences

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Objective Assess the relationship between spinal cord T2 hyperintense lesions and clinical status in multiple sclerosis (MS) with 1.5 and 3T MRI. Methods Whole cord T2-weighted fast spin-echo MRI was performed in 32 MS patients [Expanded Disability Status Scale (EDSS) score (mean±SD: 2±1.9), range 0–6.5]. Protocols at 1.5T and 3T were optimized and matched on voxel size. Results Moderate correlations were found between whole cord lesion volume and EDSS score at 1.5T (rs =.36, p=0.04), but not at 3T (rs =0.13, p=0.46). Pyramidal Functional System Score (FSS) correlated with thoracic T2 lesion number (rs=.46, p=0.01) and total spinal cord lesion number (rs=0.37, p=0.04) and volume (rs=0.37, p=0.04) at 1.5T. Bowel/bladder FSS correlated with T2 lesion volume and number in the cervical, thoracic, and total spine at 1.5T (rs 0.400.57, all p<0.05). These MRI-FSS correlations were non-significant at 3T. However, these correlation coefficients did not differ significantly between platforms (Choi’s test p>0.05). Correlations between whole cord lesion volume and timed 25-foot walk were non-significant at 1.5T and 3T (p>0.05). Lesion number and volume did not differ between MRI platforms in the MS group (p>0.05). Conclusions Despite the use of higher field MRI strength, the link between spinal lesions and MS disability remains weak. The 1.5T and 3T protocols yielded similar results for many comparisons.

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Section: Discussionmentioning

confidence: 99%

Spinal cord lesions and clinical status in multiple sclerosis: A 1.5 T and 3 T MRI study

Stankiewicz

Neema

Alsop³

et al. 2009

Journal of the Neurological Sciences

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“…Equation (5) states that the hybrid signal received by coil j is a linear combination of k space partial derivatives of hybrid signal received with uniform sensitivity and vice versa…”

Section: Theory Iia K Space Derivatives Theoremmentioning

confidence: 99%

Derivative encoding for parallel magnetic resonance imaging

Shen

2011

Med. Phys.

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Purpose: To introduce a linear shift-invariant relationship between the partial derivatives of k space signals acquired using multichannel receive coils and to demonstrate that k space derivatives can be used for image unwrapping. Methods: Fourier transform of k space derivatives contains information on the spatial origins of aliased pixels; therefore, images can be reconstructed by k space derivatives. Fully sampled phantom and brain images acquired at 3 T using a standard eight channel receive coil were used to validate the k space derivatives theorem by unwrapping aliased images. Results: Derivative encoding leads to new methods for parallel imaging reconstruction in both k space and image domains. Noise amplification in sensitivity encoding image reconstruction, which is considered to produce the optimal SNR, can be further reduced using k space derivative encoding without making any assumptions on the characteristics of the images to be reconstructed. Conclusions: This work demonstrated that the partial derivative of the k space signal acquired from one coil with respect to one direction can be expressed as a sum of partial derivatives of signals from multiple coils with respect to the perpendicular k space direction(s). This relationship between the partial derivatives of k space signals is linear and shift-invariant in the Cartesian coordinate system.

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“…Advances are being made in phased array head coil technology that enable parallel imaging with an increasing number of receiver elements (see review article by Katscher et al 101 ). For example, 12-to 16-channel head coils are becoming readily available for use with most contemporary scanning systems.…”

Section: Parallel Imaging With Large-n Array Head Coilsmentioning

confidence: 99%

Advances in Functional Magnetic Resonance Imaging: Technology and Clinical Applications

Dickerson

2007

Neurotherapeutics

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Summary:Functional MRI (fMRI) is a valuable method for use by clinical investigators to study task-related brain activation in patients with neurological or neuropsychiatric illness. Despite the relative infancy of the field, the rapid adoption of this functional neuroimaging technology has resulted from, among other factors, its ready availability, its relatively high spatial and temporal resolution, and its safety as a noninvasive imaging tool that enables multiple repeated scans over the course of a longitudinal study, and thus may lend itself well as a measure in clinical drug trials. Investigators have used fMRI to identify abnormal functional brain activity during task performance in a variety of patient populations, including those with neurodegenerative, demyelinating, cerebrovascular, and other neurological disorders that highlight the potential utility of fMRI in both basic and clinical spheres of research. In addition, fMRI studies reveal processes related to neuroplasticity, including compensatory hyperactivation, which may be a universally-occurring, adaptive neural response to insult. Functional MRI is being used to study the modulatory effects of genetic risk factors for neurological disease on brain activation; it is being applied to differential diagnosis, as a predictive biomarker of disease course, and as a means to identify neural correlates of neurotherapeutic interventions. Technological advances are rapidly occurring that should provide new applications for fMRI, including improved spatial resolution, which promises to reveal novel insights into the function of fine-scale neural circuitry of the human brain in health and disease.

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Parallel Magnetic Resonance Imaging

Cited by 16 publications

References 93 publications

Spinal cord lesions and clinical status in multiple sclerosis: A 1.5 T and 3 T MRI study

Spinal cord lesions and clinical status in multiple sclerosis: A 1.5 T and 3 T MRI study

Derivative encoding for parallel magnetic resonance imaging

Advances in Functional Magnetic Resonance Imaging: Technology and Clinical Applications

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