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Arterial Spin Labeling

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David C Alsop – 1st expert on this subject based on the ideXlab platform

  • volumetric measurement of perfusion and Arterial transit delay using hadamard encoded continuous Arterial Spin Labeling
    Magnetic Resonance in Medicine, 2013
    Co-Authors: Ajit Shankaranarayanan, David C Alsop

    Abstract:

    Creating images of the transit delay from the Labeling location to image tissue can aid the optimization and quantification of Arterial Spin Labeling perfusion measurements and may provide diagnostic information independent of perfusion. Unfortunately, measuring transit delay requires acquiring a series of images with different Labeling timing that adds to the time cost and increases the noise of the Arterial Spin Labeling study. Here, we implement and evaluate a proposed Hadamard encoding of Labeling that speeds the imaging and improves the signal-to-noise ratio efficiency. Volumetric images in human volunteers confirmed the theoretical advantages of Hadamard encoding over sequential acquisition of images with multiple Labeling timing. Perfusion images calculated from Hadamard encoded acquisition had reduced signal-to-noise ratio relative to a dedicated perfusion acquisition with either assumed or separately measured transit delays, however. Magn Reson Med 69:1014–1022, 2013. © 2012 Wiley Periodicals, Inc.

  • Arterial Spin Labeling mr imaging of renal masses correlation with histopathologic findings
    Radiology, 2012
    Co-Authors: R S Lanzman, David C Alsop, Philip M Robson, Amish D Patel, Kimiknu Mentore, Andrew A Wagner, Elizabeth M Genega, Neil M Rofsky, Ivan Pedrosa

    Abstract:

    Arterial SpinLabeling MR imaging might contribute substantially to the noninvasive assessment of renal tumors and offer complementary results to percutaneous biopsy, particularly in those patients with inconclusive results.

  • optimization of background suppression for Arterial Spin Labeling perfusion imaging
    Magnetic Resonance Materials in Physics Biology and Medicine, 2012
    Co-Authors: Nasim Maleki, David C Alsop

    Abstract:

    Object
    To present an algorithm for optimization of background suppression pulse timing for Arterial Spin Labeling (ASL) perfusion imaging.

John A. Detre – 2nd expert on this subject based on the ideXlab platform

  • Temporal and Spatial Variances in Arterial SpinLabeling Are Inversely Related to Large-Artery Blood Velocity.
    American Journal of Neuroradiology, 2017
    Co-Authors: Andrew D. Robertson, G. Matta, V.s. Basile, Sandra E. Black, Christopher K. Macgowan, John A. Detre, Bradley J. Macintosh

    Abstract:

    BACKGROUND AND PURPOSE: The relationship between extracranial large-artery characteristics and Arterial SpinLabeling MR imaging may influence the quality of Arterial SpinLabeling–CBF images for older adults with and without vascular pathology. We hypothesized that extracranial Arterial blood velocity can explain between-person differences in Arterial SpinLabeling data systematically across clinical populations. MATERIALS AND METHODS: We performed consecutive pseudocontinuous Arterial SpinLabeling and phase-contrast MR imaging on 82 individuals (20–88 years of age, 50% women), including healthy young adults, healthy older adults, and older adults with cerebral small vessel disease or chronic stroke infarcts. We examined associations between extracranial phase-contrast hemodynamics and intracranial Arterial SpinLabeling characteristics, which were defined by Labeling efficiency, temporal signal-to-noise ratio, and spatial coefficient of variation. RESULTS: Large-artery blood velocity was inversely associated with Labeling efficiency ( P = .007), temporal SNR ( P P = .05) of Arterial SpinLabeling, after accounting for age, sex, and group. Correction for Labeling efficiency on an individual basis led to additional group differences in GM-CBF compared to correction using a constant Labeling efficiency. CONCLUSIONS: Between-subject Arterial SpinLabeling variance was partially explained by extracranial velocity but not cross-sectional area. Choosing Arterial SpinLabeling timing parameters with on-line knowledge of blood velocity may improve CBF quantification.

  • Arterial Spin Labeling mri clinical applications in the brain
    Journal of Magnetic Resonance Imaging, 2015
    Co-Authors: Nicholas A Telischak, John A. Detre, Greg Zaharchuk

    Abstract:

    : Visualization of cerebral blood flow (CBF) has become an important part of neuroimaging for a wide range of diseases. Arterial Spin Labeling (ASL) perfusion magnetic resonance imaging (MRI) sequences are increasingly being used to provide MR-based CBF quantification without the need for contrast administration, and can be obtained in conjunction with a structural MRI study. ASL MRI is useful for evaluating cerebrovascular disease including arterio-occlusive disease, vascular shunts, for assessing primary and secondary malignancy, and as a biomarker for neuronal metabolism in other disorders such as seizures and neurodegeneration. In this review we briefly outline the various ASL techniques including advantages and disadvantages of each, methodology for clinical interpretation, and clinical applications with specific examples.

  • Comparison of Arterial transit times estimated using Arterial Spin Labeling
    Magnetic Resonance Materials in Physics Biology and Medicine, 2011
    Co-Authors: Yufen Chen, Danny J.j. Wang, John A. Detre

    Abstract:

    Objective
    To compare Arterial transit time estimates from two efficient transit time mapping techniques using Arterial Spin Labeling (ASL)—flow encoded Arterial Spin tagging (FEAST) and Look-Locker ASL (LL-ASL). The effects of bipolar gradients and label location were investigated.

Peter Jezzard – 3rd expert on this subject based on the ideXlab platform

  • Vessel-encoded dynamic magnetic resonance angiography using Arterial Spin Labeling.
    Magnetic resonance in medicine, 2010
    Co-Authors: Thomas W Okell, Matthias Günther, Michael A Chappell, Mark W Woolrich, David A Feinberg, Peter Jezzard

    Abstract:

    A new noninvasive MRI method for vessel selective angiography is presented. The technique combines vessel-encoded pseudocontinuous Arterial Spin Labeling with a two-dimensional dynamic angiographic readout and was used to image the cerebral arteries in healthy volunteers. Time-of-flight angiograms were also acquired prior to vessel-selective dynamic angiography acquisitions in axial, coronal, and/or sagittal planes, using a 3-T MRI scanner. The latter consisted of a vessel-encoded pseudocontinuous Arterial Spin Labeling pulse train of 300 or 1000 ms followed by a two-dimensional thick-slab flow-compensated fast low angle shot readout combined with a segmented Look-Locker sampling strategy (temporal resolution = 55 ms). Selective Labeling was performed at the level of the neck to generate individual angiograms for both right and left internal carotid and vertebral arteries. Individual vessel angiograms were reconstructed using a bayesian inference method. The vessel-selective dynamic angiograms obtained were consistent with the time-of-flight images, and the longer of the two vessel-encoded pseudocontinuous Arterial Spin Labeling pulse train durations tested (1000 ms) was found to give better distal vessel visibility. This technique provides highly selective angiograms quickly and noninvasively that could potentially be used in place of intra-Arterial x-ray angiography for larger vessels.

  • Vessel‐encoded dynamic magnetic resonance angiography using Arterial Spin Labeling
    Magnetic Resonance in Medicine, 2010
    Co-Authors: Thomas W Okell, Matthias Günther, Michael A Chappell, Mark W Woolrich, David A Feinberg, Peter Jezzard

    Abstract:

    A new noninvasive MRI method for vessel selective angiography is presented. The technique combines vessel-encoded pseudocontinuous Arterial Spin Labeling with a two-dimensional dynamic angiographic readout and was used to image the cerebral arteries in healthy volunteers. Time-of-flight angiograms were also acquired prior to vessel-selective dynamic angiography acquisitions in axial, coronal, and/or sagittal planes, using a 3-T MRI scanner. The latter consisted of a vessel-encoded pseudocontinuous Arterial Spin Labeling pulse train of 300 or 1000 ms followed by a two-dimensional thick-slab flow-compensated fast low angle shot readout combined with a segmented Look-Locker sampling strategy (temporal resolution = 55 ms). Selective Labeling was performed at the level of the neck to generate individual angiograms for both right and left internal carotid and vertebral arteries. Individual vessel angiograms were reconstructed using a bayesian inference method. The vessel-selective dynamic angiograms obtained were consistent with the time-of-flight images, and the longer of the two vessel-encoded pseudocontinuous Arterial Spin Labeling pulse train durations tested (1000 ms) was found to give better distal vessel visibility. This technique provides highly selective angiograms quickly and noninvasively that could potentially be used in place of intra-Arterial x-ray angiography for larger vessels. Magn Reson Med, 2010. © 2010 Wiley-Liss, Inc.

  • assessment of Arterial arrival times derived from multiple inversion time pulsed Arterial Spin Labeling mri
    Magnetic Resonance in Medicine, 2010
    Co-Authors: Bradley J. Macintosh, Michael A Chappell, Mark W Woolrich, Nicola Filippini, Clare E Mackay, Peter Jezzard

    Abstract:

    The purpose of this study was to establish a normal range for the Arterial arrival time (AAT) in whole-brain pulsed Arterial Spin Labeling (PASL) cerebral perfusion MRI. Healthy volunteers (N = 36, range: 20 to 35 years) provided informed consent to participate in this study. AAT was assessed in multiple brain regions, using three-dimensional gradient and Spin echo (GRASE) pulsed Arterial Spin Labeling at 3.0 T, and found to be 641 ± 95, 804 ± 91, 802 ± 126, and 935 ± 108 ms in the temporal, parietal, frontal, and occipital lobes, respectively. Mean gray matter AAT was found to be 694 ± 89 ms for females (N = 15), which was significantly shorter than for men, 814 ± 192 ms (N = 21; P < 0.0003), and significant after correcting for brain volume (P < 0.001). Significant AAT sex differences were also found using voxelwise permutation testing. An atlas of AAT values across the healthy brain is presented here and may be useful for future experiments that aim to quantify cerebral blood flow from ASL data, as well as for clinical comparisons where disease pathology may lead to altered AAT. Pulsed Arterial Spin Labeling signals were simulated using an identical sampling scheme as the empiric study and revealed AAT can be estimated robustly when simulated arrival times are well beyond the normal range. Magn Reson Med, 2010. © 2010 Wiley-Liss, Inc.