Journal of magnetic resonance imaging : JMRI
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J Magn Reson Imaging · Jun 2016
Viscoelastic shear properties of in vivo thigh muscles measured by MR elastography.
To measure the viscoelastic properties of passive thigh muscles using multifrequency magnetic resonance elastography (MMRE) and rheological models. ⋯ MMRE tests associated with data processing demonstrated that the complex shear modulus G(ω) of passive muscles could be analyzed using two rheological models. The viscoelastic data can be used as a reference for future assessment of muscular dysfunction. J. Magn. Reson. Imaging 2015. J. Magn. Reson. Imaging 2016;43:1423-1433.
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To assess arterial visibility on 4D time-of-flight (4D-TOF) by temporal magnetization transfer contrast pulse (t-MTC) and temporal tilted optimized nonsaturating excitation (t-TONE). 3D-TOF magnetic resonance angiography (MRA) is used for the noninvasive assessment of the intracranial arteries. However, it does not provide temporal information for diagnosing hemodynamics. To noninvasively obtain more detailed hemodynamics-related information, we developed a novel time-resolved MRA without the arterial spin labeling technique, termed 4D-TOF MRA using saturation pulse. ⋯ 4D-TOF with t-TONE and t-MTC enabled observation of the intracranial hemodynamics. Optimized 4D-TOF provides high-quality images without image subtraction, and good visibility of the intracranial arteries even in the prolonged observation time. J. Magn. Reson. Imaging 2016;43:1320-1326.
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J Magn Reson Imaging · May 2016
Evaluation of optimized breath-hold and free-breathing 3D ultrashort echo time contrast agent-free MRI of the human lung.
To evaluate an optimized stack of radials ultrashort echo time (UTE) 3D magnetic resonance imaging (MRI) sequence for breath-hold and free-breathing imaging of the human lung. ⋯ The optimized 3D stack of radials trajectory was shown to provide high-quality MR images of the lung parenchyma without the use of MRI contrast agents. The sequence may offer the possibility of breath-hold imaging and provides greater flexibility in trading off slice thickness and parallel imaging for scan time.
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J Magn Reson Imaging · May 2016
Age-related changes in aortic 3D blood flow velocities and wall shear stress: Implications for the identification of altered hemodynamics in patients with aortic valve disease.
To investigate age-related changes in peak systolic aortic 3D velocity and wall shear stress (WSS) in healthy controls and to investigate the importance of age-matching for 3D mapping of abnormal aortic hemodynamics in bicuspid aortic valve disease (BAV). ⋯ Significant correlations exist between age and peak systolic velocity and WSS. Therefore, robust age-matching is important when creating abnormal 3D aortic velocity and WSS maps for patients with BAV.
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J Magn Reson Imaging · May 2016
Quantification of liver perfusion using multidelay pseudocontinuous arterial spin labeling.
To develop a free-breathing multidelay pseudocontinuous arterial spin labeling (pCASL) technique for quantitative measurement of liver perfusion of the hepatic artery and portal vein, respectively. ⋯ The liver perfusion measurement using multidelay pCASL showed good correspondence with values noted in the literature. The capability to noninvasively and selectively label the hepatic artery and portal vein is a unique strength of pCASL as compared to other liver perfusion imaging techniques, such as computed tomography perfusion and dynamic contrast-enhanced MRI.