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Your search keyword '"Noseworthy, Michael D."' showing total 25 results
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25 results on '"Noseworthy, Michael D."'

3. Non‐invasive MR imaging techniques for measuring femoral arterial flow in a pediatric and adolescent cohort

Author

Caterini, Jessica E., primary, Rendall, Kate, additional, Cifra, Barbara, additional, Schneiderman, Jane E., additional, Ratjen, Felix, additional, Seed, Mike, additional, Rayner, Tammy, additional, Weiss, Ruth, additional, McCrindle, Brian W., additional, Noseworthy, Michael D., additional, Williams, Craig A., additional, Barker, Alan R., additional, and Wells, Gregory D., additional

Published
2022
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4. Amyloid‐independent vascular contributions to cortical atrophy and cognition in a multi‐center mixed cohort with low to severe small vessel disease

Author

Ottoy, Julie, primary, Ozzoude, Miracle, additional, Zukotynski, Katherine, additional, Adamo, Sabrina M., additional, Scott, Christopher J. M., additional, Gaudet, Vincent, additional, Ramirez, Joel, additional, Swardfager, Walter, additional, Lam, Benjamin, additional, Bhan, Aparna, additional, Kiss, Alex, additional, Strother, Stephen C., additional, Bocti, Christian, additional, Borrie, Michael, additional, Chertkow, Howard, additional, Frayne, Richard, additional, Hsiung, Ging‐Yuek Robin, additional, Laforce, Robert, additional, Noseworthy, Michael D., additional, Prato, Frank S., additional, Sahlas, Demetrios J., additional, Smith, Eric E., additional, Sossi, Vesna, additional, Thiel, Alexander, additional, Soucy, Jean‐Paul, additional, Tardif, Jean‐Claude, additional, Goubran, Maged, additional, and Black, Sandra E., additional

Published
2021
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24. An approach to evaluation of the point-spread function for 23 Na magnetic resonance imaging.

Author

Polak P, Schulte RF, and Noseworthy MD

Subjects
Computer Simulation, Humans, Phantoms, Imaging, Signal-To-Noise Ratio, Sodium Isotopes, Magnetic Resonance Imaging methods
Abstract

Despite the technical challenges that require lengthy acquisitions to overcome poor signal-to-noise ratio (SNR), sodium ( 23 Na) magnetic resonance imaging (MRI) is an intriguing area of research due to its essential role in human metabolism. Low SNR images can impact the measurement of the point-spread function (PSF) by adding uncertainty into the resulting quantities. Here, we present methods to calculate the PSF by using the modulation transfer function (MTF), and a 3D-printed line-pair phantom in the context of 23 Na MRI. A simulation study investigated the effect of noise on the resulting MTF curves, which were derived by direct modulation (DM) and a method utilizing Fourier harmonics (FHs). Experimental data utilized a line-pair phantom with nine spatial frequencies, filled with different concentrations (15, 30, and 60 mM) of sodium in 3% agar. MTF curves were calculated using both methods from data acquired from density-adapted 3D radial projections (DA-3DRP) and Fermat looped orthogonally encoded trajectories (FLORET). Simulations indicated that the DM method increased variability in the MTF curves at all tested noise levels over the FH method. For the experimental data, the FH method resulted in PSFs with a narrower full width half maximum with reduced variability, although the improvement in variability was not as pronounced as predicted by simulations. The DA-3DRP data indicated an improvement in the PSF over FLORET. It was concluded that a 3D-printed line-pair phantom represents a convenient method to measure the PSF experimentally. The MTFs from the noisy images in 23 Na MRI have reduced variability from a FH method over DM., (© 2021 John Wiley & Sons, Ltd.)

Published
2022
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25. Dynamic 31 P spectroscopic imaging of skeletal muscles combining flyback echo-planar spectroscopic imaging and compressed sensing.

Author

Santos-Díaz A, Harasym D, and Noseworthy MD

Subjects
Adult, Female, Humans, Leg physiology, Male, Muscle, Skeletal metabolism, Signal Processing, Computer-Assisted, Young Adult, Echo-Planar Imaging methods, Exercise physiology, Muscle, Skeletal diagnostic imaging, Phosphorus Isotopes chemistry
Abstract

Purpose: Dynamic phosphorus MR spectroscopic imaging ( 31 P-MRSI) experiments require temporal resolution on the order of seconds to concurrently assess different muscle groups. A highly accelerated pulse sequence combining flyback echo-planar spectroscopic imaging (EPSI) and compressed sensing was developed and tested in a phantom and healthy humans during an exercise-recovery challenge of the lower leg muscles, using a clinical 3T MRI., Methods: A flyback EPSI readout designed to achieve 2.25 × 2.25 cm 2 resolution over a 18 × 18 cm 2 field of view (i.e., 8 × 8 matrix) was combined with compressed sensing through the inclusion of pseudorandom gradient blips to sub-sample the ky-kt dimensions by a factor of 2.7×, achieving a temporal resolution of 9 s. The sequence was first tested in a phantom to assess performance compared to fully sampled EPSI (fidEPSI) and phase encoded chemical shift imaging (fidCSI). Then, tests were performed in 11 healthy volunteers during an exercise-recovery challenge of the lower leg muscles. Voxels containing tissue from different muscle groups were evaluated measuring percentage phosphocreatine (%PCr) depletion, time constant of PCr recovery (τPCr) and intracellular pH at rest and following exercise., Results: The sequence was capable to track the dynamic PCr response of multiple muscles simultaneously. No statistical differences were found in the metabolite ratio, pH or linewidth when compared with fidEPSI and fidCSI in the phantom study. Dynamic experiments showed differences in PCr depletion when comparing soleus with gastrocnemius muscles. Intracellular pH, τPCr and %PCr decrease were consistent with reported values., Conclusion: Highly accelerated 31 P-MRSI combining flyback EPSI and compressed sensing is capable of assessing concurrent energy metabolism in multiple muscle groups using a clinical 3T MR system., (© 2019 International Society for Magnetic Resonance in Medicine.)

Published
2019
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