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507 results on '"Noseworthy, Michael D."'

103. Reproducibility of Hyperpolarized 129Xe MRI Ventilation Defect Percent in Severe Asthma to Evaluate Clinical Trial Feasibility.

Author

Svenningsen, Sarah, McIntosh, Marrissa, Ouriadov, Alexei, Matheson, Alexander M, Konyer, Norman B, Eddy, Rachel L, McCormack, David G, Noseworthy, Michael D, Nair, Parameswaran, and Parraga, Grace

Abstract

Rationale and Objectives: 129Xe MRI has been developed to noninvasively visualize and quantify the functional consequence of airway obstruction in asthma. Its widespread application requires evidence of intersite reproducibility and agreement. Our objective was to evaluate reproducibility and agreement of 129Xe ventilation MRI measurements in severe asthmatics at two sites.Materials and Methods: In seven adults with severe asthma, 129Xe ventilation MRI was acquired pre- and post-bronchodilator at two geographic sites within 24-hours. 129Xe MRI signal-to-noise ratio (SNR) was calculated and ventilation abnormalities were quantified as the whole-lung and slice-by-slice ventilation defect percent (VDP). Intraclass correlation coefficients (ICC) and Bland-Altman analysis were used to determine intersite 129Xe VDP reproducibility and agreement.Results: Whole-lung and slice-by-slice 129Xe VDP measured at both sites were correlated and reproducible (pre-bronchodilator: whole-lung ICC = 0.90, p = 0.005, slice-by-slice ICC = 0.78, p < 0.0001; post-bronchodilator: whole-lung ICC = 0.94, p < 0.0001, slice-by-slice ICC = 0.83, p < 0.0001) notwithstanding intersite differences in the 129Xe-dose-equivalent-volume (101 ± 15 mL site 1, 49 ± 6 mL site 2, p < 0.0001), gas-mixture (129Xe/4He site 1; 129Xe/N2 site 2) and SNR (40 ± 19 site 1, 23 ± 5 site 2, p = 0.02). Qualitative 129Xe gas distribution differences were observed between sites and slice-by-slice 129Xe VDP, but not whole-lung 129Xe VDP, was significantly lower at site 1 (pre-bronchodilator VDP: whole-lung bias = -3%, p > 0.99, slice-by-slice bias = -3%, p = 0.0001; post-bronchodilator VDP: whole-lung bias = -2%, p = 0.59, slice-by-slice-bias = -2%, p = 0.0003).Conclusion: 129Xe MRI VDP at two different sites measured within 24-hours in the same severe asthmatics were correlated. Qualitative and quantitative intersite differences in 129Xe regional gas distribution and VDP point to site-specific variability that may be due to differences in gas-mixture composition or SNR. [ABSTRACT FROM AUTHOR]

Published
2021
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104. Cardiovascular risk scoring and magnetic resonance imaging detected subclinical cerebrovascular disease

Author

Anand, Sonia S, primary, Tu, Jack V, primary, Desai, Dipika, primary, Awadalla, Phillip, primary, Robson, Paula, primary, Jacquemont, Sébastien, primary, Dummer, Trevor, primary, Le, Nhu, primary, Parker, Louise, primary, Poirier, Paul, primary, Teo, Koon, primary, Lear, Scott A, primary, Yusuf, Salim, primary, Tardif, Jean-Claude, primary, Marcotte, Francois, primary, Busseuil, David, primary, Després, Jean-Pierre, primary, Black, Sandra E, primary, Kirpalani, Anish, primary, Parraga, Grace, primary, Noseworthy, Michael D, primary, Dick, Alexander, primary, Leipsic, Jonathan, primary, Kelton, David, primary, Vena, Jennifer, primary, Thomas, Melissa, primary, Schulze, Karleen M, primary, Larose, Eric, primary, Moody, Alan R, primary, Smith, Eric E, primary, and Friedrich, Matthias G, primary

Published
2019
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105. Non-Binary Approaches for Classification of Amyloid Brain PET

Author

Zukotvnski, Katherine, primary, Gaudet, Vincent C., additional, Kuo, Phillip, additional, Adamo, Sabrina, additional, Goubran, Maged, additional, Bocti, Christian, additional, Borrie, Michael, additional, Chertkow, Howard, additional, Frayne, Richard, additional, Hsiung, Robin, additional, Laforce, Robert, additional, Noseworthy, Michael D., additional, Prato, Frank S., additional, Sahlas, Jim D., additional, Scott, Christopher, additional, Smith, Eric E., additional, Sossi, Vesna, additional, Thiel, Alex, additional, Soucy, Jean-Paul, additional, Tardif, Jean-Claude, additional, and Black, Sandra E., additional

Published
2019
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111. The Use of Random Forests to Classify Amyloid Brain PET

Author

Zukotynski, Katherine, Gaudet, Vincent, Kuo, Phillip H., Adamo, Sabrina, Goubran, Maged, Scott, Christopher, Bocti, Christian, Borrie, Michael, Chertkow, Howard, Frayne, Richard, Hsiung, Robin, Laforce, Robert, Noseworthy, Michael D., Prato, Frank S., Sahlas, Demetrios J., Smith, Eric E., Sossi, Vesna, Thiel, Alexander, Soucy, Jean-Paul, Tardif, Jean-Claude, and Black, Sandra E.

Published
2024
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112. Recent advances in the detection of brown adipose tissue in adult humans: a review

Author

Ong, Frank J., primary, Ahmed, Basma A., additional, Oreskovich, Stephan M., additional, Blondin, Denis P., additional, Haq, Tahniyah, additional, Konyer, Norman B., additional, Noseworthy, Michael D., additional, Haman, Francois, additional, Carpentier, Andre C., additional, Morrison, Katherine M., additional, and Steinberg, Gregory R., additional

Published
2018
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121. Dynamic 31P spectroscopic imaging of skeletal muscles combining flyback echo‐planar spectroscopic imaging and compressed sensing.

Author

Santos‐Díaz, Alejandro, Harasym, Diana, and Noseworthy, Michael D.

Abstract

Purpose: Dynamic phosphorus MR spectroscopic imaging (31P‐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 cm2 resolution over a 18 × 18 cm2 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 31P‐MRSI combining flyback EPSI and compressed sensing is capable of assessing concurrent energy metabolism in multiple muscle groups using a clinical 3T MR system. [ABSTRACT FROM AUTHOR]

Published
2019
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132. Abstract W MP119: Sensitivity and Reliability of MRI SWI Compared With GRE Sequences for Detecting Microbleeds in a Community Population

Author

Batool, Saima, primary, Patil, Shivanand, additional, Noseworthy, Michael D, additional, O'Donnell, Martin, additional, Sharma, Mukul, additional, Islam, Shofiqul, additional, Teo, Koon, additional, Black, Sandra, additional, Lauzon, M L, additional, McCreary, Cheryl R, additional, Frayne, Richard, additional, DeJesus, Jane, additional, Rangarajan, Sumathy, additional, Yusuf, Salim, additional, and Smith, Eric E, additional

Published
2015
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137. The association among skeletal muscle phosphocreatine recovery, adiposity, and insulin resistance in children.

Author

Wells, Greg D., Banks, Laura, Caterini, Jessica E., Thompson, Sara, Noseworthy, Michael D., Rayner, Tammy, Syme, Catriona, McCrindle, Brian W., and Hamilton, Jill

Subjects
AEROBIC exercises, BODY weight, INSULIN resistance, METABOLISM, CHILDHOOD obesity, PHOSPHOCREATINE, REGRESSION analysis, STATISTICS, DATA analysis, OXIDATIVE stress, AEROBIC capacity, COOLDOWN, CROSS-sectional method, CASE-control method, SKELETAL muscle
Abstract

Background: Obesity is associated with cardiometabolic disturbances, which may have significant implications for musculoskeletal health and exercise tolerance. Objective: We sought to determine the association between muscle structure, function, and metabolism in adolescents across the weight spectrum. Methods: This cross‐sectional case–control study included overweight and obese participants (n = 24) 8–18 years of age with a body mass index (BMI) ≥ 85th percentile for age and gender, and non‐obese participants (n = 24) with a BMI < 85th percentile. Body composition, physical activity, peak aerobic capacity, cardiometabolic blood markers and insulin resistance (measured by the homeostatic model assessment of insulin resistance, HOMA‐IR), skeletal muscle mitochondrial oxidative capacity (via 31Phosphorous‐Magnetic Resonance Spectroscopy, 31P‐MRS, to assess phosphocreatine (PCr) recovery after exercise), and extramyocellular and intramyocellular lipid (IMCL) levels (via 1Hydrogen‐MRS) were assessed. Stepwise regression was performed to examine the factors associated with oxidative capacity. Results: bese and overweight patients had similar age, height, and physical activity to non‐obese controls, but obese and overweight participants exhibited higher insulin resistance. Obese and overweight participants had longer PCr recovery than non‐obese controls following 5x30s of moderate‐intensity exercise (51.2 ± 20.1 s vs. 23.9 ± 7.5 s, p = 0.004). In univariate correlation analysis, impaired PCr recovery was associated with a higher BMI z‐score (rs = 0.51, p < 0.001), circulating triglycerides (rs = 0.41, p = 0.005), and HOMA‐IR (rs = 0.46, p = 0.001). In stepwise multivariate regression analysis, impaired PCr recovery was associated with a higher BMI z‐score (β = 0.47, p = 0.002), but not insulin resistance (β = 0.07, p = 0.07) or circulating triglycerides (β = 0.16 p = 0.33). Conclusion: A slower phosphocreatine recovery following aerobic exercise is strongly associated with increasing adiposity. A slower metabolic recovery following aerobic exercise stress suggests that endurance exercise training in obese adolescents may be an optimal strategy to target exercise intolerance in this cohort. [ABSTRACT FROM AUTHOR]

Published
2017
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144. IN MEMORIAM: SKIPPER POEHLMAN

Author

Kamath, Markad V., primary, Boylan, Colm, additional, Jones, Graham, additional, Kahl, Wolfram, additional, Noseworthy, Michael D., additional, and Upton, Adrian R. M., additional

Published
2014
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149. Evidence against the Involvement of Chronic Cerebrospinal Venous Abnormalities in Multiple Sclerosis. A Case-Control Study

Author

Rodger, Ian W., primary, Dilar, Dorothy, additional, Dwyer, Janet, additional, Bienenstock, John, additional, Coret, Andu, additional, Coret-Simon, Judith, additional, Foster, Gary, additional, Franchetto, Arlene, additional, Franic, Slobodan, additional, Goldsmith, Charles H., additional, Koff, David, additional, Konyer, Norman B., additional, Levine, Mitchell, additional, McDonald, Ellen, additional, Noseworthy, Michael D., additional, Paulseth, John, additional, Ribeiro, Luciana, additional, Sayles, Mary Jane, additional, and Thabane, Lehana, additional

Published
2013
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