Blood-pool MRI assessment of myocardial microvascular reactivity
PurposeThe ability to non-invasively image myocardial microvascular dilation and constriction is essential to assessing intact function and dysfunction. Yet, conventional measurements based on blood oxygenation are not specific to changes in blood volume. The purpose of this study was to extend to t...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2023-11-01
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| Series: | Frontiers in Cardiovascular Medicine |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fcvm.2023.1216587/full |
| _version_ | 1797643254010740736 |
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| author | Sadi Loai Sadi Loai Beiping Qiang Michael A. Laflamme Michael A. Laflamme Michael A. Laflamme Hai-Ling Margaret Cheng Hai-Ling Margaret Cheng Hai-Ling Margaret Cheng |
| author_facet | Sadi Loai Sadi Loai Beiping Qiang Michael A. Laflamme Michael A. Laflamme Michael A. Laflamme Hai-Ling Margaret Cheng Hai-Ling Margaret Cheng Hai-Ling Margaret Cheng |
| author_sort | Sadi Loai |
| collection | DOAJ |
| description | PurposeThe ability to non-invasively image myocardial microvascular dilation and constriction is essential to assessing intact function and dysfunction. Yet, conventional measurements based on blood oxygenation are not specific to changes in blood volume. The purpose of this study was to extend to the heart a blood-pool MRI approach for assessing vasomodulation in the presence of blood gas changes and investigate if sex-related differences exist.MethodsAnimals [five male and five female healthy Sprague Dawley rats (200–500 g)] were intubated, ventilated, and cycled through room air (normoxia) and hypercapnia (10% CO2) in 10-minute cycles after i.v. injection of blood-pool agent Ablavar (0.3 mmol/kg). Pre-contrast T1 maps and T1-weighted 3D CINE were acquired on a 3 Tesla preclinical MRI scanner, followed by repeated 3D CINE every 5 min until the end of the gas regime. Invasive laser Doppler flowmetry of myocardial perfusion was performed to corroborate MRI results.ResultsMyocardial microvascular dilation to hypercapnia and constriction to normoxia were readily visualized on T1 maps. Over 10 min of hypercapnia, female myocardial T1 reduced by 20% (vasodilation), while no significant change was observed in the male myocardium. After return to normoxia, myocardial T1 increased (vasoconstriction) in both sexes (18% in females and 16% in males). Laser Doppler perfusion measurements confirmed vasomodulatory responses observed on MRI.ConclusionBlood-pool MRI is sensitive and specific to vasomodulation in the myocardial microcirculation. Sex-related differences exist in the healthy myocardium in response to mild hypercapnic stimuli. |
| first_indexed | 2024-03-11T14:13:04Z |
| format | Article |
| id | doaj.art-3e3e45e5864a4de5b3a8fc91b5b4341c |
| institution | Directory Open Access Journal |
| issn | 2297-055X |
| language | English |
| last_indexed | 2024-03-11T14:13:04Z |
| publishDate | 2023-11-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Cardiovascular Medicine |
| spelling | doaj.art-3e3e45e5864a4de5b3a8fc91b5b4341c2023-11-01T16:44:29ZengFrontiers Media S.A.Frontiers in Cardiovascular Medicine2297-055X2023-11-011010.3389/fcvm.2023.12165871216587Blood-pool MRI assessment of myocardial microvascular reactivitySadi Loai0Sadi Loai1Beiping Qiang2Michael A. Laflamme3Michael A. Laflamme4Michael A. Laflamme5Hai-Ling Margaret Cheng6Hai-Ling Margaret Cheng7Hai-Ling Margaret Cheng8Institute of Biomedical Engineering, University of Toronto, Toronto, ON, CanadaTranslational Biology & Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, CanadaMcEwen Stem Cell Institute, University Health Network, Toronto, ON, CanadaMcEwen Stem Cell Institute, University Health Network, Toronto, ON, CanadaPeter Munk Cardiac Centre, University Health Network, Toronto, ON, CanadaLaboratory of Medicine and Pathobiology, University of Toronto, Toronto, ON, CanadaInstitute of Biomedical Engineering, University of Toronto, Toronto, ON, CanadaTranslational Biology & Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, CanadaThe Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, CanadaPurposeThe ability to non-invasively image myocardial microvascular dilation and constriction is essential to assessing intact function and dysfunction. Yet, conventional measurements based on blood oxygenation are not specific to changes in blood volume. The purpose of this study was to extend to the heart a blood-pool MRI approach for assessing vasomodulation in the presence of blood gas changes and investigate if sex-related differences exist.MethodsAnimals [five male and five female healthy Sprague Dawley rats (200–500 g)] were intubated, ventilated, and cycled through room air (normoxia) and hypercapnia (10% CO2) in 10-minute cycles after i.v. injection of blood-pool agent Ablavar (0.3 mmol/kg). Pre-contrast T1 maps and T1-weighted 3D CINE were acquired on a 3 Tesla preclinical MRI scanner, followed by repeated 3D CINE every 5 min until the end of the gas regime. Invasive laser Doppler flowmetry of myocardial perfusion was performed to corroborate MRI results.ResultsMyocardial microvascular dilation to hypercapnia and constriction to normoxia were readily visualized on T1 maps. Over 10 min of hypercapnia, female myocardial T1 reduced by 20% (vasodilation), while no significant change was observed in the male myocardium. After return to normoxia, myocardial T1 increased (vasoconstriction) in both sexes (18% in females and 16% in males). Laser Doppler perfusion measurements confirmed vasomodulatory responses observed on MRI.ConclusionBlood-pool MRI is sensitive and specific to vasomodulation in the myocardial microcirculation. Sex-related differences exist in the healthy myocardium in response to mild hypercapnic stimuli.https://www.frontiersin.org/articles/10.3389/fcvm.2023.1216587/fullvasomodulationmicrovascular functionblood-pool imaginghearthypercapnia |
| spellingShingle | Sadi Loai Sadi Loai Beiping Qiang Michael A. Laflamme Michael A. Laflamme Michael A. Laflamme Hai-Ling Margaret Cheng Hai-Ling Margaret Cheng Hai-Ling Margaret Cheng Blood-pool MRI assessment of myocardial microvascular reactivity Frontiers in Cardiovascular Medicine vasomodulation microvascular function blood-pool imaging heart hypercapnia |
| title | Blood-pool MRI assessment of myocardial microvascular reactivity |
| title_full | Blood-pool MRI assessment of myocardial microvascular reactivity |
| title_fullStr | Blood-pool MRI assessment of myocardial microvascular reactivity |
| title_full_unstemmed | Blood-pool MRI assessment of myocardial microvascular reactivity |
| title_short | Blood-pool MRI assessment of myocardial microvascular reactivity |
| title_sort | blood pool mri assessment of myocardial microvascular reactivity |
| topic | vasomodulation microvascular function blood-pool imaging heart hypercapnia |
| url | https://www.frontiersin.org/articles/10.3389/fcvm.2023.1216587/full |
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