Poster presentation from the 16th Annual SCMR Scientific Sessions San Francisco, CA, USA. 31 January - 3 February 2013

Ellwein, Laura M

LaDisa, John F.

Leibham, Stacy

Samyn, Margaret M.

Schindler-Ivens, Sheila M.

English

PubMed

epublications@Marquette

Marquette Universitye-Publications@MarquetteBiomedical Engineering Faculty Research andPublications Biomedical Engineering, Department of12-31-2012Quantification of Thoracic Aorta Blood Flow byMagnetic Resonance Imaging During SupineCycling Exercise of Increasing IntensityLaura M. EllweinMarquette University, laura.ellwein@marquette.eduJohn F. LaDisaMarquette University, john.ladisa@marquette.eduStacy LeibhamChildren’s Hospital of WisconsinSheila M. Schindler-IvensMarquette University, sheila.schindler-ivens@marquette.eduMargaret M. SamynMarquette UniversityPublished version. Journal of Cardiovascular Magnetic Resonance, Vol. 15, Supplemental 1 ( January2013): P239. Permalink. © 2013 BioMed Central. Used with permission.POSTER PRESENTATION Open AccessQuantification of thoracic aorta blood flow bymagnetic resonance imaging during supinecycling exercise of increasing intensityLaura Ellwein2,1*, John F LaDisa2,6, Stacy Leibham4, Sheila Schindler-Ivens5, Margaret M Samyn3,2From 16th Annual SCMR Scientific SessionsSan Francisco, CA, USA. 31 January - 3 February 2013BackgroundCardiac magnetic resonance imaging (MRI) may be usedfor the diagnosis and follow-up of diseases affecting thethoracic aorta (TA). Typically, patients are imaged at rest.Quantifying TA blood flow distribution during activitymay improve understanding of disease impact by assessingpossible factors contributing to exercise intolerance. Bloodflow quantification during exercise MRI, though, has here-tofore been complicated by prolonged MRI scan times,motion artifact, and gradient field inhomogeneities. Wedeveloped a protocol for phase-contrast (PC) MRI flowquantification in the TA and head and neck arteries dur-ing three-tiered supine cycling submaximal exercise.MethodsPC-MRI was acquired in the ascending aorta (AAo) andinnominate (IA), left common carotid (LCCA), and leftsubclavian (LSA) arteries using a 1.5T Siemens MAGNE-TOM® Symphony magnet. Six healthy volunteers (28±2years) were imaged during rest and supine pedaling of anMRI-compatible cycle to reach 130%, 150%, and 170% ofresting heart rate (HR130, HR150, HR170). Scan parametersbalanced image quality with acquisition time, accountingfor subject positioning in the magnet and motion frompedaling. Time-resolved volumetric blood flow was cal-culated from PC-MRI data and estimated in the descend-ing aorta (dAo). Flow quantification included cardiacindex from AAo flow, arterial normalized mean flow(NMF,L/min/m2) and flow distribution (FD,% of AAoflow). Significance of flow quantification between HRsand rest was tested post-hoc with Student’s t-test.ResultsCardiac index increased linearly (r2=0.99) from 3.1±0.3 to5.2±0.3 L/min/m2 from rest to HR170 (p<0.05). HRincreased to 111±5.9 bpm and workload to 38±9 watts atHR170. In the dAo, NMF increased linearly with respect toHR (r2=0.99) by 46%, 72%, and 93% with significance at alllevels (Table 1). The IA showed significant increase inNMF of 39% at HR170 compared to rest. Increases in NMF2Biomedical Engineering, Marquette University, Milwaukee, WI, USAFull list of author information is available at the end of the articleTable 1 Flow quantification (mean ± SE, n=6) in the descending aorta (dAo), innominate (IA), left common carotid(LCCA), and left subclavian (LSA) arteries. (Statistically significant results are in bold, p<0.05)NMF, L/min/m2 FD, % of AAo flowRest HR130 HR150 HR170 Rest HR130 HR150 HR170dAo 2.12±0.23 3.00±0.24 3.51±0.22 3.91±0.23 67±1.6% 72±1.5% 76±0.1% 75±1.3%IA 0.50±0.03 0.59±0.07 0.59±0.07 0.69±0.07 16±0.8% 14±1.0% 13±1.0% 13±1.0%LCCA 0.23±0.01 0.27±0.02 0.24±0.02 0.26±0.03 7.6±0.7% 6.5±0.4% 5.3±0.6% 5.0±0.5%LSA 0.28±0.04 0.34±0.05 0.30±0.04 0.38±0.06 8.7±0.9% 7.9±0.7% 6.4±0.6% 7.0±2.0%NMF: Normalized mean flow; FD: Flow distribution.Ellwein et al. Journal of Cardiovascular MagneticResonance 2013, 15(Suppl 1):P239http://www.jcmr-online.com/content/15/S1/P239© 2013 Ellwein et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative CommonsAttribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction inany medium, provided the original work is properly cited.in the LCCA and LSA were not significant. FD in the dAoincreased significantly by 12% and 11% at HR150 andHR170 compared to rest, with concomitant decreases inthe LCCA (27%, 31%) and LSA (25%, 20%). FD in the IAdecreased at each HR level but without significance.ConclusionsThis investigation marks the first known flow quantifica-tion in the TA and head and neck arteries during supineexercise cardiac MRI. These pilot data show the changesin cardiac output and preferential redistribution of bloodflow during increasing exercise intensity in a group ofhealthy young adults. Future studies using the protocolintroduced here can now be conducted for various popula-tions with TA disease.FundingThis work was supported by an AHA Postdoctoral Fellow-ship award 10POST4210030 (to LME) and an NIH grantR15HL096096-01 (to JFL).Author details1Mathematics and Applied Mathematics, Virginia Commonwealth University,Richmond, VA, USA. 2Biomedical Engineering, Marquette University,Milwaukee, WI, USA. 3Pediatrics, Herma Heart Center, Children’s Hospital ofWisconsin, Milwaukee, WI, USA. 4Radiology, Children’s Hospital of Wisconsin,Milwaukee, WI, USA. 5Physical Therapy, Marquette University, Milwaukee, WI,USA. 6Medicine, Division of Cardiovascular Medicine, Medical College ofWisconsin, Milwaukee, WI, USA.Published: 30 January 2013doi:10.1186/1532-429X-15-S1-P239Cite this article as: Ellwein et al.: Quantification of thoracic aorta bloodflow by magnetic resonance imaging during supine cycling exercise ofincreasing intensity. Journal of Cardiovascular Magnetic Resonance 201315(Suppl 1):P239.Submit your next manuscript to BioMed Centraland take full advantage of: • Convenient online submission• Thorough peer review• No space constraints or color figure charges• Immediate publication on acceptance• Inclusion in PubMed, CAS, Scopus and Google Scholar• Research which is freely available for redistributionSubmit your manuscript at www.biomedcentral.com/submitEllwein et al. Journal of Cardiovascular MagneticResonance 2013, 15(Suppl 1):P239http://www.jcmr-online.com/content/15/S1/P239Page 2 of 2

Quantification of Thoracic Aorta Blood Flow by Magnetic Resonance Imaging During Supine Cycling Exercise of Increasing Intensity

Ellwein, Laura

Schindler-Ivens, Sheila

VCU Scholars Compass

Virginia Commonwealth UniversityVCU Scholars CompassMathematics and Applied MathematicsPublications Dept. of Mathematics and Applied Mathematics2013Quantification of Thoracic Aorta Blood Flow byMagnetic Resonance Imaging During SupineCycling Exercise of Increasing IntensityLaura EllweinVirginia Commonwealth University, lellwein@vcu.eduJohn F. LaDisaMarquette UniversityStacy LeibhamChildren's Hospital of WisconsinSheila Schindler-IvensMarquette UniversityMargaret M. SamynMarquette UniversityFollow this and additional works at: http://scholarscompass.vcu.edu/math_pubs© 2013 Ellwein et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of theCreative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use,distribution, and reproduction in any medium, provided the original work is properly cited.This Article is brought to you for free and open access by the Dept. of Mathematics and Applied Mathematics at VCU Scholars Compass. It has beenaccepted for inclusion in Mathematics and Applied Mathematics Publications by an authorized administrator of VCU Scholars Compass. For moreinformation, please contact libcompass@vcu.edu.Downloaded fromhttp://scholarscompass.vcu.edu/math_pubs/11POSTER PRESENTATION Open AccessQuantification of thoracic aorta blood flow bymagnetic resonance imaging during supinecycling exercise of increasing intensityLaura Ellwein2,1*, John F LaDisa2,6, Stacy Leibham4, Sheila Schindler-Ivens5, Margaret M Samyn3,2From 16th Annual SCMR Scientific SessionsSan Francisco, CA, USA. 31 January - 3 February 2013BackgroundCardiac magnetic resonance imaging (MRI) may be usedfor the diagnosis and follow-up of diseases affecting thethoracic aorta (TA). Typically, patients are imaged at rest.Quantifying TA blood flow distribution during activitymay improve understanding of disease impact by assessingpossible factors contributing to exercise intolerance. Bloodflow quantification during exercise MRI, though, has here-tofore been complicated by prolonged MRI scan times,motion artifact, and gradient field inhomogeneities. Wedeveloped a protocol for phase-contrast (PC) MRI flowquantification in the TA and head and neck arteries dur-ing three-tiered supine cycling submaximal exercise.MethodsPC-MRI was acquired in the ascending aorta (AAo) andinnominate (IA), left common carotid (LCCA), and leftsubclavian (LSA) arteries using a 1.5T Siemens MAGNE-TOM® Symphony magnet. Six healthy volunteers (28±2years) were imaged during rest and supine pedaling of anMRI-compatible cycle to reach 130%, 150%, and 170% ofresting heart rate (HR130, HR150, HR170). Scan parametersbalanced image quality with acquisition time, accountingfor subject positioning in the magnet and motion frompedaling. Time-resolved volumetric blood flow was cal-culated from PC-MRI data and estimated in the descend-ing aorta (dAo). Flow quantification included cardiacindex from AAo flow, arterial normalized mean flow(NMF,L/min/m2) and flow distribution (FD,% of AAoflow). Significance of flow quantification between HRsand rest was tested post-hoc with Student’s t-test.ResultsCardiac index increased linearly (r2=0.99) from 3.1±0.3 to5.2±0.3 L/min/m2 from rest to HR170 (p<0.05). HRincreased to 111±5.9 bpm and workload to 38±9 watts atHR170. In the dAo, NMF increased linearly with respect toHR (r2=0.99) by 46%, 72%, and 93% with significance at alllevels (Table 1). The IA showed significant increase inNMF of 39% at HR170 compared to rest. Increases in NMF2Biomedical Engineering, Marquette University, Milwaukee, WI, USAFull list of author information is available at the end of the articleTable 1 Flow quantification (mean ± SE, n=6) in the descending aorta (dAo), innominate (IA), left common carotid(LCCA), and left subclavian (LSA) arteries. (Statistically significant results are in bold, p<0.05)NMF, L/min/m2 FD, % of AAo flowRest HR130 HR150 HR170 Rest HR130 HR150 HR170dAo 2.12±0.23 3.00±0.24 3.51±0.22 3.91±0.23 67±1.6% 72±1.5% 76±0.1% 75±1.3%IA 0.50±0.03 0.59±0.07 0.59±0.07 0.69±0.07 16±0.8% 14±1.0% 13±1.0% 13±1.0%LCCA 0.23±0.01 0.27±0.02 0.24±0.02 0.26±0.03 7.6±0.7% 6.5±0.4% 5.3±0.6% 5.0±0.5%LSA 0.28±0.04 0.34±0.05 0.30±0.04 0.38±0.06 8.7±0.9% 7.9±0.7% 6.4±0.6% 7.0±2.0%NMF: Normalized mean flow; FD: Flow distribution.Ellwein et al. Journal of Cardiovascular MagneticResonance 2013, 15(Suppl 1):P239http://www.jcmr-online.com/content/15/S1/P239© 2013 Ellwein et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative CommonsAttribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction inany medium, provided the original work is properly cited.in the LCCA and LSA were not significant. FD in the dAoincreased significantly by 12% and 11% at HR150 andHR170 compared to rest, with concomitant decreases inthe LCCA (27%, 31%) and LSA (25%, 20%). FD in the IAdecreased at each HR level but without significance.ConclusionsThis investigation marks the first known flow quantifica-tion in the TA and head and neck arteries during supineexercise cardiac MRI. These pilot data show the changesin cardiac output and preferential redistribution of bloodflow during increasing exercise intensity in a group ofhealthy young adults. Future studies using the protocolintroduced here can now be conducted for various popula-tions with TA disease.FundingThis work was supported by an AHA Postdoctoral Fellow-ship award 10POST4210030 (to LME) and an NIH grantR15HL096096-01 (to JFL).Author details1Mathematics and Applied Mathematics, Virginia Commonwealth University,Richmond, VA, USA. 2Biomedical Engineering, Marquette University,Milwaukee, WI, USA. 3Pediatrics, Herma Heart Center, Children’s Hospital ofWisconsin, Milwaukee, WI, USA. 4Radiology, Children’s Hospital of Wisconsin,Milwaukee, WI, USA. 5Physical Therapy, Marquette University, Milwaukee, WI,USA. 6Medicine, Division of Cardiovascular Medicine, Medical College ofWisconsin, Milwaukee, WI, USA.Published: 30 January 2013doi:10.1186/1532-429X-15-S1-P239Cite this article as: Ellwein et al.: Quantification of thoracic aorta bloodflow by magnetic resonance imaging during supine cycling exercise ofincreasing intensity. Journal of Cardiovascular Magnetic Resonance 201315(Suppl 1):P239.Submit your next manuscript to BioMed Centraland take full advantage of: • Convenient online submission• Thorough peer review• No space constraints or color figure charges• Immediate publication on acceptance• Inclusion in PubMed, CAS, Scopus and Google Scholar• Research which is freely available for redistributionSubmit your manuscript at www.biomedcentral.com/submitEllwein et al. Journal of Cardiovascular MagneticResonance 2013, 15(Suppl 1):P239http://www.jcmr-online.com/content/15/S1/P239Page 2 of 2

http://dx.doi.org/10.1186/1532-429X-15-S1-P239

Quantification of Thoracic Aorta Blood Flow by Magnetic Resonance Imaging During Supine Cycling Exercise of Increasing Intensity

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