Alex Barker, PhD
Associate Professor, Radiology

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Graduate School :
  • PhD, University of Colorado - Boulder (2008)
Undergraduate School:
  • BS, University of Colorado - Boulder (CO) (1999)
Languages: English
Department: Radiology

Professional Titles

  • Director, Advanced Imaging Lab

Publications

  • Johnson EMI, Scott MB, Jarvis K, Allen B, Carr J, Malaisrie SC, McCarthy P, Mehta C, Fedak PWM, Barker AJ, Markl M. Global Aortic Pulse Wave Velocity is Unchanged in Bicuspid Aortopathy With Normal Valve Function but Elevated in Patients With Aortic Valve Stenosis: Insights From a 4D Flow MRI Study of 597 Subjects. J Magn Reson Imaging. 2023 Jan;57(1):126-136. PubMed PMID: 35633284
  • McLennan D, Schäfer M, Barker AJ, Mitchell MB, Ing RJ, Browne LP, Ivy DD, Morgan GJ. Abnormal flow conduction through pulmonary arteries is associated with right ventricular volume and function in patients with repaired tetralogy of Fallot: does flow quality affect afterload?. Eur Radiol. 2023 Jan;33(1):302-311. PubMed PMID: 35852579
  • Schäfer M, Browne LP, Truong U, Bjornstad P, Tell S, Snell-Bergeon J, Baumgartner A, Hunter KS, Reusch JEB, Barker AJ, Nadeau KJ, Schauer IE. Bromocriptine Improves Central Aortic Stiffness in Adolescents With Type 1 Diabetes: Arterial Health Results From the BCQR-T1D Study. Hypertension. 2023 Feb;80(2):482-491. PubMed PMID: 36472197
  • Tong TT, Nightingale M, Scott MB, Sigaeva T, Fedak PWM, Barker AJ, Di Martino ES. A classification approach to improve out of sample predictability of structure-based constitutive models for ascending thoracic aortic tissue. Int J Numer Method Biomed Eng. 2023 Jun;39(6):e3708. PubMed PMID: 37079441
  • Schäfer M, Mitchell MB, Frank BS, Barker AJ, Stone ML, Jaggers J, von Alvensleben JC, Hunter KS, Friesen RM, Ivy DD, Jacobsen R, Di Maria MV. Myocardial strain-curve deformation patterns after Fontan operation. Sci Rep. 2023 Jul 24;13(1):11912. PubMed PMID: 37488167
  • Schäfer M, Carroll A, Carmody KK, Hunter KS, Barker AJ, Aftab M, Reece TB. Aortic shape variation after frozen elephant trunk procedure predicts aortic events: Principal component analysis study. JTCVS Open. 2023 Jun;14:26-35. PubMed PMID: 37425456
  • Schäfer M, Browne LP, Truong U, Bjornstad P, Tell S, Snell-Bergeon J, Baumgartner A, Hunter KS, Reusch JEB, Barker AJ, Nadeau KJ, Schauer IE. Bromocriptine Improves Central Aortic Stiffness in Adolescents With Type 1 Diabetes: Arterial Health Results From the BCQR-T1D Study. Hypertension. 2023 Feb;80(2):482-491. PubMed PMID: 36472197
  • Sassoon DJ, Norris EC, Malone LJ, Weinman JP, Mong DA, Barker AJ, Browne LP. Unexpected extracardiac findings in cardiac computed tomography from neonates to young adults. Pediatr Radiol. 2023 May;53(5):885-891. PubMed PMID: 36697721
  • Nightingale M, Scott MB, Sigaeva T, Guzzardi D, Garcia J, Malaisrie SC, McCarthy P, Markl M, Fedak PWM, Di Martino ES, Barker AJ. Magnetic resonance imaging-based hemodynamic wall shear stress alters aortic wall tissue biomechanics in bicuspid aortic valve patients. J Thorac Cardiovasc Surg. 2023 Jan 13. [Epub ahead of print] PubMed PMID: 36797175
  • Minocha PK, Englund EK, Friesen RM, Fujiwara T, Smith SA, Meyers ML, Browne LP, Barker AJ. Reference Values for Fetal Cardiac Dimensions, Volumes, Ventricular Function and Left Ventricular Longitudinal Strain Using Doppler Ultrasound Gated Cardiac Magnetic Resonance Imaging in Healthy Third Trimester Fetuses. J Magn Reson Imaging. 2023 Oct 19. [Epub ahead of print] PubMed PMID: 37855630
  • McLennan D, Schäfer M, Barker AJ, Mitchell MB, Ing RJ, Browne LP, Ivy DD, Morgan GJ. Abnormal flow conduction through pulmonary arteries is associated with right ventricular volume and function in patients with repaired tetralogy of Fallot: does flow quality affect afterload?. Eur Radiol. 2023 Jan;33(1):302-311. PubMed PMID: 35852579
  • Lee J, Huh H, Scott MB, Elbaz MSM, Puthumana JJ, McCarthy P, Malaisrie SC, Markl M, Thomas JD, Barker AJ. Valvular and ascending aortic hemodynamics of the On-X aortic valved conduit by same-day echocardiography and 4D flow MRI. Front Cardiovasc Med. 2023;10:1256420. PubMed PMID: 38034383
  • Johnson EMI, Scott MB, Jarvis K, Allen B, Carr J, Malaisrie SC, McCarthy P, Mehta C, Fedak PWM, Barker AJ, Markl M. Global Aortic Pulse Wave Velocity is Unchanged in Bicuspid Aortopathy With Normal Valve Function but Elevated in Patients With Aortic Valve Stenosis: Insights From a 4D Flow MRI Study of 597 Subjects. J Magn Reson Imaging. 2023 Jan;57(1):126-136. PubMed PMID: 35633284
  • Jacobson NM, Brusilovsky J, Ducey R, Stence NV, Barker AJ, Mitchell MB, Smith L, MacCurdy R, Weaver JC. The Inner Complexities of Multimodal Medical Data: Bitmap-Based 3D Printing for Surgical Planning Using Dynamic Physiology. 3D Print Addit Manuf. 2023 Oct 1;10(5):855-868. PubMed PMID: 37886401
  • Cain MT, Schäfer M, Park S, Barker AJ, Vargas D, Stenmark KR, Yu YA, Bull TM, Ivy DD, Hoffman JRH. Characterization of pulmonary arterial stiffness using cardiac MRI. Int J Cardiovasc Imaging. 2023 Oct 30. [Epub ahead of print] PubMed PMID: 37902921
  • Bissell MM, Raimondi F, Ait Ali L, Allen BD, Barker AJ, Bolger A, Burris N, Carhäll CJ, Collins JD, Ebbers T, Francois CJ, Frydrychowicz A, Garg P, Geiger J, Ha H, Hennemuth A, Hope MD, Hsiao A, Johnson K, Kozerke S, Ma LE, Markl M, Martins D, Messina M, Oechtering TH, van Ooij P, Rigsby C, Rodriguez-Palomares J, Roest AAW, Roldán-Alzate A, Schnell S, Sotelo J, Stuber M, Syed AB, Töger J, van der Geest R, Westenberg J, Zhong L, Zhong Y, Wieben O, Dyverfeldt P. 4D Flow cardiovascular magnetic resonance consensus statement: 2023 update. J Cardiovasc Magn Reson. 2023 Jul 20;25(1):40. PubMed PMID: 37474977
  • Barker AJ, Friesen RM, Browne LP. Editorial for "Neonatal 4D Flow Magnetic Resonance Imaging Without General Anesthesia". J Magn Reson Imaging. 2023 Jan;57(1):83-84. PubMed PMID: 35716102
  • Abushamat LA, Enge D, Fujiwara T, Schäfer M, Clark EW, Englund EK, Scalzo RL, Johnston A, Rafferty D, Schauer IE, Whipple MO, Hunter K, Huebschmann AG, Nadeau KJ, Jarvis K, Barker AJ, Regensteiner JG, Reusch JEB. Obesity dominates early effects on cardiac structure and arterial stiffness in people with type 2 diabetes. J Hypertens. 2023 Nov 1;41(11):1775-1784. PubMed PMID: 37589719
  • Kalisz K, Scott M, Avery R, Sarnari R, Barker AJ, Carr JC, Markl M, Allen BD. Cardiac Magnetic Resonance Imaging Feature Tracking Demonstrates Altered Biventricular Strain in Obese Subjects in the Absence of Clinically Apparent Cardiovascular Disease. J Thorac Imaging. 2022 Jan 1;37(1):W1-W2. PubMed PMID: 32520847
  • Jarvis K, Scott MB, Soulat G, Elbaz MSM, Barker AJ, Carr JC, Markl M, Ragin A. Aortic Pulse Wave Velocity Evaluated by 4D Flow MRI Across the Adult Lifespan. J Magn Reson Imaging. 2022 Jan 10. [Epub ahead of print] PubMed PMID: 35001455
  • Soulat G, Scott MB, Allen BD, Avery R, Bonow RO, Malaisrie SC, McCarthy P, Fedak PWM, Barker AJ, Markl M. Association of Regional Wall Shear Stress and Progressive Ascending Aorta Dilation in Bicuspid Aortic Valve. JACC Cardiovasc Imaging. 2022 Jan;15(1):33-42. PubMed PMID: 34419402
  • Barker AJ, Berthusen A, Vigers T, Schafer M, Browne LP, Bjornstad P. Estimation of glomerular filtration rate in a pediatric population using non-contrast kidney phase contrast magnetic resonance imaging. Pediatr Nephrol. 2022 Dec 2. [Epub ahead of print] PubMed PMID: 36459246
  • Berhane H, Scott MB, Barker AJ, McCarthy P, Avery R, Allen B, Malaisrie C, Robinson JD, Rigsby CK, Markl M. Deep learning-based velocity antialiasing of 4D-flow MRI. Magn Reson Med. 2022 Jul;88(1):449-463. PubMed PMID: 35381116
  • Browne LP, Fujiwara T, Leahy RA, Friesen RM, Barker AJ. 4D flow MRI quantification and surveillance of veno-venous collateralization. Eur Heart J Cardiovasc Imaging. 2022 Sep 10;23(10):e466. PubMed PMID: 35762621
  • Browne LP, Malone LJ, Englund EK, Fujiwara T, Fluta C, Lu Q, Grover TR, Fuhr PG, Barker AJ. Free-breathing magnetic resonance imaging with radial k-space sampling for neonates and infants to reduce anesthesia. Pediatr Radiol. 2022 Jun;52(7):1326-1337. PubMed PMID: 35169882
  • Fujiwara T, Berhane H, Scott MB, Englund EK, Schäfer M, Fonseca B, Berthusen A, Robinson JD, Rigsby CK, Browne LP, Markl M, Barker AJ. Segmentation of the Aorta and Pulmonary Arteries Based on 4D Flow MRI in the Pediatric Setting Using Fully Automated Multi-Site, Multi-Vendor, and Multi-Label Dense U-Net. J Magn Reson Imaging. 2022 Jun;55(6):1666-1680. PubMed PMID: 34792835
  • Huh H, Lee J, Kinno M, Markl M, Thomas JD, Barker AJ. Two wrongs sometimes do make a right: errors in aortic valve stenosis assessment by same-day Doppler echocardiography and 4D flow MRI. Int J Cardiovasc Imaging. 2022 Feb 21. [Epub ahead of print] PubMed PMID: 35190940
  • Jarvis K, Scott MB, Soulat G, Elbaz MSM, Barker AJ, Carr JC, Markl M, Ragin A. Aortic Pulse Wave Velocity Evaluated by 4D Flow MRI Across the Adult Lifespan. J Magn Reson Imaging. 2022 Aug;56(2):464-473. PubMed PMID: 35001455
  • Kalisz K, Scott M, Avery R, Sarnari R, Barker AJ, Carr JC, Markl M, Allen BD. Cardiac Magnetic Resonance Imaging Feature Tracking Demonstrates Altered Biventricular Strain in Obese Subjects in the Absence of Clinically Apparent Cardiovascular Disease. J Thorac Imaging. 2022 Jan 1;37(1):W1-W2. PubMed PMID: 32520847
  • Lee J, El Hangouche N, Pathrose A, Soulat G, Barker AJ, Thomas JD, Markl M. Bicuspid aortic valve morphology and hemodynamics by same-day echocardiography and cardiac MRI. Int J Cardiovasc Imaging. 2022 Mar 16. [Epub ahead of print] PubMed PMID: 35294708
  • Lee J, Mitter SS, Van Assche L, Huh H, Wagner GJ, Wu E, Barker AJ, Markl M, Thomas JD. Impact of assuming a circular orifice on flow error through elliptical regurgitant orifices: computational fluid dynamics and in vitro analysis of proximal flow convergence. Int J Cardiovasc Imaging. 2022 Nov 2. [Epub ahead of print] PubMed PMID: 36322265
  • Nightingale M, Guzzardi DG, Barker AJ, Malaisrie SC, McCarthy PM, Markl M, Di Martino ES, Fedak PWM. Elastin integrity in bicuspid valve-associated aortopathy is associated with altered biomechanical properties and influenced by age. Ann Cardiothorac Surg. 2022 Jul;11(4):426-435. PubMed PMID: 35958543
  • Soulat G, Scott MB, Allen BD, Avery R, Bonow RO, Malaisrie SC, McCarthy P, Fedak PWM, Barker AJ, Markl M. Association of Regional Wall Shear Stress and Progressive Ascending Aorta Dilation in Bicuspid Aortic Valve. JACC Cardiovasc Imaging. 2022 Jan;15(1):33-42. PubMed PMID: 34419402
  • Suwa K, Rahsepar AA, Geiger J, Dolan R, Ghasemiesfe A, Barker AJ, Collins JD, Markl M, Carr JC. A Left ventricle remodeling in patients with bicuspid aortic valve. Int J Cardiovasc Imaging. 2022 Oct 31. [Epub ahead of print] PubMed PMID: 36315365
  • Pravdivtseva MS, Peschke E, Lindner T, Wodarg F, Hensler J, Gabbert D, Voges I, Berg P, Barker AJ, Jansen O, Hövener JB. 3D-printed, patient-specific intracranial aneurysm models: from clinical data to flow experiments with endovascular devices. Med Phys. 2021 Jan 11. [Epub ahead of print] PubMed PMID: 33428778
  • Schäfer M, Frank BS, Jacobsen R, Rausch CM, Mitchell MB, Jaggers J, Stone ML, Morgan GJ, Browne LP, Barker AJ, Hunter KS, Ivy DD, Younoszai A, Di Maria MV. Patients with Fontan circulation have abnormal aortic wave propagation patterns: A wave intensity analysis study. Int J Cardiol. 2021 Jan 1;322:158-167. PubMed PMID: 32853667
  • Schäfer M, Frank BS, Jacobsen R, Rausch CM, Mitchell MB, Jaggers J, Stone ML, Morgan GJ, Browne LP, Barker AJ, Hunter KS, Ivy DD, Younoszai A, Di Maria MV. Patients with Fontan circulation have abnormal aortic wave propagation patterns: A wave intensity analysis study. Int J Cardiol. 2021 Jan 1;322:158-167. PubMed PMID: 32853667
  • Schäfer M, Frank BS, Ivy DD, Abman SH, Stenmark KR, Mitchell MB, Browne LP, Barker AJ, Hunter KS, Kheyfets V, Miller-Reed K, Ing R, Morgan GJ, Truong U. Short-Term Effects of Inhaled Nitric Oxide on Right Ventricular Flow Hemodynamics by 4-Dimensional-Flow Magnetic Resonance Imaging in Children With Pulmonary Arterial Hypertension. J Am Heart Assoc. 2021 Apr 20;10(8):e020548. PubMed PMID: 33821682
  • Schäfer M, Di Maria MV, Jaggers J, Stone ML, Ivy DD, Barker AJ, Mitchell MB. High-degree Norwood neoaortic tapering is associated with abnormal flow conduction and elevated flow-mediated energy loss. J Thorac Cardiovasc Surg. 2021 Dec;162(6):1791-1804. PubMed PMID: 33653609
  • Pravdivtseva MS, Peschke E, Lindner T, Wodarg F, Hensler J, Gabbert D, Voges I, Berg P, Barker AJ, Jansen O, Hövener JB. 3D-printed, patient-specific intracranial aneurysm models: From clinical data to flow experiments with endovascular devices. Med Phys. 2021 Apr;48(4):1469-1484. PubMed PMID: 33428778
  • Oganesyan A, Hoffner-Heinike A, Barker AJ, Frank BS, Ivy DD, Hunter KS, Mitchell MB, Humphries SM, Fenster BE, Schäfer M. Abnormal pulmonary flow is associated with impaired right ventricular coupling in patients with COPD. Int J Cardiovasc Imaging. 2021 Oct;37(10):3039-3048. PubMed PMID: 34021434
  • Naresh NK, Malone L, Fujiwara T, Smith S, Lu Q, Twite MD, DiMaria MV, Fonseca BM, Browne LP, Barker AJ. Use of compressed sensing to reduce scan time and breath-holding for cardiac cine balanced steady-state free precession magnetic resonance imaging in children and young adults. Pediatr Radiol. 2021 Jun;51(7):1192-1201. PubMed PMID: 33566124
  • Mukherjee D, Barker AJ. Using Simulation-Based Active Learning Strategies for Teaching Biofluids Concepts. J Biomech Eng. 2021 Dec 1;143(12). PubMed PMID: 34729587
  • Melena I, Bjornstad P, Schäfer M, Hunter KS, Barker AJ, Baumgartner A, Chung L, Wiromrat P, Truong U, Reusch JEB, Nadeau KJ. Serum copeptin and NT-proBNP is associated with central aortic stiffness and flow hemodynamics in adolescents with type 1 diabetes: A pilot study. J Diabetes Complications. 2021 May;35(5):107883. PubMed PMID: 33712333
  • Maredia A, Guzzardi D, Aleinati M, Iqbal F, Khaira A, Madhu A, Wang X, Barker AJ, McCarthy PM, Fedak PWM, Greenway SC. Aorta-specific DNA methylation patterns in cell-free DNA from patients with bicuspid aortic valve-associated aortopathy. Clin Epigenetics. 2021 Jul 28;13(1):147. PubMed PMID: 34321094
  • Fujiwara T, Berhane H, Scott MB, Englund EK, Schäfer M, Fonseca B, Berthusen A, Robinson JD, Rigsby CK, Browne LP, Markl M, Barker AJ. Segmentation of the Aorta and Pulmonary Arteries Based on 4D Flow MRI in the Pediatric Setting Using Fully Automated Multi-Site, Multi-Vendor, and Multi-Label Dense U-Net. J Magn Reson Imaging. 2021 Nov 18. [Epub ahead of print] PubMed PMID: 34792835
  • Chen V, Barker AJ, Golan R, Scott MB, Huh H, Wei Q, Sojoudi A, Markl M. Effect of age and sex on fully automated deep learning assessment of left ventricular function, volumes, and contours in cardiac magnetic resonance imaging. Int J Cardiovasc Imaging. 2021 Dec;37(12):3539-3547. PubMed PMID: 34185211
  • Michelena HI, Della Corte A, Evangelista A, Maleszewski JJ, Edwards WD, Roman MJ, Devereux RB, Fernández B, Asch FM, Barker AJ, Sierra-Galan LM, De Kerchove L, Fernandes SM, Fedak PWM, Girdauskas E, Delgado V, Abbara S, Lansac E, Prakash SK, Bissell MM, Popescu BA, Hope MD, Sitges M, Thourani VH, Pibarot P, Chandrasekaran K, Lancellotti P, Borger MA, Forrest JK, Webb J, Milewicz DM, Makkar R, Leon MB, Sanders SP, Markl M, Ferrari VA, Roberts WC, Song JK, Blanke P, White CS, Siu S, Svensson LG, Braverman AC, Bavaria J, Sundt TM, El Khoury G, De Paulis R, Enriquez-Sarano M, Bax JJ, Otto CM, Schäfers HJ. International consensus statement on nomenclature and classification of the congenital bicuspid aortic valve and its aortopathy, for clinical, surgical, interventional and research purposes. J Thorac Cardiovasc Surg. 2021 Sep;162(3):e383-e414. PubMed PMID: 34304896
  • Mahmoudi M, Farghadan A, McConnell D, Barker AJ, Wentzel JJ, Budoff MJ, Arzani A. The Story of Wall Shear Stress in Coronary Artery Atherosclerosis: Biochemical Transport and Mechanotransduction. J Biomech Eng. 2020 Nov 6. [Epub ahead of print] PubMed PMID: 33156343
  • Browne LP, Barker AJ, Vargas D. Imaging Follow-up of Repaired Aortic Coarctation. Semin Roentgenol. 2020 Jul;55(3):301-311. PubMed PMID: 32859346
  • Schäfer M, Ivy DD, Barker AJ, Mitchell MB. Reply to Commentary: Can't flow down: More 4-dimensional flow magnetic resonance imaging studies are needed in congenital heart disease. J Thorac Cardiovasc Surg. 2020 Oct;160(4):1019-1020. PubMed PMID: 32739168
  • Malone LJ, Olson A, Barker AJ, Mong DA, Weinman JP, Browne LP. Visualization of proximal coronary arteries on high-pitch electrocardiogram-triggered computed tomography in pediatric congenital heart disease: effects of heart rate and body surface area. Pediatr Radiol. 2020 Sep;50(10):1375-1380. PubMed PMID: 32696109
  • Schäfer M, Bjornstad P, Frank BS, Baumgartner A, Truong U, Enge D, von Alvensleben JC, Mitchell MB, Ivy DD, Barker AJ, Reusch JEB, Nadeau KJ. Frequency of Reduced Left Ventricular Contractile Efficiency and Discoordinated Myocardial Relaxation in Patients Aged 16 to 21 Years With Type 1 Diabetes Mellitus (from the Emerald Study). Am J Cardiol. 2020 Aug 1;128:45-53. PubMed PMID: 32650923
  • Sassoon DJ, Fujiwara T, Mitchell MB, Di Maria M, Barker AJ, Browne LP. Novel application of 4D flow magnetic resonance imaging in a neonatal post-operative aortic dissection. Eur Heart J Cardiovasc Imaging. 2020 Dec 1;21(12):1435. PubMed PMID: 32620965
  • Kalisz K, Scott M, Avery R, Sarnari R, Barker AJ, Carr JC, Markl M, Allen BD. Cardiac Magnetic Resonance Imaging Feature Tracking Demonstrates Altered Biventricular Strain in Obese Subjects in the Absence of Clinically Apparent Cardiovascular Disease. J Thorac Imaging. 2020 Jun 5. [Epub ahead of print] PubMed PMID: 32520847
  • Johnson EMI, Heller JA, Garcia Vicente F, Sarnari R, Gordon D, McCarthy PM, Barker AJ, Etemadi M, Markl M. Detecting Aortic Valve-Induced Abnormal Flow with Seismocardiography and Cardiac MRI. Ann Biomed Eng. 2020 Jun;48(6):1779-1792. PubMed PMID: 32180050
  • Schäfer M, Frank BS, Humphries SM, Hunter KS, Carmody KL, Jacobsen R, Mitchell MB, Jaggers J, Stone ML, Morgan GJ, Barker AJ, Browne LP, Ivy DD, Younoszai A, Di Maria MV. Flow profile characteristics in Fontan circulation are associated with the single ventricle dilation and function: principal component analysis study. Am J Physiol Heart Circ Physiol. 2020 May 1;318(5):H1032-H1040. PubMed PMID: 32167782
  • Berhane H, Scott M, Elbaz M, Jarvis K, McCarthy P, Carr J, Malaisrie C, Avery R, Barker AJ, Robinson JD, Rigsby CK, Markl M. Fully automated 3D aortic segmentation of 4D flow MRI for hemodynamic analysis using deep learning. Magn Reson Med. 2020 Oct;84(4):2204-2218. PubMed PMID: 32167203
  • Scott MB, Huh H, van Ooij P, Chen V, Herrera B, Elbaz M, McCarthy P, Malaisrie SC, Carr J, Fedak PWM, Markl M, Barker AJ. Impact of age, sex, and global function on normal aortic hemodynamics. Magn Reson Med. 2020 Oct;84(4):2088-2102. PubMed PMID: 32162416
  • Schäfer M, Browne LP, Jaggers J, Barker AJ, Morgan GJ, Ivy DD, Mitchell MB. Abnormal left ventricular flow organization following repair of tetralogy of Fallot. J Thorac Cardiovasc Surg. 2020 Oct;160(4):1008-1015. PubMed PMID: 31924354
  • Schäfer M, Barker AJ, Morgan GJ, Jaggers J, Stone ML, Browne LP, Ivy DD, Mitchell MB. Increased systolic vorticity in the left ventricular outflow tract is associated with abnormal aortic flow formations in Tetralogy of Fallot. Int J Cardiovasc Imaging. 2020 Apr;36(4):691-700. PubMed PMID: 31907684
  • Frank BS, Schäfer M, Douwes JM, Ivy DD, Abman SH, Davidson JA, Burzlaff S, Mitchell MB, Morgan GJ, Browne LP, Barker AJ, Truong U, von Alvensleben JC. Novel measures of left ventricular electromechanical discoordination predict clinical outcomes in children with pulmonary arterial hypertension. Am J Physiol Heart Circ Physiol. 2020 Feb 1;318(2):H401-H412. PubMed PMID: 31858817
  • Stefek HA, Lin KH, Rigsby CK, Michelena HI, Aouad P, Barker AJ, Robinson JD. Eccentric Enlargement of the Aortic Sinuses in Pediatric and Adult Patients with Bicuspid Aortic Valves: A Cardiac MRI Study. Pediatr Cardiol. 2020 Feb;41(2):350-360. PubMed PMID: 31858201
  • Jarvis K, Pruijssen JT, Son AY, Allen BD, Soulat G, Vali A, Barker AJ, Hoel AW, Eskandari MK, Malaisrie SC, Carr JC, Collins JD, Markl M. Parametric Hemodynamic 4D Flow MRI Maps for the Characterization of Chronic Thoracic Descending Aortic Dissection. J Magn Reson Imaging. 2020 May;51(5):1357-1368. PubMed PMID: 31714648
  • Johnson EMI, Etemadi M, Malaisrie SC, McCarthy PM, Markl M, Barker AJ. Seismocardiography and 4D flow MRI reveal impact of aortic valve replacement on chest acceleration and aortic hemodynamics. J Card Surg. 2020 Jan;35(1):232-235. PubMed PMID: 31614028
  • Schäfer M, Barker AJ, Jaggers J, Morgan GJ, Stone ML, Truong U, Browne LP, Malone L, Ivy DD, Mitchell MB. Abnormal aortic flow conduction is associated with increased viscous energy loss in patients with repaired tetralogy of Fallot. Eur J Cardiothorac Surg. 2020 Mar 1;57(3):588-595. PubMed PMID: 31535124
  • Suwa K, Rahman OA, Bollache E, Rose MJ, Rahsepar AA, Carr JC, Collins JD, Barker AJ, Markl M. Effect of Aortic Valve Disease on 3D Hemodynamics in Patients With Aortic Dilation and Trileaflet Aortic Valve Morphology. J Magn Reson Imaging. 2020 Feb;51(2):481-491. PubMed PMID: 31169969
  • Suwa K, Rahman OA, Bollache E, Rose MJ, Rahsepar AA, Carr JC, Collins JD, Barker AJ, Markl M. Effect of Aortic Valve Disease on 3D Hemodynamics in Patients With Aortic Dilation and Trileaflet Aortic Valve Morphology. J Magn Reson Imaging. 2020 Feb;51(2):481-491. PubMed PMID: 31169969
  • Allen BD, Aouad PJ, Burris NS, Rahsepar AA, Jarvis KB, Francois CJ, Barker AJ, Malaisrie SC, Carr JC, Collins JD, Markl M. Detection and Hemodynamic Evaluation of Flap Fenestrations in Type B Aortic Dissection with 4D Flow MRI: Comparison with Conventional MRI and CTA. Radiol Cardiothorac Imaging. 2019 Apr;1(1). PubMed PMID: 31598608
  • Bollache E, Fedak PWM, Markl M, Barker AJ. On the 'cusp' of clinical feasibility: aortic wall shear stress derived non-invasively with 4D flow MRI. J Thorac Dis. 2019 Jul;11(7):E96-E97. PubMed PMID: 31463155
  • Elbaz MSM, Scott MB, Barker AJ, McCarthy P, Malaisrie C, Collins JD, Bonow RO, Carr J, Markl M. Four-dimensional Virtual Catheter: Noninvasive Assessment of Intra-aortic Hemodynamics in Bicuspid Aortic Valve Disease. Radiology. 2019 Dec;293(3):541-550. PubMed PMID: 31592729
  • Frank B, Schäfer M, Douwes JM, Ivy DD, Abman SH, Davidson JA, Burzlaff S, Mitchell MB, Morgan GJ, Browne L, Barker AJ, Truong U, Von Alvensleben JC. Novel Measures of Left Ventricular Electromechanical Discoordination Predict Clinical Outcomes in Children with Pulmonary Arterial Hypertension. Am J Physiol Heart Circ Physiol. 2019 Dec 20. [Epub ahead of print] PubMed PMID: 31858817
  • Friesen RM, Schäfer M, Ivy DD, Abman SH, Stenmark K, Browne LP, Barker AJ, Hunter KS, Truong U. Proximal pulmonary vascular stiffness as a prognostic factor in children with pulmonary arterial hypertension. Eur Heart J Cardiovasc Imaging. 2019 Feb 1;20(2):209-217. PubMed PMID: 29788051
  • Garcia J, Barker AJ, Markl M. The Role of Imaging of Flow Patterns by 4D Flow MRI in Aortic Stenosis. JACC Cardiovasc Imaging. 2019 Feb;12(2):252-266. PubMed PMID: 30732721
  • Jarvis K, Pruijssen JT, Son AY, Allen BD, Soulat G, Vali A, Barker AJ, Hoel AW, Eskandari MK, Malaisrie SC, Carr JC, Collins JD, Markl M. Parametric Hemodynamic 4D Flow MRI Maps for the Characterization of Chronic Thoracic Descending Aortic Dissection. J Magn Reson Imaging. 2019 Nov 12. [Epub ahead of print] PubMed PMID: 31714648
  • Jarvis K, Schnell S, Barker AJ, Rose M, Robinson JD, Rigsby CK, Markl M. Caval to pulmonary 3D flow distribution in patients with Fontan circulation and impact of potential 4D flow MRI error sources. Magn Reson Med. 2019 Feb;81(2):1205-1218. PubMed PMID: 30277276
  • Ma LE, Markl M, Chow K, Huh H, Forman C, Vali A, Greiser A, Carr J, Schnell S, Barker AJ, Jin N. Aortic 4D flow MRI in 2 minutes using compressed sensing, respiratory controlled adaptive k-space reordering, and inline reconstruction. Magn Reson Med. 2019 Jun;81(6):3675-3690. PubMed PMID: 30803006
  • McLennan D, Schäfer M, Mitchell MB, Morgan GJ, Ivy D, Barker AJ, Jacobsen R. Usefulness of 4D-Flow MRI in Mapping Flow Distribution Through Failing Fontan Circulation Prior to Cardiac Intervention. Pediatr Cardiol. 2019 Jun;40(5):1093-1096. PubMed PMID: 30982076
  • Rahman O, Scott M, Bollache E, Suwa K, Collins J, Carr J, Fedak P, McCarthy P, Malaisrie C, Barker AJ, Markl M. Interval changes in aortic peak velocity and wall shear stress in patients with bicuspid aortic valve disease. Int J Cardiovasc Imaging. 2019 Oct;35(10):1925-1934. PubMed PMID: 31144256
  • Robinson JD, Rose MJ, Joh M, Jarvis K, Schnell S, Barker AJ, Rigsby CK, Markl M. 4-D flow magnetic-resonance-imaging-derived energetic biomarkers are abnormal in children with repaired tetralogy of Fallot and associated with disease severity. Pediatr Radiol. 2019 Mar;49(3):308-317. PubMed PMID: 30506329
  • Rose MJ, Rigsby CK, Berhane H, Bollache E, Jarvis K, Barker AJ, Schnell S, Allen BD, Robinson JD, Markl M. 4-D flow MRI aortic 3-D hemodynamics and wall shear stress remain stable over short-term follow-up in pediatric and young adult patients with bicuspid aortic valve. Pediatr Radiol. 2019 Jan;49(1):57-67. PubMed PMID: 30203126
  • Schäfer M, Barker AJ, Jaggers J, Morgan GJ, Stone ML, Truong U, Browne LP, Malone L, Ivy DD, Mitchell MB. Abnormal aortic flow conduction is associated with increased viscous energy loss in patients with repaired tetralogy of Fallot. Eur J Cardiothorac Surg. 2019 Sep 18. [Epub ahead of print] PubMed PMID: 31535124
  • Schäfer M, Browne LP, Jaggers J, Barker AJ, Morgan GJ, Ivy DD, Mitchell MB. Abnormal left ventricular flow organization following repair of tetralogy of Fallot. J Thorac Cardiovasc Surg. 2019 Nov 22. [Epub ahead of print] PubMed PMID: 31924354
  • Schäfer M, Frank BS, Ivy DD, Wilson N, Morgan GJ, Barker AJ, Browne LP, Mitchell MB, Truong U. Close look at the Potts shunt flow hemodynamics in a patient with severe pulmonary hypertension: 4D-flow MRI evaluation. J Magn Reson Imaging. 2019 Jun;49(6):1800-1802. PubMed PMID: 30451346
  • Schäfer M, Ivy DD, Abman SH, Stenmark K, Browne LP, Barker AJ, Mitchell MB, Morgan GJ, Wilson N, Shah A, Kollengode M, Naresh N, Fonseca B, DiMaria M, Buckner JK, Hunter KS, Kheyfets V, Fenster BE, Truong U. Differences in pulmonary arterial flow hemodynamics between children and adults with pulmonary arterial hypertension as assessed by 4D-flow CMR studies. Am J Physiol Heart Circ Physiol. 2019 May 1;316(5):H1091-H1104. PubMed PMID: 30822118
  • Shan Y, Li J, Wang Y, Wu B, Barker AJ, Markl M, Wang C, Wang X, Shu X. Aortic stenosis exacerbates flow aberrations related to the bicuspid aortic valve fusion pattern and the aortopathy phenotype. Eur J Cardiothorac Surg. 2019 Mar 1;55(3):534-542. PubMed PMID: 30215695
  • Stefek HA, Lin KH, Rigsby CK, Michelena HI, Aouad P, Barker AJ, Robinson JD. Eccentric Enlargement of the Aortic Sinuses in Pediatric and Adult Patients with Bicuspid Aortic Valves: A Cardiac MRI Study. Pediatr Cardiol. 2019 Dec 19. [Epub ahead of print] PubMed PMID: 31858201
  • Zhong L, Schrauben EM, Garcia J, Uribe S, Grieve SM, Elbaz MSM, Barker AJ, Geiger J, Nordmeyer S, Marsden A, Carlsson M, Tan RS, Garg P, Westenberg JJM, Markl M, Ebbers T. Intracardiac 4D Flow MRI in Congenital Heart Disease: Recommendations on Behalf of the ISMRM Flow & Motion Study Group. J Magn Reson Imaging. 2019 Sep;50(3):677-681. PubMed PMID: 31317587
  • Robinson JD, Rose MJ, Joh M, Jarvis K, Schnell S, Barker AJ, Rigsby CK, Markl M. 4-D flow magnetic-resonance-imaging-derived energetic biomarkers are abnormal in children with repaired tetralogy of Fallot and associated with disease severity. Pediatr Radiol. 2018 Dec 1. [Epub ahead of print] PubMed PMID: 30506329
  • Ma LE, Vali A, Blanken C, Barker AJ, Malaisrie C, McCarthy P, Collins JD, Carr JC, Schnell S, Markl M. Altered Aortic 3-Dimensional Hemodynamics in Patients With Functionally Unicuspid Aortic Valves. Circ Cardiovasc Imaging. 2018 Aug;11(8):e007915. PubMed PMID: 30354500
  • Shan Y, Li J, Wang Y, Wu B, Barker AJ, Markl M, Wang C, Wang X, Shu X. Aortic stenosis exacerbates flow aberrations related to the bicuspid aortic valve fusion pattern and the aortopathy phenotype. Eur J Cardiothorac Surg. 2018 Sep 11. [Epub ahead of print] PubMed PMID: 30215695
  • Bollache E, Guzzardi DG, Sattari S, Olsen KE, Di Martino ES, Malaisrie SC, van Ooij P, Collins J, Carr J, McCarthy PM, Markl M, Barker AJ, Fedak PWM. Aortic valve-mediated wall shear stress is heterogeneous and predicts regional aortic elastic fiber thinning in bicuspid aortic valve-associated aortopathy. J Thorac Cardiovasc Surg. 2018 Dec;156(6):2112-2120.e2. PubMed PMID: 30060930
  • Borger MA, Fedak PWM, Stephens EH, Gleason TG, Girdauskas E, Ikonomidis JS, Khoynezhad A, Siu SC, Verma S, Hope MD, Cameron DE, Hammer DF, Coselli JS, Moon MR, Sundt TM, Barker AJ, Markl M, Della Corte A, Michelena HI, Elefteriades JA. The American Association for Thoracic Surgery consensus guidelines on bicuspid aortic valve-related aortopathy: Full online-only version. J Thorac Cardiovasc Surg. 2018 Aug;156(2):e41-e74. PubMed PMID: 30011777
  • Borger MA, Fedak PWM, Stephens EH, Gleason TG, Girdauskas E, Ikonomidis JS, Khoynezhad A, Siu SC, Verma S, Hope MD, Cameron DE, Hammer DF, Coselli JS, Moon MR, Sundt TM, Barker AJ, Markl M, Della Corte A, Michelena HI, Elefteriades JA. The American Association for Thoracic Surgery consensus guidelines on bicuspid aortic valve-related aortopathy: Executive summary. J Thorac Cardiovasc Surg. 2018 Aug;156(2):473-480. PubMed PMID: 30011756
  • Schäfer M, Wilson N, Ivy DD, Ing R, Abman S, Browne LP, Morgan G, Ross M, McLennan D, Barker AJ, Fonseca B, Di Maria M, Hunter KS, Truong U. Noninvasive wave intensity analysis predicts functional worsening in children with pulmonary arterial hypertension. Am J Physiol Heart Circ Physiol. 2018 Oct 1;315(4):H968-H977. PubMed PMID: 30004811
  • Friesen RM, Schäfer M, Ivy DD, Abman SH, Stenmark K, Browne LP, Barker AJ, Hunter KS, Truong U. Proximal pulmonary vascular stiffness as a prognostic factor in children with pulmonary arterial hypertension. Eur Heart J Cardiovasc Imaging. 2018 May 16. [Epub ahead of print] PubMed PMID: 29788051
  • Schäfer M, Truong U, Ivy DD, Fonseca B, Malone L, DiMaria M, Barker AJ, Vargas D, Hunter KS, Jone PN, Browne LP. Children with kawasaki disease present elevated stiffness of great arteries: Phase-contrast MRI study. J Magn Reson Imaging. 2018 Nov;48(5):1228-1236. PubMed PMID: 29707843
  • Schäfer M, Browne LP, Truong U, Jaggers JJ, Mitchell MB, Malone L, Morgan G, Chatfield K, McLennan D, Turbendian H, Vargas D, Fonseca B, DiMaria M, Shah A, Ivy MP, Barker AJ, Hunter KS, Wilson N, Ivy DD, Campbell DN. Aortic stiffness in adolescent Turner and Marfan syndrome patients. Eur J Cardiothorac Surg. 2018 Nov 1;54(5):926-932. PubMed PMID: 29684119
  • Schäfer M, Morgan GJ, Mitchell MB, Ross M, Barker AJ, Hunter KS, Fonseca B, DiMaria M, Vargas D, Ivy DD, Wilson N, Browne LP. Impact of different coarctation therapies on aortic stiffness: phase-contrast MRI study. Int J Cardiovasc Imaging. 2018 Sep;34(9):1459-1469. PubMed PMID: 29667078
  • Barker AJ, Markl M, Fedak PWM. Assessing wall stresses in bicuspid aortic valve-associated aortopathy: Forecasting the perfect storm?. J Thorac Cardiovasc Surg. 2018 Aug;156(2):471-472. PubMed PMID: 29666014
  • Bollache E, Fedak PWM, van Ooij P, Rahman O, Malaisrie SC, McCarthy PM, Carr JC, Powell A, Collins JD, Markl M, Barker AJ. Perioperative evaluation of regional aortic wall shear stress patterns in patients undergoing aortic valve and/or proximal thoracic aortic replacement. J Thorac Cardiovasc Surg. 2018 Jun;155(6):2277-2286.e2. PubMed PMID: 29248286
  • Geiger J, Rahsepar AA, Suwa K, Powell A, Ghasemiesfe A, Barker AJ, Collins JD, Carr JC, Markl M. 4D flow MRI, cardiac function, and T(1) -mapping: Association of valve-mediated changes in aortic hemodynamics with left ventricular remodeling. J Magn Reson Imaging. 2018 Jul;48(1):121-131. PubMed PMID: 29206322
  • Keenan KE, Ainslie M, Barker AJ, Boss MA, Cecil KM, Charles C, Chenevert TL, Clarke L, Evelhoch JL, Finn P, Gembris D, Gunter JL, Hill DLG, Jack CR Jr, Jackson EF, Liu G, Russek SE, Sharma SD, Steckner M, Stupic KF, Trzasko JD, Yuan C, Zheng J. Quantitative magnetic resonance imaging phantoms: A review and the need for a system phantom. Magn Reson Med. 2018 Jan;79(1):48-61. PubMed PMID: 29083101
  • Schäfer M, Kheyfets VO, Barker AJ, Stenmark K, Hunter KS, McClatchey PM, Buckner JK, Reece TB, Jazaeri O, Fenster BE. Reduced shear stress and associated aortic deformation in the thoracic aorta of patients with chronic obstructive pulmonary disease. J Vasc Surg. 2018 Jul;68(1):246-253. PubMed PMID: 28986100
  • Shen X, Schnell S, Barker AJ, Suwa K, Tashakkor L, Jarvis K, Carr JC, Collins JD, Prabhakaran S, Markl M. Voxel-by-voxel 4D flow MRI-based assessment of regional reverse flow in the aorta. J Magn Reson Imaging. 2018 May;47(5):1276-1286. PubMed PMID: 28925047
  • Garcia J, van der Palen RLF, Bollache E, Jarvis K, Rose MJ, Barker AJ, Collins JD, Carr JC, Robinson J, Rigsby CK, Markl M. Distribution of blood flow velocity in the normal aorta: Effect of age and gender. J Magn Reson Imaging. 2018 Feb;47(2):487-498. PubMed PMID: 28556277
  • Raghav V, Barker AJ, Mangiameli D, Mirabella L, Markl M, Yoganathan AP. Valve mediated hemodynamics and their association with distal ascending aortic diameter in bicuspid aortic valve subjects. J Magn Reson Imaging. 2018 Jan;47(1):246-254. PubMed PMID: 28390180
  • Bollache E, Barker AJ, Dolan RS, Carr JC, van Ooij P, Ahmadian R, Powell A, Collins JD, Geiger J, Markl M. k-t accelerated aortic 4D flow MRI in under two minutes: Feasibility and impact of resolution, k-space sampling patterns, and respiratory navigator gating on hemodynamic measurements. Magn Reson Med. 2018 Jan;79(1):195-207. PubMed PMID: 28266062
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Professional Memberships

  • ISMRM, Member
  • SCMR, Member

Practice Locations

Hospital Affiliation
  • Children's Hospital Colorado

General Information

Graduate Schools:
  • PhD, University of Colorado - Boulder (2008)
Undergraduate Schools:
  • BS, University of Colorado - Boulder (CO) (1999)
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Languages: English
Department: Radiology
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Contact Us
CU Anschutz
Fitzsimons Building
13001 East 17th Place
Campus Box C290
Aurora, CO 80045

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