Assessment of Cardio- & Neurovascular Hemodynamics in the Human Circulatory System using 4D flow MRI Michael Markl, Ph.D. Departments of Radiology & Biomedical Engineering Northwestern University, Chicago, IL, USA Ensight UGM, Tokyo, October 2014
Outline Methodology: Measurement of 3D blood in the human body based on 4D flow MRI. Use of Ensight: 3D visualization & quantification of cardiovascular hemodynamics. Applications: Examples of clinical relevant questions. Potential of 4D flow & Ensight to improve diagnostics. Demonstration: Use of Ensight for analysis of 3D blood flow for a clinical case of congenital heart disease.
Cardiovascular Imaging Northwestern 737 N. Michigan Ave
Cardiovascular Imaging Northwestern Imaging Core 'Center for Translational Imaging' Director: Andrew Larson, Ph.D. Neuroimaging fmri (Todd Parrish, PhD) Cardiovascular Imaging (Michael Markl, PhD) Small Animal Molecular Imaging (Daniel Procissi, PhD)
Magnetic Resonance Imaging Background MRI of the Human Body external magnetic fields no harmful radiation high soft tissue contrast flexible image orientation
MRI How to generate image contrast? Image Contrast Many mechanisms 9 Angiography 6 3 Tissue perfusion Neuronal activity Source Water Fat
Cardiovascular MRI Imaging of Blood Flow MR Signal = Vector Signal Phase ~ Flow Measurement of blood flow
Cardiovascular MRI Imaging of Blood Flow 1960: Detection of Flow / Motion with MRI, E. Hahn E. Hahn 1982-91: Direct Measurements of flow / tissue motion Initial clinical applications Moran PR. Magn Reson Imaging, 1:197 203, 1982 O Donnell M. Med Phys, 12:59 64, 1985, Nayler GL et al. J Comput Assist Tomogr, 10:715 722, 1986 Pelc NJ et al. J Magn Reson Imaging, 1:405 413, 1991
Cardiovascular MRI Imaging of Blood Flow 2D Phase-Contrast (PC) MRI ECG synchronized Anatomy and pulsatile blood flow Aorta, 3D CE-MRA Anatomy Flow y x Flow, z
Cardiovascular MRI Imaging of Blood Flow Flow Quantification Net flow, cardiac output Regurgitation, valve function, peak velocity, etc.
MR Imaging 4D Flow Data Methods Res. ~ (1.5-2.5mm) 3 T Res ~ 30-60ms T Acq ~ 5-15min respiration control 4D (3D volume + time) flow (3-dir. velocity encoding) MRI
Flow sensitive 4D Data 3D Visualization Methods Ensight, CEI - pathlines Adaptive navigator respiration control Res. ~ 2mm 3, T Res ~ 40ms, T Acq ~ 10-15min 4D (3D volume + time) flow (3-dir. velocity encoding) MRI
Applications Ensight, CEI streamlines Normal volunteer: Coherent systolic streamlines Bicuspid Aortic Valve (BAV): Flow jet & wall impingement Barker AJ, et al. Circ Cardiovasc Imaging 2012;5(4):457-466 Mahadevia R, et al. Circulation 2014;129:673-82
Applications Carotid arteries Portal vein
Congenital Heart Disease normal heart congenital heart disease
Congenital Heart Disease Single Ventricle Physiology Fontan Circulation complete reworking of cardiovascular system Normal cardiovascular physiology: After surgical Fontan correction: Gaca AM et al. Radiology 2008; 247: 617-63
Congenital Heart Disease Single Ventricle Physiology: Fontan Circulation AAo PA IVC SVC RRV LPV Markl M, et al. J Magn Reson Imaging. 2012;35:933 937
Congenital Heart Disease
Congenital Heart Disease Single Ventricle Physiology single ventricle extracardiac TCPC
Congenital Heart Disease Background Fontan Circulation Some patients develop Failing Fontan physiology Caval blood distribution to PAs Suspected to influence patient outcome through delivery of protein-rich venous return Pulmonary arteriovenous malformations, fistulas (PAVF) PAVF Shah MJ, et al. Ann Thorac Surg. 1997;63:960-3. Hiramatsu et al. Ann Thorac Cardiovasc Surg, 2008
Congenital Heart Disease Fontan Circulation: Flow Distribution Quantification
Congenital Heart Disease Flow Asymmetry: Relationship with Fontan Geometry
Congenital Heart Disease Congenital Heart Disease Significance - Long scan times & general anesthesia in young patients - Complex CHD: standard parameters provide incomplete risk stratification
Congenital Heart Disease Congenital Heart Disease Innovation - Reduced scan time & exposure to anesthesia - 4D flow: New imaging biomarkers for improved evaluation / risk stratification of CHD
Arteriovenous Malformation AVM Complex vascular network No intervening capillary bed hemorrhagic stroke Risk Stratification & Treatment Spetzler-Martin grade (SMG) X-ray angio & staged embolization 4D flow MRI AVM treatment monitoring pre-intervention assessment Arteriovenous malformations of the brain in adults. N Engl J Med 1999;340:1812-1818 Spetzler RF, Martin NA. J Neurosurg 1986;65:476-483 Stapf C, et al. Neurology 2006;66(9):1350-1355 Batjer HH, et al. Neurosurgery 1988;23(3):322-328 Kader A, et al.. Neurosurgery 1994;34(5):801-807 http://www.taafonline.org
Peak Velocity [m/s] Blood Flow [ml/s] 4D Flow MRI Arteriovenous Malformation mag 4D flow Raw Data Pre-Processing 3D PC-MRA v z mag v z v x v y v x v y denoise velocity anti-aliasing eddy-current correction Flow Quantification 1.0 Peak Velocities 8 Blood Flow 0.8 0.6 0.4 0.2 6 4 2 0.0 0 200 Time 400 [ms] 600 800 1000 0 0 200 400 Time [ms] 600 800 1000 3D Flow Visualization
Arteriovenous Malformation 3D PC-MRA & Time-Resolved Pathlines vessel anatomy & 3D blood flow over cardiac cycle large unruptured AVM SMG = 4
Arteriovenous Malformation Time-Integrated Pathlines vessel anatomy & cumulative flow over cardiac cycle large unruptured AVM SMG = 4
Arteriovenous Malformation Heterogeneity in 3D flow despite identical SMG
AVM-11 Arteriovenous Malformation Vascular Network Diagram SMG-A: low-grade AVM SMG = 2 Analysis planes: feeding arteries, contralateral arteries, draining veins, straight sinus
AVM-14 Arteriovenous Malformation Vascular Network Diagram SMG-B: high-grade AVM SMG = 4 Analysis planes: feeding arteries, contralateral arteries, draining veins, straight sinus
Arteriovenous Malformation Follow-up during Embolization large AVM SMG = 4 compacting of AVM redistribution of peak velocities Ansari S, et al. AJNR 2013
Arteriovenous Malformation 3D Flow Connectivity Mapping Tag individual vessels Color coding = origin of blood flow Complex feeding & draining patterns Ansari S, et al. AJNR 2013
Arteriovenous Malformation 3D Flow Connectivity Mapping: Visualization of complex feeding & draining patterns Ansari S, et al. AJNR 2013
Arteriovenous Malformation Intracranial 4D Flow MRI Visualization of AVM vascular network Complex & individually different flow despite similar SMG AVM Treatment Monitoring Staged Embolization: Marked changes in velocities in all territories including sagittal sinus & contralateral arteries Systemic impact of embolization on cerebral flow Pre-Operative Assessment Complex feeding & draining patterns treatment planning?
Pre- Processing Data Analysis 3D Flow Visualization 4D Flow Data Corrections Maxwell Eddy currents Anti-aliasing Data Preparation Noise masking 3D-PC-MRA Demo Ensight, CEI
Congenital Heart Disease Patient : 39-y hockey player, aortic bypass & hypoplastic DAo neurological symptoms at rest # - resolved with exercise # upper extremity weakness, dizziness, visual changes, facial tingling
Congenital Heart Disease Patient Aortic bypass & hypoplastic DAo Repeat 4D Flow after 1.5mg Atropine Mimic effect of exercise on flow Increase in heart rate 45 67-71 bpm Decrease in retrograde fraction Gupta S, et al. Circulation. 2012;125:e347-349
Evolving Technology Quantification & Biomechanical Modeling Wall shear stress 1-5 Pressure difference mapping 6-8 Turbulence & turbulent kinetic energy 9,10 Pulse wave velocity & vessel elasticity 11-15. 1. Stalder AF, et al. Magn Reson Med 2008;60(5):1218-1231. 2. Oshinski JN, et al. J Magn Reson Imaging 1995;5(6):640-647. 3. Oyre S, et al. Eur J Vasc Endovasc Surg 1998;16(6):517-524. 4. Harloff A, et al. Magn Reson Med. 2010;63(6):1529-1536 5. Frydrychowicz A et al. J Magn Reson Imaging. 2009;30(1):77-84 6. Ebbers T, et al. Biomech Eng 2002;124(3):288-293. 7. Tyszka JM, et al. J Magn Reson Imaging 2000;12(2):321-329. 8. Bock J, et al. Magn Reson Med 2011;66(4):1079-1088. 9. Dyverfeldt P, et al. Magn Reson Med 2006;56(4):850-858. 10. Stalder A.F. et al. J Magn Reson Imaging 2011; 33: 839 846 11. Laffon E, et al. J Magn Reson Imaging 2005;21(1):53-58. 12. Markl M, et al. Magn Reson Med 2010;63(6):1575-1582. 13. Peng HH, et al. J Magn Reson Imaging 2006;24(6):1303-1310. 14. Vulliemoz S, et al. Magn Reson Med 2002;47(4):649-654. 15. Hardy CJ, et al. Magn Reson Med 1994;31(5):513-520
Evolving Technology Patient - re-stenosis & post-stenotic dilatation
Summary 4D flow MRI can measurement in-vivo 3D blood in the human body Ensight can be employed for o 3D visualization of complex blood flow characteristics o Quantification of flow parameters Applications: Improved understanding of the impact of cardiovascular disease on hemodynamics