Auckland Bioengineering Institute


Cardiovascular Magnetic Resonance

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Cardiovascular magnetic resonance (CMR) imaging is capable of providing a wealth of information on heart geometry, tissue microstructure, regional wall motion, myocardial strain and strain relaxation, blood flow, perfusion and viability. However, CMR continues to be underutilized clinically, mainly due to the complex image analysis and lack of integrated biophysical evaluation procedures.

Developing new methods to understand cardiac function


We aim to develop new methods and indices to quantify cardiac function using clinical CMR images. We create biophysical models of heart structure and function to allow fast, integrated analysis of time-varying three-dimensional MRI data. Model-based image processing algorithms allow incorporation of high level expert knowledge into the low level tasks of image analysis. The technological advances arising from this work will significantly enhance the clinical evaluation of patients and treatment benefit.

Cardiovascular magnetic resonance analysis software


We have developed clinical CMR analysis software, which is being used clinically at Auckland Hospital and clinical research sites worldwide. Our biophysical models will further understanding of the processes underlying heart failure, pressure overload hypertrophy, myocardial infarction and diabetic cardio-myopathy. This research is a multidisciplinary collaboration including cardiologists, radiologists, physiologists, computer scientists and bioengineers.

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Magentic resonance images of the heart


Three-dimensional display of magentic resonance short and long axis images of the heart, in relation to a mathematical model of the left ventricle. The model is fitted to the images interactively using guide-point modelling (Radiology 2000; 216(2):597-602). Ventricular mass and volume are calculated up to the mitral valve plane (yellow disc), in order to correct for errors due to the longitudinal motion of the base.

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A cyclindrical phantom undergoing inflation


A deformable MR phantom was built to test methods of estimating stress and material stiffness from non-invasive MR images. This shows a cyclindrical phantom undergoing inflation. Tagged MR images allow measurement of 3D deformation (strain). A knowledge of the boundary conditions allows calculation of stress (coloured) and material stiffness.

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Orientation of the heart muscle fibre architecture


MRI can also be used to study the microstructure of cardiac muscle. This picture shows the orientation of the muscle fibre architecture in a cross-section of a heart. Blue denotes an angle of –60 degrees, green 0 degrees (in the plane of the image) and red 90 degrees.

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3D outline of a large anterolateral myocardial infarction


MRI tagging allows calculation of 3D strain maps in the beating heart. Also, a Gadolinium contrast agent can be injected intravenously to image regions of scar in the heart muscle. This picture shows the 3D outline of a large anterolateral myocardial infarction (red crosses), in relation to the 3D strain map obtained from MR tagging. Blue is normal contraction strain (20%) and red is impaired (0%) contraction.

Funding partners


The Cardiovascular Magnetic Resonance Group gratefully acknowledges the support of its funding partners: