Cardiac Research Page

Heart volume and shape

I started work in 3D ultrasound in Roy Martin's laboratory in the Department of Bioengineering. We used an Ascension Technology magnetic tracking system to register 2D images in space and create 3D reconstructions of the heart. Some examples of the results are shown below.

The following images are a few of the slides I used for my talk at the meeting of the Canadian Cardiovascular Society in Montreal (October 1996), entitled "Three-Dimensional Echocardiography by Rapid Free Scanning From Multiple Transthoracic Windows." CCS 96 Abstract

A paper on 3D shape analysis of the left ventricle has been published in the Journal of the American Society of Echocardiography. Abstract

Note: The figures in this paper were printed incorrectly in some cases; correct full-size figures can be found on a separate page: Shape Paper Figures

Some additional figures related to the technique are shown below:

Cylinder imaged in vitro with ideal surface points on left and traced points on right. The red lines in the right figure indicate the radial distance from the traced to the ideal points. This method was used to characterize the error in reconstruction of known geometric shapes using our 3D ultrasound imaging system.

Ventricle at end diastole in 2D profile showing surface points (yellow circles) and distances from center axis (blue lines). The reconstruction has been down-sampled by 10 for clarity. The axis is drawn from the mitral valve centroid to the apex. The distances from the central axis are used to characterize the shape of the endocardial cavity. Mitral valve points: light blue circles.

Mean maps of distances from the ventricle center axis at end diastole derived from 5 normal subjects. The segments represent regions of the ventricle wall from the apex (center ring) to base (outer ring). The distances on the color bar are in percent of the center axis length. White dot indicates angular position of aorta.

Individual maps of difference from the mean normal shape map for (left to right) normal, aortic stenosis and cardiomyopathy at end diastole. Color bar shows mapping of number of standard deviations (-5 to 5) to color. White dot indicates angular position of aorta.

Reconstructions at end diastole with difference colors mapped to wall segments (aorta on far side). Left to right: normal, aortic stenosis, cardiomyopathy. Colors same as maps above, except gray indicates segments above mitral valve centroid.

Modified distance measurement technique for the apical section. Distance measurements (blue lines) are shown for every 4th surface point.