Magnetic resonance imaging analysis of left ventricular function in normal and spontaneously hypertensive rats
We have used magnetic resonance imaging (MRI) to examine acute morphological changes in the left ventricle throughout the cardiac cycle in normal Wistar Kyoto rats (WKY) and also to follow the development of chronic changes in spontaneously hypertensive rats (SHR). This involved the development of M...
Saved in:
Published in | The Journal of physiology Vol. 513; no. 3; pp. 873 - 887 |
---|---|
Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Oxford, UK
The Physiological Society
15.12.1998
Blackwell Science Ltd Blackwell Science Inc |
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | We have used magnetic resonance imaging (MRI) to examine acute morphological changes in the left ventricle throughout the
cardiac cycle in normal Wistar Kyoto rats (WKY) and also to follow the development of chronic changes in spontaneously hypertensive
rats (SHR). This involved the development of MRI and quantitative analysis techniques for characterizing contractile changes
during the cardiac cycle.
Images of the cardiac anatomy in two age groups (8 and 12 weeks old) of young anaesthetized adult normal WKY and SHR were
acquired in planes both parallel and perpendicular to the principal cardiac axis.
Complete coverage of the heart by imaging planes was achieved with high time resolution (13 ms), with typically 12 time frames
in the cardiac cycle, using a short echo time (5 ms) multislice gradient-echo imaging sequence. Imaging was synchronized to
the R wave of the electrocardiogram.
The image slices could be reconstructed into complete geometrically and temporally coherent three-dimensional data sets. Left
ventricular (LV) volumes were thus reconstructed throughout the cardiac cycle by combining transverse cardiac image sections.
This volume analysis revealed structural and functional differences between the normal WKY and SHR in both age groups of 8
and 12 weeks. Measurements from the cardiac images were additionally validated against histological measurements.
The SHR showed a raised LV end-systolic volume and a correspondingly poorer ejection fraction as well as LV hypertrophy when
compared with the controls. Left ventricular function in the SHR appeared stable between the two age groups.
We developed a simple geometrical model of the left ventricle based on a single longitudinal image section and successfully
used this to describe some functional parameters of the left ventricle in the WKY and SHR. This geometrical model has the
potential to greatly reduce the imaging time needed to study the beating heart in future serial investigations of cardiac
physiology in rats.
Our experimental and analytical methods together form a powerful set of quantitative techniques which combine both imaging
and functional analysis and will be applicable for future studies of chronic physiological changes in animal disease models. |
---|---|
Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 ObjectType-Article-2 ObjectType-Feature-1 |
ISSN: | 0022-3751 1469-7793 |
DOI: | 10.1111/j.1469-7793.1998.873ba.x |