Left ventricular motion reconstruction from planar tagged MR images: a comparison

Abstract

Through recent development of MR techniques, it is now possible to assess regional myocardial wall function in a non-invasive way. Using MR tagging, space is marked with planes which deform with the tissue, providing markers for tracking the local motion of the myocardium. Numerous methods to reconstruct the three-dimensional displacement field have been developed. The aim of this article is to provide a framework to quantitatively compare the performance of four methods the authors have developed. Five sets of experiments are described, and their results are reported. Instructions are also provided to perform similar tests on any method using the same data.The experiments show that some characteristic properties of the methods, such as sensitivity to noise or spatial resolution, can be quantitatively classified. Cross-comparison of performances show what range values for these properties can be considered acceptable.

Combined tag tracking and strain reconstruction from tagged cardiac MR images without user‐defined myocardial contours

“…Part of the error comes from the fact that different tracking algorithms will compute different tag line centers, and part of the error comes from the data smoothing effect of the deformation model. In Declerck et al (23), the second type of tag line errors were reported for four existing cardiac deformation reconstruction algorithms (6,8,14,23), and these errors ranged from 0.5 to 1.0 pixel. The RMS tag line errors in this article are also in this range, and include the inherent errors of tracking tag lines in noisy data, which are not included in the errors reported by Declerck et al (23).…”

“…In Declerck et al (23), the second type of tag line errors were reported for four existing cardiac deformation reconstruction algorithms (6,8,14,23), and these errors ranged from 0.5 to 1.0 pixel. The RMS tag line errors in this article are also in this range, and include the inherent errors of tracking tag lines in noisy data, which are not included in the errors reported by Declerck et al (23). From this perspective, the RMS tag line differences reported for COTTER are comparable to and possibly better than those reported by existing techniques.…”

“…The second type of error is caused when a deformation model is fit to the tag line data; the model does not fit the tag lines exactly. The RMS difference between the tracked tag lines and synthetic tag lines generated by the deformation model is used to assess the quality of the deformation reconstruction (6,8,13,14,23). The RMS tag line errors reported in this article are a combination of these two errors, because the deformation model is used to track the tag lines.…”

Imaging myocardial strain

“…A number of approaches can be employed to perform this estimation. The tag data can be interpolated to solve iteratively for a set of discrete displacements [49], the data can be used to solve for low-order basis functions in finite element models of the heart [70], or the displacement field of the entire left ventricle can be fit using all of the available data [23], [53], [54]. Recently parameter-free models of left ventricular strain have been developed [25], as well as field models based on B-splines [3], [56].…”

“…Recently parameter-free models of left ventricular strain have been developed [25], as well as field models based on B-splines [3], [56]. Each of these methods has different tradeoffs between the stability of the solution, and the spatial resolution of the strain field [23]. Fig.…”