Jpa. Kuijer et al., Three-dimensional myocardial strain analysis based on short- and long-axismagnetic resonance tagged images using a 1D displacement field, MAGN RES IM, 18(5), 2000, pp. 553-564
A robust algorithm to estimate three-dimensional strain in the left-ventric
ular heart wall, based on magnetic resonance (MR) grid-tagging in two sets
of orthogonal image planes, is presented. Starting-point of this study was
to minimize global interpolation and smoothing. Only the longitudinal displ
acement was interpolated between long-axis images. Homogeneous strain analy
sis was performed using small tetrahedrons. The method was tested using a s
tack of short-axis images and three long-axis images in six healthy volunte
ers. In addition, the method was subjected to an analytical test case, in w
hich the effect of noise in tag point position on the observed strains was
explored for normally distributed noise (0.5 mm RMS). In volunteers, the er
ror in the longitudinal displacement due to interpolation between the long-
axis image planes was -0.10 +/- 0.48 mm (mean +/- SD). The resulting error
in the longitudinal strain epsilon(1) was -0.003 +/- 0.02. The analytical t
est case was used to quantify the effects of three sources of errors on the
observed strain. The SD of the difference between homogeneous strain and t
rue strain was 0.06 for epsilon(r). The error due to the 3-D reconstruction
was 0.004 for epsilon(r). The error in epsilon(r) resulting from simulated
noise in the tag point position was 0.10. Equivalent results were obtained
for all other strain parameters; thus, the error resulting from noise in t
he tag paint position dominates the error introduced by approximations in t
he method. Because the proposed method uses a minimum of global interpolati
on and smoothing, it offers the prospect to detect small regions of aberran
t contraction. (C) 2000 Elsevier Science Inc. All rights reserved.