TITLE:
Non-rigid registration and KLT filter to improve SNR and CNR in GRE-EPI myocardial perfusion imaging
AUTHORS:
Georgeta Mihai, Yu Ding, Hui Xue, Yiu-Cho Chung, Sanjay Rajagopalan, Jens Guehring, Orlando P. Simonetti
KEYWORDS:
Cardiac First Pass Perfusion; Non-Rigid Registration; KLT Filter; CNR; Dynamic MRI
JOURNAL NAME:
Journal of Biomedical Science and Engineering,
Vol.5 No.12A,
December
31,
2012
ABSTRACT: The purpose of the study was to evaluate the effect
of motion compensation by non-rigid registration combined with the
Karhunen-Loeve Transform (KLT) filter on the signal to noise (SNR) and
contrast-to-noise ratio (CNR) of hybrid gradient-echo echoplanar (GRE-EPI)
first-pass myocardial perfusion imaging. Twenty one consecutive first-pass
adenosine stress perfusion MR data sets interpreted positive for ischemia or
infarction were processed by non-rigid Registration followed by KLT
filtering. SNR and CNR were measured in abnormal and normal myocardium in
unfiltered and KLT filtered images following nonrigid registration to
compensate for respiratory and other motions. Image artifacts introduced by
filtering in registered and nonregistered images were evaluated by two observers.
There was a statistically sig- nificant increase in both SNR and CNR between
normal and abnormal myocardium with KLT filtering (mean SNR increased by
62.18% ± 21.05% and mean CNR increased by
58.84% ± 18.06%; p = 0.01). Motion correction prior to KLT filtering reduced
significantly the occurrence of filter induced artifacts (KLT only-artifacts
in 42 out of 55 image series vs. registered plus KLT-artifacts in 3 out of 55 image
series). In conclusion the combination of non-rigid registration and KLT
filtering was shown to increase the SNR and CNR of GRE-EPI perfusion images.
Subjective evaluation of image artifacts revealed that prior motion
compensation significantly reduced the artifacts introduced by the KLT filtering
process.