Analysis of the DWT Characteristics of MR Molecular Images Obtained by Using MNPCA

*Junhaeng Lee Ph.D
Department of Radiology, Nambu University, 62271, Gwangju, Republic of Korea
*corresponding author

We are suggested a method to analyze the DWT(discrete wavelet transform) characteristics of magnetic resonance(MR) molecular images obtained by using contrast agent made of magnetic nanoparticles. The magnetic nanoparticles contrast agents(MNCA) were prepared by thermal decomposition method. We transplanted gastric cancer stem cells into experimental mice four weeks before the experiment. After injecting MNCA into the prepared mice, the MR molecule images were obtained as follows: before to MNCA injection, immediately after MNCA injection, 2 hours after MNCA injection and 4 hours after MNCA injection. At this time, we were used pulse sequence which T2 TSE, T2 MPGR, T2*, and UTE. We extracted and analyzed the signal characteristics of the pulse sequence of MR molecular images obtained by MNCA. The characteristics between T2 signal (T2 MPGR, T2 TSE, T2*) and UTE (Ultra short TE) were extracted and compared. Feature extraction for each signal was performed by the DWT method. The M program for DWT 3-step decomposition was used the MATLAB Toolbox. After decomposing in 3-step, we extracted the horizontal low frequency (A4H), vertical low frequency (A4V), horizontal high frequency (H4V), vertical high frequency (V4H), horizontal diagonal high frequency (D4H) and high frequency (D4V). The extracted features were compared and analyzed for each pulse signals. The results of this study can be used to demonstrate the effectiveness of MNCA for the usefulness of MR molecular imaging and UTE signals.
Keyword: Image processing, Discrete Wavelet Transform, MR pulse sequence, T2 Weighted Image, MR Molecular Imaging, Magnetic nanoparticles
MR Molecular Imaging, Image processing, Discrete Wavelet Transform, Magnetic nanoparticles, T2WI, Ultra short TE