2007
Chao WH, Cho CW, Shih YY, Chen YY, Chang C
Correction of inhomogeneous MR images using multiscale retinexInternational Journal of Image Processing, PubMed
@article{WH2007,
title = {Correction of inhomogeneous MR images using multiscale retinex},
author = {Chao WH, Cho CW, Shih YY, Chen YY, Chang C},
url = {http://www.cscjournals.org/library/manuscriptinfo.php?mc=IJIP-1},
year = {2007},
date = {2007-06-30},
urldate = {2007-06-30},
journal = {International Journal of Image Processing},
volume = {1},
number = {1},
pages = {1-16},
abstract = {A new method for enhancing the contrast of magnetic resonance images (MRI) by retinex algorithm is proposed. It can correct the blurrings in deep anatomical structures and inhomogeneity of MRI. Multiscale retinex (MSR) employed SSR with different weightings to correct inhomogeneities and enhance the contrast of MR images. The method was assessed by applying it to phantom and animal images acquired on MRI scanner systems. Its performance was also compared with other methods based on two indices: (1) the peak signal-to-noise ratio (PSNR) and (2) the contrast-to-noise ratio (CNR). Two indices, including PSNR and CNR, were used to evaluate the performance of correction of inhomogeneity in MR images. The PSNR/CNR of a phantom and animal images were 11.8648 dB/2.0922 and 11.7580 dB/2.1157, respectively, which were higher or very close to the results of wavelet algorithm. The retinex algorithm successfully corrected a nonuniform grayscale, enhanced contrast, corrected inhomogeneity, and clarified the deep brain structures of MR images captured by surface coils and outperformed histogram equalization, local histogram equalization, and a waveletbased algorithm, and hence may be a valuable method in MR image processing.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A new method for enhancing the contrast of magnetic resonance images (MRI) by retinex algorithm is proposed. It can correct the blurrings in deep anatomical structures and inhomogeneity of MRI. Multiscale retinex (MSR) employed SSR with different weightings to correct inhomogeneities and enhance the contrast of MR images. The method was assessed by applying it to phantom and animal images acquired on MRI scanner systems. Its performance was also compared with other methods based on two indices: (1) the peak signal-to-noise ratio (PSNR) and (2) the contrast-to-noise ratio (CNR). Two indices, including PSNR and CNR, were used to evaluate the performance of correction of inhomogeneity in MR images. The PSNR/CNR of a phantom and animal images were 11.8648 dB/2.0922 and 11.7580 dB/2.1157, respectively, which were higher or very close to the results of wavelet algorithm. The retinex algorithm successfully corrected a nonuniform grayscale, enhanced contrast, corrected inhomogeneity, and clarified the deep brain structures of MR images captured by surface coils and outperformed histogram equalization, local histogram equalization, and a waveletbased algorithm, and hence may be a valuable method in MR image processing.
Shih YY, Chen YY, Hsieh WY, Huang YY, Chang C, Chen JC, Lin CI, Wang SJ, Jaw FS
Dynamic mapping of amphetamine response in the rat brain using BOLD and IRON techniquesBiomedical Engineering: Applications, Basis and Communications
@article{YY2007b,
title = {Dynamic mapping of amphetamine response in the rat brain using BOLD and IRON techniques},
author = {Shih YY, Chen YY, Hsieh WY, Huang YY, Chang C, Chen JC, Lin CI, Wang SJ, Jaw FS},
doi = {10.4015/S1016237207000203},
year = {2007},
date = {2007-06-01},
urldate = {2007-06-01},
journal = {Biomedical Engineering: Applications, Basis and Communications},
volume = {19},
number = {3},
pages = {157-63},
abstract = {Conventional blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) has been wildly used in neuroscience studies. Even though the BOLD method offers the functional information, the low signal-to-noise ratio could not provide an activated brain area accurately and the signal could not be easily inspected from the complicated neuronal interactions. In this regard, the present study aims to use an ultra-small super-paramagnetic iron oxide (USPIO) nanoparticle coated with covalently bound bifunctional poly(ethylene glycol) polymers to enhance the brain functional responses by the IRON (increased relaxation with iron oxide nanoparticles) technique. The R1 and R2 of this USPIO were 53.6 mMsec-1 and 359.8 mMsec-1, respectively, and both were higher than most of the commercial products under 0.47 T nuclear magnetic resonance measurement. In this study, the time activity curves in responsive brain areas were evaluated following USPIO injection (3 mg of Fe/kg). The amphetamine (2 mg/kg) was used as a functional stimulator to reveal the changes of relative cerebral blood volume in different brain areas. All imaging experiments were performed by Bruker Biospec BMT 47/40 4.7 T MRI system. The results show that, compared to the BOLD signals; significant event related responses were observed in striatum, insular cortex, nucleus accumbens, somatosensory cortices, and lateral thalamus using the IRON technique. Furthermore, the usability of this USPIO in detecting rCBV responses was confirmed by comparing with previous researches.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Conventional blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) has been wildly used in neuroscience studies. Even though the BOLD method offers the functional information, the low signal-to-noise ratio could not provide an activated brain area accurately and the signal could not be easily inspected from the complicated neuronal interactions. In this regard, the present study aims to use an ultra-small super-paramagnetic iron oxide (USPIO) nanoparticle coated with covalently bound bifunctional poly(ethylene glycol) polymers to enhance the brain functional responses by the IRON (increased relaxation with iron oxide nanoparticles) technique. The R1 and R2 of this USPIO were 53.6 mMsec-1 and 359.8 mMsec-1, respectively, and both were higher than most of the commercial products under 0.47 T nuclear magnetic resonance measurement. In this study, the time activity curves in responsive brain areas were evaluated following USPIO injection (3 mg of Fe/kg). The amphetamine (2 mg/kg) was used as a functional stimulator to reveal the changes of relative cerebral blood volume in different brain areas. All imaging experiments were performed by Bruker Biospec BMT 47/40 4.7 T MRI system. The results show that, compared to the BOLD signals; significant event related responses were observed in striatum, insular cortex, nucleus accumbens, somatosensory cortices, and lateral thalamus using the IRON technique. Furthermore, the usability of this USPIO in detecting rCBV responses was confirmed by comparing with previous researches.
2005
Shih YY, Chen JC, Liu RS
Development of wavelet de-noising technique for PET imagesComputerized Medical Imaging and GraphicsPubMed
@article{YY2005,
title = {Development of wavelet de-noising technique for PET images},
author = {Shih YY, Chen JC, Liu RS},
url = {https://pubmed.ncbi.nlm.nih.gov/15890257/},
doi = {10.1016/j.compmedimag.2004.12.002},
year = {2005},
date = {2005-06-01},
urldate = {2005-06-01},
journal = {Computerized Medical Imaging and Graphics},
volume = {29},
number = {4},
pages = {297-304},
abstract = {Positron emission tomography (PET) imaging provides the functional information and precise physiological uptake of radioactivity in a patient's body. But the shortcoming of PET is low signal to noise ratio (SNR) due to photon noise. The noise may influence image quality, and cause the mistake of clinical interpretation. The purpose of this research is to develop a wavelet de-noising technique to reduce the noise of PET images. By processing the image through the optimum wavelet parameters we selected, we keep the resolution and contrast but reduce almost half of coefficient of variation in the region of interest of PET images.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Positron emission tomography (PET) imaging provides the functional information and precise physiological uptake of radioactivity in a patient's body. But the shortcoming of PET is low signal to noise ratio (SNR) due to photon noise. The noise may influence image quality, and cause the mistake of clinical interpretation. The purpose of this research is to develop a wavelet de-noising technique to reduce the noise of PET images. By processing the image through the optimum wavelet parameters we selected, we keep the resolution and contrast but reduce almost half of coefficient of variation in the region of interest of PET images.