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Z-Spectrum analysis provides proton environment data (ZAPPED): a new two-pool technique for human gray and white matter.

Miyazaki M, Ouyang C, Zhou X, Murdoch JB, Fushimi Y, Okada T, Fujimoto K, Kido A, Arakawa Y, Miyamoto S, Togashi K - PLoS ONE (2015)

Bottom Line: The mean restricted exchangeable proton fraction, Fr, was found to be 0.17 in gray matter (GM) and 0.28 in white matter (WM) in healthy subjects.The percentages of Ff and Fr in GM are similar for all ages, whereas Fr shows a tendency to decrease with age in WM among healthy subjects.The ZAPPED method provides a simple phenomenological approach to estimating fractions and apparent T2 values of free and restricted MT-active protons, and it may offer clinical useful information.

View Article: PubMed Central - PubMed

Affiliation: MR Research, Toshiba Medical Research Institute, Vernon Hills, Illinois, United States of America.

ABSTRACT
A new technique - Z-spectrum Analysis Provides Proton Environment Data (ZAPPED) - was used to map cross-relaxing free and restricted protons in nine healthy subjects plus two brain tumor patients at 3T. First, MT data were acquired over a wide symmetric range of frequency offsets, and then a trio of quantitative biomarkers, i.e., the apparent spin-spin relaxation times (T2,f, T2,r) in both free and restricted proton pools as well as the restricted pool fraction Fr, were mapped by fitting the measured Z-spectra to a simple two-Lorentzian compartment model on a voxel-by-voxel basis. The mean restricted exchangeable proton fraction, Fr, was found to be 0.17 in gray matter (GM) and 0.28 in white matter (WM) in healthy subjects. Corresponding mean values for apparent spin-spin relaxation times were 785 µs (T2,f) and 17.7 µs (T2,r) in GM, 672 µs (T2,f) and 23.4 µs (T2,r) in WM. The percentages of Ff and Fr in GM are similar for all ages, whereas Fr shows a tendency to decrease with age in WM among healthy subjects. The patient ZAPPED images show higher contrast between tumor and normal tissues than traditional T2-weighted and T1-weighted images. The ZAPPED method provides a simple phenomenological approach to estimating fractions and apparent T2 values of free and restricted MT-active protons, and it may offer clinical useful information.

No MeSH data available.


Related in: MedlinePlus

Fr maps from Fig. 2b with the GM and WM masks that were obtained from SPM segmentation of the nine subjects.
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pone.0119915.g003: Fr maps from Fig. 2b with the GM and WM masks that were obtained from SPM segmentation of the nine subjects.

Mentions: Fig. 2 displays ZAPPED maps from all nine volunteers of the free proton fraction Ff (Fig. 2a) and the restricted proton fraction Fr (Fig. 2b), as well as T2 maps of the free (Fig. 2c) and restricted exchangeable components (Fig. 2d). The age and sex of the subjects are labeled on the maps. Fig. 3 displays the Fr maps from Fig. 2b with the GM and WM masks obtained from segmentation in the nine subjects using SPM. The corresponding numeric results, obtained using the segmentation approach 1 mentioned previously, and calculated average values are presented in Table 1. The mean ultra-short T2,r value in the restricted component is 17.7 ±4.3 μs in GM and 23.4±3.7 μs in WM. The corresponding long T2,f values are 785±58 μs in GM and 671±41 μs in WM. The average Z-spectrum component fractions (mean ± standard deviation) in GM are Ff = 0.83±0.02 and Fr = 0.17±0.02; in WM, these values are Ff = 0.72±0.03 and Fr = 0.28±0.03. The percentages of Ff and Fr in GM are similar for all ages, whereas Fr shows a tendency to decrease with age in WM (linear regression: Fr = 0.355–0.00165*age, R2 = 0.656, p = 0.008) among healthy subjects.


Z-Spectrum analysis provides proton environment data (ZAPPED): a new two-pool technique for human gray and white matter.

Miyazaki M, Ouyang C, Zhou X, Murdoch JB, Fushimi Y, Okada T, Fujimoto K, Kido A, Arakawa Y, Miyamoto S, Togashi K - PLoS ONE (2015)

Fr maps from Fig. 2b with the GM and WM masks that were obtained from SPM segmentation of the nine subjects.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4358893&req=5

pone.0119915.g003: Fr maps from Fig. 2b with the GM and WM masks that were obtained from SPM segmentation of the nine subjects.
Mentions: Fig. 2 displays ZAPPED maps from all nine volunteers of the free proton fraction Ff (Fig. 2a) and the restricted proton fraction Fr (Fig. 2b), as well as T2 maps of the free (Fig. 2c) and restricted exchangeable components (Fig. 2d). The age and sex of the subjects are labeled on the maps. Fig. 3 displays the Fr maps from Fig. 2b with the GM and WM masks obtained from segmentation in the nine subjects using SPM. The corresponding numeric results, obtained using the segmentation approach 1 mentioned previously, and calculated average values are presented in Table 1. The mean ultra-short T2,r value in the restricted component is 17.7 ±4.3 μs in GM and 23.4±3.7 μs in WM. The corresponding long T2,f values are 785±58 μs in GM and 671±41 μs in WM. The average Z-spectrum component fractions (mean ± standard deviation) in GM are Ff = 0.83±0.02 and Fr = 0.17±0.02; in WM, these values are Ff = 0.72±0.03 and Fr = 0.28±0.03. The percentages of Ff and Fr in GM are similar for all ages, whereas Fr shows a tendency to decrease with age in WM (linear regression: Fr = 0.355–0.00165*age, R2 = 0.656, p = 0.008) among healthy subjects.

Bottom Line: The mean restricted exchangeable proton fraction, Fr, was found to be 0.17 in gray matter (GM) and 0.28 in white matter (WM) in healthy subjects.The percentages of Ff and Fr in GM are similar for all ages, whereas Fr shows a tendency to decrease with age in WM among healthy subjects.The ZAPPED method provides a simple phenomenological approach to estimating fractions and apparent T2 values of free and restricted MT-active protons, and it may offer clinical useful information.

View Article: PubMed Central - PubMed

Affiliation: MR Research, Toshiba Medical Research Institute, Vernon Hills, Illinois, United States of America.

ABSTRACT
A new technique - Z-spectrum Analysis Provides Proton Environment Data (ZAPPED) - was used to map cross-relaxing free and restricted protons in nine healthy subjects plus two brain tumor patients at 3T. First, MT data were acquired over a wide symmetric range of frequency offsets, and then a trio of quantitative biomarkers, i.e., the apparent spin-spin relaxation times (T2,f, T2,r) in both free and restricted proton pools as well as the restricted pool fraction Fr, were mapped by fitting the measured Z-spectra to a simple two-Lorentzian compartment model on a voxel-by-voxel basis. The mean restricted exchangeable proton fraction, Fr, was found to be 0.17 in gray matter (GM) and 0.28 in white matter (WM) in healthy subjects. Corresponding mean values for apparent spin-spin relaxation times were 785 µs (T2,f) and 17.7 µs (T2,r) in GM, 672 µs (T2,f) and 23.4 µs (T2,r) in WM. The percentages of Ff and Fr in GM are similar for all ages, whereas Fr shows a tendency to decrease with age in WM among healthy subjects. The patient ZAPPED images show higher contrast between tumor and normal tissues than traditional T2-weighted and T1-weighted images. The ZAPPED method provides a simple phenomenological approach to estimating fractions and apparent T2 values of free and restricted MT-active protons, and it may offer clinical useful information.

No MeSH data available.


Related in: MedlinePlus