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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

(a) Malignant lymphoma images with ROIs.(b) ZAPPED maps of Ff, Fr, T2,f, and T2,r.
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pone.0119915.g005: (a) Malignant lymphoma images with ROIs.(b) ZAPPED maps of Ff, Fr, T2,f, and T2,r.

Mentions: The ZAPPED maps of two patients, one with a malignant lymphoma and the other with a low-grade glioma, are presented in Figs. 5 and 6, respectively. Table 3 summarizes the results: long T2,f and ultra-short T2,r values as well as the relative free and restricted fractions in tumor and in normal GM and WM tissues. In the malignant lymphoma case, the lymphoma tissue in WM has a longer T2,r value of 30.6 μs compared to 20.5 μs in normal WM tissue. The fraction of the restricted exchangeable component (Fr) in WM lymphoma tissue is also smaller (0.16) than that in normal WM tissue (0.26). An area of edema in the surrounding gray matter has a similar T2,r value as that in normal GM tissue. However, Fr is smaller in the edema area (0.10) than in normal GM tissue of healthy volunteers (0.17), as shown in Tables 1 and 3.


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)

(a) Malignant lymphoma images with ROIs.(b) ZAPPED maps of Ff, Fr, T2,f, and T2,r.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0119915.g005: (a) Malignant lymphoma images with ROIs.(b) ZAPPED maps of Ff, Fr, T2,f, and T2,r.
Mentions: The ZAPPED maps of two patients, one with a malignant lymphoma and the other with a low-grade glioma, are presented in Figs. 5 and 6, respectively. Table 3 summarizes the results: long T2,f and ultra-short T2,r values as well as the relative free and restricted fractions in tumor and in normal GM and WM tissues. In the malignant lymphoma case, the lymphoma tissue in WM has a longer T2,r value of 30.6 μs compared to 20.5 μs in normal WM tissue. The fraction of the restricted exchangeable component (Fr) in WM lymphoma tissue is also smaller (0.16) than that in normal WM tissue (0.26). An area of edema in the surrounding gray matter has a similar T2,r value as that in normal GM tissue. However, Fr is smaller in the edema area (0.10) than in normal GM tissue of healthy volunteers (0.17), as shown in Tables 1 and 3.

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