### Abstract

q-space diffusion analysis is a method to obtain the probability density function of the translational displacement of diffusing water molecules. Several quantities can be extracted from the function that indicate a characteristic of the water diffusion in tissue, e.g., the mean displacement of the diffusion, probability for zero displacement, and kurtosis of the function. These quantities are expected to give information about the microstructure of tissues in addition to that obtained from the apparent diffusion coefficient (ADC); however, this method requires high q (i.e., high b) values, which are undesirable in practical applications of the method using clinical magnetic resonance (MR) imaging equipment. We propose a method to obtain certain quantities that indicate a characteristic of the diffusion and that uses low q-value measurements. The quantities we can obtain are the moments of translational displacement, R; the n-th order moment is defined as the average of R^{n} (n: integer). Kurtosis can also be calculated from the second and fourth moments. We tried to map the moments and kurtosis using clinical MR imaging equipment. We also estimated the inherent errors of the moments obtained. Our method requires precision in measuring spin echo signals and setting q values rather than using high q-value measurements. Although our results show that further error reductions are desired, our method is workable using ordinary clinical MR imaging equipment.

Original language | English |
---|---|

Pages (from-to) | 179-189 |

Number of pages | 11 |

Journal | Magnetic Resonance in Medical Sciences |

Volume | 5 |

Issue number | 4 |

DOIs | |

Publication status | Published - 01-12-2006 |

### Fingerprint

### All Science Journal Classification (ASJC) codes

- Radiology Nuclear Medicine and imaging

### Cite this

*Magnetic Resonance in Medical Sciences*,

*5*(4), 179-189. https://doi.org/10.2463/mrms.5.179

}

*Magnetic Resonance in Medical Sciences*, vol. 5, no. 4, pp. 179-189. https://doi.org/10.2463/mrms.5.179

**q-Space imaging using small magnetic field gradient.** / Umezawa, Eizo; Yoshikawa, Mayo; Yamaguchi, Kojiro; Ueoku, Sachiko; Tanaka, Eiji.

Research output: Contribution to journal › Article

TY - JOUR

T1 - q-Space imaging using small magnetic field gradient

AU - Umezawa, Eizo

AU - Yoshikawa, Mayo

AU - Yamaguchi, Kojiro

AU - Ueoku, Sachiko

AU - Tanaka, Eiji

PY - 2006/12/1

Y1 - 2006/12/1

N2 - q-space diffusion analysis is a method to obtain the probability density function of the translational displacement of diffusing water molecules. Several quantities can be extracted from the function that indicate a characteristic of the water diffusion in tissue, e.g., the mean displacement of the diffusion, probability for zero displacement, and kurtosis of the function. These quantities are expected to give information about the microstructure of tissues in addition to that obtained from the apparent diffusion coefficient (ADC); however, this method requires high q (i.e., high b) values, which are undesirable in practical applications of the method using clinical magnetic resonance (MR) imaging equipment. We propose a method to obtain certain quantities that indicate a characteristic of the diffusion and that uses low q-value measurements. The quantities we can obtain are the moments of translational displacement, R; the n-th order moment is defined as the average of Rn (n: integer). Kurtosis can also be calculated from the second and fourth moments. We tried to map the moments and kurtosis using clinical MR imaging equipment. We also estimated the inherent errors of the moments obtained. Our method requires precision in measuring spin echo signals and setting q values rather than using high q-value measurements. Although our results show that further error reductions are desired, our method is workable using ordinary clinical MR imaging equipment.

AB - q-space diffusion analysis is a method to obtain the probability density function of the translational displacement of diffusing water molecules. Several quantities can be extracted from the function that indicate a characteristic of the water diffusion in tissue, e.g., the mean displacement of the diffusion, probability for zero displacement, and kurtosis of the function. These quantities are expected to give information about the microstructure of tissues in addition to that obtained from the apparent diffusion coefficient (ADC); however, this method requires high q (i.e., high b) values, which are undesirable in practical applications of the method using clinical magnetic resonance (MR) imaging equipment. We propose a method to obtain certain quantities that indicate a characteristic of the diffusion and that uses low q-value measurements. The quantities we can obtain are the moments of translational displacement, R; the n-th order moment is defined as the average of Rn (n: integer). Kurtosis can also be calculated from the second and fourth moments. We tried to map the moments and kurtosis using clinical MR imaging equipment. We also estimated the inherent errors of the moments obtained. Our method requires precision in measuring spin echo signals and setting q values rather than using high q-value measurements. Although our results show that further error reductions are desired, our method is workable using ordinary clinical MR imaging equipment.

UR - http://www.scopus.com/inward/record.url?scp=34249682767&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=34249682767&partnerID=8YFLogxK

U2 - 10.2463/mrms.5.179

DO - 10.2463/mrms.5.179

M3 - Article

C2 - 17332708

AN - SCOPUS:34249682767

VL - 5

SP - 179

EP - 189

JO - Magnetic Resonance in Medical Sciences

JF - Magnetic Resonance in Medical Sciences

SN - 1347-3182

IS - 4

ER -