## Abstract

Conventional approaches to quantify whole brain T*_{2} maps use nonlinear regression with intensive computational requirements that therefore likely limit quantitative T*_{2} mapping for real-time applications. To overcome these limitations an alternative method, NumART*_{2} (NUMerical Algorithm for Real-time T*_{2} mapping) that directly calculates T*_{2} by a linear combination of images obtained at three or more different echo times was developed. NumART*_{2}, linear least-squares, and nonlinear regression techniques were applied to multiecho planar images of the human brain and to simulated data. Although NumART*_{2} may overestimate T*_{2}, it yields comparable values to regression techniques in cortical and subcortical areas, with only moderate deviations for echo spacings between 18 and 40 ms. NumART*_{2}, like linear regression, requires 2% of the computational time needed for nonlinear regression and compares favorably with linear regression due to its higher precision. The use of NumART*_{2} for continuous on-line T*_{2} mapping in real time fMRI studies is shown.

Original language | English |
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Pages (from-to) | 877-882 |

Number of pages | 6 |

Journal | Magnetic Resonance in Medicine |

Volume | 48 |

Issue number | 5 |

DOIs | |

Publication status | Published - Nov 1 2002 |

## Keywords

- Functional MRI
- Multiecho acquisition
- Quantitative T*
- Real-time

## ASJC Scopus subject areas

- Radiology Nuclear Medicine and imaging
- Radiological and Ultrasound Technology