### Abstract

Several methods of flip angle mapping for magnetic resonance imaging have been proposed. We evaluated the accuracy of five methods of flip angle measurement in the presence of measurement noise. Our analysis was performed in a closed form by propagation of probability density functions (PDFs). The flip angle mapping methods compared were (1) the phasesensitive method, (2) the dual-angle method using gradient recalled echoes (GRE), (3) an extended version of the GRE dual-angle method incorporating phase information, (4) the AFI method and (5) an extended version of the AFI method incorporating phase information. Our analysis took into account differences in required imaging time for these methods in the comparison of noise efficiency. PDFs of the flip angle estimate for each method for each value of true flip angle were calculated. These PDFs completely characterize the performance of each method. Mean bias and standard deviation were computed from these PDFs to more simply quantify the relative accuracy of each method over its range of measurable flip angles. We demonstrate that the phase-sensitive method provides the lowest mean bias and standard deviation of flip angle estimate of the five methods evaluated over a wide range of flip angles.

Original language | English (US) |
---|---|

Pages (from-to) | 6157-6174 |

Number of pages | 18 |

Journal | Physics in Medicine and Biology |

Volume | 55 |

Issue number | 20 |

DOIs | |

State | Published - Oct 21 2010 |

Externally published | Yes |

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### ASJC Scopus subject areas

- Radiology Nuclear Medicine and imaging
- Radiological and Ultrasound Technology

### Cite this

*Physics in Medicine and Biology*,

*55*(20), 6157-6174. https://doi.org/10.1088/0031-9155/55/20/008

**An analysis of the accuracy of magnetic resonance flip angle measurement methods.** / Morrell, Glen R.; Schabel, Matthias.

Research output: Contribution to journal › Article

*Physics in Medicine and Biology*, vol. 55, no. 20, pp. 6157-6174. https://doi.org/10.1088/0031-9155/55/20/008

}

TY - JOUR

T1 - An analysis of the accuracy of magnetic resonance flip angle measurement methods

AU - Morrell, Glen R.

AU - Schabel, Matthias

PY - 2010/10/21

Y1 - 2010/10/21

N2 - Several methods of flip angle mapping for magnetic resonance imaging have been proposed. We evaluated the accuracy of five methods of flip angle measurement in the presence of measurement noise. Our analysis was performed in a closed form by propagation of probability density functions (PDFs). The flip angle mapping methods compared were (1) the phasesensitive method, (2) the dual-angle method using gradient recalled echoes (GRE), (3) an extended version of the GRE dual-angle method incorporating phase information, (4) the AFI method and (5) an extended version of the AFI method incorporating phase information. Our analysis took into account differences in required imaging time for these methods in the comparison of noise efficiency. PDFs of the flip angle estimate for each method for each value of true flip angle were calculated. These PDFs completely characterize the performance of each method. Mean bias and standard deviation were computed from these PDFs to more simply quantify the relative accuracy of each method over its range of measurable flip angles. We demonstrate that the phase-sensitive method provides the lowest mean bias and standard deviation of flip angle estimate of the five methods evaluated over a wide range of flip angles.

AB - Several methods of flip angle mapping for magnetic resonance imaging have been proposed. We evaluated the accuracy of five methods of flip angle measurement in the presence of measurement noise. Our analysis was performed in a closed form by propagation of probability density functions (PDFs). The flip angle mapping methods compared were (1) the phasesensitive method, (2) the dual-angle method using gradient recalled echoes (GRE), (3) an extended version of the GRE dual-angle method incorporating phase information, (4) the AFI method and (5) an extended version of the AFI method incorporating phase information. Our analysis took into account differences in required imaging time for these methods in the comparison of noise efficiency. PDFs of the flip angle estimate for each method for each value of true flip angle were calculated. These PDFs completely characterize the performance of each method. Mean bias and standard deviation were computed from these PDFs to more simply quantify the relative accuracy of each method over its range of measurable flip angles. We demonstrate that the phase-sensitive method provides the lowest mean bias and standard deviation of flip angle estimate of the five methods evaluated over a wide range of flip angles.

UR - http://www.scopus.com/inward/record.url?scp=78149321339&partnerID=8YFLogxK

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U2 - 10.1088/0031-9155/55/20/008

DO - 10.1088/0031-9155/55/20/008

M3 - Article

VL - 55

SP - 6157

EP - 6174

JO - Physics in Medicine and Biology

JF - Physics in Medicine and Biology

SN - 0031-9155

IS - 20

ER -