Pickup Stephen, Wood Andrew K W, Kundel Harold L
Department of Radiology, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
J Magn Reson Imaging. 2004 Apr;19(4):508-12. doi: 10.1002/jmri.20027.
To develop an efficient method for extracting maps of the corrected T1 from images generated using the T One by Multiple Read Out Pulses (TOMROP) sequence.
An expression is developed for the true T1 in terms of the parameters from a three-parameter fit of the TOMROP data. Solutions of gadodiamide in normal saline with concentrations of 0.0, 0.06, 0.11, 0.23, 0.46, and 0.91 mM were prepared and T1 measurements were performed using both the inversion recovery (IR) and the TOMROP methods. The TOMROP data were analyzed using the proposed technique and the results compared to those from the IR measurements.
The T1 estimates generated from the TOMROP data using the proposed method were consistent with the IR results. However, systematic errors were observed in the T1 estimates when the repetition time was not sufficient for full recovery of axial magnetization. Relaxation times determined using the proposed method were within 1% of the spectroscopiclly determined values for T1 values in the range of 0.28-2.8 seconds when a suitable delay was employed.
The proposed method of analysis was found to yield accurate T1 estimates when the assumptions used in the analysis were not violated.
开发一种高效方法,用于从使用多读出脉冲T1(TOMROP)序列生成的图像中提取校正后的T1图谱。
根据TOMROP数据的三参数拟合参数,推导出真实T1的表达式。制备了浓度分别为0.0、0.06、0.11、0.23、0.46和0.91 mM的钆双胺生理盐水溶液,并使用反转恢复(IR)法和TOMROP法进行T1测量。使用所提出的技术分析TOMROP数据,并将结果与IR测量结果进行比较。
使用所提出的方法从TOMROP数据生成的T1估计值与IR结果一致。然而,当重复时间不足以使轴向磁化完全恢复时,T1估计值中观察到系统误差。当采用合适的延迟时,使用所提出的方法确定的弛豫时间在0.28 - 2.8秒范围内的T1值的光谱测定值的1%以内。
当分析中使用的假设未被违反时,所提出的分析方法能产生准确的T1估计值。