Lu Hanzhang, Clingman Chekesha, Golay Xavier, van Zijl Peter C M
Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Magn Reson Med. 2004 Sep;52(3):679-82. doi: 10.1002/mrm.20178.
It is important to determine the longitudinal relaxation time of blood for black blood imaging, as well as for quantifying blood flow by arterial spin labeling (ASL). In this study a circulation system was used to measure blood T1 under physiological conditions at the new clinical field strength of 3.0T. It was found that 1/T1 in s(-1) was linearly dependent (P < 0.05) on hematocrit (Hct) within a normal range of 0.38-0.46. The relationships were 1/T1 = (0.52 +/- 0.15). Hct + (0.38 +/- 0.06) and 1/T1 = (0.83 +/- 0.07). Hct + (0.28 +/- 0.03) for arterial (oxygenation = 92% +/- 7%) and venous blood (69% +/- 8%), respectively, which led to estimated T1 values of 1664 +/- 14 ms (arterial) and 1584 +/- 5 ms (venous) at a typical human Hct of 0.42. The temperature dependencies of blood T1 were 22.3 +/- 0.6 ms/ degrees C and 19.8 +/- 0.8 ms/ degrees C for Hct values of 0.42 and 0.38, respectively. When a head coil transmit/receive setup was used, radiation damping caused a slight reduction (19 ms) of the measured T1 values.
确定血液的纵向弛豫时间对于黑血成像以及通过动脉自旋标记（ASL）定量血流都很重要。在本研究中，使用了一种循环系统在3.0T的新临床场强下测量生理条件下的血液T1。发现在0.38 - 0.46的正常范围内，以秒的倒数为单位的1/T1与血细胞比容（Hct）呈线性相关（P < 0.05）。对于动脉血（氧合 = 92% ± 7%）和静脉血（69% ± 8%），关系分别为1/T1 = (0.52 ± 0.15)·Hct + (0.38 ± 0.06) 和1/T1 = (0.83 ± 0.07)·Hct + (0.28 ± 0.03)，这导致在典型的人体血细胞比容为0.42时，估计的T1值分别为1664 ± 14 ms（动脉血）和1584 ± 5 ms（静脉血）。对于血细胞比容值分别为0.42和0.38时，血液T1的温度依赖性分别为22.3 ± 0.6 ms/℃和19.8 ± 0.8 ms/℃。当使用头部线圈发射/接收装置时，辐射阻尼导致测量的T1值略有降低（19 ms）。
Zotero 插件