Detre J A, Leigh J S, Williams D S, Koretsky A P
Metabolic Magnetic Resonance Research Center, University of Pennsylvania School of Medicine, Philadelphia 19104.
Magn Reson Med. 1992 Jan;23(1):37-45. doi: 10.1002/mrm.1910230106.
Measurement of tissue perfusion is important for the functional assessment of organs in vivo. Here we report the use of 1H NMR imaging to generate perfusion maps in the rat brain at 4.7 T. Blood water flowing to the brain is saturated in the neck region with a slice-selective saturation imaging sequence, creating an endogenous tracer in the form of proximally saturated spins. Because proton T1 times are relatively long, particularly at high field strengths, saturated spins exchange with bulk water in the brain and a steady state is created where the regional concentration of saturated spins is determined by the regional blood flow and regional T1. Distal saturation applied equidistantly outside the brain serves as a control for effects of the saturation pulses. Average cerebral blood flow in normocapnic rat brain under halothane anesthesia was determined to be 105 +/- 16 cc.100 g-1.min-1 (mean +/- SEM, n = 3), in good agreement with values reported in the literature, and was sensitive to increases in arterial pCO2. This technique allows regional perfusion maps to be measured noninvasively, with the resolution of 1H MRI, and should be readily applicable to human studies.
组织灌注的测量对于体内器官的功能评估很重要。在此我们报告了在4.7 T磁场下利用1H NMR成像在大鼠脑中生成灌注图。流向大脑的血水中的氢质子在颈部区域通过一个层面选择饱和成像序列被饱和，从而以近端饱和自旋的形式产生一种内源性示踪剂。由于质子T1时间相对较长，尤其是在高场强下，饱和自旋与脑中的大量水进行交换，并建立起一种稳态，其中饱和自旋的区域浓度由区域血流和区域T1决定。在脑外等距离施加的远端饱和用作饱和脉冲效应的对照。在氟烷麻醉下，正常碳酸血症大鼠脑的平均脑血流量被测定为105±16 cc·100 g-1·min-1（平均值±标准误，n = 3），与文献报道的值相符，并且对动脉pCO2的升高敏感。该技术能够以1H MRI的分辨率无创地测量区域灌注图，并且应该很容易应用于人体研究。
