Reexamining the quantification of perfusion MRI data in the presence of bolus dispersion
Reexamining the quantification of perfusion MRI data in the presence of bolus dispersion
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DOI：
10.1002/jmri.20781
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发表时间：
2007-03-01
影响因子：
4.4
通讯作者：
Smith, Michael
中科院分区：
文献类型：
--
作者：
Ko, Linda;Salluzzi, Marina;Smith, Michael
目的：通过消除算法实现引起的系统误差，确定弥散度对脑血流量（CBF）量化的真实影响。材料和方法：假设：1)引入真正的动脉组织延迟（ATD）相关弥散成分的对侧循环流量，模拟弥散对测量和进入感兴趣组织之间动脉输入函数（AIF）对CBF估计的影响；以及2)存在使进入组织的AIF峰分散和移位的动脉狭窄；增加相对于原始AIF的表观ATD。结果：先前报道的立体色散模型的CBF估计被发现是真实色散效应和算法实现引起的系统误差的混合物。两种弥散模型评估的真实CBFMEASURED/ cbfno -弥散比在短平均传递时间（MTT）（正常）和长MTT（梗死）组织中相似；这是一个没有预料到的结果。通过与ATD真正相关的弥散模型引起的CBF量化不准确性低于小ATD值时基于局部狭窄的弥散。结论：纠正先前反褶积研究中存在的系统误差消除了报道的atd相关对CBF量化的影响。分散的影响小于先前模拟研究报告的一半。
Purpose: To determine the true impact of dispersion upon cerebral blood flow (CBF) quantification by removing an algorithm implementation-induced systematic error.Materials and Methods: The impact of dispersion on the arterial input function (AIF) between measurement and entry into the tissue of interest on CBF estimates was simulated assuming: 1) contralateral circulation flow that introduces a true arterial tissue delay (ATD)-related dispersive component; and 2) the presence of an arterial stenosis that disperses and shifts the AIF peak entering the tissue; increasing the apparent ATD relative to the original AIF.Results: Previously reported CBF estimates for the sterrosis dispersion model were found to be a mixture of true dispersive effects and an algorithm implementation-induced systematic error. The true CBFMEASURED/CBFNO-DISPERSION ratios for short mean transit times (MTT) (normal) and long MTT (infarcted) tissue were similar for both dispersion models evaluated; this was an unanticipated result. The CBF quantification inaccuracies induced through the dispersion model truly related to ATD were lower than for the local stenosis-based dispersion for small ATD values.Conclusion: Correcting the systematic error present in a previous deconvolution study removes the reported ATD-related impact on CBF quantification. The impact of dispersion was smaller than half that reported in previous simulation studies.