MRI Systems Development Department, MRI Systems Division, Toshiba Medical Systems Corporation, Systems Group, Otawara, Tochigi, Japan.
Magn Reson Med Sci. 2009;8(3):107-20. doi: 10.2463/mrms.8.107.
We assessed errors in cerebral blood flow (CBF) obtained from our proposed reference-based method without using arterial input function (AIF) indices in dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI).
We calculated CBF and the referential tissue-related ratio (CBFratio) using numerical simulation and 3 nondeconvolution methods and a deconvolution method of block-circulant singular value decomposition (cSVD). We compared errors with and without simulated noise as parameters of mean transit time (MTT), AIF delay and temporal resolution, and clinical DSC-MRI maps.
The errors in CBF obtained using maximum upslope (US) were smallest among the nondeconvolution methods and almost equivalent to errors in the cSVD method under practical imaging conditions. In addition, errors in the CBFratio obtained using reference-based US (Ref-US) referring to white matter were smallest, even compared to all errors in CBF and CBFratio. The Ref-US method introduced less error than the cSVD method, especially at low flow rates, was further robust against AIF noise and coarse temporal resolution, and was comparably robust against transit delay. In pixel-by-pixel correlations between absolute value maps for US and for cSVD-CBF in clinical DSC-MRI, those correlation coefficients (r) between the 2 maps were stable, r > 0.9, despite variation in the slopes of the linear regression line, so the 2 CBFratio maps were visually well correlated in any case.
The Ref-US technique without AIF measurement can become a practical perfusion methodology for DSC-MRI in patients even with acute stroke because it balances robustness with systematic and random errors and it is simply performed.
在动态磁敏感对比（DSC）磁共振成像（MRI）中不使用动脉输入函数（AIF）指数的情况下，评估我们提出的基于参考的方法获得的脑血流（CBF）中的误差。
我们使用数值模拟和 3 种非解卷积方法以及块循环奇异值分解（cSVD）的解卷积方法计算 CBF 和参考组织相关比（CBFratio）。我们比较了有和无模拟噪声时的误差，作为平均通过时间（MTT）、AIF 延迟和时间分辨率的参数，以及临床 DSC-MRI 图。
在非解卷积方法中，最大上升斜率（US）获得的 CBF 误差最小，在实际成像条件下几乎与 cSVD 方法的误差相当。此外，参考 US（Ref-US）参考白质的 CBFratio 误差最小，甚至比 CBF 和 CBFratio 的所有误差都小。Ref-US 方法比 cSVD 方法引入的误差更小，特别是在低血流率下，对 AIF 噪声和粗糙的时间分辨率更稳健，对通过延迟的稳健性也相当。在临床 DSC-MRI 中 US 和 cSVD-CBF 的绝对值图之间的像素对像素相关性中，2 种图之间的相关系数（r）非常稳定，r>0.9，尽管线性回归线的斜率存在差异，因此在任何情况下，2 种 CBFratio 图的视觉相关性都很好。
即使在急性卒中患者中，不使用 AIF 测量的 Ref-US 技术也可以成为 DSC-MRI 的实用灌注方法，因为它平衡了系统性和随机性误差的稳健性，并且操作简单。
