Precision, signal-to-noise ratio, and dose optimization of magnitude and phase arterial input functions in dynamic susceptibility contrast MRI
Precision, signal-to-noise ratio, and dose optimization of magnitude and phase arterial input functions in dynamic susceptibility contrast MRI
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DOI：
10.1002/jmri.20859
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发表时间：
2007-03-01
影响因子：
4.4
通讯作者：
Conturo, Thomas E.
中科院分区：
文献类型：
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作者：
Kotys, Melanie S.;Akbudak, Erbil;Conturo, Thomas E.
目的：为了确定在动态磁敏感对比（DSC）灌注MRI中精确测量动脉输入功能（AIF）的最佳条件，材料和方法：对几种剂量和基线MRI噪声水平[SNR（I-0）]下基于幅度（Delta R-2*）和基于相位（Delta（phi））的AIF进行数值模拟。将随机噪声（1000次实现）添加到真实的/虚构的MRI信号（源自颈内动脉AIF）中，并确定AIF信号、噪声和信噪比（SNR）。最佳剂量被定义为最大化AIF首过平均SNR（SNRmean）的剂量，而不是最大化AIF峰值SNR（SNRpeak）的剂量，因为与SNRpeak相比，SNRmean预测的剂量可使AIF诱导的脑血流量（CBF）变异性降低24%至40%。与Delta R-2* 相比，Delta（phi）信号在所有剂量和时间点上具有4至80倍的SNR，并且在相应的最佳剂量下具有约10倍的SNR平均值。对于Delta R-2* 方法，最佳剂量引起85%至90%的信号下降，对于Delta（phi），最佳剂量引起70%至75%的信号下降，其中两倍剂量误差导致SNR平均值的1.7倍损失。结论：AIF信噪比受信号类型影响最大，其次是剂量，最后是SNR（I-0）。
Purpose: To determine optimal conditions for precise measurement of arterial input function (AIFs) in dynamic susceptibility contrast (DSC) perfusion MRI.Materials and Methods: Magnitude-based (Delta R-2* and phase-based (Delta(phi)) AIFs were numerically simulated for several doses and baseline MRI noise levels [SNR(I-0)]. Random noise (1000 realizations) was added to real/imaginary MRI signals (derived from an internal carotid AIF), and AIF signal, noise, and signal-to-noise ratio (SNR) were determined. The optimal dose was defined as the dose that maximizes mean AIF SNR over the first-pass (SNRmean), rather than SNR at the AIF peak (SNRpeak) because, compared to SNRpeak, doses predicted by SNRmean reduced the AIF-induced variability in cerebral blood flow (CBF) by 24% to 40%.Results: The AIF SNR is most influenced by choice of AIF signal, then optimal dosing, each with little penalty. Compared to Delta R-2*, Delta(phi) signal has 4 to 80 times the SNR over all doses and time points, and -10-fold SNRmean at respective optimal doses. Optimal doses induce 85% to 90% signal drop for the Delta R-2* method, and 70% to 75% for Delta(phi), with two-fold dose errors causing similar to 1.7-fold loss in SNRmean. Increases in SNR(I-0) proportionally increase AIF SNR, but at a cost.Conclusion: AIF SNR is affected most by signal type, then dosing, and lastly, SNR(I-0).