Kosior Jayme Cameron, Smith Michael R, Kosior Robert Karl, Frayne Richard
Department of Electrical and Computer Engineering, University of Calgary, Calgary, Alberta, Canada.
J Magn Reson Imaging. 2009 Jan;29(1):183-8. doi: 10.1002/jmri.21605.
To evaluate the use of bolus signals obtained from tissue as reference functions (or local reference functions [LRFs]) rather than arterial input functions (AIFs) when deriving cross-calibrated cerebral blood flow (CBF(CC)) estimates via deconvolution.
AIF and white matter (WM) LRF CBF(CC) maps (cross-calibrated so that normal WM was 23.7 mL/minute/100 g) derived using singular value decomposition (SVD) were examined in 28 ischemic stroke patients. Median CBF(CC) estimates from normal gray matter (GM) and ischemic tissue were obtained.
AIF and LRF median CBF(CC) estimates resembled one another for all 28 patients (average paired CBF(CC) difference 0.4 +/- 1.7 mL/minute/100 g and -0.4 +/- 1.4 mL/minute/100 g in GM and ischemic tissue, respectively). Wilcoxon signed-rank comparisons of patient median CBF(CC) measurements revealed no statistically significant differences between using AIFs and LRFs (P > 0.05).
If CBF is quantified using a patient-specific cross-calibration factor, then LRF CBF estimates are at least as accurate as those from AIFs. Therefore, until AIF quantification is achievable in vivo, perfusion protocols tailored for LRFs would simplify the methodology and provide more reliable perfusion information.
在通过去卷积推导交叉校准脑血流量（CBF(CC)）估计值时，评估将从组织获得的团注信号用作参考函数（或局部参考函数[LRF]）而非动脉输入函数（AIF）的情况。
在28例缺血性中风患者中，检查了使用奇异值分解（SVD）得出的AIF和白质（WM）LRF CBF(CC)图（进行交叉校准，使正常WM为23.7毫升/分钟/100克）。获得了正常灰质（GM）和缺血组织的CBF(CC)估计值中位数。
28例患者的AIF和LRF CBF(CC)估计值中位数彼此相似（GM和缺血组织中平均配对CBF(CC)差异分别为0.4±1.7毫升/分钟/100克和-0.4±1.4毫升/分钟/100克）。患者CBF(CC)测量值的Wilcoxon符号秩比较显示，使用AIF和LRF之间无统计学显著差异（P>0.05）。
如果使用患者特异性交叉校准因子对CBF进行量化，那么LRF CBF估计值至少与AIF的估计值一样准确。因此，在体内实现AIF量化之前，为LRF量身定制的灌注方案将简化方法并提供更可靠的灌注信息。
