Influence of cardiac motion on diffusion-weighted magnetic resonance imaging of the liver
Influence of cardiac motion on diffusion-weighted magnetic resonance imaging of the liver
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DOI：
10.1007/s10334-009-0183-1
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发表时间：
2009-10-01
影响因子：
2.3
通讯作者：
Luijten, Peter R.
中科院分区：
文献类型：
--
作者：
Kwee, Thomas C.;Takahara, Taro;Luijten, Peter R.
目的：应用动态DWI技术评估肝脏弥散加权磁共振成像（DWI）中心脏运动引起的信号损失。3名志愿者在屏息状态下，分别在心脏舒张期（DWI(diast)）或收缩期（DWI(syst)）进行动态冠状动脉DWI，并在相位编码（P，左右）、频率编码（M，上-下）或切片选择（S，前后）方向进行运动探测梯度（mpg）。采用非参数检验，将左、右肝叶DWI（系统）与DWI（系统）的肝背景对比（lbc）进行比较。信号衰减比（sdr）计算为(1-(LBCDWI(syst)/LBCDWI(diast))) × 100%。进一步分析DWI（系统）以确定mpg哪个方向受心脏运动影响最大。在左肝叶，DWI（syst）的lbc（中位数3.35）显著低于DWI(diast)（中位数4.84）（P < 0.0001）。在右肝叶，DWI（syst）的lbc（中位数4.17）也显著低于DWI(diast)（中位数5.35）（P < 0.0001）。左、右肝叶的sdr分别为25.5%和17.3%。在DWI（syst）中，MPGs的M方向（左肝叶）和P方向（右肝叶）的lbc含量显著最低（P < 0.05）。DWI显示双肝叶信号强度受心脏运动影响。在左肝叶，信号损失主要发生在mpg的上下方向，而在右肝叶，信号损失主要发生在mpg的左右方向。
To assess cardiac motion-induced signal loss in diffusion-weighted magnetic resonance imaging (DWI) of the liver using dynamic DWI.Three volunteers underwent dynamic coronal DWI of the liver under breathholding, in the diastolic (DWI(diast)) or systolic (DWI(syst)) cardiac phase, and with motion probing gradients (MPGs) in phase encoding (P, left-right), frequency encoding (M, superior-inferior), or slice select (S, anterior-posterior) direction. Liver-to-background contrasts (LBCs) of DWI(syst) were compared to those of DWI(diast), for both the left and right liver lobes, using nonparametric tests. Signal decrease ratios (SDRs) were calculated as (1-(LBCDWI(syst)/LBCDWI(diast))) x 100%. DWI(syst) was further analyzed to determine which direction of MPGs was most affected by cardiac motion.In the left liver lobe, LBCs of DWI(syst) (median 3.35) were significantly lower (P < 0.0001) than those of DWI(diast) (median 4.84). In the right liver lobe, LBCs of DWI(syst) (median 4.17) were also significantly lower (P < 0.0001) than those of DWI(diast) (median 5.35 ). SDRs of the left and right liver lobes were 25.5% and 17.3%, respectively. In DWI(syst), the significantly lowest (P < 0.05) LBCs were observed in the M direction (left liver lobe) and P direction (right liver lobe) of MPGs.Signal intensity of both liver lobes are affected by cardiac motion in DWI. In the left liver lobe, signal loss especially occurs in the superior-inferior direction of MPGs, whereas in the right lobe, signal loss especially occurs in the left-right direction of MPGs.