Hamaguchi Hiroyuki, Tha Khin Khin, Sugimori Hiroyuki, Nakanishi Mitsuhiro, Nakagawa Shin, Fujiwara Taro, Yoshida Hirokazu, Takamori Sayaka, Shirato Hiroki
Department of Radiological Technology, Hokkaido University Hospital, Japan.
Department of Radiobiology and Medical Engineering, Hokkaido University Graduate School of Medicine, Japan Global Station for Quantum Medical Science and Engineering, Global Institution for Collaborative Research and Education, Hokkaido University, Japan
Neuroradiol J. 2016 Aug;29(4):254-9. doi: 10.1177/1971400916643337. Epub 2016 Apr 12.
The effect of respiratory gating on the major diffusion-imaging metrics and that of cardiac gating on mean kurtosis (MK) are not known. For evaluation of whether the major diffusion-imaging metrics-MK, fractional anisotropy (FA), and mean diffusivity (MD) of the brain-varied between gated and non-gated acquisitions, respiratory-gated, cardiac-gated, and non-gated diffusion-imaging of the brain were performed in 10 healthy volunteers. MK, FA, and MD maps were constructed for all acquisitions, and the histograms were constructed. The normalized peak height and location of the histograms were compared among the acquisitions by use of Friedman and post hoc Wilcoxon tests. The effect of the repetition time (TR) on the diffusion-imaging metrics was also tested, and we corrected for its variation among acquisitions, if necessary. The results showed a shift in the peak location of the MK and MD histograms to the right with an increase in TR (p ≤ 0.01). The corrected peak location of the MK histograms, the normalized peak height of the FA histograms, the normalized peak height and the corrected peak location of the MD histograms varied significantly between the gated and non-gated acquisitions (p < 0.05). These results imply an influence of respiration and cardiac pulsation on the major diffusion-imaging metrics. The gating conditions must be kept identical if reproducible results are to be achieved.
呼吸门控对主要扩散成像指标的影响以及心脏门控对平均峰度（MK）的影响尚不清楚。为了评估大脑的主要扩散成像指标——MK、分数各向异性（FA）和平均扩散率（MD）在门控和非门控采集之间是否存在差异，对10名健康志愿者进行了大脑的呼吸门控、心脏门控和非门控扩散成像。为所有采集构建了MK、FA和MD图，并构建了直方图。通过Friedman检验和事后Wilcoxon检验比较了各采集中直方图的归一化峰值高度和位置。还测试了重复时间（TR）对扩散成像指标的影响，如有必要，我们对各采集中TR的变化进行了校正。结果显示，随着TR的增加，MK和MD直方图的峰值位置向右移动（p≤0.01）。MK直方图的校正峰值位置、FA直方图的归一化峰值高度、MD直方图的归一化峰值高度和校正峰值位置在门控和非门控采集之间存在显著差异（p<0.05）。这些结果表明呼吸和心脏搏动对主要扩散成像指标有影响。如果要获得可重复的结果，门控条件必须保持一致。
