Shiodera Taichiro, Nitta Shuhei, Takeguchi Tomoyuki, Yui Masao, Yamashita Yuichi, Yamamoto Takao, Yamada Shinya
Corporate Research and Development Center, Toshiba Corporation, 1, Komukai-Toshiba-cho, Saiwai-ku, Kawasaki, 212-0001, Japan,
MAGMA. 2014 Oct;27(5):425-33. doi: 10.1007/s10334-013-0416-1. Epub 2013 Dec 31.
The Time-Spatial Labeling Inversion Pulse (Time-SLIP) technique enables tracing of regional fluid flows without the use of contrast medium. The objective of this study is to quantify automatically slow and complex fluid flows using the Time-SLIP technique.
Series images were acquired with a 1.5-T MRI scanner using the Time-SLIP technique with half-Fourier fast spin-echo (FSE) and balanced steady-state free precession (bSSFP) sequences. In this method, labeled fluid regions in images were automatically detected based on image processing techniques for a given point. The flow velocity of the labeled fluid region was calculated using regression fitting for the region's position. To evaluate our method, constant and non-constant laminar flows in a water phantom were studied. In addition, volunteer experiments were conducted to quantify the flow of cerebrospinal fluid.
In the constant flow experiments the correlation factor r (2) between the flow velocity calculated from our method and the laminar peak velocity calculated from the volumetric flow rate was 0.9992 for the FSE sequence and 0.9982 for the bSSFP sequence. In the non-constant flow study, the flow velocity was calculated accurately for any period inversion time even when the flow velocity was changed, and the quantification error was negligible. In the volunteer experiments, r (2) between the flow velocity calculated by the proposed method and that obtained by manual annotation was 0.9383.
The experimental results showed that our proposed method can quickly and accurately provide information on flow velocities especially for slower and complex flows. Our method is, therefore, expected to be useful in diagnostic support systems.
时空标记反转脉冲（Time-SLIP）技术能够在不使用造影剂的情况下追踪区域流体流动。本研究的目的是使用Time-SLIP技术自动量化缓慢且复杂的流体流动。
使用1.5-T MRI扫描仪，采用Time-SLIP技术结合半傅里叶快速自旋回波（FSE）和平衡稳态自由进动（bSSFP）序列采集系列图像。在该方法中，基于给定的点，利用图像处理技术自动检测图像中的标记流体区域。使用该区域位置的回归拟合计算标记流体区域的流速。为评估我们的方法，对水模中的恒定和非恒定层流进行了研究。此外，还进行了志愿者实验以量化脑脊液的流动。
在恒定流实验中，对于FSE序列，我们的方法计算出的流速与根据体积流量计算出的层流峰值流速之间的相关系数r²为0.9992，对于bSSFP序列为0.9982。在非恒定流研究中，即使流速发生变化，在任何反转时间周期内都能准确计算流速，且量化误差可忽略不计。在志愿者实验中，所提出的方法计算出的流速与手动标注获得的流速之间的r²为0.9383。
实验结果表明，我们提出的方法能够快速准确地提供流速信息，尤其是对于较慢和复杂的流动。因此，我们的方法有望在诊断支持系统中发挥作用。
