基于四维 CT 的简化肺部通气成像算法的可用性。

Availability of a simplified lung ventilation imaging algorithm based on four-dimensional computed tomography.

机构信息

Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100021, China.

出版信息

Phys Med. 2019 Sep;65:53-58. doi: 10.1016/j.ejmp.2019.08.006. Epub 2019 Aug 12.

DOI:10.1016/j.ejmp.2019.08.006

PMID:31430587

Abstract

PURPOSE

It is still not conclusive which four-dimensional computed tomography (4DCT)-based ventilation imaging algorithm is most accurate and efficient. In this study, we proposed a simplified algorithm (VIAAVG) which only requires the average computed tomography (AVG CT) as input, and quantitatively compared its accuracy and efficiency with three other popular algorithms.

MATERIAL AND METHODS

Fifty patients with lung or esophageal cancer who underwent radiotherapy were enrolled. Single photon emission computed tomography (SPECT) ventilation images (VI-SPECT) and 4DCT were acquired 1-3 days before the first treatment session. The end of exhalation and the end of inhalation CT were registered to derive deformable vector field (DVF) using MIMvista. 4DCT-based ventilation images (CTVI) were first calculated respectively by means of four algorithms (VIAJAC, VIAHU, VIAPRO and VIAAVG). The computation times were compared using paired t-test. The corresponding CTVIs (CTVIJAC, CTVIHU, CTVIPRO and CTVIAVG) and VI-SPECT were segmented into three equal sub-volumes (high, medium and low function lung, respectively) after smoothing and normalization. The Dice Similarity Coefficients (DSCs) were calculated for each sub-volume between each CTVI and VI-SPECT. The average DSCs for high, medium and low function lung in different CTVIs for each patient were compared using paired t-test.

RESULTS

The mean DSCs for CTVIJAC, CTVIHU, CTVIPRO and CTVIAVG were 0.3255, 0.4465, 0.5865 and 0.5958, respectively. The average computation times for CTVIJAC, CTVIHU, CTVIPRO and CTVIAVG were 18.3 s, 24.2 s, 144.8 s and 15.0 s.

CONCLUSION

VIAAVG is available for clinical use because of its high accuracy, improved efficiency and less input requirement compared to the other algorithms.

摘要

目的

目前仍不确定哪种四维计算机断层扫描（4DCT）-基于通气成像算法最为准确和高效。本研究提出了一种简化算法（VIAAVG），仅需平均计算机断层扫描（AVG CT）作为输入，并与其他三种常用算法进行了定量比较。

材料和方法

本研究纳入了 50 例肺癌或食管癌患者，这些患者在首次治疗前 1-3 天接受了单光子发射计算机断层扫描（SPECT）通气成像（VI-SPECT）和 4DCT 检查。通过 MIMvista 将呼气末和吸气末 CT 进行配准，以获得变形矢量场（DVF）。分别采用 4 种算法（VIAJAC、VIAHU、VIAPRO 和 VIAAVG）计算基于 4DCT 的通气图像（CTVI）。采用配对 t 检验比较计算时间。将相应的 CTVI（CTVIJAC、CTVIHU、CTVIPRO 和 CTVIAVG）和 VI-SPECT 进行平滑和归一化处理后，分成 3 个相等的子容积（分别为高、中、低功能肺）。分别计算每个 CTVI 与 VI-SPECT 之间的每个子容积的 Dice 相似系数（DSC）。使用配对 t 检验比较每个患者不同 CTVI 中高、中、低功能肺的平均 DSC。