用于磁共振引导放疗的基于视频编码器的机载磁共振图像压缩

On-board MRI image compression using video encoder for MR-guided radiotherapy.

作者信息

Shang Jiawen, Huang Peng, Zhang Ke, Dai Jianrong, Yan Hui

机构信息

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

出版信息

Quant Imaging Med Surg. 2023 Aug 1;13(8):5207-5217. doi: 10.21037/qims-22-1378. Epub 2023 Jun 20.

DOI:10.21037/qims-22-1378

PMID:37581063

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC10423359/

Abstract

BACKGROUND

Magnetic resonance imaging (MRI) is currently used for online target monitoring and plan adaptation in modern image-guided radiotherapy. However, storing a large amount of data accumulated during patient treatment becomes an issue. In this study, the feasibility to compress MRI images accumulated in MR-guided radiotherapy using video encoders was investigated.

METHODS

Two sorting algorithms were employed to reorder the slices in multiple MRI sets for the input sequence of video encoder. Three cropping algorithms were used to auto-segment regions of interest for separate data storage. Four video encoders, motion-JPEG (M-JPEG), MPEG-4 (MP4), Advanced Video Coding (AVC or H.264) and High Efficiency Video Coding (HEVC or H.265) were investigated. The compression performance of video encoders was evaluated by compression ratio and time, while the restoration accuracy of video encoders was evaluated by mean square error (MSE), peak signal-to-noise ratio (PSNR), and video quality matrix (VQM). The performances of all combinations of video encoders, sorting methods, and cropping algorithms were investigated and their effects were statistically analyzed.

RESULTS

The compression ratios of MP4, H.264 and H.265 with both sorting methods were improved by 26% and 5%, 42% and 27%, 72% and 43%, respectively, comparing to those of M-JPEG. The slice-prioritized sorting method showed a higher compression ratio than that of the location-prioritized sorting method for MP4 (P=0.00000), H.264 (P=0.00012) and H.265 (P=0.00000), respectively. The compression ratios of H.265 were improved significantly with the applications of morphology algorithm (P=0.01890 and P=0.00530), flood-fill algorithm (P=0.00510 and P=0.00020) and level-set algorithm (P=0.02800 and P=0.00830) for both sorting methods. Among the four video encoders, H.265 showed the best compression ratio and restoration accuracy.

CONCLUSIONS

The compression ratio and restoration accuracy of video encoders using inter-frame coding (MP4, H.264 and H.265) were higher than that of video encoders using intra-frame coding (M-JPEG). It is feasible to implement video encoders using inter-frame coding for high-performance MRI data storage in MR-guided radiotherapy.

摘要

背景

磁共振成像（MRI）目前用于现代图像引导放射治疗中的在线靶区监测和计划调整。然而，存储患者治疗期间积累的大量数据成为一个问题。在本研究中，研究了使用视频编码器压缩在磁共振引导放射治疗中积累的MRI图像的可行性。

方法

采用两种排序算法对多个MRI序列中的切片进行重新排序，以作为视频编码器的输入序列。使用三种裁剪算法自动分割感兴趣区域以进行单独的数据存储。研究了四种视频编码器，即运动JPEG（M-JPEG）、MPEG-4（MP4）、高级视频编码（AVC或H.264）和高效视频编码（HEVC或H.265）。通过压缩比和时间评估视频编码器的压缩性能，同时通过均方误差（MSE）、峰值信噪比（PSNR）和视频质量矩阵（VQM）评估视频编码器的恢复精度。研究了视频编码器、排序方法和裁剪算法所有组合的性能，并对其效果进行了统计分析。

结果

与M-JPEG相比，MP4、H.264和H.265在两种排序方法下的压缩比分别提高了26%和5%、42%和27%、72%和43%。对于MP4（P = 0.00000）、H.264（P = 0.00012）和H.265（P = 0.00000），切片优先排序方法的压缩比分别高于位置优先排序方法。对于两种排序方法，应用形态学算法（P = 0.01890和P = 0.00530）、泛洪填充算法（P = 0.00510和P = 0.00020）和水平集算法（P = 0.02800和P = 0.00830）后，H.265的压缩比显著提高。在四种视频编码器中，H.265表现出最佳的压缩比和恢复精度。