快速非局部均值（FNLM）滤波器在儿科患者胸部 CT 中肺结节检测中的应用。

Utility of fast non-local means (FNLM) filter for detection of pulmonary nodules in chest CT for pediatric patient.

机构信息

Department of Bio-Convergence Engineering, Korea University, Seoul, Republic of Korea; Department of Diagnostic Radiology, Severance Hospital, Seoul, Republic of Korea.

出版信息

Phys Med. 2021 Jan;81:52-59. doi: 10.1016/j.ejmp.2020.11.038. Epub 2021 Jan 10.

DOI:10.1016/j.ejmp.2020.11.038

PMID:33440281

Abstract

PURPOSE

This study was aimed to evaluate the utility based on imaging quality of the fast non-local means (FNLM) filter in diagnosing lung nodules in pediatric chest computed tomography (CT).

METHODS

We retrospectively reviewed the chest CT reconstructed with both filtered back projection (FBP) and iterative reconstruction (IR) in pediatric patients with metastatic lung nodules. After applying FNLM filter with six h values (0.0001, 0.001, 0.01, 0.1, 1, and 10) to the FBP images, eight sets of images including FBP, IR, and FNLM were analyzed. The image quality of the lung nodules was evaluated objectively for coefficient of variation (COV), contrast to noise ratio (CNR), and point spread function (PSF), and subjectively for noise, sharpness, artifacts, and diagnostic acceptability.

RESULTS

The COV was lowest in IR images and decreased according to increasing h values and highest with FBP images (P < 0.001). The CNR was highest with IR images, increased according to increasing h values and lowest with FBP images (P < 0.001). The PSF was lower only in FNLM filter with h value of 0.0001 or 0.001 than in IR images (P < 0.001). In subjective analysis, only images of FNLM filter with h value of 0.0001 or 0.001 rarely showed unacceptable quality and had comparable results with IR images. There were less artifacts in FNLM images with h value of 0.0001 compared with IR images (p < 0.001).

CONCLUSION

FNLM filter with h values of 0.0001 allows comparable image quality with less artifacts compared with IR in diagnosing metastatic lung nodules in pediatric chest CT.

摘要

目的

本研究旨在评估快速非局部均值（FNLM）滤波器在诊断小儿胸部 CT 中肺结节的成像质量基础上的实用性。

方法

我们回顾性分析了小儿转移性肺结节患者行滤波反投影（FBP）和迭代重建（IR）胸部 CT 重建的图像。在 FBP 图像上应用六个 h 值（0.0001、0.001、0.01、0.1、1 和 10）的 FNLM 滤波器后，分析了包括 FBP、IR 和 FNLM 的八组图像。客观评估肺结节的图像质量，包括变异系数（COV）、对比噪声比（CNR）和点扩散函数（PSF），并进行主观评估，包括噪声、锐度、伪影和诊断可接受性。

结果

IR 图像的 COV 最低，随着 h 值的增加而降低，而 FBP 图像的 COV 最高（P<0.001）。IR 图像的 CNR 最高，随着 h 值的增加而增加，而 FBP 图像的 CNR 最低（P<0.001）。只有 h 值为 0.0001 或 0.001 的 FNLM 滤波器的 PSF 低于 IR 图像（P<0.001）。在主观分析中，只有 h 值为 0.0001 或 0.001 的 FNLM 滤波器图像很少出现不可接受的质量，与 IR 图像具有可比性。与 IR 图像相比，h 值为 0.0001 的 FNLM 图像的伪影更少（p<0.001）。