Objective

A method for Orthogonal Phase Encoding Reduction of Artifact (OPERA) was developed and tested.

Materials and methods

Because the position of ghosts and aliasing artifacts is predictable along columns or rows, OPERA combines the intensity values of two images acquired using the same parameters, but with swapped phase-encoding directions, to correct the artifacts. Simulations and phantom experiments were conducted to define the efficacy, robustness, and reproducibility. Clinical validation was performed on a total of 1003 images by comparing the OPERA-corrected images and the corresponding image standard in terms of Signal-to-Noise Ratio (SNR) and Contrast-to-Noise Ratio (CNR). The method efficacy was also rated using a Likert-type scale response by two experienced independent radiologists using a single-blinded procedure.

Results

Simulations and phantom experiments demonstrated the robustness and effectiveness of OPERA in reducing artifacts strength. OPERA application did not significantly change the SNR [+ 4.16%; inter-quartile range (IQR): 2.72–5.01%] and CNR (+ 4.30%; IQR: 2.86–6.04%) values. The two radiologists observed a total of 893 original images with artifacts (89.03% of the total images), a reduction in the perceived artifacts of 82.0% and 83.9% (p < 0.0001), and an improvement in the perceived SNR (82.8% and 88.5%; K = 0.714) and perceived CNR (86.9–88.9%; K = 0.722).

Discussion

The study demonstrated that OPERA reduces MR artifacts and improves the perceived image quality.

中文翻译：

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OPERA：一种减少重影和混叠伪影的新方法。

客观的

开发并测试了一种用于减少伪像 (OPERA) 的正交相位编码方法。

材料和方法

由于重影和混叠伪影的位置可以沿列或行进行预测，因此 OPERA 将使用相同参数获取的两个图像的强度值组合在一起，但相位编码方向已交换，以校正伪影。进行了模拟和体模实验以定义功效、稳健性和再现性。通过在信噪比 (SNR) 和对比度噪声比 (CNR) 方面比较 OPERA 校正图像和相应的图像标准，对总共 1003 张图像进行了临床验证。该方法的功效还由两名经验丰富的独立放射科医生使用单盲程序使用李克特型量表反应进行评级。

结果

模拟和幻影实验证明了 OPERA 在减少伪影强度方面的稳健性和有效性。OPERA 应用程序没有显着改变 SNR [+ 4.16%; 四分位距 (IQR)：2.72–5.01%] 和 CNR (+ 4.30%；IQR：2.86–6.04%) 值。两位放射科医生共观察到 893 张带有伪影的原始图像（占总图像的 89.03%），感知伪影减少了 82.0% 和 83.9%（p  < 0.0001），感知 SNR 提高（82.8% 和88.5%；K  = 0.714）和感知 CNR（86.9–88.9%；K  = 0.722）。

讨论

该研究表明 OPERA 减少了 MR 伪影并提高了感知图像质量。