Objective An improved water-fat separation method based on region-growing was proposed for use in regions with low signal-noise ratio (SNR).Methods Region-growing method was applied to 4 sub-images acquired by a downsampling operation on the acquired phasor maps.The spatial smoothing constraint was exploited to calculate 4 error phasor maps to construct the final smooth error phasor map,which was used in two-point Dixon technique for water-fat separation.Results The simulation experiment showed that the proposed method produced smaller errors,and for dinical images of the knees,abdomen and lower limbs,the proposed method achieved accurate water-fat separations.Conclusion The proposed method is more robust and reliable than the original global region-growing algorithm,and serves as a promising water-fat separation method for clinical applications.%目的 提出一种改进的基于区域增长的水脂分离方法,使其可以在低信噪比情况下更可靠.方法 对获取的两幅场向量图分别进行隔行隔列降采样,得到四幅子图像.每幅子图像分别运用区域增长算法获得误差向量图,然后再利用空间相邻像素相位平滑的性质来合并获得的四幅子误差向量图,从而获得一幅平滑的误差向量图,并实现水和脂肪的准确分离.结果 提出方法分别应用于仿真数据和真实数据,仿真数据表明本文方法产生的误差更小.真实数据实验结果表明,提出方法在膝盖、腹部和大腿等部位都能够准确的实现水和脂肪的分离.结论 相对于原始全局区域增长方法,提出方法更加可靠和稳定,能够在不同解剖部位实现准确水脂分离.
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