压缩感知磁共振成像中的噪声功率谱。

Noise power spectrum in compressed sensing magnetic resonance imaging.

机构信息

Department of Radiological Technology, Toranomon Hospital, 2-2-2 Toranomon, Minato-ku, Tokyo, 105-8470, Japan.

Medical Imaging and Applied Radiology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan.

出版信息

Radiol Phys Technol. 2021 Mar;14(1):93-99. doi: 10.1007/s12194-021-00608-4. Epub 2021 Jan 23.

DOI:10.1007/s12194-021-00608-4

PMID:33484401

Abstract

Compressed sensing magnetic resonance imaging (CS-MRI) uses random undersampling and nonlinear iterative reconstruction. This study was conducted to clarify the noise power spectrum (NPS) characteristics of CS-MRI. We measured two-dimensional (2D) NPS of CS-MRI with various acceleration factors (AF) and denoising factors (DF) and compared their appearance to those of conventional parallel MR images. Results showed that the 2D NPS of CS-MRI exhibited the following characteristics: (1) local decrease in the low-frequency region, (2) gradual decrease in the high-frequency region, and (3) a stripe pattern aligned at unequal intervals in the phase-encoding direction. Specifically, the 2D NPS of CS-MRI reflects the random undersampling pattern of k-space data. Additionally, 2D NPS allowed visualization of AF-dependent noise characteristics of CS-MRI. Furthermore, 1D NPS graph shapes clarified the CS-MRI noise characteristic dependence on AF and DF.

摘要

压缩感知磁共振成像（CS-MRI）使用随机欠采样和非线性迭代重建。本研究旨在阐明 CS-MRI 的噪声功率谱（NPS）特性。我们测量了具有不同加速因子（AF）和去噪因子（DF）的二维（2D）CS-MRI 的 NPS，并将其与传统的并行 MR 图像进行了比较。结果表明，CS-MRI 的 2D NPS 具有以下特征：（1）低频区域的局部减小，（2）高频区域的逐渐减小，（3）在相位编码方向上以不均匀间隔排列的条纹图案。具体来说，CS-MRI 的 2D NPS 反映了 k 空间数据的随机欠采样模式。此外，2D NPS 可以可视化 CS-MRI 的 AF 相关噪声特性。此外，1D NPS 图形形状阐明了 CS-MRI 噪声特性对 AF 和 DF 的依赖性。