IEEE Trans Ultrason Ferroelectr Freq Control. 2021 Jun;68(6):2075-2085. doi: 10.1109/TUFFC.2021.3055498. Epub 2021 May 25.
Ultrasound vascular imaging based on ultrafast plane wave imaging and singular value decomposition (SVD) clutter filtering has demonstrated superior sensitivity in blood flow detection. However, ultrafast ultrasound vascular imaging is susceptible to electronic noise due to the weak penetration of unfocused waves, leading to a lower signal-to-noise ratio (SNR) at larger depths. In addition, incoherent clutter artifacts originating from strong and moving tissue scatterers that cannot be completely removed create a strong mask on top of the blood signal that obscures the vessels. Herein, a method that can simultaneously suppress the background noise and incoherent artifacts is proposed. The method divides the tilted plane or diverging waves into two subgroups. Coherent spatial compounding is performed within each subgroup, resulting in two compounded data sets. An SVD-based clutter filter is applied to each data set, followed by a correlation between the two data sets to produce a vascular image. Uncorrelated noise and incoherent artifacts can be effectively suppressed with the correlation process, while the coherent blood signal can be preserved. The method was evaluated in wire-target simulations and phantom, in which around 7-10-dB SNR improvement was shown. Consistent results were found in a flow channel phantom with improved SNR by the proposed method (39.9 ± 0.2 dB) against conventional power Doppler (29.1 ± 0.6 dB). Last, we demonstrated the effectiveness of the method combined with block-wise SVD clutter filtering in a human liver, breast tumor, and inflammatory bowel disease data sets. The improved blood flow visualization may facilitate more reliable small vessel imaging for a wide range of clinical applications, such as cancer and inflammatory diseases.
基于超快速平面波成像和奇异值分解 (SVD) 杂波滤波的超声血管成像在血流检测中表现出更高的灵敏度。然而，由于非聚焦波的弱穿透性，超快速超声血管成像容易受到电子噪声的影响，导致较大深度处的信号噪声比 (SNR) 较低。此外，源于强散射体和运动组织的非相干杂波伪影无法完全去除，在血流信号上方形成强烈的遮蔽，使血管难以显现。本文提出了一种可以同时抑制背景噪声和非相干伪影的方法。该方法将倾斜平面或发散波分为两组。在每组内进行相干空间复合，得到两组复合数据集。对每组数据应用基于 SVD 的杂波滤波器，然后对两组数据进行相关处理，生成血管图像。相关过程可以有效抑制不相关噪声和非相干伪影，同时保留相干血流信号。该方法在模拟线靶和体模中进行了评估，结果显示 SNR 提高了约 7-10dB。在具有血流通道的体模中，与传统的功率多普勒相比，该方法（39.9±0.2dB）的 SNR 提高了 7-10dB。最后，我们在人体肝脏、乳腺肿瘤和炎症性肠病数据集上展示了该方法与分块 SVD 杂波滤波相结合的有效性。这种血流可视化的改进可能有助于更可靠地进行小血管成像，适用于广泛的临床应用，如癌症和炎症性疾病。
