School of Microelectronics, Tianjin University, Tianjin, China.
Department of Biomedical Engineering, Chang Gung University, Taoyuan, Taiwan.
Med Phys. 2024 Nov;51(11):8074-8086. doi: 10.1002/mp.17389. Epub 2024 Sep 5.
Duchenne muscular dystrophy (DMD) is a genetic neuromuscular disorder that leads to mobility loss and life-threatening cardiac or respiratory complications. Quantitative ultrasound (QUS) envelope statistics imaging, which characterizes fat infiltration and fibrosis in muscles, has been extensively used for DMD evaluations.
Notably, changes in muscle microstructures also result in acoustic attenuation, potentially serving as another crucial imaging biomarker for DMD. Expanding upon the reference frequency method (RFM), this study contributes to the field by introducing the robust RFM (RRFM) as a novel approach for ultrasound attenuation imaging in DMD.
The RRFM algorithm was developed using an iterative reweighted least squares technique. We conducted standard phantom measurements with a clinical ultrasound system equipped with a linear array transducer to assess the improvement in attenuation estimation bias by RRFM. Additionally, 161 DMD patients, included in both a validation dataset (n = 130) and a testing dataset (n = 31), underwent ultrasound scanning of the gastrocnemius for RRFM-based attenuation imaging. The diagnostic performances for ambulatory functions and discrimination between early and late ambulatory stages were evaluated and compared with those of QUS envelope statistics imaging (involving Nakagami distribution, homodyned K distribution, and entropy values) using the area under the receiver operating characteristic curve (AUROC).
The results indicated that the RRFM method more closely matched the actual attenuation properties of the phantom, reducing measurement bias by 50% compared to conventional RFM. The AUROCs for RRFM-based attenuation imaging, used to discriminate between early and late ambulatory stages, were 0.88 and 0.92 for the validation and testing datasets, respectively. These performances significantly surpassed those of QUS envelope statistics imaging (p < 0.05).
Ultrasound attenuation imaging employing RRFM may serve as a sensitive tool for evaluating the progression of ambulatory function deterioration, offering substantial potential for the health management and follow-up care of DMD patients.
杜氏肌营养不良症（DMD）是一种遗传性神经肌肉疾病，可导致运动能力丧失，并引发危及生命的心脏或呼吸并发症。定量超声（QUS）包络统计成像技术广泛应用于 DMD 评估，可用于描述肌肉中的脂肪浸润和纤维化。
值得注意的是，肌肉微观结构的变化也会导致声衰减，这可能成为 DMD 的另一个重要成像生物标志物。本研究在参考频率法（RFM）的基础上进行扩展，引入稳健 RFM（RRFM）作为 DMD 超声衰减成像的一种新方法。
RRFM 算法是使用迭代重加权最小二乘法技术开发的。我们使用配备线性阵列换能器的临床超声系统进行标准体模测量，以评估 RRFM 对衰减估计偏差的改善。此外，我们对 161 名 DMD 患者（包括验证数据集[ n = 130]和测试数据集[ n = 31]）进行了跟腱超声扫描，用于 RRFM 衰减成像。使用接收器工作特征曲线下面积（AUROC）评估和比较 RRFM 衰减成像在评估运动功能和区分早期和晚期运动阶段方面的诊断性能，以及与 QUS 包络统计成像（涉及 Nakagami 分布、同调 K 分布和熵值）的诊断性能。
结果表明，RRFM 方法更接近体模的实际衰减特性，与传统 RFM 相比，测量偏差降低了 50%。RRFM 衰减成像用于区分早期和晚期运动阶段的验证数据集和测试数据集的 AUROC 分别为 0.88 和 0.92，明显优于 QUS 包络统计成像（ p < 0.05）。
RRFM 衰减成像可能是评估运动功能恶化进展的敏感工具，为 DMD 患者的健康管理和随访提供了重要的潜力。
