Robust sound speed estimation for ultrasound-based hepatic steatosis assessment
Robust sound speed estimation for ultrasound-based hepatic steatosis assessment
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DOI：
10.1088/1361-6560/aa6226
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发表时间：
2017-05-07
影响因子：
3.5
通讯作者：
Tanter, Mickael
中科院分区：
文献类型：
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作者：
Imbault, Marion;Faccinetto, Alex;Tanter, Mickael
肝脏脂肪变性是一种常见疾病，其患病率随着非酒精性脂肪性肝病（NAFLD）的发生而沿着增加。目前，用于诊断和量化肝脂肪变性的最准确的非侵入性成像方法是MRI，其估计质子密度脂肪分数（PDFF）作为脂肪含量分数的量度。然而，MRI存在一些局限性，包括成本、禁忌症和可用性差。尽管放射科医生广泛使用常规超声进行肝脂肪变性评估，但它仍然依赖于定性和操作者。有趣的是，已知软组织内的声速与肌肉略有不同（1.575 mm）。μ s（-1））对脂肪（1.450 mm .μ s（-1））。基于这一事实，当脂肪含量增加时，脂肪变性可能会影响肝脏声速。本研究的主要目的是提出一种稳健的方法，用于肝脏局部的声速估计（SSE），并评估其用于脂肪变性检测和分期的准确性。该技术首先在两个体模上进行验证，并以0.006和0.003 mm的精度评估SSE。μ s（-1）。然后进行了初步临床试验（N = 17例患者）。SSE结果与MRI质子密度脂肪分数（R-2 = 0.69）和活检（AUROC = 0.952）结果高度相关。这种基于局部散斑噪声时空特性评估的新方法为肝脂肪变性的诊断和分期提供了一种有效的方法。
Hepatic steatosis is a common condition, the prevalence of which is increasing along with non-alcoholic fatty liver disease (NAFLD). Currently, the most accurate noninvasive imaging method for diagnosing and quantifying hepatic steatosis is MRI, which estimates the proton-density fat fraction (PDFF) as a measure of fractional fat content. However, MRI suffers several limitations including cost, contra-indications and poor availability. Although conventional ultrasound is widely used by radiologists for hepatic steatosis assessment, it remains qualitative and operator dependent. Interestingly, the speed of sound within soft tissues is known to vary slightly from muscle (1.575 mm . mu s(-1)) to fat (1.450 mm . mu s(-1)). Building upon this fact, steatosis could affect liver sound speed when the fat content increases. The main objectives of this study are to propose a robust method for sound speed estimation (SSE) locally in the liver and to assess its accuracy for steatosis detection and staging. This technique was first validated on two phantoms and SSE was assessed with a precision of 0.006 and 0.003 mm . mu s(-1) respectively for the two phantoms. Then a preliminary clinical trial (N = 17 patients) was performed. SSE results was found to be highly correlated with MRI proton density fat fraction (R-2 = 0.69) and biopsy (AUROC = 0.952) results. This new method based on the assessment of spatio-temporal properties of the local speckle noise for SSE provides an efficient way to diagnose and stage hepatic steatosis.