Center for Ultrasound Research and Translation, Massachusetts General Hospital, Boston, MA, USA.
Joint Department of Physics, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, London, UK.
Ultrasound Med Biol. 2023 Nov;49(11):2327-2335. doi: 10.1016/j.ultrasmedbio.2023.06.021. Epub 2023 Aug 6.
Non-alcoholic fatty liver disease (NAFLD) is a significant cause of diffuse liver disease, morbidity and mortality worldwide. Early and accurate diagnosis of NALFD is critical to identify patients at risk of disease progression. Liver biopsy is the current gold standard for diagnosis and prognosis. However, a non-invasive diagnostic tool is desired because of the high cost and risk of complications of tissue sampling. Medical ultrasound is a safe, inexpensive and widely available imaging tool for diagnosing NAFLD. Emerging sonographic tools to quantitatively estimate hepatic fat fraction, such as tissue sound speed estimation, are likely to improve diagnostic accuracy, precision and reproducibility compared with existing qualitative and semi-quantitative techniques. Various pulse-echo ultrasound speed of sound estimation methodologies have been investigated, and some have been recently commercialized. We review state-of-the-art in vivo speed of sound estimation techniques, including their advantages, limitations, technical sources of variability, biological confounders and existing commercial implementations. We report the expected range of hepatic speed of sound as a function of liver steatosis and fibrosis that may be encountered in clinical practice. Ongoing efforts seek to quantify sound speed measurement accuracy and precision to inform threshold development around meaningful differences in fat fraction and between sequential measurements.
非酒精性脂肪性肝病 (NAFLD) 是全球弥漫性肝病发病率和死亡率的重要原因。早期、准确地诊断 NAFLD 对于识别疾病进展风险患者至关重要。肝活检是目前诊断和预后的金标准。然而，由于组织采样的高成本和并发症风险，人们希望有一种非侵入性的诊断工具。医学超声是诊断 NAFLD 的一种安全、廉价且广泛可用的成像工具。新兴的超声定量估计肝脂肪分数的工具，如组织声速估计，可能会比现有的定性和半定量技术提高诊断的准确性、精度和可重复性。已经研究了各种脉冲回波超声声速估计方法，其中一些最近已经商业化。我们综述了最新的体内声速估计技术，包括它们的优点、局限性、技术变异性来源、生物学混杂因素以及现有的商业实现。我们报告了肝声速与肝脂肪变性和纤维化的预期范围，这些可能在临床实践中遇到。目前的研究旨在量化声速测量的准确性和精度，为脂肪分数和连续测量之间的有意义差异制定阈值提供依据。
