Ultrasound Elastography for Lung Disease Assessment

Abstract

Ultrasound elastography (US-E) is a noninvasive, safe, cost-effective and reliable technique to assess the mechanical properties of soft tissue and provide imaging biomarkers for pathological processes. Many lung diseases such as acute respiratory distress syndrome, chronic obstructive pulmonary disease, and interstitial lung disease are associated with dramatic changes in mechanical properties of lung tissues. Nevertheless, USE is rarely used to image the lung because it is filled with air. The large difference in acoustic impedance between air and lung tissue results in the reflection of the ultrasound wave at the lung surface and, consequently, the loss of most ultrasound energy. In recent years, there has been an increasing interest in USE applications in evaluating lung diseases. This article provides a comprehensive review of the technological advances of USE research on lung disease diagnosis. We introduce the basic principles and major techniques of USE and provide information on various applications in lung disease assessment. Finally, the potential applications of USE to the diagnosis of COVID-19 pneumonia is discussed. Index Terms-COVID-19 pneumonia, endobronchial ultrasound elastography (US-E), lung cancer, lung disease, lung ultrasound surface wave elastography (LUSWE), pulmonary fibrosis. I. INTRODUCTION L UNG disease is one of the leading causes of death worldwide. Interstitial lung diseases (ILDs) include more than 200 diseases, such as pulmonary fibrosis, pulmonary edema, pneumonia, and so on. Idiopathic pulmonary fibrosis (IPF) is increasingly recognized as a public health concern, with more than 50 000 cases annually diagnosed [1], and lung cancer is by far the leading cause of cancer death among both men and women, making up almost 25% of all cancer deaths. Meanwhile, in 2020, the world is experiencing the Covid-19 pandemic, which has resulted in many cases of pneumonia. More than ever, accurate diagnosis and monitoring of lung diseases are concerns of global scale.

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