Noninvasive measurement of lung elastic properties

Abstract

Many lung diseases are associated with dramatic changes in mechanical properties of the lung. Chest radiographs and computed tomography (CT) are the most common clinical methods for evaluating lung disease, but they are expensive, use radiation, and do not measure lung stiffness. Shear wave elastography (SWE) uses ultrasound radiation force (URF) to generate wave propagation in the tissue. However, URF should not be applied to the lung, because there are air and blood in the alveoli. Relatively high-intensity ultrasound can cause alveolar hemorrhage and lung injury. We have developed a noninvasive, and clinically feasible technology, lung ultrasound surface wave elastography (LUSWE), that is capable of measuring lung elastic properties with speed and accuracy. LUSWE uses a handheld shaker to generate a local small harmonic vibration on the chest surface. The resulting wave propagates through the intercostal muscle and propagates on the lung. The surface wave speed is noninvasively measured using an ultrasound technique. LUSWE is safe because diagnostic ultrasound is only used to detect the wave propagation along the lung duo to mechanical wave generation on the chest. LUSWE may be used to assess multiple lung disorders such as lung fibrosis or lung edema.