Assessment of diaphragmatic function by ultrasonography: Current approach and perspectives

Abstract

This article reports the various methods used to assess diaphragmatic function by ultrasonography. The excursions of the two hemidiaphragms can be measured using two-dimensional or M-mode ultrasonography, during respiratory maneuvers such as quiet breathing, voluntary sniffing and deep inspiration. On the zone of apposition to the rib cage for both hemidiaphragms, it is possible to measure the thickness on expiration and during deep breathing to assess the percentage of thickening during inspiration. These two approaches make it possible to assess the quality of the diaphragmatic function and the diagnosis of diaphragmatic paralysis or dysfunction. These methods are particularly useful in circumstances where there is a high risk of phrenic nerve injury or in diseases affecting the contractility or the motion of the diaphragm such as neuro-muscular diseases. Recent methods such as speckle tracking imaging and ultrasound shear wave elastography should provide more detailed information for better assessment of diaphragmatic function.

Keywords: Ultrasound; Hemidiaphragm; Motion; Thickness; Paralysis; Dysfunction; Two-dimensional mode; M-mode; Speckle tracking imaging; Ultrasound shear wave elastography

Core tip: Ultrasonography provides a simple and non-invasive means of assessing diaphragmatic function. This article describes the different methods used to measure diaphragmatic excursion and thickness and detect diaphragmatic paralysis or dysfunction. Furthermore, the paper presents the various pathological conditions for which diaphragmatic ultrasound may be useful such as circumstances at high risk of phrenic nerve injury and diseases affecting diaphragmatic function. The development of methods such as speckle tracking imaging and ultrasound shear wave elastography should provide more detailed information for better assessment of diaphragmatic function.