Lung imaging: how to get better look inside the lung

Abstract

In the last years, imaging has played a key role in the diagnosis and monitoring and critical illness, including acute respiratory distress syndrome (ARDS). Chest X-ray (CXR) and computed tomography (CT) are the conventional techniques most performed in the critically ill patients, the latter being the gold standard to assess lung aeration in ARDS patients. In addition, two bedside techniques are now gaining popularity alongside the conventional ones: lung ultrasound (LUS) and electrical impedance tomography (EIT). These techniques do not involve the use of ionizing radiations, are non-invasive and relatively easy to use, and are under extensive investigation as a complement, and for some application a substitution of conventional techniques. At last, positron emission tomography (PET) and magnetic resonance imaging (MRI) can provide functional information on the lung and respiratory function, and are increasingly used in research to improve the understanding of the pathophysiological mechanisms underlying ARDS. The purpose of this review is to give an up-to-date overview of the conventional and emerging imaging techniques available the diagnosis and management of patients with ARDS.

Keywords: Acute respiratory distress syndrome (ARDS); chest X-ray (CXR); computed tomography (CT); electrical impedance tomography (EIT); lung ultrasound (LUS); magnetic resonance imaging (MRI); positron emission tomography (PET).

Conflict of interest statement

Conflicts of Interest: The authors have no conflicts of interest to declare.

Figures

Figure 1

Chest X-ray of two patients with ARDS. (A) Patient with a severe ARDS in early phase, during non-invasive ventilation; (B) patient with a late fibrotic pattern in the context of a severe ARDS. ARDS, acute respiratory distress syndrome.

Figure 2

Computed tomography of two patients with ARDS. (A) Patient with a severe ARDS in early phase, showing diffuse bilateral infiltrates and small dorsal consolidated areas; (B) patient with a fibrotic pattern developed in the late phase of an ARDS, showing diffuse infiltrates with areas of ‘honeycomb’ pattern and left pleural effusion. The scans were obtained on the same patients and same day as in Figure 1. ARDS, acute respiratory distress syndrome.