High-Resolution Computed Tomography and Lung Ultrasound in Patients with Systemic Sclerosis: Which One to Choose?

Abstract

Imaging plays a pivotal role in systemic sclerosis for both diagnosis management of pulmonary complications, and high-resolution computed tomography (HRCT) is the most sensitive technique for the evaluation of systemic sclerosis-associated interstitial lung disease (SSc-ILD). Indeed, several studies have demonstrated that HRCT helps radiologists and clinicians to make a correct diagnosis on the basis of recognised typical patterns for SSc-ILD. Most SSc patients affected by ILD have a non-specific interstitial pneumonia pattern (NISP) on HRCT scan, whilst a minority of cases fulfil the criteria for usual interstitial pneumonia (UIP). Moreover, several recent studies have demonstrated that lung ultrasound (LUS) is an emergent tool in SSc diagnosis and follow-up, although its role is still to be confirmed. Therefore, this article aims at evaluating the role of LUS in SSc screening, aimed at limiting the use of CT to selected cases.

Keywords: diagnostic imaging; high-resolution computed tomography (HRCT); interstitial lung disease (ILD); lung ultrasound (LUS); systemic sclerosis (SSc); systemic sclerosis-associated interstitial lung disease (SSc-ILD).

Figure 1

HRCT scan of a patient with systemic sclerosis. The axial scan (A) shows diffuse, bilateral, symmetrical ground-glass opacities in the lung parenchyma. The alterations have a basal predominance, as better appreciated on the coronal reconstruction (B). Note the dilated esophagus (arrow in A), an important accessory finding in this disease.

Figure 2

To the left (A), an HRCT scan of a patient with systemic sclerosis showing extensive ground-glass opacities and reticulations with traction bronchiectasis (white arrows) in the basal regions of both lungs. The findings are compatible with a fibrotic NSIP pattern. Note also, in this case, a dilated esophagus (black arrow). To the right (B), ultrasonographic scans (4–13 MHz broadband linear transducer) with the presence of 2 ultrasound B-line (white arrows) in the same patients.

Figure 3

UIP pattern in a patient with systemic sclerosis. On the axial HRCT images at different levels (A,B), there are bilateral reticular opacities with inter- and intralobular septal thickening, more prevalent in the peripheral regions of the lungs, traction bronchiectasis, ground-glass opacities, and honeycombing. On the axial image in the mediastinal window (C), the dilated esophagus, with an air-fluid level within the lumen, can be well appreciated (arrow).

Figure 4

Ultrasonographic scans (4–13 MHz broadband linear transducer). Ultrasound B-lines (or comet-tails) are defined as hyperechogenic artefact consistent with thickened subpleural interlobular septa (white arrows). They originate from the pleural line and are roughly perpendicular to it. They have a narrow base and form a ray that spreads away from the pleural line towards the bottom of the screen and move synchronously with the lung respiration. The pathological pleural line shows irregularities (★).