Evaluation of connective tissue disease-related interstitial lung disease using ultrasound elastography: a preliminary study

Current evidence for lung ultrasound elastography in the field of pneumology: a systematic review

Background and objectives

Elastography is a technology that has strongly impacted several medical specialties; however, it is not yet applied as part of standard clinical practice in the field of pulmonology. The objective of this systematic review is to analyse the evidence available to date in relation to pleuropulmonary ultrasound elastography, focusing on the three pathologies with the most publications: subpleural consolidations, interstitial lung diseases and pleural effusion.

Methods

Original in vivo studies published up until 12 August 2023 in the Embase, MEDLINE or Web of Science databases were included. The QUADAS-2 tool was applied to analyse bias.

Results

We found 613 records in database search. After duplicates removal, we screened 246 records and finally included 18 papers. The average cohort sample size was 109 patients. The elastography modes most frequently used were strain (22.2%), transient elastography (22.2%), point shear-wave elastography (38.9%) and two-dimensional shear-wave elastography (22.2%). The possibility of a meta-analysis was ruled out because of the heterogeneity of the studies included.

Discussion

The currently available literature indicates that pleuropulmonary ultrasound elastography produces promising and consistent results, although the lack of standardisation in the use of the technique and in the elastography modes employed still impedes its use in daily clinical pneumology practice. The development of a clinical guideline establishing a common nomenclature and standardised techniques for pleuropulmonary elastography will be imperative to generate quality scientific evidence in this field.

Screening value of lung ultrasound and pleural shear wave elastography in connective tissue disease-related interstitial lung disease: a preliminary study

OBJECTIVE

To explore the diagnostic value of lung ultrasound (LUS) and pleural shear wave elastography (SWE) for connective tissue disease-interstitial lung disease (CTD-ILD).

METHODS

We selected 104 patients diagnosed with connective tissue disease (CTD) at our hospital. All patients underwent LUS, SWE, and high-resolution computed tomography (HRCT). With HRCT as the imaging gold standard for diagnosis, patients were categorized into CTD-ILD and CTD-non-ILD groups. We employed paired chi-square tests to compare the diagnostic differences between HRCT and LUS for ILD. Receiver operating characteristic (ROC) curves were used to assess the diagnostic value of pleural SWE for ILD. Correlation analysis was performed between pleural elasticity values and lung ultrasound scores.

RESULTS

The sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of LUS for diagnosing CTD-ILD were 93.3%, 86.2%, 6.761, and 0.078, respectively. There was no statistically significant difference in the results between HRCT and LUS (P = 1.000), with a kappa value of 0.720 (P < 0.001). There was a statistically significant difference in the pleural elasticity in the bilateral lower back region between the case and control groups (P < 0.001). The area under the receiver operating characteristic (ROC) curve (AUC) for pleural SWE in diagnosing CTD-ILD was 0.685. In CTD-ILD patients, there was no significant correlation between pleural elasticity values and LUS scores (P > 0.05).

CONCLUSION

The LUS can serve as an important imaging method for screening for CTD-ILD and assessing the severity of the disease. However, pleural SWE has been shown to demonstrate lower diagnostic efficacy for CTD-ILD, and its ability to assess disease severity is limited.

Lung ultrasound in a nutshell. Lines, signs, some applications, and misconceptions from a radiologist's point of view. Part 2

In recent years, lung ultrasound (LUS) has developed rapidly, and it is gaining growing popularity in various scenarios. There are constant attempts to introduce it to new fields. In addition, knowledge regarding lung and LUS has been augmented by the recent COVID-19 pandemics. In the first part of this review we discuss lines, signs and pheno-mena, profiles, some applications, and misconceptions. An aim of the second part of the review is mainly to discuss some advanced applications of LUS, including lung elastography, lung spectroscopy, colour and spectral Doppler, contrast-enhanced ultrasound of lung, speckled tracking of pleura, quantification of pulmonary oedema, predicting success of talc pleurodesis, asthma exacerbations, detecting chest wall invasion by tumours, lung biopsy, estimating pleural effusion volume, and predicting mechanical ventilatory weaning outcome. For this purpose, we reviewed literature concerning LUS.

Ultrasound in the Study of Thoracic Diseases: Innovative Aspects

Thoracic ultrasound (TU) has rapidly gained popularity over the past 10 years. This is in part because ultrasound equipment is available in many settings, more training programmes are educating trainees in this technique, and ultrasound can be done rapidly without exposure to radiation. The aim of this review is to present the most interesting and innovative aspects of the use of TU in the study of thoracic diseases. In pleural diseases, TU has been a real revolution. It helps to differentiate between different types of pleural effusions, guides the performance of pleural biopsies when necessary and is more cost-effective under these conditions, and assists in the decision to remove thoracic drainage after talc pleurodesis. With the advent of COVID19, the use of TU has increased for the study of lung involvement. Nowadays it helps in the diagnosis of pneumonias, tumours and interstitial diseases, and its use is becoming more and more widespread in the Pneumology ward. In recent years, TU guided biopsies have been shown to be highly cost-effective, with other advantages such as the absence of radiation and the possibility of being performed at bedside. The use of contrast in ultrasound to increase the cost-effectiveness of these biopsies is very promising. In the study of the mediastinum and peripheral pulmonary nodules, the introduction of echobronchoscopy has brought about a radical change. It is a fully established technique in the study of lung cancer patients. The introduction of elastography may help to further improve its cost-effectiveness. In critically-ill patients, diaphragmatic ultrasound helps in the assessment of withdrawal of mechanical ventilation, and is now an indispensable tool in the management of these patients. In neuromuscular patients, ultrasound is a good predictor of impaired lung function. Currently, in Neuromuscular Disease Units, TU is an indispensable tool. Ultrasound study of the intercostal musculature is also effective in the study of respiratory function, and is widely used in Respiratory Rehabilitation. In Intermediate Care Units, thoracic ultrasound is indispensable for patient management. In these units there are ultrasound protocols for the management of patients with acute dyspnoea that have proven to be very effective.

A study of the diagnostic value of a modified transthoracic lung ultrasound scoring method in interstitial lung disease

Background

Interstitial lung disease (ILD) is a serious complication of connective tissue disease (CTD) with significant morbidity and mortality. Lung ultrasound (LUS) has been widely used in the diagnosis of a variety of lung diseases. However, there is no standard ultrasound scanning method or scoring method for connective tissue disease associated with interstitial lung disease (CTD-ILD); therefore, it is necessary to establish a set of standard evaluation methods.

Methods

A total of 60 consecutive patients with clinically confirmed CTD and suspected ILD were prospectively included in this study. LUS and high-resolution computed tomography (HRCT) were used to examine all patients. The time between HRCT and LUS examinations was less than 2 weeks. The ultrasonographic results were evaluated with the modified scoring method and the Buda scoring method. The imaging results were evaluated with the HRCT Warrick scoring method. The primary aim was to evaluate the diagnostic value of a modified ultrasound scoring method in CTD-ILD.

Results

The results of the Youden index for the diagnosis of CTD-ILD by the modified method, the Buda method, and the HRCT method were 0.845, 0.711, and 0.911, respectively, with areas under the receiver operating characteristic (ROC) curve (AUC) of 0.982 [95% confidence interval (CI): 0.945-1.000], 0.950 (95% CI: 0.851-0.990), and 0.985 (95% CI: 0.949-1.000), respectively. With a clinical diagnosis as the gold standard, the consistency of the modified method and the HRCT method for CTD-ILD was high (Kappa values =0.872 and 0.913, respectively). The values of the modified method and the Buda method consistently and significantly increased with the increasing severity of CTD-ILD. For the former, there were significant differences between the mild, moderate, and severe groups (P<0.05). The ROC curve used to calculate the modified ultrasound score predicted the critical values of mild and severe pulmonary fibrotic lesions at 34 points (sensitivity, 100%; specificity, 92.9%; AUC =0.933; 95% CI: 0.807-1.000) and 64.5 points (sensitivity, 92.0%; specificity, 85.3%; AUC =0.972; 95% CI: 0.929-1.000).

Conclusions

The modified ultrasound method has a higher diagnostic value than the Buda method for CTD-ILD.