# Application of Transthoracic and Endobronchial Elastography—A Systematic Review

## TL;DR

This review examines how ultrasound elastography is used in thoracic imaging to evaluate lung and pleural diseases, finding potential but highlighting the need for standardized methods.

## Contribution

The paper systematically reviews the clinical applications and methodological challenges of transthoracic and endobronchial elastography in thoracic imaging.

## Key findings

- Shear wave elastography helps distinguish malignant from benign pleural effusions and subpleural lesions.
- Surface wave elastography shows higher stiffness in interstitial lung disease, correlating with disease severity.
- Elastography-guided biopsy improves diagnostic yield compared to conventional methods.

## Abstract

Ultrasound elastography is increasingly applied in thoracic imaging, but its clinical role remains unclear. This systematic review of 30 studies found that most research focused on transthoracic applications, particularly shear wave elastography for distinguishing malignant from benign pleural effusions or subpleural lesions, and surface wave elastography for assessing interstitial lung disease. However, substantial variation in methods, ultrasound techniques, and diagnostic thresholds restricts comparison across studies. Overall, elastography shows potential value in thoracic disease evaluation and procedural guidance, but standardized protocols and larger validation studies are needed before widespread clinical adoption.

Introduction: Ultrasound elastography is increasingly used across medical imaging, yet its role in thoracic disease remains poorly defined. While both transthoracic ultrasonography (TUS) and endobronchial ultrasound (EBUS) offer real-time assessment of pleural and pulmonary structures, the diagnostic and clinical value of elastography in this context remains uncertain. Materials and Method: A systematic search of MEDLINE, EMBASE, and the Cochrane Library was conducted according to PRISMA guidelines (April 2023; updated January 2025). Original studies evaluating transthoracic or endobronchial elastography for pleural or pulmonary conditions were included. Data extraction and quality assessment were performed independently by three reviewers, with QUADAS-2 used to evaluate risk of bias. Results: Thirty studies met inclusion criteria. Twenty-eight evaluated TUS elastography and two examined EBUS. Shear wave elastography was most frequently applied, particularly for differentiating malignant from benign pleural effusion or subpleural lesions. Surface wave elastography demonstrated consistently higher stiffness values in patients with interstitial lung disease compared with healthy controls, correlating with radiological and functional disease severity. Elastography-guided pleural biopsy improved diagnostic yield compared with conventional ultrasound-guided biopsy. Overall, substantial methodological variation existed among scanning techniques, elastography modalities, reporting methods, and diagnostic thresholds, limiting cross-study comparison. Conclusions: Ultrasound elastography shows promise for evaluating pleural effusion and pulmonary lesions, procedural guidance, and interstitial lung disease possibly improving diagnostic possibilities with bedside evaluation and reducing patient exposure to radiation. However, methodological variation and limited high-quality evidence preclude clinical implementation. Standardized acquisition protocols and multicentre validation studies are necessary to define its diagnostic utility in thoracic imaging.