# Lung Ultrasound for Pleural Effusion in Cancer Patients: Advanced Ultrasound for Pleural Lesions—A Narrative Review

## TL;DR

This review discusses how lung ultrasound, especially new techniques like contrast-enhanced ultrasound and elastography, can improve the diagnosis of pleural effusion in cancer patients.

## Contribution

The paper highlights recent advances in lung ultrasound techniques for better diagnosis of malignant pleural effusion in cancer patients.

## Key findings

- B-mode ultrasound can detect small-volume pleural effusions and estimate their volume.
- Shear-wave elastography and contrast-enhanced ultrasound provide functional data on tissue stiffness and perfusion.
- Advanced ultrasound techniques may help distinguish between benign and malignant pleural lesions.

## Abstract

Lung ultrasound is typically the first-line imaging modality for detecting or excluding pleural effusion. Malignant pleural effusion represents an advanced disease stage, with imaging and pathology playing central roles in diagnosis. This review summarizes recent advances in lung ultrasound, particularly contrast-enhanced ultrasound and elastography, which hold promise for improving the diagnostic workup in malignant pleural effusion.

Background: Pleural effusion (PE) is a frequent complication in patients with malignancies and is often associated with poor prognosis. Lung ultrasound (LUS) has become an indispensable bedside tool for detecting, characterizing, and guiding the management of pleural effusions. Methods: This narrative review summarizes the current evidence on the diagnostic performance of LUS for PE in cancer patients, emphasizing recent advances in functional ultrasound techniques. Results: B-mode LUS can detect small-volume effusions and estimate their volume. Sonographic features such as echogenicity, septations, and pleural abnormalities can help differentiate transudative from exudative effusions. Shear-wave elastography and contrast-enhanced ultrasound provide additional functional information on tissue stiffness and perfusion. This information may help distinguish between malignant and benign pleural lesions and facilitate targeted biopsy when cytology is nondiagnostic. Compared with computed tomography, LUS offers superior evaluation of juxtadiaphragmatic and pleural surface abnormalities. It facilitates safe, real-time thoracocentesis. Recent innovations, including improved quality, affordable handheld ultrasound systems and artificial intelligence-based analysis, are expected to further enhance diagnostic precision and accessibility. Conclusions: Although LUS is a sensitive and versatile tool for assessing PE in cancer patients, it has limited diagnostic accuracy in distinguishing between benign and malignant effusions. Advanced techniques, such as shear-wave elastography and contrast-enhanced ultrasound, may further support the differentiation of malignant and benign diseases. Ongoing technological advances are likely to enhance the diagnostic accuracy and accessibility of lung ultrasound.