Can ultrasound shear wave elastography differentiate between malignant and benign pleural effusions?

Abstract

BackgroundMalignant pleural effusion is a common and unfortunately serious condition that is related to life poor quality and mortality. The majority of malignant pleural effusion is metastatic in nature, with the most encountered primary neoplasm in men is the lung cancer while in women is the breast cancer. Ultrasound elastography, with its ability of evaluating tissue stiffness, has been used to differentiate malignant from benign diseases. Shear wave elastography (SWE) has been explored in several organs, like the liver, breast, thyroid, lymph nodes and prostate, with the pleura can now be included among the growing list of SWE applications. Shear wave elastography may help in the differentiation of transudative and exudative types of pleural effusions.ResultsIn this study, a total of 36 patients were included, 50% revealed malignant pleural effusions (10/18 mesothelioma) and (8/18 metastatic), while the 50% revealed benign pleural effusions (9/18 transudates) and (9/18 exudates). By using sensitivity analysis test of the SWE values with V1 represents the minimum value, V2 the maximum value to calculate the cutoff values that will be used in our final diagnosis in order to differentiate benign and malignant cases. V1 shear wave elastography can significantly predict the malignant pleural effusion with p value 0.001 using a cutoff 48 kPa with calculated sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were as follows 94.4%, 88.9%, 89.5% & 94.4% respectively with diagnostic accuracy of 92%. SWE maximum value (V2) can significantly predict the malignant pleural effusion with p value 0.001 using a cutoff 54.2 kPa, with calculated sensitivity, specificity, PPV and NPV were as follows 94.4%, 94.4%, 94.4% and 94.4% respectively with diagnostic accuracy 94.4%. So, through comparing both cutoff values, we concluded that the cutoff value 2 is better with greater specificity, PPV and NPV in relation to the final diagnosis.ConclusionsCombination of both conventional transthoracic ultrasound and SWE quantitative and qualitative abilities in assessment of both pleural and parenchymal lesions can result in high diagnostic accuracy. Shear wave elastography alone is a sensitive, specific, useful, cost-effective, widely available and noninvasive tool for assessment of tissue stiffness and in matters of high sensitivity. 54.2 kPa can be used as the cutoff value to distinguish MPE from benign pleural disease.