Medical Student Researcher
Rune Wiig Nielsen
Odense Respiratory Research Unit (ODIN), Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
| Projekt styring | ||
| Projekt status | Open | |
| Data indsamlingsdatoer | ||
| Start | 01.09.2021 | |
| Slut | - | |
Diagnostic Accuracy of Shear Wave Elastography in Predicting Malignant Origins of Pleural Effusions in an Emergency Department
Short summary
Ultrasound is a valuable diagnostic tool in the diagnostic work-up of dyspnea and can identify even small pleural effusions. Incorporating Shear Wave Elastography (SWE) represents a possible tool in stratifying pleural effusions by risk of underlying malignancy. Patients with unilateral pleural effusion of unknown origin were included in the ED and subjected to a Focused Lung Ultrasound (FLUS) scan during their first 48 hours after admittance.
Rationale
Pleural effusion (PE) is a common condition with an annual incidence of approximately 1.3 million in the United States of America (USA) [1]. PEs are categorized into transudates or exudates based on biochemical composition, encompassing level of protein and lactate dehydrogenase (LD), with the higher-osmolality exudates occurring due to local inflammation [1-3]. An important sub-group of pleural effusions are the malignant pleural effusions (MPE), in some settings accounting for 35% of all PE's [4]. In 95% of cases, MPE originate from metastases in the pleural space and are a sign of disseminated or advanced cancer. Lung and breast cancer are the most common causes, but also lymphomas, genitourinary metastases and gastrointestinal metastases may give rise to MPE [4, 5]. Thoracic ultrasound (TUS) represents an important tool in determining optimal choice of invasive diagnostic procedure and patient imaging, and may as such reduce the number of invasive diagnostic procedures needed to determine the underlying pathology of a PE, by stratification of risk for underlying malignancy. Two ultrasound approaches have previously shown some potential in separating MPEs from other pleural effusions of non-malignant origin, both assessing pleural and diaphragmatic thickening and diaphragmatic nodules, one employing Shear Wave Elastography (SWE) in evaluating stiffness of pleural thickenings [6, 7]. SWE is a novel technique in TUS, but is known to have capabilities in differentiating malignant from non-malignant tissue, due to the stiffer nature of the former [8]. However, both studies were conducted at specialist centers on a highly selected patient population by physicians experienced in TUS. As ultrasound is and is frequently applied in the setting an emergency department (ED), where several patients with newly discovered pleural effusion of unknown origin are first identified, the utility of TUS' ability to differentiate between malignant and benign origin should also be investigated in this setting of more unselected patients [9]. The aim of this prospective study was to appraise the diagnostic accuracy of ultrasonographic findings commonly associated with malignant pleural effusions among patients presenting with acute unilateral effusion of unknown origin, as well as calculating optimal cut-off values for SWE in this regard. Secondly, we sought to identify patient subgroups in whom FLUS examination might be of particular benefit by considering additional lab results or baseline characteristics.
Description of the cohort
This prospective observational study was conducted at the ED and Department of Respiratory Medicine at Odense University Hospital (OUH), a Danish tertiary referral center with an annual census of approximately 65,000 emergency visits. Patients were enrolled between September 2021 and April 2022. Patients were deemed eligible for enrollment if they I) presented as hemodynamically stable, II) had no permanent cognitive disabilities, III) were at least 18 years old and otherwise capable of providing IV) informed consent, and V) were diagnosed with unilateral pleural effusions of unknown cause by prior patient imaging. Patients were included as a convenience sample, either at the ED during the first two days of admittance, or from the outpatient respiratory clinic when they were referred for planned thoracocentesis.
Data and biological material
Patients with unilateral pleural effusion of unknown origin were included in the ED and subjected to a Focused Lung Ultrasound (FLUS) scan during their first 48 hours after admittance. Two index tests were applied: i) traditional 2D FLUS examination registering presence of diaphragmatic noduli, pleural thickenings and other findings associated with malignancy, and ii) a SWE examination of different Regions of Interest, registering tissue stiffness of intrathoracic points of interest. Reference test was defined as subsequent diagnosis of malignant pleural effusion (MPE) in the three months following inclusion.