From the Guidelines
A contrast-enhanced chest CT scan with IV contrast is recommended to evaluate pleural effusion. This type of CT scan involves the administration of intravenous contrast material, which enhances the visualization of pleural fluid collections and underlying pathology, as supported by the American College of Radiology guidelines 1. The contrast helps differentiate between pleural thickening, masses, and fluid, allowing for better characterization of the effusion.
When performing this scan, acquiring the CT scan 60 seconds after the IV contrast bolus optimizes visualization of the pleura, as noted in the study published in the Journal of the American College of Radiology 1. The use of CT chest with IV contrast is also recommended for patients with suspected malignant pleural effusion or suspected unilateral pleural effusion with an increased pretest probability of malignancy, as stated in the guidelines 1.
Some key points to consider when evaluating pleural effusion with a CT scan include:
- The ability to identify the location and extent of the effusion
- The detection of loculations or septations within the fluid
- The potential to reveal underlying causes such as malignancy, infection, or pulmonary embolism
- The use of CT guidance for diagnostic thoracentesis in cases where the effusion is small or loculated, as mentioned in the guidelines 1.
It is essential to inform patients about potential contrast reactions and assess kidney function before administering contrast material, as with any contrast-enhanced CT scan. Overall, a contrast-enhanced chest CT scan with IV contrast is the recommended imaging modality for evaluating pleural effusion, given its ability to provide detailed information about the effusion and underlying pathology 1.
From the Research
CT Scan Types for Pleural Effusion Evaluation
To evaluate pleural effusion, the following types of CT scans can be used:
- Contrast-enhanced CT scan: This type of scan is useful in differentiating between pleural exudates and transudates, and in identifying pleural thickening and other abnormalities 2.
- Non-contrast CT scan: This type of scan can be used to evaluate the size and location of the pleural effusion, as well as to identify any associated lung or mediastinal abnormalities.
Characteristics of CT Scans for Pleural Effusion
The following characteristics of CT scans can be useful in evaluating pleural effusion:
- Pleural thickening: This is a common finding in exudative pleural effusions, and can be identified on contrast-enhanced CT scans 2.
- Pleural nodules: These are more commonly seen in malignant pleural effusions, and can be identified on CT scans 3, 4.
- Loculation: This is a characteristic of exudative pleural effusions, and can be identified on CT scans 3.
- Extrapleural fat thickening: This is a finding that can be seen in exudative pleural effusions, and can be identified on contrast-enhanced CT scans 2.
Scoring Systems for CT Scans
A CT scan scoring system has been developed to help differentiate between benign and malignant pleural effusions 4. This system assigns points for various CT scan findings, including:
- Pleural lesions (e.g. nodules, masses, or thickening) ≥ 1 cm
- Liver metastases, abdominal mass, or lung mass or nodule ≥ 1 cm
- Absence of pleural loculations, pericardial effusions, or cardiomegaly
This scoring system has been shown to have high sensitivity and specificity for identifying malignant pleural effusions 4.