Gerta Repečkaitė1, Rokas Kurtinaitis1, Laima Dobrovolskienė Md Phd.1, Algidas Basevičius Md Phd.1 Domas Golubickas1
1Department of Radiology of Lithuanian University of Health Sciences Kaunas, Lithuania.
Background: Fluid in the pleural cavity is a common clinical problem with many potential causes. Despite the clinical and radiological findings providing important data about the cause(s) of content in the pleural cavity, tube thoracostomy or diagnostic thoracentesis are still required to relieve the pressure and characterize the fluid. These procedures could be avoided by applying a non-invasive method such as measurement of fluid CT attenuation values (CT – AV).
Aim: To evaluate CT attenuation values as a diagnostic tool to distinguish between hydrothorax, pyothorax and haemothorax.
Materials and methods: For this retrospective observational study we reviewed 89 patient medical records and chest CT scans performed between October 2012 and January 2017. Patients with the diagnosis of either haemothorax, pyothorax or hydrothorax were included. CT – AV were measured in three CT scan slices with the highest amount of pleural effusion. We calculated the mean CT – AV for every study participant and evaluated the accuracy to distinguish pleural contents between haemothorax, pyothorax and hydrothorax groups using Receiver Operating Characteristic (ROC).
Results: The mean CT – AV of haemothorax were significantly (P < 0.001) higher from those of pyothorax and hydrothorax. The pyothorax mean CT – AV were also significantly higher than hydrothorax values (P = 0.042). The diagnostic accuracy of CT – AV to distinguish between haemothorax, pyothorax and hydrothorax was statistically significant (P < 0.001).
Conclusion: CT attenuation values between hydrothorax, pyothorax, and haemothorax are distinguishable.
Key words: pleural effusions, hemothorax, pyothorax, CT attenuation.