To decide the optimal antibiotics and application of chest tube, examination of pleural fluid is fundamental in the management of empyema. Some criteria for drainage of pleural fluid have been recommended but some controversies have been suggested. Recently, newer radiologic methods including ultrasound and computed tomography scanning, have been applied to the diagnosis and management of pleural effusions. We undertook a retrospective analysis of 30 patients with pleural effusion who had CT scans of the chest in order to apply the criteria of Light et at retrospectively to patients with loculation and to correlate the radiologic appearance of pleural effusions with pleural fluid chemistry.

We analyzed the records of 30 out of 147 patients with pleural effusion undergoing chest CT scans.

1) Six of the pleural fluid cultures yielded gram negative organisms and three anaerobic bacterias and one Staphylococcus aureus and one non-hemolytic Streptococci. No organism was cultured in nineteen cases(63.0%). 2) The reasons for taking chest CT scans were to rule out malignancy or parenchymal lung disease(46.7%), Poor response to antibiotics(40.0%), hard to aspirate pleural fluid(10.0%) and to decide the site for chest tube insertion(3.3%). 3) There was no significant correlations between ATS stages and loculation but there was a tendency to Inoculate in stage III. 4) There was a significant inverse relationship between the level of pH and loculation(P<0.05) but there appeared to be no relationship between pleural fluid, LDH, glucose, protein, loculation and pleural thickening. 5) In 12 out of 30, therapeutic measures were changed according to the chest CT scan findings.

We were unable to identify any correlations between the plerual fluid chemistry, ATS stages and loculations except pH, and we suggest that tube thoracotomy should be individualized according to the clinical judgement arid serial observation. All patients with empyema do not need a chest CT scan but a CT scan can provide determination of loculation, guiding and assessing therapy which should decrease morbidity and hospital stay.