The aim of this study is to compare the rigid thoracoscopy with CT-guided pleural needle biopsy by the diagnostic efficacy and safety in patients with pleural effusion.

Pleural needle biopsy with Abrams needle, which can be performed by all chest physicians, is a simple, safe and cheap method of obtaining tissue from pleura, but its diagnostic rate is between 7 % -72 %, ~ 50 %. Problems for Abrams needle are scattered tumoral involvement on pleura, blind performance, small tissue sampling, to tend to early and dense fibrosis and usually involvement of lower pleural surface and diaphragmatic pleura.

Pleural needle biopsy with Abrams' needle, which can be performed by all chest physicians, if done with image guided and if this increase the diagnosis rate, the number of second procedure which is more expensive and hard will decrease.

The study aims the comparison of rigid thoracoscopy with CT-guided pleural needle biopsy by the diagnostic efficacy and safety in patients with pleural effusion.

It has been planned that a total of 120 patients accepted to the study who have pleural effusion at plain chest roentgenogram. All patients are being randomized after underwent contrast-enhanced CT. Undiagnosed patients of biopsy group are performed thoracoscopy and undiagnosed patients of thoracoscopy group followed up.

Two groups will compare by age, sex, Karnofsky performance status (KPS), diagnosis and complication rate.

Inclusion Criteria:

1. Ages between 18-85
2. Pleural effusion in conventional radiography
3. At least 10x10 cm space in pleural space with effusion
4. No bleeding diathesis
5. Informed consent

Exclusion Criteria:

1. Patients who went under pleural biopsy before
2. Arrythmia
3. Hypertensive attack during biopsy
4. Bleeding diathesis
5. Hypoxemia