biapical pleural parenchymalbiapical pleural thickeningparacentesis and thoracentesisthoracentesis pneumothoraxthoracentesis procedurethoracentesis complicationsminimal biapical pleural thickeningdiagnostic thoracentesisbiapical pleural scarringtherapeutic thoracentesisthoracentesis techniqueultrasound thoracentesis