Diagnostic Modalities in Sarcoidosis: BAL, EBUS, and PET

Advances have been made in minimally invasive diagnostic procedures in sarcoidosis, including bronchoalveolar lavage (BAL), endobronchial ultrasonographyguided transbronchial needle aspiration (EBUS-TBNA), and positron emission tomography (PET). Several independent groups found almost identical predictive values of the CD4:CD8 ratio in BAL for the diagnosis of sarcoidosis. A CD4:CD8 ratio greater than 3.5 shows a high specificity of 93 to 96% for sarcoidosis, but the sensitivity is low (53 to 59%). EBUS-TBNA is a safe and useful tool for diagnosing sarcoidosis stage I and II with a sensitivity of 83 to 93% and a specificity of 100%. Novel imaging techniques have been explored, such as PET using L-[3-(18)F] fluoro-alpha-methyltyrosine ((18)F-F MT), which is more specific for malignancy than (18)F-fluorodeoxyglucose ((18)F-FDG)-PET. The combined modality of FMT-PET with FDG-PET could successfully discriminate sarcoidosis from malignancy. These recent developments including novel biopsy procedures and novel imaging techniques could be of value to diagnosing sarcoidosis.