Diagnosis of sarcoidosis
To describe the recent advances in the diagnostic procedures for sarcoidosis and explore future directions. Novel imaging techniques have been explored in sarcoidosis, such as positron emission tomography using L-[3-F]-alpha-methyltyrosine, which is more specific for malignancy than F-fluorodeoxyglucose positron emission tomography. The combined modality of L-[3-F]-alpha-methyltyrosine-positron emission tomography with fluorodeoxyglucose-positron emission tomography could successfully discriminate sarcoidosis from malignancy. The finding of delayed enhancement in cardiac magnetic resonance imaging could identify cardiac involvement of sarcoidosis with higher sensitivity than echocardiography, thallium scintigraphy, and gallium scintigraphy. Endobronchial ultrasonograpy-guided transbronchial needle aspiration is a safe and useful tool for diagnosing sarcoidosis with a diagnostic accuracy, sensitivity and specificity of 85-93, 78-89, and 92-96%, respectively. Developments in genetics have demonstrated that 99% of the human leukocyte antigen DRB1*0301/DQB1*0201-positive patients with Löfgren's syndrome show a spontaneous remission, in contrast to only 55% of the human leukocyte antigen DRB1*0301/DQB1*0201-negative patients. These alleles could be novel promising factors for discriminating a prognosis in Löfgren's syndrome. Recent development including novel imaging techniques, novel biopsy procedures, and genetic analyses could be of value for the diagnosis of sarcoidosis.