Molecular imaging in sarcoidosis.

PURPOSE OF REVIEW: In recent years molecular imaging techniques have made important advances as regards the study of sarcoidosis. This paper reviews new developments in these techniques as well as their present role and limitations in the assessment of patients with sarcoidosis.

RECENT FINDINGS: PET with (18)F-fluorodeoxyglucose ((18)F-FDG PET) has proved to be more sensitive than (67)gallium ((67)Ga) scan for assessing the inflammatory activity of sarcoidosis. Integrated (18)F-FDG PET/computed tomography (CT) scanners have improved diagnostic accuracy, and an emerging role for (18)F-FDG PET/CT in monitoring therapy has been described. The use of MRI is well established in neurosarcoidosis and musculoskeletal sarcoidosis. MRI is also the test of choice in suspected cardiac sarcoidosis. It provides anatomical information and quantification of ventricular function, and reveals very early changes in the signal of the myocardium in delayed enhancement.

SUMMARY: (18)F-FDG PET/CT is useful in the detection of occult granuloma sites and residual activity in patients with fibrotic pulmonary sarcoidosis. It has an emerging role in the therapeutic management of patients with multisystemic sarcoidosis. MRI is indicated when neurosarcoidosis or cardiac or musculoskeletal involvement is suspected. Although most lesions detected are nonspecific in appearance, some patterns may be present in the early stages.