ABSTRACT
Sarcoidosis is a granulomatous disease of unknown etiology that involves the lungs
or intrathoracic lymph nodes in more than 90% of patients. The clinical spectrum of
sarcoidosis is protean, but pulmonary manifestations often dominate. Chest radiographs
are abnormal in 90 to 95% of patients with sarcoidosis; the most characteristic feature
is bilateral hilar lymphadenopathy (BHL), present in 50 to 80% of patients. Pulmonary
parenchymal infiltrates are present in 25 to 50% of patients. In this article, we
review the radiographic features of sarcoidosis (both typical and atypical), and the
impact of chest radiographic stage on long-term prognosis. Computed tomographic (CT)
scans are more sensitive than chest radiographs in delineating parenchymal, mediastinal,
and hilar structures, and distinctive CT patterns may be virtually pathognomonic for
sarcoidosis in some patients. Routine CT scan is not appropriate to diagnose or manage sarcoidosis, but CT may be invaluable in patients
with atypical clinical or chest radiographic findings or specific complications of
sarcoidosis (pulmonary or extrapulmonary), or to assess prognosis. High-resolution
thin-section CT scans (HRCT) may be helpful in selected patients with stage II or III sarcoidosis to discriminate active inflammation from irreversible
fibrosis. This article discusses the salient HRCT features of sarcoidosis, accuracy
of CT in the differential diagnosis, and correlations of HRCT with disease extent
and activity, pulmonary function, and lesion reversibility.
KEYWORDS
Sarcoidosis - computed tomography (CT) - high-resolution thin-section CT scans (HRCT)
- chest radiographs - granulomatous inflammation
