Purpose: The aim of our study was to evaluate the frequency of the crescent sign on follow-up radiographs in patients with invasive pulmonary aspergillosis, correlated with initial CT and clinical findings.
Method: Retrospective analysis of serial chest radiographs was performed to see the frequency of the crescent sign in 21 consecutive patients with pathologically proved invasive pulmonary aspergillosis. The appearance of the crescent sign was correlated with the pattern of parenchymal lesions on initial CT scans, the presence and duration of neutropenia, and underlying diseases.
Results: The crescent sign was seen in 10 of 21 patients (48%) on follow-up radiographic examinations. It was seen in patients with initially large [consolidation or mass; 9/11 (82%) patients] rather than small [nodule(s); 1/10 (10%) patients] parenchymal lesions (p = 0.002) on CT. The sign appeared in 7 of 17 (41%) patients with neutropenia 1-10 days after recovery from neutropenia. It appeared in three of four patients (75%) without neutropenia 4--8 days after treatment with amphotericin B. The appearance was not related to the duration (32 days in patients with crescent sign and 17 days without sign) of the neutropenic period (p > 0.05). The sign was seen in 8 of 15 (53%) patients with acute myelogenous leukemia and 2 of 6 (33%) patients with other diseases (p > 0.05).
Conclusion: The crescent sign appears in about half of patients with invasive pulmonary aspergillosis with recovery from neutropenia, especially when the initial lesion is a consolidation or mass on CT scans.