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Summer-type hypersensitivity pneumonitis is an immunologic disease that occurs only in Japan. It is a form of hypersensitivity pneumonitis in which the clinical symptoms appear in the summer and subside spontaneously in mid autumn. The purpose of our study was to determine the CT findings in this condition, to compare the CT findings with those on chest radiographs, and to assess the variations in the CT findings over time. Accordingly, high-resolution CT scans and chest radiographs of 15 patients with summer-type hypersensitivity pneumonitis were retrospectively studied. Seven patients had sequential CT examinations 18-37 days apart. The CT scans and chest radiographs were reviewed by two observers independently. CT findings included diffuse micronodules (n = 15), slightly elevated lung density (n = 13), and patchy air-space consolidation (n = 13). In one patient, the findings on a chest radiograph were normal, while CT showed parenchymal abnormalities. In two cases, follow-up CT showed micronodular abnormalities after findings on the chest radiograph had returned to normal. Our results show that high-resolution CT findings of summer-type hypersensitivity pneumonitis include pulmonary micronodules, increased lung density, and air-space consolidation. High-resolution CT appears to be more useful than plain chest radiographs in the evaluation of pulmonary parenchymal abnormalities in this condition.

Fluoroscopically guided percutaneous biopsy of thoracic lesions is widely accepted. However, some lesions are not sufficiently visible on fluoroscopy. When this is the case, sonographic guidance may be helpful. Real-time sonographically guided needle biopsy was performed in 38 such cases, including 27 pulmonary nodules adjacent to the chest wall, three mediastial tumors, five chest wall masses, and three pleural lesions. Definitive diagnoses were made in 30 cases (78.9%), including 21 (91.3%) of 23 malignancies and nine (60%) of 15 benign lesions. Sonographically guided needle biopsy could be performed safely and easily, taking advantage of the real-time monitoring of needle position for the pulmonary masses located adjacent to the chest wall, even when fluoroscopic or CT guidance was not effective. It is suitable for biopsying chest wall tumors, pleural lesions, and anterior mediastinal masses. It is particularly suited to biopsying small pulmonary nodules adjacent to the chest wall, nodules in the apical or juxtadiaphragmatic regions, and those obscured by pleural effusion.