Perfusion and ventilation isotope lung scans in constrictive bronchiolitis obliterans. A series of three cases

Constrictive bronchiolitis obliterans (BO) has been defined as a syndrome of airflow limitation due to bronchiolar and peribronchiolar inflammation and fibrosis. However, chest roentgenograms are frequently normal, and alternative radiographic evaluation or other manifestations of the disease would be required. Here we report three patients with BO. We performed a technetium-99^m-labeled macroaggregate human albumin lung perfusion scan and a ventilation scan using krypton-81^m. We observed multiple matched defects in the perfusion and ventilation scans in these patients, which represent narrowing or obliteration of the bronchiolar lumen and its adjacent pulmonary arteriole. We propose that this is a useful diagnostic approach for an imaging study of BO.