Prestenotic bronchial radioaerosol deposition: a new ventilation scan sign of bronchial obstruction.

Abstract

This study was performed to assess the diagnostic usefulness of aerosol ventilation scanning in bronchial obstruction and bronchial stenosis. Seven patients of bronchial obstruction and one patient with stenosis were studied. In each patient, obstruction was confirmed by bronchography, bronchoscopy and/or CT scan. Ventilation scanning was performed using the 99mTc-phytate aerosol generated by a BARC jet nebulizer. Scan manifestations were assessed in correlation with those of plain chest radiography, bronchography, CT scan and/or bronchoscopy. In every patient, the ventilation scan showed characteristic intense aerosol deposition in a short, slightly dilated, clubbed, bronchial segment immediately proximal to obstruction or stenosis. Typically, it was accompanied by a distal airspace deposition defect. Intense, segmental, bronchial aerosol deposition with distal lung defect was a specific finding of bronchial obstruction and stenosis. The sign was especially useful when obstruction was obscured by the associated, bizarre lung disease and in a small bronchus.