Clinical evaluation of 133Xe serial scintigraphy in the central (hilar) bronchogenic carcinoma

The purpose of this study is to evaluate regional perfusion and ventilation in the central bronchogenic carcinoma using 133Xe serial scintigraphy. Scintigraphic findings were compared with those of bronchography and pulmo-angiography. We discussed the mechanism of the characteristic 133Xe-trapping phenomenon in the central bronchogenic carcinoma. 133Xe-trapping was seen in 24 cases of 32 patients with central bronchogenic carcinoma (75%). In 8 cases, while 133Xe-trapping was not seen in the scintiphotos of the lung, ventilatory dead space was observed, which would indicate a combined lesion of bronchial obstruction and arterial interruption. In 14 of the 24 cases, the 133Xe-trapped lung area was located in the main lesion and in 10 of them in the adjacent lesion. Thus, a decreased perfusion and/or a bronchial stenosis were observed in all the 133Xe-trapping cases. The finding of 133Xe serial scintigraphy in a case of early central bronchogenic carcinoma indicated that the 133Xe-trapping phenomenon could not be obtained in the area of irreversible obstructive pneumonia accompanied by bronchogenic carcinoma. It is assumed that in cases of secondary pulmonary changes such as, local emphysema and reversible pneumonia, the trapping phenomenon can be seen. As a screening method of central bronchogenic carcinoma, this examination is very significant because of its simple technique and its low radiation doses. It also allows a quantitative control of radiation therapy. (auth.)