Radioisotopic diagnosis of Mac Leod syndrom

Six patients with a typical Mac Leod syndrom have been studied. The local pulmonary ventilation was measured by means of xenon-133 and the local pulmonary circulation by means of albumin microspheres labelled with technetium-99m. The matrix of ventilation indexes, which measured the local respiratory flow during the first inspiration, demonstrated a severe decrease of ventilation in the whole diseased lung. At the end of the 'wash in' period, the scintigraphic image was almost normal; this fact demonstrated the existence of a normal alveolar volume. During the 'wash out' period, a gas trapping was noted, corresponding to the decrease of aerial flow observed during the first breath. The circulation scintigraphies showed in all cases a dramatic hypovascularisation of the diseased lung. These findings pictured the syndrom of the 'well aerated and poorly ventilated lung' with partial suppression of the circulation secundary to multiple distal bronchial stenosis. Identical scintigraphic findings were found in four cases of bronchial carcinoma with a partial stenosis of the stem bronchus