Imaging of ventilatory lung motion using perfusion lung scintigrams

Applying perfusion lung scintigrams, functional images representing the motion of the regional pulmonary areas and lung edges during ventilation were obtained in patients with various respiratory diseases. Perfusion lung images at maximal inspiration (I) and expiration (E) were recorded for 7 - 20 seconds and stored after the intravenous injection of 99mTc-macroaggregated albumin (6 - 10 mCi), using a scintillation camera with a small digital computer. Changes of the radioactivity during ventilation in each pixel were calculated using an expression as (E - I)/I, and the functional image of (E - I)/I was obtained. The image of (E - I)/I consisted of positive and negative components. The positive component of (E - I)/I visualized the motion of the regional pulmonary areas during ventilation, that nearly corresponded with regional ventilation on videodensigram and inhalation image of 81mKr. The negative component of (E - I)/I visualized the motion of the lung edges including the diaphragm during ventilation. The sum total of positive (E - I)/I in the both lungs of the anterior image was correlated with that of the posterior image (n = 30, r = 0.81) and vital capacity (n = 30, r = 0.83). The sum total of positive (E - I)/I in the right lung of the anterior image was correlated with that of the right lateral image, but there was no correlation between the sum total of positive (E - I)/I in the left lung of the anterior image and left lateral image. This technique seems to be useful for the estimation of the regional pulmonary ventilation and motion of the lung edges. (author)