Abstract |
Perfusion and ventilaion imagings of the lung are well
established procedure for diagnosing pulmonary
embolism, differentiation it from chronic obstructive
lung disease, and making an early detection of chronic
obstructive lung disease. To evaluate the usefulness of
radioaerosol inhalation imaging (RII) in chronic
obstructive lung disease, especially pulmonary
emphysema, we analyzed RIIs of five normal adult non-
smokers, five asymptomatic smokers (age 25-42 years
with the mean 36), and 21 patients with pulmonary
emphysema (age 59-78 years with the mean 67).
Scintigrams were obtained with radioaerosol produced by
a BARC nebulizer with 15 mCi of Tc- 99m-phytate.
Scanning was performed in the anterior, posterior, and
lateral projections after five to l0-minute inhalation
of the radioaerosol on sitting position. The scans were
analyzed and correlated with the results of pulmonary
function studies and chest radiographs. Also lung
perfusion scan with Tc-99m-MAA was performed in 12
patients. In five patients, we performed fo1low-up
scans for the evaluation of the effects of a
bronchodilator. Based on the X-ray findings and
clinical symptoms, pulmonary emphysema was classified
into four types: centrilobular (3 patients), panlobular
(4 patients), intermediate (10 patients), and combined
(4 patients). RII findings were patternized according
to the type, extent, and intensity of the aerosol
deposition in the central bronchial and
bronchopulmonary system and lung parenchyma. 10
controls, normal five non-smokers and three
asymptomatic smokers revealed homogeneous parenchymal
deposition in the entire lung fields without central
bronchial deposition. The remaining two of asymptomatic
smokers revealed mild central airway deposition. The
great majority of the patients showed either central
(9/21) or combined type (10/21) of bronchopulmonary
deposition and the remaining two patients peripheral
bronchopulmonary deposition. Parenchymal aerosol
deposition in pulmonary emphysema was diffuse (6/21),
discrete(6/21), intermediate (3/21), or combined
(6/21). In 12 patients studied also with perfusion
scans, perfusion defects matched closely with
ventilation defects in location and configuration. But
the size of the ventilation defects was generally
larger than the perfusion defects. In all four patients
treated with bronchodilators, the follow-up study
demonstrated decrease in abnormal of radioaerosol
deposition in the central airway with improvement of
ventilation defects. RII was useful technique for the
evaluation of regional ventilatory abnormality and the
effects of treatment with bronchodilators in pulmonary
emphysema. |