The role of lung imaging in pulmonary embolism

Abstract

SummaryThe advantages of lung scanning in suspected pulmonary embolism are its diagnostic sensitivity, simplicity and safety. The ability to delineate regional pulmonary ischaemia, to quantitate its extent and to follow its response to therapy provides valuable clinical data available by no other simple means. The negative scan effectively excludes pulmonary embolism but, although certain ofits features favour the diagnosis of embolism, the positive scan inherently lacks specificity and requires angiographic confirmation when embolectomy, caval plication or infusion of a thrombolytic agent are contemplated. The addition of simple ventilation imging techniques with radioxenon overcomes this limitation by providing accurate analog estimation or digital quantitation of regional ventilation: perfusion (V/Q) ratios fundamental to understanding the pathophysiologic consequences of embolism and other diseases of the lung.

Effect of acute cold exposure on lung perfusion and tracheal smooth muscle contraction in rabbit

“…Also there are perfusion changes accompanying airway diseases such as the changes of perfusion associated with obstructive airway disease (Lavender and Finn 1987). Lung scan depends on the response of the pulmonary circulation to abnormal ventilation (Mishkin and Johnson 1973). Alveolar hypoxia is a potent cause of pulmonary vasoconstriction (Arborelius 1969).…”