ventilation/perfusion scan

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ventilation/perfusion scan

Abbreviation: V/Q scan

An imaging procedure used in the diagnosis of pulmonary embolism. The procedure has two parts: the injection of microscopic spheres into the bloodstream to evaluate perfusion of the lung; and the inhalation of xenon gas to assess pulmonary aeration. Certain patterns of mismatching between ventilation and perfusion of the lung are considered diagnostic of pulmonary embolism.