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Updated: Aug 15, 2026

Quantitative Mapping of Specific Ventilation in the Human Lung using Proton Magnetic Resonance Imaging and Oxygen as a Contrast Agent
Published on: June 5, 2019
The incidence and etiology of the ventilation/perfusion reverse mismatch defect
1Department of Radiology, Hammersmith Hospital, London.
Abstract:
Kr-81m ventilation and Tc-99m perfusion images of 392 patients were examined retrospectively for the incidence and etiology of the reverse mismatch defect, which is characterized by a region of lung where the perfusion defect exceeds the ventilation defect. Forty-six patients (11.7%) showed such defects. The most frequent causes were pneumonia (15%), atelactasis (15%), pleural effusions (15%), chronic obstructive airway disease (24%), and bronchial obstruction (31%). The significance of the reverse mismatch defect is discussed.
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