Ventilation – perfusion (V/Q) scintigraphy Segmental defect Occlusion of a branch of a branch of the pulmonary artery Wedge shape and pleural based Conforms to segmental anatomy of the lung Large (>75%), moderate (25~75%), small (<25%) A branching lung network model (MRI-based)

Ventilation – perfusion scintigraphy V / Q match Both scintigrams are abnormal in the same area, defects of equal size V / Q mismatch Abnormal perfusion in the area of normal ventilation or much larger perfusion abnormality than ventilation defect

V/Q scan Normal 99mTc-MAA perfusion & 81mKr ventillation Matching perfusion & ventillation defect Scintigraphic image of pulmonary embolism

Perfusion Scintigraphy planar technique

Perfusion Scintigraphy planar technique

Perfusion Scintigraphy SPECT technique

Lung uptake ratio before planned pulmonectomy

Ventilation Scintigraphy planar technique

Pulmonary artery agenesia

Dynamic inhalation lung scintigraphy (DIS) Normal DTPA clearance Faster DTPA clearance Enhanced 99mTc DTPA clearance: • smoking (reversible) • alveolitis • sarcoidosis • pneumonitis • flame inhalation • interstitial pneumonia • lung manifestations of immunological diseases