Reduced ventilation–perfusion (V/Q) mismatch following endobronchial valve insertion demonstrated by Gallium‐68 V/Q photon emission tomography/computed tomography

Abstract

Endobronchial valves ( EBVs) are increasingly deployed in the management of severe emphysema. Initial studies focussed on volume reduction as the mechanism, with subsequent improvement in forced expiratory volume in 1 s ( FEV ₁ ). More recent studies have emphasized importance of perfusion on predicting outcomes, though findings have been inconsistent. Gallium‐68 ventilation–perfusion (V/Q) photon emission tomography ( PET)/computed tomography ( CT) is a novel imaging modality with advantages in spatial resolution, quantitation, and speed over conventional V/Q scintigraphy. We report a pilot case in which V/Q‐PET/ CT demonstrated discordant findings compared with quantitative CT analysis, and directed left lower lobe EBV placement. The patient experienced a significant improvement in 6‐min walk distance ( 6MWD) without change in spirometry. Post‐ EBV V/Q‐ PET/ CT demonstrated a marked decrease in unmatched (detrimental) V/Q areas and improvement in overall V/Q matching on post‐ EBV V/Q‐ PET/ CT. These preliminary novel findings suggest that EBVs improve V/Q matching and may explain the observed functional improvements.