Imaging ventilation using 19F perfluorinated gas magnetic resonance imaging: strategies for imaging collateral ventilation

Collateral Ventilation (CV) has become an important clinical issue with the increasing use of bronchoscopic lung volume reduction (BLVR) using endobronchial valve surgery in patients with severe COPD. The endobronchial valve BLVR procedure often uses one way valves to occlude segmental bronchi in lung regions with severe overinflation resulting from airway narrowing and collapse during exhalation. For BLVR to succeed, CV to the treated region must be minimal or absent. Current approaches to evaluating CV for both planning and follow-up of BLVR procedures involve CT imaging to assess fissure closure. Current techniques to assess regional lung function (including CV) are limited. Standard pulmonary function testing involving analysis of inert gas wash-in/wash-out can only provide statistical distributions without anatomic correlates. Herein we propose the use of fluorine magnetic resonance imaging of biologically inert perfluorinated gas mixed with oxygen to evaluate regional ventilation, in particular, interlobar collateral ventilation. We have evaluated normal subjects and subjects diagnosed with chronic obstructive pulmonary disease and have observed gas transfer at lobar fissures consistent with collateral ventilation.