The computed tomography assessment of lung volume changes after bronchial valve treatment

¹ Dept of Radiology, Vancouver General Hospital; and James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, Vancouver, BC, CANADA
² Dept of Radiology, Vancouver General Hospital
³ Spiration Inc, Redmond, WA, USA

	Abstract

To correlate clinical outcome measures following treatment with bronchial valves with regional lung volume.

Computed Tomography (CT) scan data from 57 subjects with severe emphysema were obtained from 9 North American clinical trial sites. IBV^® Valves were placed to occlude segmental and subsegmental bronchi in right and left upper lobes using a flexible bronchoscope. Subjects underwent St. George's Respiratory Questionnaire (SGRQ), pulmonary function (PFT), and exercise capacity. CT scans were analyzed at baseline and 1, 3 or 6 months after treatment to measure total and lobar lung density, volume and mass.

Total lung volumes measured using CT were strongly correlated with PFT (R²=0.79) and did not change with treatment. However, the treated upper lobes decreased in volume in 88% of the observations, mean 335 mL±444 (p<0.001), or -10.2% in the 6 month data. The untreated lobes had an 11.6% increase in volume. Changes in regional lung volume were associated with clinically meaningful improvements in SGRQ (-8.95±16.22) (p<0.01) but not clinically meaningful PFT changes.

The significant health status improvements reported by subjects following bilateral bronchial valve treatment are associated with regional lung volume changes and inter-lobar shift measured using CT.