Computed tomography and monitoring of emphysema.

I t is well known that there have been no successful therapeutic interventions for subjects with emphysema. In the 1990s, investigators became very interested in lung volume reduction surgery (LVRS), first described by BRANTIGAN and MUELLER [1] in 1957, as a treatment for severe emphysema. While many sites promoted the use of LVRS for severe emphysema the criteria for the selection of patients, the effects on mortality and the magnitude and durability of benefits were not well established [2]. It was for these reasons that the National Emphysema Treatment Trial (NETT) was formed in the USA. While the first report from this study was bleak and warned that subjects who have a low forced expiratory volume in one second and either homogeneous emphysema or a very low diffusing capacity of the lung for carbon monoxide (DL,CO) had a high risk of dying after this procedure [3], the end results of the study did show that in a select population (upper-lobe patients with low exercise capacity) there was a benefit [2], which persisted for several years [4]. The investigators concluded that the effects of LVRS are durable, that it can be recommended for upper-lobe-predominant emphysema patients with low exercise capacity and that it should be considered for palliation in patients with upper-lobe emphysema and high exercise capacity [4]. One of the key factors in the outcome of these studies was the location of the emphysema, as described using computed tomography (CT).