OBJECTIVES: To evaluate morphological changes in the number and size of low-attenuation clusters on computed tomography (CT) in patients with emphysema. MATERIALS AND METHODS: In 27 patients who had follow-up CT scans for 6 months or greater, initial 27 scans and follow-up 39 scans were analyzed. The number per slice (LAN/s) and mean size (LAS) of low-attenuation clusters less than -950 HU, and total low-attenuation area below -950 HU per slice (LAA-950/s) were calculated. RESULTS: LAS and LAA-950/s were significantly increased over time. No significant correlation was found between LAN/s and follow-up period. LAS increased in 37 of 39 (95%) follow-up scans, whereas LAN/s decreased in 17 of 39 (44%) follow-up scans. CONCLUSIONS: On the morphological progression of emphysema, the mean size of low-attenuation clusters was significantly increased during the follow-up period, whereas no significant correlation was found between the number of low-attenuation clusters and follow-up period.
OBJECTIVES: To evaluate morphological changes in the number and size of low-attenuation clusters on computed tomography (CT) in patients with emphysema. MATERIALS AND METHODS: In 27 patients who had follow-up CT scans for 6 months or greater, initial 27 scans and follow-up 39 scans were analyzed. The number per slice (LAN/s) and mean size (LAS) of low-attenuation clusters less than -950 HU, and total low-attenuation area below -950 HU per slice (LAA-950/s) were calculated. RESULTS:LAS and LAA-950/s were significantly increased over time. No significant correlation was found between LAN/s and follow-up period. LAS increased in 37 of 39 (95%) follow-up scans, whereas LAN/s decreased in 17 of 39 (44%) follow-up scans. CONCLUSIONS: On the morphological progression of emphysema, the mean size of low-attenuation clusters was significantly increased during the follow-up period, whereas no significant correlation was found between the number of low-attenuation clusters and follow-up period.