Characteristics of low attenuation area (LAA) of the lungs on HRCT were studied in 132 patients with asthma, and long-term spa therapy on the LAA of the lungs was observed in 5 patients with asthma, whose me an %LAA was more than 30%.
1. The morphology of LAA of the lungs on HRCT observed in asthma was different from that in pulmonary emphysema. 2. The LAA of the lungs in asthma was closely related to residual volume (RV). 3. The mean %LAA value significantly decreased from 33.5% before spa therapy to 24.5% at 24 months after beginning of the therapy. CT number also significantly increased after long-term spa therapy. 4. %FEV1.0 value significantly improved from 52.1% before spa therapy to 72.1% at 24 months after spa therapy. The RV value also decreased by spa therapy, however, the decrease was not significant. These results suggest that LAA of the lungs in asthma is associated with hyperinflation, and the LAA of the lungs decreases after long-term spa therapy.

Clinical effects of spa therapy for patients with pulmonary emphysema (PE) were evaluated by observing changes in %LAA of the lung on HRCT, %RV, %FVC, %FEV 1.0, and %DLco values after the long-term therapy. The subjects in this study 16 patients with PE. The subjects were divided into two groups according to the extent of %LAA<-950 HU of the lung on HRCT: %LAA<50% (N=6) and 50%≤%LAA (N=8). 1. Spa therapy significantly improved %LAA (42.5% at the initial stage to 36.3% 24 months after spa therapy), %RV (202.1% to 156.1%) and %DLco 71.0% to 85.7%), but not %FVC and %FEV 1.0, in patients with PE of %LAA<50%, however, significant. Improvement of these parameters was not observed in patients without spa therapy. 2. Spa therapy did not improve the values of %LAA, %RV, and %DLco, as well as %FVC and %FEV 1.0, in patients with PE of 50%≤%LAA. These parameters tended to decrease in the patients of 50%≤%LAA. These results suggest that spa therapy improves %LAA and parameters related to pulmonary function when they are at early stage of PE, however, the therapy was not remarkably effective for these parameters when they were at advanced stage of PE.