Characteristics of the elderly in high - resolution computed tomography lung densitometry

To determine the characteristics of the elderly in high - resolution computed tomography (HRCT) lung densitometry, mean lung density (MLD) and relative area of the lungs showing attenuation values less than -950 HU (RA(950)) on HRCT were evaluated in nonsmoking control subjects (n = 80) and patients with asthma (n = 80) in relation to their age and pulmonary function. MLD was significantly decreased, and RAW was significantly increased with increasing age in both asthmatics and controls. The MLD values were significantly lower in asthmatics compared with controls in subjects aged between 60 and 69 years and over age 70. RAgsov alues were significantly higher in asthmatics compared with controls in subjects aged between 50 and 59 years, between 60 and 69, and over 70. % FEV(1) and FEV(1) / FVC were significantly decreased in elderly asthmatic patients over 70 years of age compared with the values in those under 49. Percent residual volume (% RV) was significantly larger in patients over 70 years of age than in those between 50 and 59, and under 49 years. RAW was significantly larger in patients with steroid-dependent intractable asthma (SDIA) between 50 and 59 years of age, and between 60 and 69 compared with RA 950 in those without SDIA. However, RAW did not differ significantly between SDIA and non-SDIA in patients over age 70. The results suggested that in % LAA of the lungs on HRCT was significantly increased in the elderly subjects with and without asthma, and it was significantly higher in the elderly asthmatics than the elderly controls.

高齢者の病態的特徴を明らかにするために，健常者80例および非喫煙喘息患者80例を対象として，平均肺CT値（MLD）ならびに高分解能CT（HRCT）による－950HU以下の肺low attenuation area（RA950）を評価し，年齢及び肺機能との関連を検討した。　 1．健常者，喘息患者いずれにおいても年齢とともにMLDは有意に減少し，RA(950)は有意に増加した。MLDは，60－69歳と70歳以上の年 齢層において，健常者に比して喘息患者で有意に低値を示した。RA(950)。は，50－59歳・60－69歳・70歳以上の年齢層において，健常者に比して喘息患者で有意に高値を示した。　 2．喘息患者において，1秒量（% FEV(1)）および1秒（FEV(1)/ FVC）は，49歳以下の年齢層に比して70歳以上の年齢層で有意に低値を示した。一方，残気量（% RV）は，50－59歳ならびに49歳以下の年齢層に比して70歳以上の年齢層で有意に高値を示した。 3．50－59歳および60－69歳の年齢層では，RA(950)は，ステロイド依存性重症難治性喘息（SDIA）患者において非SDIA患者に比して有意に高値を示した。しかし，70歳以上の年齢層では両者に有意の差は認められなかった。これらの結果より，HRCT上の肺low attenuation areaは高齢者において有意に増加すること，さらに嘱息患者の方が健常者に比してより高値を示すことが示唆された。