interstitial lung abnormality（ILA）とは

Interstitial lung abnormality（ILA）

検診CTの転移探しの胸部CTで肺野，ことに下肺野胸膜下に軽微な間質性変化を認めることは，先生方もよくご経験されることと思う。Hatabuらはこの病態をinterstitial lung abnormality（ILA）と名づけ，光を与えた^1）。

The term interstitial lung abnormalities refer to specific CT findings that are potentially compatible with interstitial lung disease in patients without clinical suspicion of the disease. ILAs have been described as non-dependent abnormalities affecting more than 5％ of any lung zone（upper, middle, and lower lung zones are demarcated by the levels of the inferior aortic arch and right inferior pulmonary vein）. The following subcategories are of prognostic significance：first, ground-glass opacity and reticular opacities without a predominant subpleural localisation；second, ground-glass opacity and reticular opacities with a predominant subpleural localisation without evidence of fibrosis；and finally, traction bronchiectasis, architectural distortion, and honeycombing, providing evidence of lung fibrosis.