Quantitative computed tomography assessment of lung structure and functionin pulmonary emphysema

Accurate diagnosis and quantification of pulmonary emphysema during life is important to understand the natural history of the disease, to assess the extent of the disease, and to evaluate and follow-up therapeutic interventi ons. Since pulmonary emphysema is defined through pathological criteria, new met hods of diagnosis and quantification should be validated by comparisons aga inst histological references. Recent studies have addressed the capability of computed tomography (CT) to quantify pulmonary emphysema accurately. The studies reviewed in this arti cle have been based on CT scans obtained after deep inspiration or expirati on, on subjective visual grading and on objective measurements of attenuati on values. Especially dedicated software was used for this purpose, which p rovided numerical data, on both two- and three-dimensional approaches, and compared CT data with pulmonary function tests. More recently, fractal and textural analyses were applied to computed tomog raphy scans to assess the presence, the extent, and the types of emphysema. Quantitative computed tomography has already been used in patient selectio n for surgical treatment of pulmonary emphysema and in pharmacotherapeutica l trials. However, despite numerous and extensive studies, this technique h as not yet been standardized and important questions about how best to use computed tomography for the quantification of pulmonary emphysema are still unsolved.