Pulmonary emphysema: histopathologic correlation with minimum intensity projection imaging, high-resolution computed tomography, and pulmonary function test results

To prospectively evaluate the use of minimum-intensity projection (minIP) imaging, high-resolution (HR) computed tomography (CT), and pulmonary function tests for quantifying emphysema with histopathologic examination.

MinIP and HRCT imaging data (n = 23) were obtained, and relative areas of the lung with attenuation values below thresholds from -940 to -1000 Hounsfield units (HU) and first to 13th percentiles were calculated for both data. Pulmonary function tests were performed before lung resection. These parameters were compared with mean alveolar perimeters measured on resected samples.

Strongest correlations with mean alveolar perimeter were obtained at -990 HU and the fifth percentile by minIP, -1000 HU and the seventh percentile by HRCT, and diffusion capacity. The correlation between the mean alveolar perimeter and relative areas below -990 HU by minIP showed significantly higher extension (0%-51%) than those below -1000 HU by HRCT (1%-21%).

MinIP imaging is more than 2(1/2) times more predictive for quantifying emphysema than HRCT, although diffusion capacity of lung for carbon monoxide is also a valid index.