Differentiation of causes of inhomogeneous lung density in high resolution computed tomography.

HRCT is a method of imaging, which achieves optimum quality of anatomical lung structures, the modality of choice in assessment of lung parenchyma. It enables assessment of pathological changes at the level of lung lobule. The most important factors, deciding of high resolution are thin collimation, 2-3 mm and image reconstruction with the sharp "bone" algorithm. HTCT enables imaging of subtle differences in lung density, invisible on plain radiograms and even in conventional computed tomography. The aim of the study was the assessment of the diagnostic possibilities of HRCT in diagnosing and differentiating cases of inhomogeneous lung density. The presence of inhomogeneous lung density in HRCT examination can be result of ground glass opacities, air-trapping, and mosaic perfusion. These signs are visible only on HRCT scans and are involved with gravitational effect and respiratory mechanism. The expiratory HRCT scans are very important in differentiating causes of inhomogeneous lung density.