[High-resolution x-ray computed tomography in the study of the pulmonary parenchyma. Personal experience]

High-resolution CT (HRCT) scans were performed on 156 patients, using a bone-reconstruction algorithm, 1.5 mm sections at 4 cm intervals from apex to base of the lungs and a 512 x 512 matrix. The patients either appeared to have a pathologic condition on chest film, or they presented positive clinical symptoms--i.e., cough, dyspnea, fever--and questionable/negative chest films. Since HRCT is capable of showing the secondary lobule, we employed it to study both its anatomy and the alterations that can modify its normal morphology--i.e., thickening of interlobular septa, reticular pattern, nodular pattern, high-density areas, sub-pleural lines, honeycomb pattern. HRCT findings in secondary lobules, airways, and pleura were examined. They were: lymphangitic spread of carcinoma, pulmonary fibrosis, sarcoidosis, pneumoconiosis, interstitial edema, inflammatory disorders, bronchiectasis, emphysema, and bullae. Even though some limitations still exist due to the non-specificity of HRCT findings, the latter is the best method currently available to recognize and locate interstitial conditions and, sometimes, to make a diagnosis--e.g., of lymphangitic spread of carcinoma, interstitial edema, fibrosis, emphysema, bronchiectasis. Moreover, HRCT can accurately locate pathologic areas for lung biopsy and can be used instead of chest radiographs in the follow-up.