The influences of kilovolt peak, milliamperage, reconstruction algorithm, targeting, and image magnification on thin-section (1.5-mm) computed tomography (CT) of the lung were studied in phantoms and patients. Retrospective targeted reconstruction (25-cm field of view) improved spatial resolution, while magnification did not. The bone reconstruction algorithm improved spatial resolution, compared with the standard algorithm, and in patients, bone algorithm images were considered superior to standard reconstructions. Although using the bone algorithm increases the visible image noise, increasing the kilovolt peak and the milliamperage can reduce this noise. However, in the patients studied, this reduction in noise was not usually judged as significant, except in the posterior, paravertebral part of the lung. An optimal technique for CT of the lung parenchyma should include thin-collimation, targeted scans reconstructed with a high-spatial-frequency algorithm and, in some patients, increased kilovolt peak or milliamperage.

No abstract

High-resolution computed tomography (CT) scans of 12 isolated, inflated, fresh lungs obtained at autopsy were compared with thin, paper-mounted lung sections obtained at the same levels. In six lungs considered intrinsically normal, high-resolution CT showed normal interlobular septa and pulmonary arteries in the lobular core, but lobular bronchioles were not visible. Edematous fluid resulted in thickening and increased visibility of interlobular septa. In three emphysematous lungs, high-resolution CT accurately demonstrated the degree of emphysema and suggested its centrilobular nature. In two lungs with honeycombing, cysts lined by fibrosis were easily seen on high-resolution CT scans. In less severely involved areas, septal thickening and intralobular fibrosis were seen on high-resolution CT scans, but small (1 mm) cysts were invisible. High-resolution CT was able to demonstrate some features of the normal secondary pulmonary lobule and structural alterations produced by various diseases.

Chest computed tomography (CT), including high-resolution CT with thin (1.5-mm) sections was used to evaluate proved (pathologically or clinically) lymphangitic spread (LS) of tumor in 12 patients. These appearances were compared with thin-section scans obtained in 11 healthy subjects. Thin-section CT demonstrated findings consistent with thickening of the normal lung interstitium. In all patients, thin sections showed an increase in the number of peripheral lines (1-2 cm in length) that were diffuse in generalized disease and localized in focal disease. Normal peripheral arcades were not increased in number, but the limbs forming the arcades were thickened in all patients. A diffuse increase in linear and curvilinear structures (reticular pattern) was seen toward the center of the lung. Polygonal structures 1-2 cm in diameter were seen in seven patients with LS but not in healthy subjects. Fissures were thickened in nine patients. Selected 1.5-mm-thick CT sections are recommended through abnormal areas (seen at CT or on chest radiographs) or if these are normal at three levels (midapex, hilus, and 3 cm above the diaphragm) when scanning patients with tumors known to cause LS.

No abstract