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Purpose: To evaluate the effect of reducing image size on observers' ability to detect lung nodules on computed tomographic (CT) scans., Materials and Methods: Stimuli were 80 single sections from 13 normal chest CT studies. On half of the images, 3-5-mm-diameter nodules were superimposed electronically at random locations. Four observers viewed images in six formats and sizes that ranged from 6 on 1 (133 x 133 mm) to 80 on 1 (40 x 40 mm). The images were viewed at a fixed distance of 55 cm and at an unrestricted, variable distance., Results: With the fixed viewing distance, nodule detection decreased with smaller image sizes. The area under the receiver operating characteristic curve (Az) decreased from 0.857 for the 6-on-1 format to 0.671 for the 80-on-1 format (P = .0001). With a variable viewing distance, Az decreased from 0.884 to 0.834 across all formats (difference not statistically significant). However, there was a significant drop in performance with the smallest images (P < .05). Overall, Az for the fixed and variable viewing distances was significantly different (P < .001)., Conclusion: Reducing image size leads to decreased lung nodule detection on CT scans viewed at a fixed distance; however, the observer can compensate for the smaller image by adjusting the viewing distance.

Purpose: To determine radiologists' ability to find lung nodules on spiral computed tomographic (CT) scans of the chest with both rapid sequential (cine) and conventional film-based viewing., Materials and Methods: Eight radiologists searched for lung nodules on spiral CT images (10-mm collimation, 10 mm/sec table speed) presented in two formats. Cine viewing was performed at a computer work-station; sections were viewed in 2-mm increments at frame rates up to 10 frames per second. Film-based viewing of images from a laser printer was performed with a lightbox; sections were viewed at 4-mm increments. Eight 3-5-mm-diameter simulated nodules were superimposed on each of five normal CT scans., Results: Radiologists found a higher fraction of nodules with the cine presentation than with film (mean, 0.69 +/- 0.02 [standard error] versus 0.58 +/- 0.03, respectively [P = .006]). Diameter thresholds for nodule detection (50% correctly localized) were 3.3 and 3.5 mm, respectively., Conclusion: Cine viewing of spiral CT images of the chest improved radiologists' ability to detect nodules.

The authors describe the radiologic features of precision electrocautery excision of pulmonary lesions (Perelman technique). Thin-walled cavities were seen on chest radiographs obtained in three patients at the site of the resected lesion subsequent to this surgical procedure. Knowledge of these findings can avoid a false diagnosis of abscess, septic emboli, or additional metastasis.

The authors reviewed chest radiographs of 16 patients with biopsy-proved lymphocytic interstitial pneumonia (LIP) who also had acquired immunodeficiency syndrome (AIDS) or AIDS-related complex (ARC). Radiographs revealed fine reticular or reticulonodular infiltrates in the pulmonary interstitium in five patients, coarse reticulonodular infiltrates in two, and reticular or reticulonodular opacities with superimposed patchy alveolar infiltrates in nine. Pathologic examination of biopsy specimens revealed lymphocytes, plasma cells, and reticulum cells aggregated about the small arteries and compressing the distal airways. Throughout the course of AIDS or ARC, the radiographic findings of LIP remained stable in 12 of 16 patients. AIDS/ARC-related LIP appears to be a benign reaction of bronchial-associated lymphatic tissue to the human immunodeficiency virus (HIV). However, this indolent process cannot be correctly diagnosed based on radiographic findings alone; the use of lung biopsy is required to differentiate LIP from other infections. The authors suggest that patients with these radiographic findings, HIV seropositivity, but no other signs of opportunistic infection or neoplasia should be classified as having AIDS.