Conversion to soft-copy sonography: effects on imaging time and costs.

OBJECTIVE: To determine the effect of conversion to soft-copy interpretation on the number of images and imaging time. MATERIALS AND METHODS: Before and 1 year after conversion to soft-copy interpretation, 20 consecutive normal abdominal, renal, and cranial sonograms were performed by each of three technologists (360 sonograms total). The number of images and imaging time per sonogram were recorded. For each technologist and each examination type, the differences between number of images and the imaging times before and after conversion were compared. Multivariate repeated measures analysis of variance was used to analyze the data. RESULTS: After conversion to soft-copy, the number of images significantly increased for all imaging types (P = 0.004), and the imaging time significantly decreased (P < 0.001). After conversion, there were 213 more images. The average number of images increased 1.0 per abdominal sonogram, 0.5 per renal sonogram, and 2.0 per cranial sonogram. The additional storage requirement for the 213 images was 64 MB; total long-term storage media cost increased $1.06. On average, there was a 19% decrease in imaging time, with abdominal imaging time decreasing 2 min and 18 s, renal 1 min and 46 s, and cranial 40 s. This would potentially allow time for two additional sonograms to be performed per day and would generate up to $112,000 additional revenue per year. CONCLUSION: Following soft-copy conversion, there was a significant increase in the number of images acquired per examination, with an increased storage requirement but a negligible increase in storage cost. Technologist efficiency significantly improved.

Estimation of total lung capacity from chest radiography and chest CT in children: comparison with body plethysmography.

OBJECTIVE: The purpose of this study was to evaluate two methods of estimating lung volume using chest radiographs and one using chest CT in children. Estimates made with these techniques were compared with total lung capacity calculated with body plethysmography. MATERIALS AND METHODS: CT scans and posteroanterior and lateral radiographs of the chest were obtained in 21 children (14 girls and seven boys) for follow-up evaluation after lung transplantation. Lung volume was measured by CT using a previously validated technique of tracing the margins of the lungs on each axial CT scan. Two methods were used to estimate lung volume on chest radiographs: a technique previously described in adults and children that requires 21 measurements on posteroanterior and lateral radiographs, and a modification of a simplified technique previously reported in adults that uses only two measurements on a posteroanterior radiograph alone. Estimated lung volumes from CT and from both methods using chest radiographs were compared with total lung capacity determined from body plethysmography using regression analysis, and 95% prediction intervals were generated. RESULTS: All three methods of estimating lung volumes from radiographs correlated well with total lung capacity from plethysmography (r = .89-.92). However, we found no statistically significant or clinically meaningful difference among the methods of estimating lung volume. CONCLUSIONS: Lung volumes in children can be accurately estimated from specific measurements made on chest radiographs and on CT scans. Of the two methods tested with chest radiographs, the technique that required only two measurements from a posteroanterior chest radiograph was as accurate as the more complicated technique that required 21 measurements.