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Vol.38 No.6 contents | Japanese/English |
- Original Article -
Studies on Single Exposure Dual Energy Subtraction Chest Computed Radiography for Detection of Lung Nodules
Miwako DoiDepartment of Radiology Osaka Medical College
We assessed the usefulness of single exposure dual energy subtraction radiography in detecting lung nodules. In a phantom study, we compared the detectability of energy subtraction images (ES), standard FCR (Fuji Computed Radiography) images (FCR), or the combination of FCR and ES images (FCR+ES) with conventional film-screen images (Conv), using simulated nodules and the chest phantom. Simulated nodules were placed on each of the following 5 sites: 1) lung field overlaid with no major pulmonary vessels or ribs, 2) lung field with overlying pulmonary vessels, 3) 1 overlying rib, 4) 2 overlying ribs, and 5) lung field with overlying mediastinum and diaphragm. A total of 300 sample films were obtained with many patterns of placement of simulated nodules. Evaluation was made using a 5-grade method by 8 radiologists. In the clinical study, 68 patients with or without lung nodules were examined. We classified the nodules by location and size. Using similar methods to those of the phantom study, we compared ES, FCR, or FCR+ES with Conv. These results were analyzed by the ROC method and statistically assessed. In the phantom study, FCR+ES were significantly superior to Conv at the site with 2 overlying ribs. ES,FCR, and FCR+ES were significantly superior to Conv at the site with overlying mediastinum and diaphragm. In the clinical study, ES and FCR+ES were significantly superior to Conv in all cases. In terms of nodular sites, ES and FCR+ES were significantly superior to Conv at the sites overlaid with 1 rib and 2 ribs. In terms of nodular sizes, ES and FCR+ES were significantly superior to Conv in both size groups. These findings indicate the usefulness of ES and FCR+ES in the detection of lung nodules.
key words: Energy subtraction, Computed Radiography, Lung nodules, ROC analysis
Received: May 11, 1998
Accepted: August 26, 1998
JJLC 38 (6): 669-680, 1998
