Single-exposure dual-energy subtraction chest radiography: Detection of pulmonary nodules and masses in clinical practice

Abstract

The purpose of this retrospective study was to evaluate the impact of energy subtraction (ES) chest radiography on the detection of pulmonary nodules and masses in daily routine. Seventy-seven patients and 25 healthy subjects were examined with a single exposure digital radiography system. Five blinded readers evaluated first the nonsubtracted PA and lateral chest radiographs alone and then together with the subtracted PA soft tissue images. The size, location and number of lung nodules or masses were registered with the confidence level. CT was used as standard of reference. For the 200 total lesions, a sensitivity of 33.5-52.5% was found at non-subtracted and a sensitivity of 43.5-58.5% at energy-subtracted radiography, corresponding to a significant improvement in four of five readers (p<0.05). However, in three of five readers the rate of false positives was higher with ES. With ES, sensitivity, but not the area under the alternative freeresponse receiver operating characteristics (AFROC) curve, showed a good correlation with reader experience (R=0.90, p=0.026). In four of five readers, the diagnostic confidence improved with ES (p=0.0036). We conclude that single-exposure digital ES chest radiography improves detection of most pulmonary nodules and masses, but identification of nodules <1 cm and false-positive findings remain a problem.

Comparison of Dual-Energy Subtraction and Electronic Bone Suppression Combined With Computer-Aided Detection on Chest Radiographs: Effect on Human Observers' Performance in Nodule Detection

“…Furthermore, the residents seemed to profit more from dual-energy subtraction and BSI with or without CAD than the chest radiologist. This result is consonant with the results from other studies showing that dual-energy subtraction and CAD are especially helpful to inexperienced readers to improve their sensitivity in lung nodule detection at the cost of reduced specificity [10,25,26]. In fact, the increased sensitivity of the enhanced images compared with the nonenhanced radiographs came predominantly from the residents, whereas the expert radiologist increased his number of TPs by no more than 5%.…”

“…On the other hand, computer-aided detection (CAD) techniques have been developed for chest radiography, analogous to those used with chest CT, to aid in the detection of lung nodules. Studies have analyzed the diagnostic gain from bone subtraction or suppression and CAD separately [7][8][9][10][11][12][13] Z. Szucs-Farkas received fees from the Riverain Technologies Group for collecting anonymized patient data for a different reader study. That study is not related to the current investigation in any way.…”

Improved detection of pulmonary nodules on energy-subtracted chest radiographs with a commercial computer-aided diagnosis software: comparison with human observers

“…Study subjects were a subgroup of a patient collective that had been analyzed for pulmonary lesions in a human observer study [6]. In the current investigation, readers' data were only used for cross-reference with CAD results and to compare the effect of ES on nodule detection by human observers and the CAD software.…”

“…Dual-energy radiography with energy subtraction (ES) has been developed to produce soft tissue images of the chest and, thus, to eliminate or reduce the disturbing effects of the ribs and the clavicles. Though the method has been shown to improve the detection rate and diagnostic confidence for both calcified and non-calcified lung nodules, it can also increase the number of falsepositive (FP) findings in human observer studies [3][4][5][6]. Computer-aided detection (CAD) programs are increasingly used to yield a secondary opinion in reading chest radiographs in detecting and characterizing pulmonary nodules [7][8][9][10][11].…”

Effectiveness of the single‐shot dual‐energy subtraction technique for portal images

“…In the single‐shot technique, a single X‐ray exposure is used to expose two stacked detectors, which may be separated by a filter. ( 8 , 9 ) The dual‐shot exposure technique employs two separate exposures: a high‐energy exposure and a low‐energy exposure, which are subsequently applied to the same detector. ( 10 , 11 ) Since the dual‐shot technique requires additional radiation, we employed the single‐shot technique for the present study.…”