CsI-detector-based dual-exposure dual energy in chest radiography for lung nodule detection: results of an international multicenter trial

Abstract

To assess both sensitivity and specificity of digital chest radiography alone and in conjunction with dual-exposure dual-energy chest radiography for the detection and classification of pulmonary nodules. One hundred patients with a total of 149 lung nodules (3-45 mm; median, 11 mm) confirmed by CT were included in this study. Dual-exposure dual-energy chest radiographies of each patient were obtained using a CsI detector system. Experienced board-certified chest radiologists from four different medical centers in Europe reviewed standard chest radiographs alone and in conjunction with dual-energy images blinded and in random order. The reviewers rated the probability of presence, calcification and malignancy of all lung nodules on a five-point rating scale. Lesions detected were identified by applying a specific coordinate system to enable precise verification by the study leader. A receiver-operating characteristic (ROC) analysis was performed. In addition to the 149 true-positive CT proven lesions, 236 false-positive lung nodules were described in digital chest radiographies in conjunction with dual-energy chest radiographies. The cumulative sensitivity of chest radiography in conjunction with dual energy was 43%, specificity was 55%. For digital radiography alone, sensitivity was 35% and specifity was 83%. For the dual energy system, positive predictive value was 58%, and negative predictive value was 66% compared to the digital radiography with a positive predictive value of 59% and a negative predictive value of 65%. Areas under the curve in a ROC analysis resulted in 0.631 (95% confidence interval =0.61 to 0.65) for radiography with dual energy and 0.602 (95% confidence interval =0.58 to 0.63) for digital radiography alone. This difference was not statistically significant. For the detection of lesion calcification or the determination of malignancy, ROC analysis also failed to show significant differences. CsI-based flat-panel dual-exposure dual-energy imaging added to standard chest radiography did not show statistically significant improvement for the detection of pulmonary nodules, nor the identification of calcifications, nor the determination of malignancy.

Role of digital tomosynthesis and dual energy subtraction digital radiography in detecting pulmonary nodules

“…This is partly due to the fact that as the lesion size becomes smaller, the advantage of anatomical noise reduction is negated. This is inferred from studies by Kashani et al [9], and Ruhl et al [10], who found no statistically significant difference in detection of pulmonary nodules (based on their size) by addition of DES-DR. Similarly, DT images are affected by the inherent tomographic noise that is related to the limited angle reconstruction involved in this technique.…”

Lung Nodules: Improved Detection with Software That Suppresses the Rib and Clavicle on Chest Radiographs

“…In this study, we found a 4.3% decrease in specifi city. This can be compared with the report on dualenergy subtraction by Rühl et al ( 30 ), where the sensitivity increased from an average of 35% with the conventional chest radiograph to 43% with the dualenergy images. Specifi city decreased from 83% to 55%; this is a decrease in specifi city of 28%.…”

Missed lung cancer: when, where, and why?

“…Dual-energy subtraction imaging is employed to produce illustrations of two different tissues, such as calcified structures and soft tissue, by using the known energy dependence of X-ray attenuation of both materials. Once two images are generated, it is possible to remove the overlying anatomic noise from the bones; consequently lung lesion conspicuity results are improved (39).…”