Comparison between chest digital tomosynthesis and CT as a screening method to detect artificial pulmonary nodules: a phantom study

Abstract

Objectives: The objective of this study was to evaluate the imaging capabilities of chest digital tomosynthesis (DT) as a screening method for the detection of artificial pulmonary nodules, and to compare its efficiency with that of CT. Methods: DT and CT were used to detect artificial pulmonary nodules (5 mm and 8 mm in diameter, ground-glass opacities) placed in a chest phantom. Using a threedimensional filtered back-projection algorithm at acquisition angles of 8 u , 20 u , 30 u and 40 u , DT images of the desired layer thicknesses were reconstructed from the image data acquired during a single tomographic scan. Both standard and sharp CT reconstruction kernels were used, and the detectability index (DI) valves computed for both the DT scan acquisition angles and CT reconstruction kernel types were considered. For the observer study, we examined 50 samples of artificial pulmonary nodules using both DT and CT imaging. On the basis of evaluations made by five thoracic radiologists, a jackknife free-response receiver operating characteristic (JAFROC) study was performed to compare and assess the differences in detection accuracy between CT and DT imaging. Results: For each increased acquisition angle, DI obtained by DT imaging was similar to that obtained by CT imaging. The difference in the observer-averaged JAFROC figure of merit for the five readings was 0.0363 (95% confidence interval: 20.18, 0.26; F50.101; p50.75). Conclusion: With the advantages of a decreased radiation dose and the practical accessibility of examination, DT may be a useful alternative to CT for the detection of artificial pulmonary nodules. Detecting and characterising pulmonary nodules is one of the most challenging tasks in thoracic imaging; even experienced chest radiologists may miss up to 30% of such lesions on conventional chest radiographs [1]. Nodules are often only retrospectively visible while reviewing previous images of patients with a known history of nodules [2], and identifying them prospectively remains a difficult task. Because of its high sensitivity, normal-dose helical CT is currently considered as the standard method for the diagnosis of lung cancer. Early reports indicate that low-dose helical CT has the potential to detect lung cancer in the initial stage, thus decreasing morbidity [3]. In addition, CT solves the problem of impaired visibility caused by overlapping anatomical structures, which leads to lower detection rates.X-ray CT has progressed over the last three decades, and it now constitutes a powerful tool for medical diagnosis. The use of CT as a non-invasive imaging technique has become essential, especially since the advent of spiral CT in the 1990s, which led to shorter scan times and improved three-dimensional (3D) spatial resolution. Although CT provides high resolution in the tomographic plane, it has limited axial resolution. Therefore, the partial-volume effect (PVE) may make it difficult to evaluate structures that are not oriented in the direction of the CT tomographic plane.CT-particularly high-r...

X-ray absorption tomography employing a conical shell beam

“…In recent years, tomosynthesis has undergone a resurgence of interest in diagnostic imaging applications such as breast cancer screening [1] and the detection of pulmonary nodules [2]. More advanced approaches have investigated coded apertures and multiple X-ray sources for compressive tomosynthesis to reduce radiation exposure [3].…”

Tomosynthesis can facilitate accurate measurement of joint space width under the condition of the oblique incidence of X-rays in patients with rheumatoid arthritis

“…8 Tomosynthesis can detect overlapping structures clearly because it is a tomographic technique. Radiation exposure in tomosynthesis is relatively low; it resulted in a reduction of dose by a factor of 28 compared with CT in a wrist assessment, according to Noël et al 11 For these reasons, tomosynthesis is expected to be applied to the detection of early RA bone lesions with low risk of radiation exposure, [9][10][11][12] although the accuracy of measurement for JSN with tomosynthesis has not yet been validated. We therefore conducted this study to elucidate the potential of tomosynthesis for the quantification of JSW with oblique incidence of X-rays.…”

“…[6][7][8] CT, therefore, is not a first-line examination, and although the continued use of radiographs in RA is debated, it is still recommended to acquire a baseline radiograph. Because tomosynthesis, a recently developed modality, is superior to radiography for the evaluation of overlapping structure such as intercarpal joints with lower radiation exposure than CT, it is expected to be applied to joint destruction evaluation, [9][10][11][12] although the accuracy of measurement of JSN with tomosynthesis has not yet been validated.…”

Optimization of exposure parameters in digital tomosynthesis considering effective dose and image quality

“…Gomi et al compared chest digital tomosynthesis (CDT) and conventional CT images of chest phantom which contains pulmonary nodules under 120 kVp and 1 mAs [2]. Another study conducted by Yamada et al was the performance evaluation of CDT for early detection of pulmonary emphysema, and this study used 120 kVp and 0.04 mAs [3].…”