Effect of radiation dose reduction and iterative reconstruction on computer-aided detection of pulmonary nodules: Intra-individual comparison. Issue 2 (February 2016)

• Record Type: Journal Article
• Authors: Den Harder, Annemarie M.; Willemink, Martin J.; van Hamersvelt, Robbert W.; Vonken, Evert-jan P.A.; Milles, Julien; Schilham, Arnold M.R.; Lammers, Jan-Willem; de Jong, Pim A.; Leiner, Tim; Budde, Ricardo P.J.
• Is Part Of: European journal of radiology. Volume 85:Issue 2(2016)
• Page Start: 346
• Page End: 351
• Publication Date: 2016-02
• Subjects: Chest CT -- Pulmonary nodules -- Iterative reconstruction -- Computer-aided detection; Medical radiology -- Periodicals; Radiology -- Periodicals; Radiologie médicale -- Périodiques; Medical radiology; Periodicals; 616.075705
• DOI: 10.1016/j.ejrad.2015.12.003
• Languages: English
• ISSNs: 0720-048X

Abstract

Abstract: Objective: To evaluate the effect of radiation dose reduction and iterative reconstruction (IR) on the performance of computer-aided detection (CAD) for pulmonary nodules. Methods: In this prospective study twenty-five patients were included who were scanned for pulmonary nodule follow-up. Image acquisition was performed at routine dose and three reduced dose levels in a single session by decreasing mAs-values with 45%, 60% and 75%. Tube voltage was fixed at 120 kVp for patients ≥80 kg and 100 kVp for patients <80 kg. Data were reconstructed with filtered back projection (FBP), iDose 4 (levels 1, 4, 6) and IMR (levels 1–3). All noncalcified solid pulmonary nodules ≥4 mm identified by two radiologists in consensus served as the reference standard. Subsequently, nodule volume was measured with CAD software and compared to the reference consensus. The numbers of true-positives, false-positives and missed pulmonary nodules were evaluated as well as the sensitivity. Results: Median effective radiation dose was 2.2 mSv at routine dose and 1.2, 0.9 and 0.6 mSv at respectively 45%, 60% and 75% reduced dose. A total of 28 pulmonary nodules were included. With FBP at routine dose, 89% (25/28) of the nodules were correctly identified by CAD. This was similar at reduced dose levels with FBP, iDose 4 and IMR. CAD resulted in a median number of false-positives findings of 11 per scan with FBP at routine dose (93% of the CAD marks) increasing to 15 per scan with iDose 4 (95% of the CAD marks) and 26 per scan (96% of the CAD marks) with IMR at the lowest dose level. Conclusion: CAD can identify pulmonary nodules at submillisievert dose levels with FBP, hybrid and model-based IR. However, the number of false-positive findings increased using hybrid and especially model-based IR at submillisievert dose while dose reduction did not affect the number of false-positives with FBP.