Comparison of Filtered Back Projection, Hybrid Iterative Reconstruction, Model-Based Iterative Reconstruction, and Virtual Monoenergetic Reconstruction Images at Both Low- and Standard-Dose Settings in Measurement of Emphysema Volume and Airway Wall Thickness: A CT Phantom Study

• Published in: Korean journal of radiology 2018, 19(4), , pp.809-817
• Main Authors: Kim, Cherry, Lee, Ki Yeol, Shin, Chol, Kang, Eun-Young, Oh, Yu-Whan, Ha, Moin, Ko, Chang Sub, Cha, Jaehyung
• Format: Article
• Language: English
• Subjects: Algorithms; Chronic obstructive pulmonary disease; Emphysema; Humans; Laboratories; Lung - diagnostic imaging; Medical imaging; Phantoms, Imaging; Pulmonary Emphysema - diagnosis; Pulmonary Emphysema - diagnostic imaging; Radiation; Radiation Dosage; Radiographic Image Interpretation, Computer-Assisted - methods; Thoracic Imaging; Tomography; Tomography, X-Ray Computed - instrumentation; Tomography, X-Ray Computed - methods; Variance analysis; 방사선과학
• ISSN: 1229-6929; 2005-8330
• DOI: 10.3348/kjr.2018.19.4.809

To evaluate the accuracy of emphysema volume (EV) and airway measurements (AMs) produced by various iterative reconstruction (IR) algorithms and virtual monoenergetic images (VME) at both low- and standard-dose settings. Computed tomography (CT) images were obtained on phantom at both low- (30 mAs at 120 kVp) and standard-doses (100 mAs at 120 kVp). Each CT scan was reconstructed using filtered back projection, hybrid IR (iDose ; Philips Healthcare), model-based IR (IMR-R1, IMR-ST1, IMR-SP1; Philips Healthcare), and VME at 70 keV (VME70). The EV of each air column and wall area percentage (WA%) of each airway tube were measured in all algorithms. Absolute percentage measurement errors of EV (APE ) and AM (APE ) were then calculated. Emphysema volume was most accurately measured in IMR-R1 (APE in low-dose, 0.053 ± 0.002; APE in standard-dose, 0.047 ± 0.003; all < 0.001) and AM was the most accurate in IMR-SP1 on both low- and standard-doses CT (APE in low-dose, 0.067 ± 0.002; APE in standard-dose, 0.06 ± 0.003; all < 0.001). There were no significant differences in the APE of IMR-R1 between low- and standard-doses (all > 0.05). VME70 showed a significantly higher APE than iDose , IMR-R1, and IMR-ST1 (all < 0.004). VME70 also showed a significantly higher APE compared with the other algorithms (all < 0.001). IMR was the most accurate technique for measurement of both EV and airway wall thickness. However, VME70 did not show a significantly better accuracy compared with other algorithms.