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Low-Dose Computed Tomography of the Chest Using Iterative Reconstruction Versus Filtered Back Projection: Comparison of Image Quality

Lee, Youkyung MD, PhD*; Jin, Kwang Nam MD*; Lee, Nyoung Keun MD

Journal of Computer Assisted Tomography: September/October 2012 - Volume 36 - Issue 5 - p 512–517
doi: 10.1097/RCT.0b013e318260ce39
Thoracic Imaging

Objective: The purpose of this study was to compare image quality of iterative reconstruction (IR) to filtered back projection (FBP) in low-dose computed tomography of the chest.

Methods: Forty-three consecutive patients were retrospectively enrolled. Eight series of images were reconstructed using FBP and 7 levels of IR in each subject. Image noise, signal-to-noise ratio (SNR), and SNR improvement were measured. Two radiologists evaluated subjective artifact, image artificiality, and subjective overall image quality with 4- or 5-point scales.

Results: Iterative reconstruction showed significantly lower image noise (135.5 ± 36.6 vs 219.9 ± 40.9) and higher SNR (0.36 ± 0.12 vs 0.21 ± 0.05) than FBP (P < 0.001). Signal-to-noise ratio improvement was 72.4% ± 44.9%. Subjective artifact of FBP was significantly higher than IR images (P < 0.001). Image artificiality of IR was significantly higher than that of FBP (P < 0.001). Overall, subjective image quality was poor in FBP and acceptable or good in IR.

Conclusions: With the use of IR, low-dose computed tomography of the chest would achieve less image noise and better image quality compared to the FBP.

From the *Department of Radiology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Korea; and †Department of Radiology, Seoul National University Hospital, Seoul, Korea.

Received for publication March 30, 2012; accepted May 22, 2012.

Reprints: Kwang Nam Jin, MD, Department of Radiology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Boramae-gil 41, Dongjak-gu, Seoul 156-010, Korea (e-mail:

The authors have no conflicts of interest to declare.

© 2012 Lippincott Williams & Wilkins, Inc.