Performance of Half-dose Chest Computed Tomography in Lung Malignancy Using an Iterative Reconstruction Technique

• Published in: Kosin Medical Journal (Online) Vol. 32; no. 1; pp. 47 - 57
• Main Authors: Kang, Hee, Park, Jung Gu, Park, Se Kyoung, Kim, Beom Su, Lee, Ki Nam, Oh, Kyeung Seung
• Format: Journal Article
• Language: English
• Published: Kosin University College of Medicine 01.06.2017; 고신대학교 의과대학 학술지
• Subjects: chest ct; low-dose ct; noise reduction; reconstruction technique; safire; 의학일반
• ISSN: 2005-9531; 2586-7024
• DOI: 10.7180/kmj.2017.32.1.47

Objectives The purpose of this study was to evaluate the performance of half-dose chest CT using an iterative reconstruction technique in patients with lung malignancies. Methods The Dual-source CT scans were obtained and half-dose datasets were reconstructed with 5 different strengths in 38 adults with lung malignancies. Two radiologists graded subjective image quality; noise, contrast and sharpness at the central/peripheral lung, mediastinum and chest wall of the reconstructed half-dose images, compared with those of standard-dose images, using a three-point scale. A lesion assessment; lesion conspicuity and diagnostic confidence, was also performed. The quantitative image noises; contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) were measured and compared with those of standard-dose images. Results The subjective image noise in the half-dose images was less than that of the standard-dose images. The contrast in strengths 2 to 5 was superior, the sharpness of the lung parenchyma in strengths 3 to 5 was inferior, and the CNR/SNR in all strengths were higher than those of standard-dose images ( P < 0.05). The improvement of subjective image noise and contrast, the decrease in sharpness, were correlated with strength level ( P < 0.05). The lesion conspicuity in half-dose images of strengths 4 and 5 was decreased. The diagnostic confidence of the half-dose images of all strengths was comparable to that of the standard-dose images ( P < 0.05). Conclusions Half-dose chest CT images using an iterative reconstruction technique show decreased image noise, increased contrast, and diagnostic confidence comparable to standard-dose images. Images reconstructed with strength 2 and 3 appear to be the optimal choice in clinical practice.