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

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.

The application value of iterative reconstruction SAFIRE technique in liver CT / 实用放射学杂志

Objective To study the value of SAFIRE reconstruction technique in the liver plain CT scan by the comparison of dis-plays to the liver separately by SAFIRE and traditional FBP reconstructions after DSCT scan.Methods 48 patients clinically doub-ted to have hepatic lesions were scanned by DSCT in liver,then the average CT value,noise,signal to noise ratio (SNR),contrast to noise ratio (CNR)and subjective scoring on image quality were compared after FBP and SAFIRE 1-5 reconstructions.Results There was no statistical difference on the average CT value of liver parenchyma in all 6 groups (P >0.05).The differences were sta-tistically significant (P <0.05)on noise,SNR,CNR and subjective scoring.SAFIRE 5 reconstruction had the least noise and the largest SNR and CNR.For the images of SAFIRE 1 and SAFIRE 5,the image subjective scoring was lower than that by FBP;for the images of SAFIRE 2-4,the image subjective scoring is higher than that by FBP;and SAFIRE 3 had the highest score.But for the rate of lesion detection,all the images were the same.Conclusion SAFIRE reconstruction strength 3 could produce the idealest image quality.SAFIRE reconstruction can decrease noise and improve SNR and CNR,and have a potential effect on decreasing the scan dose.