Zih-Cen Lin MD, Presenter: Nothing to Disclose

Yu-Ting Kuo MD, Abstract Co-Author: Nothing to Disclose

Gin-Chung Liu MD, Abstract Co-Author: Nothing to Disclose

Chien-Hung Lee Lee, Abstract Co-Author: Nothing to Disclose

Chiao-Yun Chen MD, Abstract Co-Author: Nothing to Disclose

Twei-Shiun Jaw MD, Abstract Co-Author: Nothing to Disclose

Jui-Sheng Hsu MD, PhD, Abstract Co-Author: Nothing to Disclose

Ding-Kwo Wu MD, Abstract Co-Author: Nothing to Disclose

To investigate feasibility of low-tube-voltage scan using SAFIRE compared with weighted average 120 kVp protocol for detecting hypovascular liver tumor on DECT

We reviewed database of dual-energy triple-phase CT for liver tumor survey from dual source CT scanner (SOMATOM Definition Flash, Siemens Medical Solutions). Total 55 patients (33 men, 22 women; mean age: 62 years) diagnosed as hypovascular liver tumor were enrolled. Images obtained in the portal venous phase were used for analysis. Source images acquired with 80 kVp and weighted average 120 kVp were analyzed in the work station using filtered backed projection (FBP) and SAFIRE reconstruction. All four imaging sets were evaluated about the signal-to-noise ratio (SNR) of liver, bilateral paraspinal muscles, aorta, spleen, and pancreas. The contrast-to-noise ratio (CNR), image noise and effective dose were also measured in each imaging data set. Subjective lesion conspicuity and image quality were rated by two independent readers (5-point scale). Repeated measure ANOVA was used for statistical analysis.

In both 120 and 80 kVp data sets, SAFIRE reconstruction outperformed FBP in the image noise, SNR in liver, paraspinal muscle, aorta, spleen, pancreas and CNR in hypovascular tumors. Better SNR (5.9±3.6) and CNR (7.1±3.3) (p<0.001) of hypovascular liver tumors can be achieved in 80 kVp with SAFIRE reconstruction than 120 kVp with FBP but no difference in image noise. There are intermediate to high correlations (k =0.48~0.96) between two observers in image quality rating. The 80 kVp data set with SAFIRE reconstruction demonstrated better lesion conspicuity, image quality and image noise than 120 kVp with FBP. These four imaging sets share the same detection rate (94%) of hypovascular tumors. Mean effective dose of 80 kVp is 3.5±1.0 mSv, with dose saving rate is 41% when compared with 120 kVp.

Low-tube-voltage CT images reconstructed with SAFIRE are able to achieve high CNR, SNR without sacrificing detection of hypovascular liver tumor during portal venous phase. This low-dose technique also saves patient’s radiation dose when compared with standard-dose scan.

For patients with hypovascular liver tumor requiring repeated CT studies, low-tube-voltage CT technique with SAFIRE can be used to save radiation dose without sacrificing diagnostic accuracy.

Lin, Z, Kuo, Y, Liu, G, Lee, C, Chen, C, Jaw, T, Hsu, J, Wu, D, Detection of Hypovascular Liver Tumors with Dual-Energy CT (DECT): Effects of Low-Tube-Voltage Scan Using Sinogram Affirmed Iterative Reconstruction (SAFIRE).  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12026467.html