Shu Xu, Presenter: Nothing to Disclose

Yang Hou MD, Abstract Co-Author: Nothing to Disclose

Qiyong Guo MD, Abstract Co-Author: Nothing to Disclose

To evaluate 256-slice computed tomography (CT) images of the liver tumors reconstructed using iDOSE(iterative reconstruction) reconstruction on routine- and Low-dose CT.

This prospective study was approved by the institutional review board. Informed patient consent was obtained. 200 patients with clinical diagnosis of liver tumors were scanned on a 256-slice CT scanner (Brilliance iCT, Philips). Patients were randomly divided into four groups(A, B, C, D). Patients in group A were scanned with routine-dose, reconstructed with filtered back projection(FBP). While patients in group B, C, D were scanned with 30%, 50% and 70% RDR respectively. Images in the three low-dose groups were reconstructed with iterative reconstruction technique (iDose, Philips). Quantitative noise and contrast-to-noise [CNR, CNR= (Enhancementliver - Enhancementmusle) / Noisebackground] measurements were performed. Qualitative ranking of sharpness of image, contrast between tumors and normal liver tissue, noise，and image quality were graded [scale: 1(worse) - 4(best)] . Data was analyzed using completely randomized design analysis of variance and Kruskal Wallis test.

In the comparison of quantitative noise，the groups with iDOSE reconstruction were significantly lower than group A(with FBP reconstruction, 14.27±3.44）（p<0.01）.The CNR of groups with iDOSE reconstruction were significantly higher than group A(with FBP reconstruction, 2.61±1.77）（p<0.01）.While there was no significant difference in CNR among the three groups with iDOSE reconstruction（p>0.05）.There was no significant difference among the four groups for tumor tissue contrast and qualitative noise score(p=0.09，p=0.74). There was no significant difference between group B and A, C and A for tumor sharpness and image quality scores. However, a significant difference in tumor sharpness and image quality scores was observed beween group D and group A(p <0.01).

iDOSE algrithm could improve image quality for low-dose hepatic enhanced CT. When the radiation dose was reduced by 50%, images maintaining the diagnostic quality of routine dose CT or even better images could be acquired with iDOSE.  

Compared with regular FBP,iDOSE enable significant reduction of image noise without loss of diagnostic information ,thus having the potential to reduce radiation dose in hepatic CT

Xu, S, Hou, Y, Guo, Q, Evaluation of an iDOSE (Iterative Reconstruction) Algorithm for Hepatic-enhanced 256-Slice CT: Image Quality of the Liver Tumors on Routine and Low-Dose CT.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11008614.html