Qiong Li, Presenter: Nothing to Disclose

Shiyuan Liu PhD, Abstract Co-Author: Nothing to Disclose

Hong Yu MD, PhD, Abstract Co-Author: Nothing to Disclose

Yan Jiang MD, Abstract Co-Author: Employee, Koninklijke Philips NV

　　　To prospectively evaluate dose reduction and image quality features of chest CT reconstructed by using knowledge based iterative reconstruction technique(IMR,Philips Healthcare) compared with hybrid iterative reconstruction( iDose4,Philips healthcare) and filtered back projection (FBP) techniques.

　　　Institutional review board approval was obtained for this study. 42 patients (54.3±6.7 years, 28 male) underwent unenhanced chest CT with both ultra-low lose(ULD) and routine low dose (LD) protocols for once. All images were reconstructed with a 1mm slice by IMR which included 3 different settings (L1 body routine, L1 body sharpPLus and L1 body soft tissue), iDose4 (level 4)and FBP techniques, respectively. Total dose-length product (DLP) of both ULD and LD protocols were recorded. Image quality assessments for both normal lung and mediastinal structures were performed by 2 radiologists according to the features of structure demarcation, noise and artifacts using a five point scale. Standard deviation(SD) of CT attenuation in the descending aorta was measured as objective image noise. 　　　

　　The radiation dose of ULD-CT was 0.62±0.02mSv compared with 2.54± 0.63 mSv for LD-CT (P<0.001) , there was a 75.6% decrease in ED. All three settings of IMR reduced image noise significantly than iDose4 and FBP (p<0.01, respectively). Both IR algorithms showed better image quality than FBP, and all IMR settings were better than iDose4 (p<0.01, respectively), IMR-sharpPlus images enabled exhibited the lung parenchyma, while IMR-routine or soft tissue images enabled showed the mediastinal images.

　　　Diagnostically acceptable chest CT image acquired with radiation exposure in the range of a posterior to anterior and lateral chest X-ray can be obtained by using IMR. IMR allows more noise reduction and significant image quality improvement in ultra-low dose chest CT compared to iDose4 techniques and FBP. Different settings of IMR can be the complement for each other which may provide more diagnosis information to reach lower dose CT without compromising image quality.

Different settings of IMR can be the complement for each other which may provide more diagnosis information to reach lower dose CT without compromising image quality.  

Li, Q, Liu, S, Yu, H, Jiang, Y, Knowledge Based Iterative Reconstruction Technique for Radiation Dose Reduction in Chest CT: Comparison with Hybrid Iterative Reconstruction and Filtered Back Projection Techniques.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14015463.html