Qin Liu MA, BA, Presenter: Nothing to Disclose

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

Pengfei Zhao, Abstract Co-Author: Nothing to Disclose

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

To evaluate the radiation dose and image quality (IQ) of an iterative reconstruction (AIDR 3D) in combination with SureExposure3D on a 640-slice CT and determine the optimal dose reduction using AIDR 3D for neonates and children chest CT that can provide IQ comparable to filtered back projection (FBP).

29 normal swines whose weight ranged 3-12kg (7.62±2.67) underwent 640-slice MDCT chest CT(Aquilion one ,Toshiba) for 5 times with 80kvp and different mAs. SureExposure3D technique were used and the index of noise were set to SD10 (Group A, routine dose), SD12.5, SD15, SD17.5, SD20 (Group B-E) to reduce dose successively. Group A were reconstructed with FBP, Group B-E were reconstructed using AIDR 3D (strong level). Two radiologists graded subject image quality in both lung and mediastinal images using a 5-point scale in a blinded manner. Object IQ parameters of image noise, signal-to-noise (SNR) were measured in each group. A receiver-operating characteristic (ROC) analysis was performed to establish a radiation reduction threshold up to which comparable IQ (score≥4) was maintained.

Group B, C, D has significantly lower noise , better SNR than Group A(P<0.001). Also subject  IQ has significant difference between these groups （p<0.001),while group E has 5 swines whose scores were  below 3 in mediastial images.The ROC curve of IQ established SD17.5 (Group D) as optimal cut-off point (AUC:0.75,95%CI:0.578-0.923).Group D provided equivalent subjective image score and objective IQ measurements (nosie:3.88±0.72; SNR:1.48±0.28) compared with FBP images in Group A (noise:3.75±0.69; SNR:1.33±0.25).The ED of group D was 43% lower than that of group A (0.034±0.006mSv vs 0.060±0.011mSv ,P<0.001).

Using AIDR 3D technique, 80kvp with SureExposure3D (SD17.5) can provide comparable or even better IQ compared with routine dose with FBP reconstruction, and reduce 43% dose in little swine model.  

The results of little swine model may be applied to reducing radiation dose of chest CT in neonates and children with serious lung infections.

Liu, Q, Hou, Y, Zhao, P, Guo, Q, The Optimal Dose Reduction Level in Chest CT with 640-slice CT Volume Scan Mode Using Iterative Reconstruction (AIDR 3D) in Little Swine Model.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13022337.html