Xiao Zhu Lin MD, Abstract Co-Author: Nothing to Disclose

Xueqin Xu, Presenter: Nothing to Disclose

Haruhiko Machida MD, Abstract Co-Author: Nothing to Disclose

Isao Tanaka, Abstract Co-Author: Nothing to Disclose

Fuhua Yan, Abstract Co-Author: Nothing to Disclose

Kemin Chen MD, PhD, Abstract Co-Author: Nothing to Disclose

Rika Fukui, Abstract Co-Author: Nothing to Disclose

Eiko Ueno MD, Abstract Co-Author: Nothing to Disclose

To compare CT images of the pancreas reconstructed with model-based iterative reconstruction (MBIR), adaptive statistical iterative reconstruction (ASIR), and filtered back projection (FBP) techniques for pancreatic duct depiction and image quality.

Institutional review board approval, with waived consent, was obtained. Forty patients (24 men, 16 women; age range, 37–91 years; mean age, 63 years) underwent biphasic contrast-enhanced abdominal CT. Data were reconstructed with FBP, 40% ASIR-FBP blending, and MBIR to obtain trans-axial multi-planar reformatted images. Two abdominal radiologists (A, B) assessed the depiction of main pancreatic duct (conspicuity of the wall and clarity of inside of the pancreatic duct), image noise, and overall image quality on a 5-point scale independently. Objective CT value and noise were measured in the pancreatic parenchyma, and the contrast-to-noise ratio (CNR) of the pancreatic duct was calculated. Paired t and Wilcoxon signed rank tests were used for quantitative and qualitative assessment, respectively. Statistical analysis included analysis of inter-observer agreement.

For the subjective scores for the overall image quality (A, B) and image noise (A, B), MBIR (4.3±0.7, 4.5±0.5) and (4.7±0.5, 4.8±0.4) and 40%ASIR (3.5±0.6, 3.5±0.5) and (3.7±0.4, 3.7±0.5) were significantly higher than those with FBP (2.9±0.5, 2.8±0.6) and (2.9±0.5, 2.8±0.5) (p0.05). Objective image noise of pancreatic parenchyma was lower with MBIR (11±3(HU)), 40%ASiR (17±4(HU)) than with FBP (24±5(HU)) (P<0.001). Objective CNR of pancreatic duct with MBIR (8.4±2.8), 40% ASIR (5.6±1.9) was higher than that with FBP (4.4±1.5) (P<0.001).

Our initial results suggest pancreatic CT images reconstructed with MBIR and 40%ASiR have lower image noise, better image quality, and higher conspicuity and CNR of the pancreatic duct compared with a regular FBP algorithm.

Image reconstructed with MBIR has the potential to improve the confidence in diagnosis of pancreatic diseases and early detection of pancreatic duct adenocarcinoma.

Lin, X, Xu, X, Machida, H, Tanaka, I, Yan, F, Chen, K, Fukui, R, Ueno, E, CT of the Pancreas: Comparison of Pancreatic Duct Depiction and Image Quality between Model-based Iterative, Adaptive Statistical Iterative, and Filtered Back Projection Reconstruction Techniques.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12043621.html