采用新型降噪技术降低低千伏（80kV）CT 肠造影剂量的可行性：优化和验证。

Feasibility of dose reduction using novel denoising techniques for low kV (80 kV) CT enterography: optimization and validation.

机构信息

Department of Radiology, Mayo Clinic, Rochester, MN 55905, USA.

出版信息

Acad Radiol. 2010 Oct;17(10):1203-10. doi: 10.1016/j.acra.2010.07.001.

DOI:10.1016/j.acra.2010.07.001

PMID:20832023

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC2939058/

Abstract

RATIONALE AND OBJECTIVES

The aim of this study was to optimize and validate projection-space denoising (PSDN) strategies for application to 80-kV computed tomographic (CT) data to achieve 50% dose reduction.

MATERIALS AND METHODS

Image data obtained at 80 kV (mean CT dose index volume, 7.9 mGy) from dual-source, dual-energy CT enterographic (CTE) exams in 42 patients were used. For each exam, nine 80 kV image data sets were reconstructed using PSDN (three levels of intensity) with or without image-based denoising and compared to commercial reconstruction kernels. For optimization, qualitative analysis selected optimal denoising strategies, with quantitative analysis measuring image contrast, noise, and sharpness (full width at half maximum bowel wall thickness, maximum CT number gradient). For validation, two radiologists examined image quality, comparing low-dose 80-kV optimally denoised images to full-dose mixed-voltage images.

RESULTS

PSDN algorithms generated the best 80-kV image quality (41 of 42 patients), while the commercial kernels produced the worst (39 of 42) (P < .001). Overall, 80-kV PSDN approaches resulted in higher contrast (mean, 332 vs 290 Hounsfield units), slightly less noise (mean, 20 vs 26 Hounsfield units), but slightly decreased image sharpness (relative bowel wall thickness, 1.069 vs 1.000) compared to full-dose mixed-voltage images. Mean image quality scores for full-dose CTE images were 4.9 compared to 4.5 for optimally denoised half-dose 80-kV CTE images and 3.1 for nondenoised 80-kV CTE images (P < .001).

CONCLUSION

Optimized denoising strategies improve the quality of 80-kV CTE images such that CT data obtained at 50% of routine dose levels approaches the image quality of full-dose exams.

摘要

背景与目的

本研究旨在优化和验证投影空间去噪（PSDN）策略，以应用于 80kV 计算机断层扫描（CT）数据，实现 50%的剂量降低。

材料与方法

使用来自 42 名患者的双源双能 CT 肠造影（CTE）检查的 80kV 图像数据（平均 CT 剂量指数容积为 7.9mGy）。对于每个检查，使用 PSDN（三种强度水平）对 9 个 80kV 图像数据集进行重建，同时使用和不使用基于图像的去噪，并与商业重建核进行比较。为了进行优化，定性分析选择了最佳的去噪策略，定量分析测量了图像对比度、噪声和锐度（全宽半高肠壁厚度、最大 CT 数梯度）。为了验证，两位放射科医生检查了图像质量，将低剂量 80kV 最佳去噪图像与全剂量混合电压图像进行比较。

结果

PSDN 算法生成了最佳的 80kV 图像质量（42 名患者中有 41 名），而商业核则生成了最差的图像质量（42 名患者中有 39 名）（P<0.001）。总体而言，80kV PSDN 方法导致更高的对比度（平均 332 与 290 亨斯菲尔德单位），略低的噪声（平均 20 与 26 亨斯菲尔德单位），但图像锐度略降低（相对肠壁厚度 1.069 与 1.000）与全剂量混合电压图像相比。全剂量 CTE 图像的平均图像质量评分为 4.9，而最佳去噪半剂量 80kV CTE 图像为 4.5，未去噪 80kV CTE 图像为 3.1（P<0.001）。