Abstract
Objectives
To evaluate image quality, diagnostic acceptability, and lesion conspicuity in abdominal dual-energy CT (DECT) using deep learning image reconstruction (DLIR) compared to those using adaptive statistical iterative reconstruction-V (Asir-V) at 50% blending (AV-50), and to identify potential factors impacting lesion conspicuity.
Methods
The portal-venous phase scans in abdominal DECT of 47 participants with 84 lesions were prospectively included. The raw data were reconstructed to virtual monoenergetic image (VMI) at 50 keV using filtered back-projection (FBP), AV-50, and DLIR at low (DLIR-L), medium (DLIR-M), and high strength (DLIR-H). A noise power spectrum (NPS) was generated. CT number and standard deviation values of eight anatomical sites were measured. Signal-to-noise (SNR), and contrast-to-noise ratio (CNR) values were calculated. Five radiologists assessed image quality in terms of image contrast, image noise, image sharpness, artificial sensation, and diagnostic acceptability, and evaluated the lesion conspicuity.
Results
DLIR further reduced image noise (p < 0.001) compared to AV-50 while better preserved the average NPS frequency (p < 0.001). DLIR maintained CT number values (p > 0.99) and improved SNR and CNR values compared to AV-50 (p < 0.001). DLIR-H and DLIR-M showed higher ratings in all image quality analyses than AV-50 (p < 0.001). DLIR-H provided significantly better lesion conspicuity than AV-50 and DLIR-M regardless of lesion size, relative CT attenuation to surrounding tissue, or clinical purpose (p < 0.05).
Conclusions
DLIR-H could be safely recommended for routine low-keV VMI reconstruction in daily contrast-enhanced abdominal DECT to improve image quality, diagnostic acceptability, and lesion conspicuity.
Key Points
• DLIR is superior to AV-50 in noise reduction, with less shifts of the average spatial frequency of NPS towards low frequency, and larger improvements of NPS noise, noise peak, SNR, and CNR values.
• DLIR-M and DLIR-H generate better image quality in terms of image contrast, noise, sharpness, artificial sensation, and diagnostic acceptability than AV-50, while DLIR-H provides better lesion conspicuity than AV-50 and DLIR-M.
• DLIR-H could be safely recommended as a new standard for routine low-keV VMI reconstruction in contrast-enhanced abdominal DECT to provide better lesion conspicuity and better image quality than the standard AV-50.
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Abbreviations
- Asir-V:
-
Adaptive statistical iterative reconstruction-V
- CNR:
-
Contrast-to-noise ratio
- DECT:
-
Dual-energy computed tomography
- DLIR:
-
Deep learning image reconstruction
- faverage :
-
Average spatial frequency of noise power spectrum
- FBP:
-
Filtered back-projection
- fpeak :
-
Peak spatial frequency of noise power spectrum
- HU:
-
Hounsfield unit
- keV:
-
Kiloelectron volt
- NPS:
-
Noise power spectrum
- ROI:
-
Region of interest
- SD:
-
Standard deviation
- SNR:
-
Signal-to-noise ratio
- VMI:
-
Virtual monoenergetic images
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Acknowledgements
The authors would like to express their gratitude to Dr. Zhen Pan for her assistance in image quality assessment, and Dr. Shiqi Mao for his advice on data visualization.
Funding
This study has received funding from the National Natural Science Foundation of China (82271934, 82101986), the Yangfan Project of Science and Technology Commission of Shanghai Municipality (22YF1442400, 20YF1427200), Shanghai Science and Technology Commission Science and Technology Innovation Action Clinical Innovation Field (18411953000), Medicine and Engineering Combination Project of Shanghai Jiao Tong University (YG2019ZDB09, YG2021QN08), Research Fund of Tongren Hospital, Shanghai Jiao Tong University School of Medicine (TRKYRC-XX202204, TRGG202101, TRYJ2021JC06, 2020TRYJ(LB)06, 2020TRYJ(JC)07), and Guangci Innovative Technology Launch Plan of Ruijin Hospital, Shanghai Jiao Tong University School of Medicine (2022-13).
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The scientific guarantor of this publication is Prof. Huan Zhang from the Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine.
Conflict of interest
Dr. Jingyu Zhong acknowledges his position as a member of the Musculoskeletal section of the Scientific Editorial Board of European Radiology. Mr. Wei Lu and Dr. Jianying Li are employees of GE Healthcare. However, they neither had access nor control over the data acquisition and analysis. All other authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article.
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Huan Zhang, Weiwu Yao, and Lianjun Du are co-corresponding authors.
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Zhong, J., Wang, L., Shen, H. et al. Improving lesion conspicuity in abdominal dual-energy CT with deep learning image reconstruction: a prospective study with five readers. Eur Radiol 33, 5331–5343 (2023). https://doi.org/10.1007/s00330-023-09556-6
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DOI: https://doi.org/10.1007/s00330-023-09556-6