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Study on analytical noise propagation in convolutional neural network methods used in computed tomography imaging

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Abstract

Neural network methods have recently emerged as a hot topic in computed tomography (CT) imaging owing to their powerful fitting ability; however, their potential applications still need to be carefully studied because their results are often difficult to interpret and are ambiguous in generalizability. Thus, quality assessments of the results obtained from a neural network are necessary to evaluate the neural network. Assessing the image quality of neural networks using traditional objective measurements is not appropriate because neural networks are nonstationary and nonlinear. In contrast, subjective assessments are trustworthy, although they are time- and energy-consuming for radiologists. Model observers that mimic subjective assessment require the mean and covariance of images, which are calculated from numerous image samples; however, this has not yet been applied to the evaluation of neural networks. In this study, we propose an analytical method for noise propagation from a single projection to efficiently evaluate convolutional neural networks (CNNs) in the CT imaging field. We propagate noise through nonlinear layers in a CNN using the Taylor expansion. Nesting of the linear and nonlinear layer noise propagation constitutes the covariance estimation of the CNN. A commonly used U-net structure is adopted for validation. The results reveal that the covariance estimation obtained from the proposed analytical method agrees well with that obtained from the image samples for different phantoms, noise levels, and activation functions, demonstrating that propagating noise from only a single projection is feasible for CNN methods in CT reconstruction. In addition, we use covariance estimation to provide three measurements for the qualitative and quantitative performance evaluation of U-net. The results indicate that the network cannot be applied to projections with high noise levels and possesses limitations in terms of efficiency for processing low-noise projections. U-net is more effective in improving the image quality of smooth regions compared with that of the edge. LeakyReLU outperforms Swish in terms of noise reduction.

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References

  1. M.H. Touch, D.P. Clark, W. Barber et al., A neural network-based method for spectral distortion correction in photon counting X-ray CT. Phys. Med. Biol. 61(16), 6132–6153 (2016). https://doi.org/10.1088/0031-9155/61/16/6132

    Article  Google Scholar 

  2. M.D. Holbrook, D.P. Clark, C.T. Badea, Deep learning based spectral distortion correction and decomposition for photon counting CT using calibration provided by an energy integrated detector, in SPIE Medical Imaging 2021: Physics of Medical Imaging (2021). https://doi.org/10.1117/12.2581124

  3. K.C. Liang, L. Zhang, H.K. Yang et al., A model-based unsupervised deep learning method for low-dose CT reconstruction. IEEE Access 8, 159260–159273 (2020). https://doi.org/10.1109/ACCESS.2020.3020406

    Article  Google Scholar 

  4. Y.K. Zhang, D.L. Hu, Q.L. Zhao et al., CLEAR: comprehensive learning enabled adversarial reconstruction for subtle structure enhanced low-Dose CT imaging. IEEE Trans. Med. Imaging 40(11), 3089–3101 (2021). https://doi.org/10.1109/TMI.2021.3097808

    Article  Google Scholar 

  5. H.K. Yang, K.C. Liang, K.J. Kang et al., Slice-wise reconstruction for low-dose cone-beam CT using a deep residual convolutional neural network. Nucl. Sci. Tech. 30, 59 (2019). https://doi.org/10.1007/s41365-019-0581-7

    Article  Google Scholar 

  6. X.R. Yin, Q.L. Zhao, J. Liu et al., Domain progressive 3D residual convolution network to improve low-dose CT imaging. IEEE Trans. Med. Imaging 38(12), 2903–2913 (2019). https://doi.org/10.1109/TMI.2019.2917258

    Article  Google Scholar 

  7. J. Liu, Y. Zhang, Q.L. Zhao et al., Deep iterative reconstruction estimation (DIRE): approximate iterative reconstruction estimation for low dose CT imaging. Phys. Med. Biol. 64(13), 135007 (2019). https://doi.org/10.1088/1361-6560/ab18db

    Article  Google Scholar 

  8. D.L. Hu, J. Liu, T.L. Lv et al., Hybrid-domain neural network processing for sparse-view CT reconstruction. IEEE Trans. Radiat. Plasma. Med. Sci. 5(1), 88–98 (2021). https://doi.org/10.1109/TRPMS.2020.3011413

    Article  Google Scholar 

  9. D. Hu, Y. Zhang, J. Liu et al., DIOR: deep iterative optimization-based residual-learning for limited-angle CT reconstruction. IEEE Trans. Med. Imaging 41, 1778–1790 (2022). https://doi.org/10.1109/TMI.2022.3148110

    Article  Google Scholar 

  10. Y.J. Ma, Y. Ren, P. Feng et al., Sinogram denoising via attention residual dense convolutional neural network for low-dose computed tomography. Nucl. Sci. Tech. 32, 41 (2021). https://doi.org/10.1007/s41365-021-00874-2

    Article  Google Scholar 

  11. W. Fang, D.F. Wu, K. Kim et al., Iterative material decomposition for spectral CT using self-supervised Noise2Noise prior. Phys. Med. Biol. 66(15), 1–17 (2021). https://doi.org/10.1088/1361-6560/ac0afd

    Article  Google Scholar 

  12. T.L. Lyu, W. Zhao, Y.S. Zhu et al., Estimating dual-energy CT imaging from single-energy CT data with material decomposition convolutional neural network. Med. Image Anal. 70, 102001 (2021). https://doi.org/10.1016/j.media.2021.102001

    Article  Google Scholar 

  13. A. Zheng, H.K. Yang, L. Zhang et al., Interweaving network: a novel monochromatic image synthesis method for a photon-counting detector CT system. IEEE Access 8, 217710 (2020). https://doi.org/10.1109/ACCESS.2020.3041078

    Article  Google Scholar 

  14. K.C. Liang, L. Zhang, H.K. Yang et al., Metal artifact reduction for practical dental computed tomography by improving interpolation-based reconstruction with deep learning. Med. Phys. 46(12), e823–e834 (2019). https://doi.org/10.1002/mp.13644

    Article  Google Scholar 

  15. W. Fang, L. Li, Z.Q. Chen, Removing ring artefacts for photon-counting detectors using neural networks in different domains. IEEE Access 8, 42447–42457 (2020). https://doi.org/10.1109/ACCESS.2020.2977096

    Article  Google Scholar 

  16. P.J. Liu, M. Wang, Y.N. Wang et al., Impact of deep learning-based optimization algorithm on image quality of low-dose coronary CT angiography with noise reduction: a prospective study. Acad. Radiol. 27(9), 1241–1248 (2020). https://doi.org/10.1016/j.acra.2019.11.010

    Article  Google Scholar 

  17. A. Steuwe, M. Weber, O.T. Bethge et al., Influence of a novel deep-learning based reconstruction software on the objective and subjective image quality in low-dose abdominal computed tomography. Br. J. Radiol. 94, 20200677 (2021). https://doi.org/10.1259/bjr.20200677

    Article  Google Scholar 

  18. C. Park, K.S. Choo, Y. Jung et al., CT iterative vs deep learning reconstruction: comparison of noise and sharpness. Eur. Radiol. 31(5), 3156–3164 (2021). https://doi.org/10.1007/s00330-020-07358-8

    Article  Google Scholar 

  19. J. Greffier, A. Hamard, F. Pereira et al., Image quality and dose reduction opportunity of deep learning image reconstruction algorithm for CT: a phantom study. Eur. Radiol. 30(7), 3951–3959 (2020). https://doi.org/10.1007/s00330-020-06724-w

    Article  Google Scholar 

  20. C.T. Jensen, X.M. Liu, E.P. Tamm et al., Image quality assessment of abdominal CT by use of new deep learning image reconstruction: initial experience. AJR 215(1), 50–57 (2020). https://doi.org/10.2214/ajr.19.22332

    Article  Google Scholar 

  21. R. Singh, S.R. Digumarthy, V.V. Muse et al., Image quality and lesion detection on deep learning reconstruction and iterative reconstruction of submillisievert chest and abdominal CT. AJR 214(3), 566–573 (2020). https://doi.org/10.2214/AJR.19.21809

    Article  Google Scholar 

  22. X. He, S. Park, Model observers in medical imaging research. Theranostics 3(10), 774–786 (2013). https://doi.org/10.7150/thno.5138

    Article  Google Scholar 

  23. S. Leng, L.Y. Yu, Y. Zhang et al., Correlation between model observer and human observer performance in CT imaging when lesion location is uncertain. Med. Phys. 40(8), 081908 (2013). https://doi.org/10.1118/1.4812430

    Article  Google Scholar 

  24. L.Y. Yu, B.Y. Chen, J.M. Kofler et al., Correlation between a 2D channelized Hotelling observer and human observers in a low-contrast detection task with multislice reading in CT. Med. Phys. 44(8), 3990–3999 (2017). https://doi.org/10.1002/mp.12380

    Article  Google Scholar 

  25. G. Kim, M. Han, H. Shim et al., A convolutional neural network-based model observer for breast CT images. Med. Phys. 47(4), 1619–1632 (2020). https://doi.org/10.1002/mp.14072

    Article  Google Scholar 

  26. D. Piccini, R. Demesmaeker, J. Heerfordt et al., Deep learning to automate reference-free image quality assessment of whole-heart MR images. Radiol. Artif. Intell. 2(3), e190123 (2020). https://doi.org/10.1148/ryai.2020190123

    Article  Google Scholar 

  27. H. Gong, L.Y. Yu, S. Leng et al., A deep learning- and partial least square regression-based model observer for a low-contrast lesion detection task in CT. Med. Phys. 46(5), 2052–2063 (2019). https://doi.org/10.1002/mp.13500

    Article  Google Scholar 

  28. H. Gong, Q. Hu, A. Walther et al., Deep-learning-based model observer for a lung nodule detection task in computed tomography. J. Med. Imaging 7(4), 042807 (2020). https://doi.org/10.1117/1.JMI.7.4.042807

    Article  Google Scholar 

  29. H. Gong, J.G. Fletcher, J.P. Heiken et al., Deep-learning model observer for a low-contrast hepatic metastases localization task in computed tomography. Med. Phys. 49(1), 70–83 (2021). https://doi.org/10.1002/mp.15362

    Article  Google Scholar 

  30. A.H. Abdelaziz, S. Watanabe, J. Hershey et al., Uncertainty propagation through deep neural networks, in InterSpeech (2015). https://hal.inria.fr/hal-01162550

  31. J. Lee, Y Bahri, R. Novak et al., Deep neural networks as Gaussian processes, in the 6th International Conference on Learning Representations (ICRL 2018) (2018). arXiv:1711.00165

  32. R. Tanno, D.E. Worrall, E. Kaden et al., Uncertainty modelling in deep learning for safer neuroimage enhancement: demonstration in diffusion MRI. Neuroimage 225, 117366 (2021). https://doi.org/10.1016/j.neuroimage.2020.117366

    Article  Google Scholar 

  33. N. Ueda, R. Nakano, Generalization error of ensemble estimators, in Proceedings of International Conference on Neural Networks (ICNN’96) (1996), pp. 90–95. https://doi.org/10.1109/ICNN.1996.548872

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Authors

Contributions

All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by XYG, LZ, and YXX. The first draft of the manuscript was written by XYG and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

Corresponding author

Correspondence to Yu-Xiang Xing.

Additional information

This work was supported by the National Natural Science Foundation of China (Nos. 62031020 and 61771279).

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Guo, XY., Zhang, L. & Xing, YX. Study on analytical noise propagation in convolutional neural network methods used in computed tomography imaging. NUCL SCI TECH 33, 77 (2022). https://doi.org/10.1007/s41365-022-01057-3

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  • DOI: https://doi.org/10.1007/s41365-022-01057-3

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