Deep learning-based CT-free attenuation correction for cardiac SPECT: a new approach

Abstract Background Computed tomography attenuation correction (CTAC) is commonly used in cardiac SPECT imaging to reduce soft-tissue attenuation artifacts. However, CTAC is prone to inaccuracies due to CT artifacts and SPECT-CT mismatch, along with additional radiation exposure to patients. Thus, t...

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Main Authors: Pei Yang, Zeao Zhang, Jianan Wei, Lisha Jiang, Liqian Yu, Huawei Cai, Lin Li, Quan Guo, Zhen Zhao
Format: Article
Language:English
Published: BMC 2025-02-01
Series:BMC Medical Imaging
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Online Access:https://doi.org/10.1186/s12880-025-01570-y
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author Pei Yang
Zeao Zhang
Jianan Wei
Lisha Jiang
Liqian Yu
Huawei Cai
Lin Li
Quan Guo
Zhen Zhao
author_facet Pei Yang
Zeao Zhang
Jianan Wei
Lisha Jiang
Liqian Yu
Huawei Cai
Lin Li
Quan Guo
Zhen Zhao
author_sort Pei Yang
collection DOAJ
description Abstract Background Computed tomography attenuation correction (CTAC) is commonly used in cardiac SPECT imaging to reduce soft-tissue attenuation artifacts. However, CTAC is prone to inaccuracies due to CT artifacts and SPECT-CT mismatch, along with additional radiation exposure to patients. Thus, these limitations have led to increasing interest in CT-free AC, with deep learning (DL) offering promising solutions. We proposed a new DL-based CT-free AC methods for cardiac SPECT. Methods We developed a feature alignment attenuation correction network (FA-ACNet) based on the 3D U-Net framework to generate predicted DL-based AC SPECT (Deep AC). The network was trained on 167 cardiac SPECT/CT studies using 5-fold cross validation and tested in an independent testing set (n = 35), with CTAC serving as the reference. During training, multi-scale features from non-attenuation-corrected (NAC) SPECT and CT were processed separately and then aligned with the encoded features from NAC SPECT using adversarial learning and distance metric learning techniques. The performance of FA-ACNet was evaluated using mean square error (MSE), structural similarity index (SSIM) and peak signal-to-noise ratio (PSNR). Additionally, semi-quantitative evaluation of Deep AC images was performed and compared to CTAC using Bland-Altman plots. Results FA-ACNet achieved an MSE of 16.94 ± 2.03 × 10− 6, SSIM of 0.9955 ± 0.0006 and PSNR of 43.73 ± 0.50 after 5-fold cross validation. Compared to U-Net, MSE and PSNR improved by aligning multi-scale features from NAC SPECT and CT with those from NAC SPECT. In the testing set, FA-ACNet achieved an MSE of 11.98 × 10− 6, SSIM of 0.9976 and PSNR of 45.54. The 95% limits of agreement (LoAs) between the Deep AC and CTAC images for the summed stress/rest scores (SSS/SRS) were [− 2.3, 2.8] and [-1.9,2.1] in the training set and testing set respectively. Changes in perfusion categories were observed in 4.19% and 5.9% of studies assessed for global perfusion scores in the training set and testing set. Conclusion We propose a novel DL-based CT-free AC approach for cardiac SPECT, which can generate AC images without the need for a CT scan. By leveraging multi-scale features from both NAC SPECT and CT, the performance of CT-free AC is significantly enhanced, offering a promising alternative for future DL-based AC strategies.
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spelling doaj-art-34f5029994504ded972f18309c019b002025-02-09T12:59:58ZengBMCBMC Medical Imaging1471-23422025-02-0125111110.1186/s12880-025-01570-yDeep learning-based CT-free attenuation correction for cardiac SPECT: a new approachPei Yang0Zeao Zhang1Jianan Wei2Lisha Jiang3Liqian Yu4Huawei Cai5Lin Li6Quan Guo7Zhen Zhao8Department of Nuclear Medicine, West China Hospital of Sichuan UniversityMachine Intelligence Laboratory, College of Computer Science, Sichuan UniversityMachine Intelligence Laboratory, College of Computer Science, Sichuan UniversityDepartment of Nuclear Medicine, West China Hospital of Sichuan UniversityDepartment of Nuclear Medicine, West China Hospital of Sichuan UniversityDepartment of Nuclear Medicine, West China Hospital of Sichuan UniversityDepartment of Nuclear Medicine, West China Hospital of Sichuan UniversityMachine Intelligence Laboratory, College of Computer Science, Sichuan UniversityDepartment of Nuclear Medicine, West China Hospital of Sichuan UniversityAbstract Background Computed tomography attenuation correction (CTAC) is commonly used in cardiac SPECT imaging to reduce soft-tissue attenuation artifacts. However, CTAC is prone to inaccuracies due to CT artifacts and SPECT-CT mismatch, along with additional radiation exposure to patients. Thus, these limitations have led to increasing interest in CT-free AC, with deep learning (DL) offering promising solutions. We proposed a new DL-based CT-free AC methods for cardiac SPECT. Methods We developed a feature alignment attenuation correction network (FA-ACNet) based on the 3D U-Net framework to generate predicted DL-based AC SPECT (Deep AC). The network was trained on 167 cardiac SPECT/CT studies using 5-fold cross validation and tested in an independent testing set (n = 35), with CTAC serving as the reference. During training, multi-scale features from non-attenuation-corrected (NAC) SPECT and CT were processed separately and then aligned with the encoded features from NAC SPECT using adversarial learning and distance metric learning techniques. The performance of FA-ACNet was evaluated using mean square error (MSE), structural similarity index (SSIM) and peak signal-to-noise ratio (PSNR). Additionally, semi-quantitative evaluation of Deep AC images was performed and compared to CTAC using Bland-Altman plots. Results FA-ACNet achieved an MSE of 16.94 ± 2.03 × 10− 6, SSIM of 0.9955 ± 0.0006 and PSNR of 43.73 ± 0.50 after 5-fold cross validation. Compared to U-Net, MSE and PSNR improved by aligning multi-scale features from NAC SPECT and CT with those from NAC SPECT. In the testing set, FA-ACNet achieved an MSE of 11.98 × 10− 6, SSIM of 0.9976 and PSNR of 45.54. The 95% limits of agreement (LoAs) between the Deep AC and CTAC images for the summed stress/rest scores (SSS/SRS) were [− 2.3, 2.8] and [-1.9,2.1] in the training set and testing set respectively. Changes in perfusion categories were observed in 4.19% and 5.9% of studies assessed for global perfusion scores in the training set and testing set. Conclusion We propose a novel DL-based CT-free AC approach for cardiac SPECT, which can generate AC images without the need for a CT scan. By leveraging multi-scale features from both NAC SPECT and CT, the performance of CT-free AC is significantly enhanced, offering a promising alternative for future DL-based AC strategies.https://doi.org/10.1186/s12880-025-01570-yDeep learningSPECTMyocardial perfusion imagingAttenuation correction
spellingShingle Pei Yang
Zeao Zhang
Jianan Wei
Lisha Jiang
Liqian Yu
Huawei Cai
Lin Li
Quan Guo
Zhen Zhao
Deep learning-based CT-free attenuation correction for cardiac SPECT: a new approach
BMC Medical Imaging
Deep learning
SPECT
Myocardial perfusion imaging
Attenuation correction
title Deep learning-based CT-free attenuation correction for cardiac SPECT: a new approach
title_full Deep learning-based CT-free attenuation correction for cardiac SPECT: a new approach
title_fullStr Deep learning-based CT-free attenuation correction for cardiac SPECT: a new approach
title_full_unstemmed Deep learning-based CT-free attenuation correction for cardiac SPECT: a new approach
title_short Deep learning-based CT-free attenuation correction for cardiac SPECT: a new approach
title_sort deep learning based ct free attenuation correction for cardiac spect a new approach
topic Deep learning
SPECT
Myocardial perfusion imaging
Attenuation correction
url https://doi.org/10.1186/s12880-025-01570-y
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