Xinyi Gao1 and Dening Ma2
1Department of Radiology, Zhejiang Cancer Hospital, Hangzhou, China, 2Department of Colorectal Surgery, Zhejiang Cancer Hospital, Hangzhou, China
Synopsis
Keywords: Pelvis, Safety, rectal cancer, GBCAs, deep learning
Motivation: It would be clinically beneficial if GBCAs enhancement could be accurately synthesized without any GBCAs administration though AI.
Goal(s): To evaluate the feasibility of deep learning in synthesizing VTE based on noncontrast rectal cancer MRIs obtained without the use of gadolinium.
Approach: Deep learning networks were trained and validated on nonenhanced conventional pelvic MRI (T1WI, T2WI, DWI-ADC) using GAN. MRI scans included 697 rectal cancer patients from two hospitals.
Results: Quantitative and qualitative evaluation of three-channel VTE was significantly better than that of two-channel and one-channel (P<0.001). The T staging accuracy of VTE was comparable with that of RTE.
Impact: VTE synthesized
by deep learning based on noncontrast MRI can overcome the limitations of RTE and aid in the clinical diagnosis and
management of rectal cancer as a noninvasive, save, affordable and time-saving method
that does not require GBCAs.
Introduction
Gadolinium-based
contrast agents MRI assists the diagnosis and surveillance of rectal cancer,
whereas safety concerns have been raised recently. We aim to explore whether
deep learning generative adversarial network (GAN) can synthesize clinically applicable virtual T1WI
enhancement (VTE) of rectal cancer based on non-contrast pelvic MRI scans.Methods
Deep learning networks were trained and validated on nonenhanced conventional pelvic MRI (T1WI, T2WI,
DWI-ADC) using GAN. MRI scans included 697 rectal cancer patients (634
retrospective, 63 prospective) from two hospitals from June 2020 to October 2022. The real T1WI enhancement (RTE) images served as
the ground truth. The similarity between VTE and RTE were quantified using Mean Absolute Error (MAE), Peak Signal Noise Ratio (PSNR), Structural Similarity (SSIM) and
qualitatively evaluated by two radiologists. The image quality of input was
quantitatively evaluated by Natural Image Quality Evaluator (NIQE). Ablation
experiment was conducted to explore the best model. T staging was evaluated on
VTE and RTE by two radiologists and compared with pathology.Results
Participants included
493 men and 204 women (average age, 60.87 ± 12.08 years) were enrolled. Quantitative and qualitative evaluation of
three-channel VTE was significantly better than that of two-channel and
one-channel (P<0.001).
In internal validation (IV), external validation (EV) and prospective
validation (PV): MAE was 0.03 ± 0.01, 0.04 ± 0.01 and 0.03 ± 0.01; PSNR was
25.86 ± 1.63, 22.34 ± 1.21 and 25.68 ± 1.28; SSIM was 0.87 ± 0.55, 0.66 ± 0.06
and 0.88 ± 0.03, respectively. The T staging accuracy of VTE was comparable
with that of RTE in IV, EV, and PV (VTE vs RTE, 71.72% vs 70.71%, 69.31% vs
69.31%, and 73.02% vs 71.43%, respectively). The
correlation analysis between NIQE and MAE or SSIM or PSNR was statistically significant
(P < 0.001).Discussion
As a technical development
and proof-of-concept
study, this study underlines
the potential of deep learning GAN for synthesizing VTE from clinical routine
multiparametric nonenhanced MRIs of rectal cancer obtained without GBCAs
injection. Overall, the quantitative and qualitative assessment on two-center
dataset showed good consistency between VTE and RTE. The diagnostic ability of
VTE in rectal cancer T staging was comparable to that of RTE. This study
demonstrated the current frontier in image contrast generation, which has the
potential to be harnessed in the future for rectal cancer patient care. Conclusion
The deep learning GAN could
synthesize enhancement of rectal cancer from nonenhanced conventional
pelvic MRI scans with good image quality quantitatively and
qualitatively and allows accurate assessment of rectal cancer patients’ T
staging. As a technical development and proof of concept study, this research
demonstrates the current frontier in image contrast generation, which has the
potential to be harnessed in the future for rectal cancer patient care.Acknowledgements
None.References
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