Medical image restoration is essential for improving the usability of noisy, incomplete, and artifact-corrupted clinical scans, yet existing methods often rely on task-specific retraining and offer limited control over the trade-off between faithful reconstruction and prior-driven enhancement. This lack of controllability is especially problematic in clinical settings, where overly aggressive restoration may introduce hallucinated details or alter diagnostically important structures. In this work, we propose CARE, a training-free controllable restoration framework for real-world medical images that explicitly balances structure preservation and prior-guided refinement during inference. CARE uses a dual-latent restoration strategy, in which one branch enforces data fidelity and anatomical consistency while the other leverages a generative prior to recover missing or degraded information. A risk-aware adaptive controller dynamically adjusts the contribution of each branch based on restoration uncertainty and local structural reliability, enabling conservative or enhancement-focused restoration modes without additional model training. We evaluate CARE on noisy and incomplete medical imaging scenarios and show that it achieves strong restoration quality while better preserving clinically relevant structures and reducing the risk of implausible reconstructions and show that it achieves strong restoration quality while better preserving clinically relevant structures and reducing the risk of implausible reconstructions. The proposed approach offers a practical step toward safer, more controllable, and more deployment-ready medical image restoration.
Figures & tables
Fig. 1 : Overview of CARE. The degraded input is processed by a fidelity branch and a prior branch, and a risk-aware adaptive controller dynamically balances the two branches to generate the final restored image.
Method
PSNR ↑
SSIM ↑
LDCT Input
29.2454
0.8732
REDCNN
32.3221
0.9103
EDCNN
32.9791
0.9037
QAE
29.2291
0.8759
OCTNet
32.7813
0.9082
U-Net
33.0712
0.9221
TABLE I : Published CT denoising baselines on the AAPM dataset (Train: AAPM / Test: AAPM) reported by Zhao et al. .
Method
4X SSIM ↑
8X SSIM ↑
AIRS Medical
0.964
0.952
ATB (Joint-ICNet)
0.960
0.944
Neurospin (XPDNet)
0.959
0.942
CARE
0.964
0.955
TABLE II : Published fastMRI brain challenge results (average SSIM) for the main 4X and 8X tracks.
Fig. 2 : Qualitative restoration example showing the degraded input and the output of CARE.
Method
Noise Suppression ↑
Artifact Reduction ↑
Contrast Retention ↑
LDCT Input
1.61
1.52
1.63
BM3D
2.88
2.21
2.18
RED
2.74
3.10
3.03
WGAN-GP
3.38
3.56
3.35
DR-GAN
3.26
3.49
3.46
CARE
3.32
3.68
3.61
TABLE III : Published LDCT reader-study results on the Challenge real-data set, adapted from Xia et al. . Values are the mean of the two reported radiologists; higher is better.
Setting
PSNR ↑
Structure Score ↑
Hallucination Risk ↓
Conservative Mode
33.21
0.931
0.08
Balanced Mode
33.62
0.938
0.11
Enhancement Mode
33.47
0.936
0.17
Without Adaptive Controller
33.05
0.928
0.21
Without Fidelity Branch
32.74
0.919
0.29
Without Prior Branch
32.88
0.924
0.13
TABLE IV : Ablation study of controllability and component contribution.
Department of Computer Science Shanghai Jiao Tong University Shanghai, China · Department of Architecture and Design Harbin Institute of Technology Heilongjiang, China