高分辨率磁共振成像(MRI)可以增强病变诊断,预后,和划界。然而,梯度功率和硬件限制禁止记录薄片或sub-1mm分辨率。此外,长扫描时间在临床上是不可接受的。使用统计或分析方法生成的常规高分辨率图像包括捕获复杂,具有复杂图案和结构的高维图像数据。本研究旨在利用尖端的扩散概率深度学习技术来创建一个从低分辨率对应对象生成高分辨率MRI的框架。通过最小化不可预测性和不确定性来改进去噪扩散概率模型(DDPM)。DDPM包括两个进程。正向过程采用马尔可夫链将高斯噪声系统地引入低分辨率MRI图像。在相反的过程中,训练U-Net模型以对前向过程图像进行去噪,并根据其低分辨率对应物的特征生成高分辨率图像。使用在脑肿瘤分割挑战2020(BraTS2020)中收集的来自机构前列腺患者和脑部患者的T2加权MRI图像证明了所提出的框架。对于前列腺数据集,双三次插值模型(双三次),条件生成对抗网络(CGAN),我们提出的DDPM框架将低分辨率图像的噪声质量度量提高了4.4%,5.7%,12.8%,分别。我们的方法将信噪比提高了11.7%,超过Bicubic(9.8%)和CGAN(8.1%)。在BraTS2020数据集中,拟议的框架和Bicubic将分辨率降低的图像的PSNR提高了9.1%和5.8%。方法的多尺度结构相似性指数分别为0.970±0.019,0.968±0.022,0.967±0.023,CGAN,还有Bicubic,分别。本研究探索了一种基于深度学习的扩散概率框架,用于提高MR图像分辨率。这样的框架可以用于通过获得高分辨率图像来改善临床工作流程,而不损失长扫描时间。未来的研究可能会集中在前瞻性地测试该框架在不同临床适应症下的有效性。
Objective. High-resolution magnetic resonance imaging (MRI) can enhance lesion diagnosis, prognosis, and delineation. However, gradient power and hardware limitations prohibit recording thin slices or sub-1 mm resolution. Furthermore, long scan time is not clinically acceptable. Conventional high-resolution images generated using statistical or analytical methods include the limitation of capturing complex, high-dimensional image data with intricate patterns and structures. This study aims to harness cutting-edge diffusion probabilistic deep learning techniques to create a framework for generating high-resolution MRI from low-resolution counterparts, improving the uncertainty of denoising diffusion probabilistic models (DDPM).Approach. DDPM includes two processes. The forward process employs a Markov chain to systematically introduce Gaussian noise to low-resolution MRI images. In the reverse process, a U-Net model is trained to denoise the forward process images and produce high-resolution images conditioned on the features of their low-resolution counterparts. The proposed framework was demonstrated using T2-weighted MRI images from institutional prostate patients and brain patients collected in the Brain Tumor Segmentation Challenge 2020 (BraTS2020).Main results. For the prostate dataset, the bicubic interpolation model (Bicubic), conditional generative-adversarial network (CGAN), and our proposed DDPM framework improved the noise quality measure from low-resolution images by 4.4%, 5.7%, and 12.8%, respectively. Our method enhanced the signal-to-noise ratios by 11.7%, surpassing Bicubic (9.8%) and CGAN (8.1%). In the BraTS2020 dataset, the proposed framework and Bicubic enhanced peak signal-to-noise ratio from resolution-degraded images by 9.1% and 5.8%. The multi-scale structural similarity indexes were 0.970 ± 0.019, 0.968 ± 0.022, and 0.967 ± 0.023 for the proposed method, CGAN, and Bicubic, respectively.Significance. This study explores a deep learning-based diffusion probabilistic framework for improving MR image resolution. Such a framework can be used to improve clinical workflow by obtaining high-resolution images without penalty of the long scan time. Future investigation will likely focus on prospectively testing the efficacy of this framework with different clinical indications.