Unpaired MR-CT brain dataset for unsupervised image translation.

The data presented in this article deals with the problem of brain tumor image translation across different modalities. The provided dataset represents unpaired brain magnetic resonance (MR) and computed tomography (CT) image data volumes of 20 patients. This includes 179 two-dimensional (2D) axial MR and CT images. The MR cases are acquired using Siemens Verio scanner, while the CT images with a Siemens Somatom scanner. The MR and CT tumor volumes were collected, diagnosed and annotated by experienced radiologists specialized in oncology and radiotherapy. The collected image volumes can be useful for researchers working in the field of artificial intelligence (AI) applications for brain tumor detection, classification and segmentation in MR and CT modalities. The provided tumor masks per each tumor volume can assist data scientists with limited background in cancer imaging. Moreover, clinical interpretation is given per each tumor volume, which can assist in deep learning model training with multiple source data (non-imaging or textual data) as well. The provided dataset can facilitate for annotation-efficient lesion segmentation using bidirectional MR-CT cross-modality image translation.

Paired-unpaired Unsupervised Attention Guided GAN with transfer learning for bidirectional brain MR-CT synthesis.

Medical image acquisition plays a significant role in the diagnosis and management of diseases. Magnetic Resonance (MR) and Computed Tomography (CT) are considered two of the most popular modalities for medical image acquisition. Some considerations, such as cost and radiation dose, may limit the acquisition of certain image modalities. Therefore, medical image synthesis can be used to generate required medical images without actual acquisition. In this paper, we propose a paired-unpaired Unsupervised Attention Guided Generative Adversarial Network (uagGAN) model to translate MR images to CT images and vice versa. The uagGAN model is pre-trained with a paired dataset for initialization and then retrained on an unpaired dataset using a cascading process. In the paired pre-training stage, we enhance the loss function of our model by combining the Wasserstein GAN adversarial loss function with a new combination of non-adversarial losses (content loss and L1) to generate fine structure images. This will ensure global consistency, and better capture of the high and low frequency details of the generated images. The uagGAN model is employed as it generates more accurate and sharper images through the production of attention masks. Knowledge from a non-medical pre-trained model is also transferred to the uagGAN model for improved learning and better image translation performance. Quantitative evaluation and qualitative perceptual analysis by radiologists indicate that employing transfer learning with the proposed paired-unpaired uagGAN model can achieve better performance as compared to other rival image-to-image translation models.