Pseudo-Computed Tomography generation from Noisy Magnetic Resonance ‎Imaging with Deep Learning Algorithm ‎

Magnetic Resonance Imaging (MRI) applications offer superior soft tissue contrast compared with computed tomography (CT) for accurate radiotherapy planning. Although, MRI images suffer from poor image quality and lack electron density for radiation dose calculation. The present study aims to use the deep learning (DL) approach to 1) enhance the quality of MRI images and 2) generate synthetic CT images using MRI images for more accurate radiotherapy planning.

In this paper, the pix2pix Generative Adversarial Network was utilized to synthesize CT images from noisy MRI images of 20 arbitrarily patients with brain disease. The standard statistical measurements investigated the accuracy comparison of the modeled Hounsfield unit (HU) value from MRI images and referenced CT of each patient. The famous quality metrics that were used to compare synthetic CTs and referenced CTs were the mean absolute error (MAE), the structural similarity index (SSIM), and peak signal-to-noise ratio (PSNR(.

The higher quality measurements between the synthetic pseudo-CT and the referenced CT images as PSNR, and SSIM, should correlate to the lower MAE value. For the overall brain among blind test data, the measured peak signal-to-noise ratio, mean absolute error, and structural similarity index values were about 16.5, 28.13, and 93.46, respectively.  

The proposed method provides an acceptable level of statistical measurements computed on the Pseudo-CT and referenced CT, and it could be concluded that the p-CT can be implemented in radiotherapy treatment planning with acceptable accuracy.