Enhanced-Quality Gan (EQ-GAN) on Lung CT Scans: Toward Truth and Potential Hallucinations

Lung Computed Tomography (CT) scans are extensively used to screen lung diseases. Strategies such as large slice spacing and low-dose CT scans are often preferred to reduce radiation exposure and therefore the risk for patients' health. The counterpart is a significant degradation of image quality and/or resolution. In this work we investigate a generative adversarial network (GAN) for lung CT image enhanced-quality (EQ). Our EQ-GAN is trained on a high-quality lung CT cohort to recover the visual quality of scans degraded by blur and noise. The capability of our trained GAN to generate EQ CT scans is further illustrated on two test cohorts. Results confirm gains in visual quality metrics, remarkable visual enhancement of vessels, airways and lung parenchyma, as well as other enhancement patterns that require further investigation. We also compared automatic lung lobe segmentation on original versus EQ scans. Average Dice scores vary between lobes, can be as low as 0.3 and EQ scans enable segmentation of some lobes missed in the original scans. This paves the way to using EQ as pre-processing for lung lobe segmentation, further research to evaluate the impact of EQ to add robustness to airway and vessel segmentation, and to investigate anatomical details revealed in EQ scans.