Time-of-flight MR angiography (TOF-MRA) is a non-contrast-enhanced imaging technique widely used to visualize intracranial vasculature. In this study, we investigated the use of ultra-thin slice (up to 0.4 mm) to improve the delineation of the cerebral arteries in TOF-MRA. To reduce the noise while preserving the image quality, Compressed SENSE AI (CS-AI) reconstruction was used. Our results showed that the improved noise reduction by CS-AI enabled better visualization of vessels, especially on the thinner slices compared to conventional Compressed-SENSE. The usefulness of CS-AI was also demonstrated in clinical cases with moyamoya disease and suspected aneurysm patients.