This in-vivo study aimed to investigate the relationship between thrombus characteristics and the aneurysm wall (AW) in partially thrombosed intracranial aneurysms (pTIAs) using MPRAGE at 7T MRI. The AWs with the highest signal intensity ratio of thrombus were significantly thicker. In the histopathological examinations, three cases with hypointensity of the thrombus showed only a few macrophages in the thrombus and a thin AW. Three cases with hyperintensity of the thrombus in the MPRAGE showed abundant macrophages in the thrombus. In 7T MPRAGE, the signal intensity ratio of thrombus in pTIAs correlates with AW thickness and histologic features indicating wall instability.