The carotid artery atherosclerotic disease is one of the most common causes of ischemic stroke. Post-contrast plaque enhancement (PPE), which may result from endothelial dysfunction or be secondary to intraplaque inflammation, is a vulnerable plaque feature that correlates with increased stroke risk independent of stenosis. Although PPE can be detected with vessel wall MRI, better quantitative methods to measure PPE are needed. This work presents a new 3D high resolution dynamic T1 mapping technique for accurate T1 quantification of contrast uptake within vulnerable carotid atherosclerotic plaque. The proposed method may provide important mechanistic implications for the pathophysiology of PPE.