A quantitative 2D time-of-flight (qTOF) MR angiography technique for measuring single-vessel blood flow and diameter

Motivation: To address the gap in MRI techniques for assessing cerebral small vessels with slow flow non-invasively. Goal(s): To develop a quantitative 2D time-of-flight (qTOF) technique for measuring blood velocity and the size of cerebral small vessels. Approach: We developed an analytic qTOF framework to generate realistic TOF model images, which are optimized to match the acquired TOF images for extracting blood velocity and vessel size. Results: The proposed qTOF framework was validated in simulation and phantom studies, and demonstrated in vivo. Incorporating a second acquisition improved blood velocity and vessel size estimation. Flow velocities were comparable to those measured by phase-contrast MRI. Impact: A quantitative Time-of-Flight technique was developed to provide insights into blood flow and the size of cerebral small vessels, and dynamically in response to changing brain activity, helping to elucidate the role of cerebral small vessels in healthy brain function.