time-of-flight angiography
Non-contrast MRI technique that creates vascular images by exploiting the flow-related enhancement of moving blood relative to stationary tissue.
Full Definition
Time-of-flight (TOF) angiography is a non-invasive MRI technique that generates vascular images without contrast agents by utilizing the natural contrast between flowing blood and stationary tissues. The method relies on gradient-echo sequences with short repetition times that saturate stationary tissue while fresh, unsaturated blood flowing into the imaging slice maintains high signal intensity. TOF angiography is particularly effective for imaging arteries with rapid flow and is commonly used for evaluating the circle of Willis, detecting aneurysms, and assessing stenosis. The technique offers excellent visualization of cerebral vasculature without radiation or contrast exposure, making it ideal for screening and follow-up imaging in patients with contraindications to iodinated contrast.
Usage
Usage note: TOF-MRA is acceptable abbreviation; distinguish from contrast-enhanced MRA in protocols.
In Context
- "Time-of-flight angiography revealed a 3mm anterior communicating artery aneurysm without the need for contrast injection." — Vascular screening report
- "The follow-up imaging protocol included time-of-flight angiography to assess post-surgical vessel patency." — Post-operative monitoring