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Updated: Jun 19, 2026
Blood Flow Imaging with Ultrafast Doppler
Published on: October 14, 2020
3D noncontrast MR angiography of the distal lower extremities using flow-sensitive dephasing (FSD)-prepared balanced
Zhaoyang Fan1, John Sheehan, Xiaoming Bi
1Department of Radiology, Northwestern University, Chicago, Illinois, USA.
Abstract:
While three-dimensional contrast-enhanced MR angiography (MRA) is becoming the method of choice for clinical peripheral arterial disease (PAD) examinations, safety concerns with contrast administration in patients with renal insufficiency have triggered a renaissance of noncontrast MRA. In this work, a noncontrast-MRA technique using electrocardiography-triggered three-dimensional segmented balanced steady-state free precession with flow-sensitive dephasing (FSD) magnetization preparation was developed and tested in the distal lower extremities. FSD preparation was used to induce arterial flow voids at systolic cardiac phase while having little effect on venous blood and static tissues. High-spatial-resolution MRA was obtained by means of magnitude subtraction between a dark-artery scan with FSD preparation at systole and a bright-artery scan without FSD preparation at mid-diastole. In nine healthy volunteers, FSD parameters, including the gradient waveform and the first-order gradient moment, were optimized for excellent MRA image quality. Furthermore, arterial stenosis and occlusion in two peripheral arterial disease patients were identified using the noncontrast-MRA technique, as confirmed by contrast-enhanced MRA. In conclusion, FSD-prepared balanced steady-state free precession in conjunction with electrocardiography gating and image subtraction provides a promising noncontrast-MRA strategy for the distal lower extremities.
Insights
A new noncontrast MR angiography (MRA) technique uses flow-sensitive dephasing (FSD) to visualize lower extremity arteries without contrast agents. This method is a promising alternative for patients with kidney issues, offering clear imaging of peripheral arterial disease.
Area of Science:
- Medical Imaging
- Cardiovascular Imaging
- Magnetic Resonance Imaging
Background:
- Contrast-enhanced MR angiography (MRA) is standard for peripheral arterial disease (PAD).
- Renal insufficiency raises safety concerns regarding contrast agents.
- This necessitates the development of noncontrast MRA techniques.
Purpose of the Study:
- To develop and evaluate a novel noncontrast MRA technique for the distal lower extremities.
- To assess the efficacy of flow-sensitive dephasing (FSD) preparation for arterial signal void.
- To provide a safe imaging alternative for PAD patients with renal insufficiency.
Main Methods:
- Electrocardiography-triggered, 3D segmented balanced steady-state free precession (bSSFP) with FSD preparation.
- FSD magnetization preparation to induce arterial flow voids during systole.
- Magnitude image subtraction between dark-artery (systole, FSD) and bright-artery (diastole, no FSD) scans.
Main Results:
- Optimized FSD parameters achieved excellent MRA image quality in healthy volunteers.
- The technique successfully identified arterial stenosis and occlusion in PAD patients.
- Noncontrast MRA findings were confirmed by contrast-enhanced MRA.
Conclusions:
- FSD-prepared bSSFP MRA with ECG gating and subtraction is a viable noncontrast imaging strategy.
- This technique offers a promising alternative for distal lower extremity MRA in patients with renal insufficiency.
- Further validation may establish this as a clinical standard for PAD assessment.
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