Inversion-prepared pulse sequences can be used for noncontrast MR angiography (MRA) but suffer from long scan times when acquired using conventional nonaccelerated techniques. This work proposes a subtraction-based spin-labeling, three-dimensional fast inversion recovery MRA (FIR-MRA) method for imaging the intracranial arteries. FIR-MRA uses alternating cycles of nonselective and slab-selective inversions, leading to dark-blood and bright-blood images, respectively. The signal difference between these images eliminates static background tissue and generates the angiogram. To reduce scan time, segmented fast gradient recalled echo readout and parallel imaging are applied. The inversion recovery with embedded self-calibration method used allows for parallel acceleration at factors of 2 and above. An off-resonance selective inversion provides effective venous suppression, with no detriment to the depiction of arteries. FIR-MRA was compared against conventional three-dimensional time-of-flight angiography at 3 T in eight normal subjects. Results showed that FIR-MRA had superior vessel conspicuity in the distal vessels (P < 0.05), and equal or better vessel continuity and venous suppression. However, FIR-MRA had inferior vessel sharpness (P < 0.05) in four of nine vessel groups. The clinical utility of FIR-MRA was demonstrated in three MRA patients.
- Inversion recovery
- Magnetic resonance angiography
- Non-contrast-enhanced angiography
- Parallel imaging
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging