Sagittal fresh blood imaging with interleaved acquisition of systolic and diastolic data for improved robustness to motion

Abstract

Purpose To improve robustness to patient motion of ‘fresh blood imaging’ (FBI) for lower extremity non-contrast MRA. Methods In FBI, two sets of 3D fast spin echo images are acquired at different cardiac phases and subtracted to generate bright-blood angiograms. Routinely performed with a single coronal slab and sequential acquisition of systolic and diastolic data, FBI is prone to subtraction errors due to patient motion. In this preliminary feasibility study, FBI was implemented with two sagittal imaging slabs, and the systolic and diastolic acquisitions were interleaved to minimize sensitivity to motion. The proposed technique was evaluated in volunteers and patients. Results In ten volunteers, imaged while performing controlled movements, interleaved FBI demonstrated better tolerance to subject motion than sequential FBI. In one patient with peripheral arterial disease, interleaved FBI offered better depiction of collateral flow by reducing sensitivity to inadvertent motion. Conclusions FBI with interleaved acquisition of diastolic and systolic data in two sagittal imaging slabs offers improved tolerance to patient motion.

Comparison of Nonenhanced MR Angiographic Subtraction Techniques for Infragenual Arteries at 1.5 T: A Preliminary Study

“…Also, lower accuracy with high diastolic flow approached significance (P = .08). Our findings highlight the delicacy of appropriate constant-FA MR angiography refocusing-FA selection (17,19), which might benefit from a scout sequence similar to the m 1 Future work includes accelerating nonenhanced MR angiography with compressed sensing to exploit MR angiographic sparsity and other refinements, to address patient motion, and to tailor imaging to each leg (34,35). For implementation as a true nonenhanced MR angiographic protocol, complete threestation evaluation is planned.…”

Retrospective multi‐phase non‐contrast‐enhanced magnetic resonance angiography (ROMANCE MRA) for robust angiogram separation in the presence of cardiac arrhythmia

“…With large R‐R variations, background tissues experience different T 1 relaxation induced signal recovery between the systolic and diastolic data acquisitions, resulting in residual background artifacts after subtraction. Additionally, to secure sufficient arterial signal recovery ( T 1 relaxation time for blood at 3.0 T ∼ 1550 ms ) a single or double R‐R interval is to be used as an effective TR, which does not allow flexible selection of TR to balance signal‐to‐noise ratio with imaging efficiency. Particularly in a subject with a large variance of heart rates, an effective TR can be incidentally elongated when an R‐R interval is not long enough to accommodate a trigger delay and data acquisition, potentially increasing imaging time.…”

Highly accelerated subtractive femoral non‐contrast‐enhanced MRA using compressed sensing with k‐space subtraction, phase and intensity correction

“…For cardiac-gated 3D FSE, the signal intensity of some background tissues, such as muscle and fat, may appear slightly higher on the DB images. 12,21 Its representation in the image domain should become negative after subtraction. However, when using k-space-subtraction methods, the negative signal loses its polarity when taking the magnitude of the reconstructed image, and appears as background artifacts on the subtracted angiograms ( Figure 1A).…”

“…For cardiac‐gated 3D FSE, the signal intensity of some background tissues, such as muscle and fat, may appear slightly higher on the DB images 12,21 . Its representation in the image domain should become negative after subtraction.…”

“…Another problem with subtractive NCE‐MRA is that some background tissues have different intensity levels in BB and DB images, resulting in residual signal in the subtracted images 17‐21 . The reasons for this include different schemes applied in BB and DB acquisitions, 19 R‐R variations caused by the irregular heartbeats, 20 and the variation in TRs between consecutive readouts 21 .…”