Non‐contrast‐enhanced vascular magnetic resonance imaging using flow‐dependent preparation with subtraction

Abstract

Recent concerns over contrast agent safety have encouraged new developments in non-contrast-enhanced vascular imaging techniques. This work investigates the potential for imaging both arteries and veins with vascular anatomy by nonenhanced static subtraction angiography (VANESSA), a method using controllable flow suppression together with subtraction of bright-and dark-blood images. The lower legs of eight healthy volunteers and three patients were imaged using a modified motion-sensitized driven equilibrium preparation, with three-dimensional balanced steady-state free precession readout. The vascular signal decreased with increasing motion-suppression gradient amplitude, and was suppressed when the velocity-encoding parameter was (approximately) less than the measured flow velocity. Selected pairs of images were subtracted to depict vessels with either fast flow (e.g. arteries), slow flow (e.g. veins), or both. Several methodological modifications improved image quality and reduced the background signal from static tissues. Subjectively assessed image quality in volunteers was rated as excellent for 56/64 arterial segments, and good or excellent for 35/64 veins. In conclusion, VANESSA enables rapid noncontrast-enhanced imaging of arteries and veins, combining information on both morphology and flow. This study demonstrates good technical performance in volunteers and evaluation in patients with vascular disease is warranted. Magn Reson Med 67:628-637,

Non‐contrast enhanced MR angiography: Physical principles

“…The FSD technique has been applied to peripheral arteries using a single module with flow-dephasing in the craniocaudal direction (68,69,71). The total acquisition time for a 40-cm coverage is 3-4 minutes, similar to cardiac-gated 3D FSE NCE-MRA.…”

Endoleak detection after endovascular aneurysm repair using unenhanced MRI with flow suppression technique: Feasibility study in comparison with contrast-enhanced CT

“…Similar to contrast-enhanced CT, MSDE-prepared BTFE sequences can demonstrate endoleaks of any flow speed, by using a low VENC of 5 cm/s [17], as well as those from any direction, by using MSGs along three axes [19]. In comparison with contrast-enhanced CT, the benefit of MSDEprepared BTFE sequences is self-evident; it is a truly noninvasive method, requiring no radiation exposure or contrastinjection.…”

“…MSDE is a novel preparation sequence using motion-sensitizing gradients (MSGs) along all three axes. These MSGs cause dephasing of the magnetization of moving protons, resulting in the suppression of signals from flowing blood, that is, 'flow suppression' [19]. Subtraction images reconstructed from these images, with and without flow suppression, are expected to demonstrate endoleaks as well as flowing blood in the stent grafts.…”

Comparison of computed tomographic angiography and noncontrast magnetic resonance angiography in preoperative evaluation of living renal donors

“…[13] Another NCE renal MRA technique - a nonsubtractive version of arterial spin labeling (ASL), slab-selective (SS) inversion recovery (IR) imaging - has become popular. [1415161718]…”