Acceleration of ASL-based time-resolved MR angiography by acquisition of control and labeled images in the same shot (ACTRESS).
OBJECTIVE
Noncontrast 4D-MR-angiography (MRA) using arterial spin labeling (ASL) is beneficial because high spatial and temporal resolution can be achieved. However, ASL requires acquisition of labeled and control images for each phase. The purpose of this study is to present a new accelerated 4D-MRA approach that requires only a single control acquisition, achieving similar image quality in approximately half the scan time.


METHODS
In a multi-phase Look-Locker sequence, the first phase was used as the control image and the labeling pulse was applied before the second phase. By acquiring the control and labeled images within a single Look-Locker cycle, 4D-MRA was generated in nearly half the scan time of conventional ASL. However, this approach potentially could be more sensitive to off-resonance and magnetization transfer (MT) effects. To counter this, careful optimizations of the labeling pulse were performed by Bloch simulations. In in-vivo studies arterial visualization was compared between the new and conventional ASL approaches.


RESULTS
Optimization of the labeling pulse successfully minimized off-resonance effects. Qualitative assessment showed that residual MT effects did not degrade visualization of the peripheral arteries.


CONCLUSIONS
This study demonstrated that the proposed approach achieved similar image quality as conventional ASL-MRA approaches in just over half the scan time. Magn Reson Med 79:224-233, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.|Philips Electronics Japan, Ltd., Healthcare, Tokyo, Japan.
Yuriko
http://orcid.org/0000-0002-4851-7872
Y
Suzuki
Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Hokkaido, Japan.
Noriyuki
N
Fujima
Philips Electronics Japan, Ltd., Healthcare, Tokyo, Japan.
Tetsuo
T
Ogino
Diagnostic Image Analysis Group, Radboud University Medical Center, Nijmegen, The Netherlands.
James Alastair
JA
Meakin
Philips Electronics Japan, Ltd., Healthcare, Tokyo, Japan.
Akira
A
Suwa
Faculty of Health Sciences, Hokkaido University, Hokkaido, Japan.
Hiroyuki
H
Sugimori
Philips Healthcare, Asia Pacific, Tokyo, Japan.
Marc
M
Van Cauteren
C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.
Matthias J P
MJP
van Osch
D000054:Acceleration; D000328:Adult; D000792:Angiography / Q000379:methods*; D015901:Angiography, Digital Subtraction; D001158:Arteries; D003198:Computer Simulation; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011846:Radio Waves; D013113:Spin Labels; D013997:Time Factors; D055815:Young Adult
D013113:Spin Labels
FOCI pulse; Time-resolved MR angiography (MRA); arterial spin labeling (ASL); hyperbolic secant (HS) pulse; noncontrast 4D-MRA