Dual echo vessel-encoded ASL for simultaneous BOLD and CBF reactivity assessment in patients with ischemic cerebrovascular disease.
OBJECTIVE
Blood oxygenation level-dependent (BOLD)-weighted and vessel-encoded arterial spin labeling (VE-ASL) MRI provide complementary information and can be used in sequence to gauge hemodynamic contributions to cerebrovascular reactivity. Here, cerebrovascular reactivity is assessed using dual echo VE-ASL MRI to understand how VE labeling preparations influence BOLD and ASL contrast in flow-limited and healthy perfusion territories.


METHODS
Patients (n = 12; age = 55 +/- 14 years; 6F/6M) presenting with ischemic steno-occlusive cerebrovascular disease underwent 3.0T angiographic imaging, T1 -weighted structural, and planning-free dual echo hypercarbic hyperoxic (i.e., carbogen) VE-ASL MRI. Vasculopathy extent, timecourses, and cerebrovascular reactivity (signal change and Z-statistic) for different VE-ASL images were contrasted across flow territories and Bonferroni-corrected P-values reported.


RESULTS
BOLD cerebrovascular reactivity (i.e., long-TE VE-ASL) Z-statistics were similarly sensitive to asymmetric disease (P ≤ 0.002) regardless of labeling scenario. Cerebral blood flow reactivity correlated significantly with BOLD reactivity (Z-statistic). However, BOLD signal changes did not differ significantly between labeling scenarios (P > 0.003) or across territories (P > 0.002), indicating BOLD signal changes in response to carbogen offer low sensitivity to lateralizing disease.


CONCLUSIONS
Dual echo VE-ASL can provide simultaneous cerebral blood flow and qualitative BOLD contrast consistent with lateralizing disease severity in patients with asymmetric steno-occlusive disease. The methodological strengths and limitations of composite BOLD and VE-ASL measurements in the clinic are discussed.
Department of Radiology and Radiological Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
Carlos C
CC
Faraco
Megan K
MK
Strother
Lindsey M
LM
Dethrage
Lori
L
Jordan
Robert
R
Singer
Paul F
PF
Clemmons
Manus J
MJ
Donahue
D000465:Algorithms; D001783:Blood Flow Velocity / Q000502:physiology*; D002545:Brain Ischemia / Q000503:physiopathology*; D002536:Cerebral Arteries / Q000502:physiology; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D010100:Oxygen
arterial spin labeling; blood oxygenation level dependent; cerebrovascular reactivity; hemodynamics; stroke; vessel-encoded arterial spin labeling