@article {L{\"o}vblad1231, author = {K.-O. L{\"o}vblad and M.-L. Montandon and M. Viallon and C. Rodriguez and S. Toma and X. Golay and P. Giannakopoulos and S. Haller}, title = {Arterial Spin-Labeling Parameters Influence Signal Variability and Estimated Regional Relative Cerebral Blood Flow in Normal Aging and Mild Cognitive Impairment: FAIR versus PICORE Techniques}, volume = {36}, number = {7}, pages = {1231--1236}, year = {2015}, doi = {10.3174/ajnr.A4291}, publisher = {American Journal of Neuroradiology}, abstract = {BACKGROUND AND PURPOSE: Arterial spin-labeling is a noninvasive method to map cerebral blood flow, which might be useful for early diagnosis of neurodegenerative diseases. We directly compared 2 arterial spin-labeling techniques in healthy elderly controls and individuals with mild cognitive impairment.MATERIALS AND METHODS: This prospective study was approved by the local ethics committee and included 198 consecutive healthy controls (mean age, 73.65 {\textpm} 4.02 years) and 43 subjects with mild cognitive impairment (mean age, 73.38 {\textpm} 5.85 years). Two pulsed arterial spin-labeling sequences were performed at 3T: proximal inversion with a control for off-resonance effects (PICORE) and flow-sensitive alternating inversion recovery technique (FAIR). Relative cerebral blood flow maps were calculated by using commercial software and standard parameters. Data analysis included spatial normalization of gray matter{\textendash}corrected relative CBF maps, whole-brain average, and voxelwise comparison of both arterial spin-labeling sequences.RESULTS: Overall, FAIR yielded higher relative CBF values compared with PICORE (controls, 32.7 {\textpm} 7.1 versus 30.0 {\textpm} 13.1 mL/min/100 g, P = .05; mild cognitive impairment, 29.8 {\textpm} 5.4 versus 26.2 {\textpm} 8.6 mL/min/100 g, P \< .05; all, 32.2 {\textpm} 6.8 versus 29.3 {\textpm} 12.3 mL/min/100 g, P \< .05). FAIR had lower variability (controls, 36.2\% versus 68.8\%, P \< .00001; mild cognitive impairment, 18.9\% versus 22.9\%, P \< .0001; all, 34.4\% versus 64.9\% P \< .00001). The detailed voxelwise analysis revealed a higher signal for FAIR, notably in both convexities, while PICORE had higher signal predominantly in deep cerebral regions.CONCLUSIONS: Overall, FAIR had higher estimated relative CBF and lower interindividual variability than PICORE. In more detail, there were regional differences between both arterial spin-labeling sequences. In summary, these results highlight the need to calibrate arterial spin-labeling sequences.ASLarterial spin-labelingFAIRflow-sensitive alternating inversion recovery techniqueMCImild cognitive impairmentPICOREproximal inversion with a control for off-resonance effectsrCBFrelative cerebral blood flow}, issn = {0195-6108}, URL = {https://www.ajnr.org/content/36/7/1231}, eprint = {https://www.ajnr.org/content/36/7/1231.full.pdf}, journal = {American Journal of Neuroradiology} }