title: Four-phase single-capillary stepwise model for kinetics in arterial spin labeling MRI.
abstract: An extended model for extracting measures of brain perfusion from pulsed arterial spin labeling (ASL) data while considering transit effects and restricted permeability of capillaries to blood water is proposed. We divided the time course of the signal difference between control and labeled images into four phases with respect to the arrival time of labeled blood water at the voxel of interest (t(A)), transit time through the arteries in the voxel (t(ex)), and duration of the bolus of labeled spins (tau). Dividing the labeled slab of blood water into many discrete segments, and adapting numerical integration methods allowed us to conveniently model restricted capillary-tissue exchange based on a modified distributed parameter model. We compared this four-phase single-capillary stepwise (FPSCS) model with models that treat water as a freely diffusible tracer, using both simulations and experimental ASL brain imaging data at 1.5T from eight healthy subjects (24-80 years old). The FPSCS model yielded less errors in the least-squares sense in fitting brain ASL data in comparison with freely diffusible tracer models of water (P = 0.055). These results imply that restricted permeability of capillaries to water should be considered when brain ASL data are analyzed.
authors.affiliation: Department of Radiology, University of California-San Francisco, and VA Medical Center 114M, 4150 Clement Street, San Francisco, CA 94121, USA.
authors.forename: Ka-loh
authors.initials: KL
authors.lastname: Li
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Zhu
authors.forename: Nola
authors.initials: N
authors.lastname: Hylton
authors.forename: Geon-Ho
authors.initials: GH
authors.lastname: Jahng
authors.forename: Michael W
authors.initials: MW
authors.lastname: Weiner
authors.forename: Norbert
authors.initials: N
authors.lastname: Schuff
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D002199:Capillary Permeability / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004578:Electron Spin Resonance Spectroscopy; D006801:Humans; D007700:Kinetics; D016018:Least-Squares Analysis; D016014:Linear Models; D008875:Middle Aged; D008955:Models, Cardiovascular; D018709:Statistics, Nonparametric
references.citation: Circulation. 1985 Nov;72(5 Pt 2):IV63-8
references.pmid: 4053329
references.citation: Magn Reson Med. 1992 Jan;23(1):37-45
references.pmid: 1734182
references.citation: Proc Natl Acad Sci U S A. 1994 Jan 4;91(1):33-7
references.pmid: 8278387
references.citation: Magn Reson Med. 1995 Sep;34(3):293-301
references.pmid: 7500865
references.citation: Magn Reson Med. 1995 Dec;34(6):878-87
references.pmid: 8598815
references.citation: NMR Biomed. 1996 Apr;9(2):79-83
references.pmid: 8887372
references.citation: J Cereb Blood Flow Metab. 1996 Nov;16(6):1236-49
references.pmid: 8898697
references.citation: Ann N Y Acad Sci. 1997 Sep 26;826:263-71
references.pmid: 9329698
references.citation: NMR Biomed. 1997 Jun-Aug;10(4-5):191-6
references.pmid: 9430347
references.citation: Circ Res. 1974 Sep;35(3):483-503
references.pmid: 4608628
references.citation: J Clin Invest. 1973 May;52(5):991-1009
references.pmid: 4573356
references.citation: Magn Reson Med. 2003 Feb;49(2):307-14
references.pmid: 12541251
references.citation: Magn Reson Med. 2002 Jul;48(1):27-41
references.pmid: 12111929
references.citation: Magn Reson Med. 1998 Sep;40(3):383-96
references.pmid: 9727941
references.citation: Magn Reson Med. 1999 Apr;41(4):829-40
references.pmid: 10332861
references.citation: Magn Reson Med. 1999 Jun;41(6):1246-54
references.pmid: 10371458
references.citation: Eur J Radiol. 1999 May;30(2):115-24
references.pmid: 10401592
references.citation: J Appl Physiol. 1954 Jun;6(12):731-44
references.pmid: 13174454
references.citation: Neuroimage. 2002 Mar;15(3):488-500
references.pmid: 11848692
references.citation: Magn Reson Med. 1999 Nov;42(5):890-4
references.pmid: 10542347
references.citation: Br J Radiol. 2000 May;73(869):470-81
references.pmid: 10884742
references.citation: NMR Biomed. 1997 Jun-Aug;10(4-5):237-49
references.pmid: 9430354
references.citation: Prog Neurobiol. 2001 Aug;64(6):575-611
references.pmid: 11311463
references.citation: J Cereb Blood Flow Metab. 2001 Apr;21(4):440-55
references.pmid: 11323530
references.citation: Magn Reson Med. 2001 Jun;45(6):1021-9
references.pmid: 11378880
references.citation: Magn Reson Med. 2001 Sep;46(3):465-75
references.pmid: 11550237
references.citation: Magn Reson Med. 2000 Sep;44(3):440-9
references.pmid: 10975897