title: Measurement of vascular water transport in human subjects using time-resolved pulsed arterial spin labelling.
abstract: Most approaches to arterial spin labelling (ASL) data analysis aim to provide a quantitative measure of the cerebral blood flow (CBF). This study, however, focuses on the measurement of the transfer time of blood water through the capillaries to the parenchyma (referred to as the capillary transfer time, CTT) as an alternative parameter to characterise the haemodynamics of the system. The method employed is based on a non-compartmental model, and no measurements need to be added to a common time-resolved ASL experiment. Brownian motion of labelled spins in a potential was described by a one-dimensional general Langevin equation as the starting point, and as a Fokker-Planck differential equation for the averaged distribution of labelled spins at the end point, which takes into account the effects of flow and dispersion of labelled water by the pseudorandom nature of the microvasculature and the transcapillary permeability. Multi-inversion time (multi-TI) ASL data were acquired in 14 healthy subjects on two occasions in a test-retest design, using a pulsed ASL sequence and three-dimensional gradient and spin echo (3D-GRASE) readout. Based on an error analysis to predict the size of a region of interest (ROI) required to obtain reasonably precise parameter estimates, data were analysed in two relatively large ROIs, i.e. the occipital lobe (OC) and the insular cortex (IC). The average values of CTT in OC were 260 ± 60 ms in the first experiment and 270 ± 60 ms in the second experiment. The corresponding IC values were 460 ± 130 ms and 420 ± 139 ms, respectively. Information related to the water transfer time may be important for diagnostics and follow-up of cerebral conditions or diseases characterised by a disrupted blood-brain barrier or disturbed capillary blood flow.
authors.affiliation: Department of Medical Radiation Physics, Lund University, Lund, Sweden.
authors.forename: Adnan
authors.initials: A
authors.lastname: Bibic
authors.affiliation: Department of Medical Radiation Physics, Lund University, Lund, Sweden.
authors.forename: Linda
authors.initials: L
authors.lastname: Knutsson
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, Helsingborg Hospital, Helsingborg, Sweden.|Department of Anaesthesiology and Intensive Care Medicine, Lund University, Skåne University Hospital, Malmö, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Schmidt
authors.affiliation: Centre for Mathematical Sciences, Lund University, Lund, Sweden.
authors.forename: Erik
authors.initials: E
authors.lastname: Henningsson
authors.affiliation: Department of Medical Radiation Physics, Lund University, Skåne University Hospital, Malmö, Sweden.
authors.forename: Sven
authors.initials: S
authors.lastname: Månsson
authors.affiliation: Department of Radiology, Lund University, Skåne University Hospital, Malmö, Sweden.
authors.forename: Kasim
authors.initials: K
authors.lastname: Abul-Kasim
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, Lund University, Skåne University Hospital, Malmö, Sweden.
authors.forename: Jonas
authors.initials: J
authors.lastname: Åkeson
authors.affiliation: Frauenhofer MEVIS, Bremen, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Gunther
authors.affiliation: Department of Medical Radiation Physics, Lund University, Lund, Sweden.|Lund University Bioimaging Centre, Lund University, Lund, Sweden.|Department of Diagnostic Radiology, Lund University, Lund, Sweden.
authors.forename: Freddy
authors.initials: F
authors.lastname: Ståhlberg
authors.affiliation: Department of Medical Radiation Physics, Lund University, Lund, Sweden.
authors.forename: Ronnie
authors.initials: R
authors.lastname: Wirestam
mesh_terms: D000328:Adult; D001693:Biological Transport, Active / Q000502:physiology; D001834:Body Water / Q000378:metabolism*; D002196:Capillaries / Q000502:physiology*; D002199:Capillary Permeability / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003198:Computer Simulation; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008955:Models, Cardiovascular; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013113:Spin Labels
chemical_list: D013113:Spin Labels
keywords: Langevin modelling; arterial spin labelling; blood-brain barrier; capillary transfer time; microvasculature