title: The QUASAR reproducibility study, Part II: Results from a multi-center Arterial Spin Labeling test-retest study.
abstract: Arterial Spin Labeling (ASL) is a method to measure perfusion using magnetically labeled blood water as an endogenous tracer. Being fully non-invasive, this technique is attractive for longitudinal studies of cerebral blood flow in healthy and diseased individuals, or as a surrogate marker of metabolism. So far, ASL has been restricted mostly to specialist centers due to a generally low SNR of the method and potential issues with user-dependent analysis needed to obtain quantitative measurement of cerebral blood flow (CBF). Here, we evaluated a particular implementation of ASL (called Quantitative STAR labeling of Arterial Regions or QUASAR), a method providing user independent quantification of CBF in a large test-retest study across sites from around the world, dubbed "The QUASAR reproducibility study". Altogether, 28 sites located in Asia, Europe and North America participated and a total of 284 healthy volunteers were scanned. Minimal operator dependence was assured by using an automatic planning tool and its accuracy and potential usefulness in multi-center trials was evaluated as well. Accurate repositioning between sessions was achieved with the automatic planning tool showing mean displacements of 1.87+/-0.95 mm and rotations of 1.56+/-0.66 degrees . Mean gray matter CBF was 47.4+/-7.5 [ml/100 g/min] with a between-subject standard variation SD(b)=5.5 [ml/100 g/min] and a within-subject standard deviation SD(w)=4.7 [ml/100 g/min]. The corresponding repeatability was 13.0 [ml/100 g/min] and was found to be within the range of previous studies.
authors: Center of Functionally Integrative Neuroscience, Aarhus University Hospital, Nørrebrogade 44, Aarhus C, Denmark. esben.thade.petersen@gmail.com
authors: Esben Thade
authors: ET
authors: Petersen
authors: Kim
authors: K
authors: Mouridsen
authors: Xavier
authors: X
authors: Golay
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001810:Blood Volume / Q000502:physiology; D001931:Brain Mapping; D002536:Cerebral Arteries / Q000033:anatomy & histology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012984:Software; D013113:Spin Labels; D055815:Young Adult
chemical_list: D013113:Spin Labels