title: A novel application of four-dimensional magnetic resonance angiography using an arterial spin labeling technique for noninvasive diagnosis of Moyamoya disease.
abstract: BACKGROUND
  Noncontrast-enhanced time-resolved four-dimensional magnetic resonance angiography using an arterial spin labeling technique (ASL-4D MRA) is emerging as a next generation angiography for the management of neurovascular diseases. This study evaluated the feasibility of ASL-4D MRA for the diagnosis of Moyamoya disease (MMD) and MMD staging by using digital subtraction angiography (DSA) and time-of-flight MRA (TOF MRA) as current standards.
  
  
  METHODS
  Eleven consecutive non-operated patients who underwent DSA for the diagnosis of MMD were recruited. Two independent observers evaluated the three tests. The data were analyzed for inter-observer and inter-modality agreements on MMD stage. Nine of 22 hemispheres underwent surgical revascularization and ASL-4D MRA was repeated postoperatively.
  
  
  RESULTS
  Time-resolved inflow of blood through the cerebral vessels, including moyamoya vessels, was visualized in all the 22 non-operated hemispheres. MMD stages assessed by DSA and ASL-4D MRA were completely matched in 18 hemispheres, with a significant positive correlation between these modalities (r=0.93, P<0.001). Inter-observer agreement with ASL-4D MRA (κ=0.91±0.04, P<0.001) and inter-modality agreement between ASL-4D MRA and DSA (κ=0.93±0.04, P<0.001) were both excellent. MMD stages assessed by ASL-4D MRA have also a significant positive correlation with those assessed by TOF MRA (r=0.68, P=0.004). Repeated ASL-4D MRA clearly demonstrated the bypassed arteries and changes in the dynamic flow patterns of cerebral arteries in all the nine hemispheres after surgical revascularization. Of these, postoperative focal hyperperfusion was detected by single photon emission tomography in 7 hemispheres. In five of the seven hemispheres (71%) with postoperative hyperperfusion, ASL-4D MRA demonstrated focal hyperintense signals in the bypassed arteries, although TOF MRA did not.
  
  
  CONCLUSIONS
  Noninvasive ASL-4D MRA is feasible for the diagnosis of MMD staging. This next generation angiography may be useful for monitoring disease evolution and treatment response in cerebral arteries after revascularization surgery in MMD.
authors.affiliation: Department of Neurosurgery, Hokkaido University Graduate School of Medicine, N15 W7, Kita-ku, Sapporo 060-8638, Japan.
authors.forename: Haruto
authors.initials: H
authors.lastname: Uchino
authors.affiliation: Department of Neurosurgery, Hokkaido University Graduate School of Medicine, N15 W7, Kita-ku, Sapporo 060-8638, Japan. Electronic address: masakiitou-nsu@umin.ac.jp.
authors.forename: Masaki
authors.initials: M
authors.lastname: Ito
authors.affiliation: Department of Radiology, Hokkaido University Graduate School of Medicine, N15 W7, Kita-ku, Sapporo 060-8638, Japan.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Fujima
authors.affiliation: Department of Neurosurgery, Hokkaido University Graduate School of Medicine, N15 W7, Kita-ku, Sapporo 060-8638, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Kazumata
authors.affiliation: Department of Neurosurgery, Hokkaido University Graduate School of Medicine, N15 W7, Kita-ku, Sapporo 060-8638, Japan.
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Yamazaki
authors.affiliation: Department of Neurosurgery, Hokkaido University Graduate School of Medicine, N15 W7, Kita-ku, Sapporo 060-8638, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Nakayama
authors.affiliation: Department of Neurosurgery, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0914, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kuroda
authors.affiliation: Department of Neurosurgery, Hokkaido University Graduate School of Medicine, N15 W7, Kita-ku, Sapporo 060-8638, Japan.
authors.forename: Kiyohiro
authors.initials: K
authors.lastname: Houkin
mesh_terms: D000328:Adult; D015901:Angiography, Digital Subtraction / Q000379:methods; D001921:Brain / Q000098:blood supply; D002536:Cerebral Arteries / Q000000981:diagnostic imaging; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods; D008297:Male; D008875:Middle Aged; D009072:Moyamoya Disease / Q000175:diagnosis*; D013113:Spin Labels; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D055815:Young Adult
chemical_list: D013113:Spin Labels
keywords: Arterial spin labeling; Cerebrovascular; Four-dimensional magnetic resonance angiography; Moyamoya disease; Postoperative hyperperfusion