title: Feasibility and validity of monitoring subarachnoid hemorrhage by a noninvasive MRI imaging perfusion technique: Pulsed Arterial Spin Labeling (PASL).
abstract: OBJECTIVE
  To evaluate the validity of pulsed arterial spin labeling (PASL) imaging with cerebral blood flow (CBF) quantification for monitoring subarachnoid hemorrhage (SAH); to describe changes in the perfusion signal in the absence of or following several classic complications.
  
  
  METHODS
  Fifteen patients and 14 healthy volunteers were assigned to SAH and control populations, respectively. ASL imaging was performed three times: between Day 0 (D0, i.e., day of onset of SAH symptoms) and D3, between D7 and D9 and between D12 and D14. ASL points were classified as complicated (symptomatic vasospasm, intraparenchymal hematoma or severe intracranial hypertension) or uncomplicated. Perfusion and CBF maps were generated after automated processing. The inversion time (TI) was fixed at 1800 ms.
  
  
  RESULTS
  CBF mean value of Day0-3 uncomplicated SAH patients (47 ± 11.7 mL/min/100g) was significantly higher than that of the volunteers (36.5 ± 7.6 mL/min/100g; P=0.014). In a case-by-case analysis, we observed a global or regional hypoperfusion pattern when SAH was complicated by vasospasm or severe intracranial hypertension, particularly at the junctional areas. Furthermore, we have faced major vascular artefacts, visible as serpiginous high signals and related to the retention of labeled protons in arteries concerning by angiographic vasospasm.
  
  
  CONCLUSIONS
  PASL is an interesting perfusion technique to non-invasively highlight perfusion changes in complicated SAH and can provide a new element in the decision to perform urgent endovascular treatment. However, the increase in arterial transit time makes the Buxton quantification model inapplicable and leads to false high CBF values in the single-TI PASL technique.
authors.affiliation: EA7315, Laboratoire Angevin de Recherche en Ingénierie des Systèmes (LARIS), Université d'Angers, Angers, France; Pôle d'Imagerie, CHU d'Angers, Angers, France. Electronic address: matthieu.labriffe@gmail.com.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Labriffe
authors.affiliation: EA7315, Laboratoire Angevin de Recherche en Ingénierie des Systèmes (LARIS), Université d'Angers, Angers, France; Pôle d'Anesthésie Réanimation, CHU d'Angers, Angers, France.
authors.forename: Aram
authors.initials: A
authors.lastname: Ter Minassian
authors.affiliation: Pôle d'Imagerie, CHU d'Angers, Angers, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Pasco-Papon
authors.affiliation: EA7315, Laboratoire Angevin de Recherche en Ingénierie des Systèmes (LARIS), Université d'Angers, Angers, France; Département de Neurologie Pédiatrique, CHU d'Angers, Angers, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: N'Guyen
authors.affiliation: Pôle d'Imagerie, CHU d'Angers, Angers, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Aubé
mesh_terms: D000328:Adult; D000368:Aged; D002560:Cerebrovascular Circulation / Q000502:physiology; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D013113:Spin Labels; D013345:Subarachnoid Hemorrhage / Q000000981:diagnostic imaging*
chemical_list: D013113:Spin Labels
keywords: Arterial spin labeling; Cerebral blood flow; MRI; Perfusion; Subarachnoid hemorrhage