title: Quantitative measurement of blood flow in paediatric brain tumours-a comparative study of dynamic susceptibility contrast and multi time-point arterial spin labelled MRI.
abstract: OBJECTIVE
  Arterial spin-labelling (ASL) MRI uses intrinsic blood water to quantify the cerebral blood flow (CBF), removing the need for the injection of a gadolinium-based contrast agent used for conventional perfusion imaging such as dynamic susceptibility contrast (DSC). Owing to the non-invasive nature of the technique, ASL is an attractive option for use in paediatric patients. This work compared DSC and multi-timepoint ASL measures of CBF in paediatric brain tumours.
  
  
  METHODS
  Patients (n = 23; 20 low-grade tumours and 3 high-grade tumours) had DSC and multi-timepoint ASL with and without vascular crushers (VC). VC removes the contribution from larger vessel blood flow. Mean perfusion metrics were extracted from control and T1-enhanced tumour regions of interest (ROIs): arterial arrival time (AAT) and CBF from the ASL images with and without VC, relative cerebral blood flow (rCBF), relative cerebral blood volume, delay time (DT) and mean transit time (MTT) from the DSC images.
  
  
  RESULTS
  Significant correlations existed for: AAT and DT (r = 0.77, p = 0.0002) and CBF and rCBF (r = 0.56, p = 0.02) in control ROIs for ASL-noVC. No significant correlations existed between DSC and ASL measures in the tumour region. Significant differences between control and tumour ROI were found for MTT (p < 0.001) and rCBF (p < 0.005) measures.
  
  
  CONCLUSIONS
  Significant correlations between ASL-noVC and DSC measures in the normal brain suggest that DSC is most sensitive to macrovascular blood flow. The absence of significant correlations within the tumour ROI suggests that ASL is sensitive to different physiological mechanisms compared with DSC measures.
  
  
  CONCLUSIONS
  ASL provides information which is comparable with that of DSC in healthy tissues, but appears to reflect a different physiology in tumour tissues.
authors.affiliation: 1 Florey Institute of Neuroscience and Mental Health, Heidelberg, Melbourne, VIC, Australia.|2 Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, VIC, Australia.
authors.forename: Rishma
authors.identifier: http://orcid.org/0000-0002-1484-4250
authors.initials: R
authors.lastname: Vidyasagar
authors.affiliation: 3 Department of Radiology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK.
authors.forename: Laurence
authors.initials: L
authors.lastname: Abernethy
authors.affiliation: 4 Department of Paediatric Oncology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK.
authors.forename: Barry
authors.initials: B
authors.lastname: Pizer
authors.affiliation: 3 Department of Radiology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK.
authors.forename: Shivaram
authors.initials: S
authors.lastname: Avula
authors.affiliation: 5 Centre for Imaging Sciences, Faculty of Medicine and Human Sciences, University of Manchester, Manchester, UK.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Parkes
mesh_terms: D000293:Adolescent; D001783:Blood Flow Velocity; D001932:Brain Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D009389:Neovascularization, Pathologic / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013113:Spin Labels; D055815:Young Adult
chemical_list: D013113:Spin Labels