title: Non-invasive assessment of vasospasm following aneurysmal SAH using C-arm FDCT parenchymal blood volume measurement in the neuro-interventional suite: Technical feasibility.
abstract: BACKGROUND
  Cerebral vasospasm is the leading cause of morbidity and mortality in patients with aneurysmal subarachnoid haemorrhage (SAH) surviving the initial ictus. Commonly used techniques for vasospasm assessment are digital subtraction angiography and transcranial Doppler sonography. These techniques can reliably identify only the major vessel spasm and fail to estimate its haemodynamic significance. To overcome these issues and to enable comprehensive non-invasive assessment of vasospasm inside the interventional suite, a novel protocol involving measurement of parenchymal blood volume (PBV) using C-arm flat detector computed tomography (FDCT) was implemented.
  
  
  METHODS
  Patients from the neuro-intensive treatment unit (ITU) with suspected vasospasm following aneurysmal SAH were scanned with a biplane C-arm angiography system using an intravenous contrast injection protocol. The PBV maps were generated using prototype software. Contemporaneous clinically indicated MR scan including the diffusion- and perfusion-weighted sequences was performed. C-arm PBV maps were compared against the MR perfusion maps.
  
  
  RESULTS
  Distribution of haemodynamic impairment on C-arm PBV maps closely matched the pattern of abnormality on MR perfusion maps. On visual comparison between the two techniques, the extent of abnormality indicated PBV to be both cerebral blood flow and cerebral blood volume weighted.
  
  
  CONCLUSIONS
  C-arm FDCT PBV measurements allow an objective assessment of the severity and localisation of cerebral hypoperfusion resulting from vasospasm. The technique has proved feasible and useful in very sick patients after aneurysmal SAH. The promise shown in this early study indicates that it deserves further evaluation both for post-SAH vasospasm and in other relevant clinical settings.
authors.affiliation: Oxford Neurovascular and Neuroradiology Research Unit, John Radcliffe Hospital, UK m.kamran@oxon.org.
authors.forename: Mudassar
authors.initials: M
authors.lastname: Kamran
authors.affiliation: Department of Neuroradiology, Oxford Neurovascular and Neuroradiology Research Unit, John Radcliffe Hospital, UK.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Downer
authors.affiliation: Department of Neuroradiology, Oxford Neurovascular and Neuroradiology Research Unit, John Radcliffe Hospital, UK.
authors.forename: Rufus
authors.initials: R
authors.lastname: Corkill
authors.affiliation: Oxford Neurovascular and Neuroradiology Research Unit, John Radcliffe Hospital, UK.
authors.forename: James V
authors.initials: JV
authors.lastname: Byrne
mesh_terms: D000328:Adult; D001810:Blood Volume; D001811:Blood Volume Determination; D002544:Cerebral Infarction / Q000209:etiology; D002560:Cerebrovascular Circulation; D038524:Diffusion Magnetic Resonance Imaging; D017809:Fatal Outcome; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D013345:Subarachnoid Hemorrhage / Q000150:complications* / Q000000981:diagnostic imaging* / Q000523:psychology; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D020301:Vasospasm, Intracranial / Q000000981:diagnostic imaging* / Q000209:etiology* / Q000523:psychology
keywords: C-arm flat detector computed tomography; MR perfusion weighted imaging; Subarachnoid haemorrhage; parenchymal blood volume; vasospasm