title: Optimisation of vascular input and output functions in CT-perfusion imaging using 256(or more)-slice multidetector CT.
abstract: OBJECTIVE
  To evaluate the accuracy and reproducibility of CT-perfusion (CTP) by finding the optimal artery for the arterial input function (AIF) and re-evaluating the necessity of the venous output function (VOF).
  
  
  METHODS
  Forty-four acute ischaemic stroke patients who underwent non-enhanced CT, CTP and CT-angiography using 256-slice multidetector computed tomography (MDCT) were evaluated. The anterior cerebral artery (ACA), middle cerebral artery (MCA), internal carotid artery (ICA) and basilar artery were selected as the AIF. Subsequently the resulting area under the time-enhancement curve of the AIF (AUCAIF) and quantitative perfusion measurements were analysed by repeated measures ANOVA and subsequently the paired t test. To evaluate reproducibility we examined if the VOF could be deleted by comparing the perfusion measurements using versus not using the VOF (paired t test).
  
  
  RESULTS
  The AUCAIF and perfusion measurements resulting from the different AIFs showed significant group differences (all P < 0.0001). The ICA had the largest AUCAIF and resulted in the highest mean transient time (MTT) and lowest cerebral blood flow (CBF), whereas the basilar artery showed the lowest cerebral blood volume (CBV). Not using the VOF showed significantly higher CBV and CBF in 66 % of patients on the ipsilateral (P < 0.0001 and P = 0.007, respectively) and contralateral hemisphere (P < 0.0001 and P = 0.019, respectively).
  
  
  CONCLUSIONS
  Selecting the ICA as the AIF and continuing the use of the VOF would improve the accuracy of CTP.
  
  
  CONCLUSIONS
  • Perfusion imaging is an increasingly important aspect of multidetector computed tomography (MDCT). • Vascular input functions were evaluated for CT-perfusion using 256-slice MDCT. • Selecting different arterial input functions (AIFs) leads to variation in quantitative values. • Using the internal carotid artery for AIF provides optimal perfusion values. • Deleting the venous output function would be detrimental for validity.
authors.affiliation: Department of Radiology, University Medical Center Utrecht, Heidelberglaan 100, Hp: E.01.132, 3584 CX Utrecht, Netherlands. jmniesten@gmail.com
authors.forename: Joris M
authors.initials: JM
authors.lastname: Niesten
authors.forename: Irene C
authors.initials: IC
authors.lastname: van der Schaaf
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Riordan
authors.forename: Hugo W A M
authors.initials: HW
authors.lastname: de Jong
authors.forename: Willem P T M
authors.initials: WP
authors.lastname: Mali
authors.forename: Birgitta K
authors.initials: BK
authors.lastname: Velthuis
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D002533:Cerebral Angiography / Q000379:methods*; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D055420:Perfusion Imaging / Q000379:methods*; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*