title: Automatic measurements of arterial input and venous output functions on cerebral computed tomography perfusion images: a preliminary study.
abstract: BACKGROUND
  The current automatic techniques for measuring arterial input function (AIF) and venous output (VOF) on cerebral computed tomography perfusion images are prone to motion artifact and random noise, and their failure rates vary between 10% and 65%. We developed a new automatic technique to overcome these problems.
  
  
  METHODS
  A principle axis transformation was applied to perfusion images to correct for translational and rotational motion artifacts. Bone voxels and neighboring voxels were removed from the perfusion images. Only brain voxels were included in the AIF and VOF measurement procedures. The selection criteria, such as large area under the concentration-time curve, early arrival of contrast agents, and narrow effective width, were used to select appropriate arterial and venous voxels for the AIF and VOF measurements. The proposed automatic technique was tested in 20 patients with unilateral cerebral arterial stenosis. The results of the proposed technique were compared to the results obtained by manual measurements and commercially available automatic selection software.
  
  
  RESULTS
  The AIFs and VOFs were successfully measured using the proposed automatic technique in all 20 patients. The curve shapes, including the area under the concentration-time curve, peak concentration, time to peak, and effective width of the automatically measured AIFs or VOFs were comparable to that were measured manually.
  
  
  CONCLUSIONS
  The proposed automatic measurement technique successfully overcomes the motion artifact and random noise problems encountered in measuring AIF and VOF. It can be easily integrated into software for the automatic calculation of cerebral blood volume and flow.
authors.affiliation: Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, Taipei, Taiwan.
authors.forename: Yi-Hsuan
authors.initials: YH
authors.lastname: Kao
authors.affiliation: School of Medicine, National Yang Ming University, Taipei, Taiwan; Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Medical Imaging, Cheng Hsin General Hospital, Taipei, Taiwan. Electronic address: mhteng@gmail.com.
authors.forename: Michael
authors.initials: M
authors.lastname: Mu Huo Teng
authors.affiliation: Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, Taipei, Taiwan; Department of Radiation Oncology, Taipei Medical University Hospital, Taipei, Taiwan.
authors.forename: Yi-Tzu
authors.initials: YT
authors.lastname: Kao
authors.affiliation: Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, Taipei, Taiwan; Department of Radiation Oncology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan.
authors.forename: Yi-Ju
authors.initials: YJ
authors.lastname: Chen
authors.affiliation: Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, Taipei, Taiwan.
authors.forename: Chen-Hsin
authors.initials: CH
authors.lastname: Wu
authors.affiliation: Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, Taipei, Taiwan.
authors.forename: Wen-Chun
authors.initials: WC
authors.lastname: Chen
authors.affiliation: Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, Taipei, Taiwan.
authors.forename: Fang-Ying
authors.initials: FY
authors.lastname: Chiu
authors.affiliation: School of Medicine, National Yang Ming University, Taipei, Taiwan; Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Feng-Chi
authors.initials: FC
authors.lastname: Chang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002533:Cerebral Angiography / Q000379:methods*; D002536:Cerebral Arteries / Q000000981:diagnostic imaging / Q000503:physiopathology; D002550:Cerebral Veins / Q000000981:diagnostic imaging / Q000503:physiopathology; D002561:Cerebrovascular Disorders / Q000000981:diagnostic imaging / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: Arterial input function; Cerebral perfusion; Computed tomography; Image processing; Segmentation; Venous output function