title: Quantitative flow measurement by digital subtraction angiography in cerebral carotid stenosis using optical flow method.
abstract: OBJECTIVE
  We analyzed intracranial regional blood flows using an optical flow method (OFM) and digital subtraction angiography in patients with internal carotid artery (ICA) stenosis. We also retrospectively explored the correlation between the patients' diagnoses and the severity of the ICA stenoses.
  
  
  METHODS
  OFM, an image-processing algorithm to estimate motion, was applied to determine the mean velocity V(mean) in the vessels. A group of 40 patients without vascular anomalies acted as the control group. The patients were classified as having either moderate stenosis (< 80%, n=14) or severe stenosis (> 80%, n=23).
  
  
  RESULTS
  The V(mean) of the ICAs was significantly lower in the stenotic group compared with the control group (p< 0.01). The V(mean) of the ICAs was inversely correlated with the severity of the stenosis (p< 0.05). The receiver operating characteristic curve of the V(mean) in an AP view showed substantial discriminatory power, with an optimal cutoff value of 3.48 pixels/frame for the detection of patients with carotid stenosis. The sensitivity and specificity were 84% and 50%, respectively. On a lateral view, the best cutoff for the V(mean) was 4.01 pixels/frame, and the sensitivity and specificity were 92% and 43%, respectively.
  
  
  CONCLUSIONS
  Digital subtraction angiography combined with the OFM is a feasible parametric method for intracranial blood flow measurements in patients with moderate to severe carotid stenosis.
authors.affiliation: Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung City, Taiwan.
authors.forename: Tzung-Chi
authors.initials: TC
authors.lastname: Huang
authors.forename: Tung-Hsin
authors.initials: TH
authors.lastname: Wu
authors.forename: Yang-Hsien
authors.initials: YH
authors.lastname: Lin
authors.forename: Wan-Yuo
authors.initials: WY
authors.lastname: Guo
authors.forename: Wei-Chien
authors.initials: WC
authors.lastname: Huang
authors.forename: Chung-Jung
authors.initials: CJ
authors.lastname: Lin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D015901:Angiography, Digital Subtraction / Q000379:methods*; D001783:Blood Flow Velocity / Q000502:physiology; D016893:Carotid Stenosis / Q000175:diagnosis* / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012039:Regional Blood Flow / Q000502:physiology