title: Head and neck vascular lesions: characterization of the flow pattern by the use of three-phase CT.
abstract: OBJECTIVE
  This study was designed to evaluate the usefulness of three-phase CT to characterize the hemodynamics of vascular lesions in the head and neck area.
  
  
  METHODS
  We analyzed vascular malformations of head and neck regions in 21 patients with the use of three-phase CT, including pre-contrast phase, vascular phase (scan delay: 20-35 seconds after intravenous contrast material injection) and equilibrium phase (scan delay: 3-5 minutes) imaging. The flow characteristic of each lesion was determined and categorized as either a high- or a low-flow lesion according to findings on selective arteriography and/or direct puncture venography. The CT number was acquired from two areas in a vascular lesion, sorted by the enhancement pattern: area 1, a highly enhanced area seen on the vascular phase; area 2, a delayedly enhanced area seen on the equilibrium phase. The CT numbers of each phase were compared between high- and low-flow lesions with use of the unpaired t-test. The flow patterns of high- and low-flow lesions were analyzed by assessment of time-density curves of three phase CT.
  
  
  RESULTS
  High-flow lesions were detected in nine patients and low-flow lesions were detected in 12 patients. On the vascular phase, the CT number of areas 1 and 2 of high-flow lesions was significantly higher than for low-flow lesions (p < 0.05). Contrary to early peaks seen in time-density curves of high-flow lesions, low-flow lesions showed a delayed peak.
  
  
  CONCLUSIONS
  Three-phase CT seems to be a valuable non-invasive method to differentiate a high-flow lesion from a low flow lesion of head and neck vascular lesions.
authors: Department of Radiology, East-West Neomedical Center, Kyung Hee University, College of Medicine, Seoul, Korea.
authors: Chang-Woo
authors: CW
authors: Ryu
authors: Jae Kyun
authors: JK
authors: Kim
authors: Sang Joon
authors: SJ
authors: Kim
authors: Jeong Hyun
authors: JH
authors: Lee
authors: Jeoung Hyun
authors: JH
authors: Kim
authors: Hong Il
authors: HI
authors: Ha
authors: Dae Chul
authors: DC
authors: Suh
mesh_terms: D000293:Adolescent; D000328:Adult; D000792:Angiography / Q000379:methods; D001165:Arteriovenous Malformations / Q000000981:diagnostic imaging*; D002648:Child; D005260:Female; D006257:Head / Q000098:blood supply*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009333:Neck / Q000098:blood supply*; D014057:Tomography, X-Ray Computed / Q000379:methods*