title: Transcranial Doppler sonography evaluation of anterior cerebral artery hypoplasia or aplasia.
abstract: OBJECTIVE
  Transcranial Doppler (TCD) sonography is useful to evaluate intracranial arteries, however, interpretation of the TCD results in anterior cerebral artery (ACA) is difficult because of hypoplasia or aplasia. We try to define useful TCD indices and cut-off values to determine the variations of ACA.
  
  
  METHODS
  Consecutive patients who underwent TCD and magnetic resonance angiography (MRA) were included. Patients with cerebrovascular abnormality or inadequate temporal windows were excluded. ACA status was classified as normal (NL), hypoplasia (HP), and aplasia (AP) according to MRA. TCD indices of mean flow velocity (MFV), pulsatility index (PI), ACA/middle cerebral artery (MCA) flow velocity ratio (ACA/MCA FVR), and asymmetry index (AI) of ACA were blindly compared with MRA between three groups.
  
  
  RESULTS
  Two hundred and forty-one patients were included, and 193 patients (80%) were classified as NL, 34 (14%) as HP and 14 (6%) as AP. MFV was significantly lower in HP and AP (p<0.001), however, PI and ACA/MCA FVR were not different. AI was significantly different between NL and HP (21.5% vs. 50.4%), NL and AP (21.5% vs. 105.2%) (p<0.001).
  
  
  CONCLUSIONS
  MFV of ACA should be interpreted with caution for its frequent anatomical variations. AI is useful to differentiate hypoplasia and aplasia from normal ACA with optimal criteria.
authors.affiliation: Department of Neurology, Seoul National University Boramae Hospital, College of Medicine, Seoul National University, 395 Shindaebang 2-dong, Dongjak-gu, Seoul, 156-707, Republic of Korea.
authors.forename: Hyung-Min
authors.initials: HM
authors.lastname: Kwon
authors.forename: Yong-Seok
authors.initials: YS
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D002539:Cerebral Arterial Diseases / Q000145:classification / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D011673:Pulsatile Flow / Q000502:physiology; D012680:Sensitivity and Specificity; D017585:Ultrasonography, Doppler, Transcranial