title: Computer-assisted carotid plaque characterisation.
abstract: OBJECTIVE
  To determine the relationship between plaque echogenicity as measured by computer and the incidence of cerebral brain infarction.
  
  
  METHODS
  Eighty-seven patients with 148 plaques producing more than 50% internal carotid artery stenosis were studied. Sixty-nine plaques were in asymptomatic patients, 35 were associated with amaurosis fugax, 19 with transient ischaemic attacks and 25 with stroke. All patients had a CT brain scan and the presence of ipsilateral cerebral infarction was noted. Images of the plaques obtained with an ATL Ultramark-4 Duplex scanner (7.5 MHz high resolution probe) were transferred to a computer. Using an image analysis program a histogram for each plaque was obtained with the number of pixels plotted against the grey scale (0-225). The median of the grey scale was used as a measure of echogenicity.
  
  
  RESULTS
  Fifty-three (36%) of the 148 plaques were associated with ipsilateral CT brain infarction. Plaques with a grey scale median more than 32 (echogenic) were associated with an incidence of 11% (7/64) CT infarction. In contrast, plaques with grey scale median below or equal to 32 (echolucent) were associated with 55% (46/84) incidence of CT infarction (chi 2 = 30.35, p < 0.001, relative risk = 22, 95% confidence interval from 4.7 to 108).
  
  
  CONCLUSIONS
  This study indicates that computer analysis of carotid plaque can identify high-risk carotid plaques. The potential of such analysis in the identification of asymptomatic high-risk patients should be explored in further studies.
authors.affiliation: Academic Vascular Unit, St Mary's Hospital Medical School, London, UK.
authors.forename: N
authors.initials: N
authors.lastname: el-Barghouty
authors.forename: G
authors.initials: G
authors.lastname: Geroulakos
authors.forename: A
authors.initials: A
authors.lastname: Nicolaides
authors.forename: A
authors.initials: A
authors.lastname: Androulakis
authors.forename: V
authors.initials: V
authors.lastname: Bahal
mesh_terms: D001161:Arteriosclerosis / Q000150:complications / Q000000981:diagnostic imaging*; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging; D016893:Carotid Stenosis / Q000150:complications / Q000000981:diagnostic imaging*; D002544:Cerebral Infarction / Q000209:etiology; D002561:Cerebrovascular Disorders / Q000209:etiology; D003936:Diagnosis, Computer-Assisted; D006801:Humans; D007091:Image Processing, Computer-Assisted; D015588:Observer Variation; D011446:Prospective Studies; D011859:Radiography; D018616:Ultrasonography, Doppler, Duplex