title: Sonographic characterisation of radiation-induced carotid artery stenosis.
abstract: OBJECTIVE
  To study the distribution, extent and sonographic characterisation of radiation-induced carotid artery stenosis in nasopharyngeal carcinoma (NPC) patients.
  
  
  METHODS
  The distribution of plaques, the extent of stenosis, and the sonographic characterisation of the plaque at maximum stenosis were recorded in 71 NPC patients. The results were compared with the ultrasound results of a control group of 142 patients presenting with symptoms of cerebrovascular disease or carotid bruit.
  
  
  RESULTS
  NPC patients had a higher incidence of carotid stenosis (77 vs. 50.7%). The common carotid arteries were most commonly affected by radiation-induced stenosis (93/142 vs. 37/284 in the control group), whereas the carotid bulb was the most commonly affected (56/284) site in the control group. Significantly more NPC patients had moderate-to-severe stenosis (21/71 vs. 27/142). Analysis of the sonographic appearance of radiation-induced and atherosclerotic plaques showed more diffuse involvement in the post-radiation group. Non-calcified plaques and intraplaque hypoechoic foci were also more frequent in the post-radiation group.
  
  
  CONCLUSIONS
  Radiation-induced carotid stenosis is more diffuse in distribution, is associated with more severe luminal stenosis and has different sonographic plaque characterisation compared with carotid stenosis without radiation exposure.
authors.affiliation: Department of Diagnostic Radiology and Organ Imaging, Prince of Wales Hospital, Chinese University of Hong Kong, ROC. wynnie@cuhk.edu.hk
authors.forename: W W M
authors.initials: WW
authors.lastname: Lam
authors.forename: K H
authors.initials: KH
authors.lastname: Liu
authors.forename: S F
authors.initials: SF
authors.lastname: Leung
authors.forename: K S
authors.initials: KS
authors.lastname: Wong
authors.forename: N M C
authors.initials: NM
authors.lastname: So
authors.forename: H Y
authors.initials: HY
authors.lastname: Yuen
authors.forename: C
authors.initials: C
authors.lastname: Metreweli
mesh_terms: D000328:Adult; D000368:Aged; D017536:Carotid Artery, Common / Q000528:radiation effects*; D016893:Carotid Stenosis / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000532:radiotherapy*; D012720:Severity of Illness Index; D017211:Treatment Failure; D017585:Ultrasonography, Doppler, Transcranial / Q000009:adverse effects*