title: Comparison between three-dimensional volume-selective turbo spin-echo imaging and two-dimensional ultrasound for assessing carotid artery structure and function.
abstract: OBJECTIVE
  To compare a volume-selective three-dimensional turbo spin echo (TSE) technique with ultrasound (US) for assessing carotid artery wall structure and function.
  
  
  METHODS
  A three-dimensional volume-selective TSE technique was used to image the carotid artery in 10 healthy subjects and five hypertensive subjects (each of whom were scanned three times while they received different hypertension treatments). Lumen and wall area were measured on MR images. Two-dimensional US measurements of the intima-media thickness (IMT) and lumen diameter were taken in three orientations through a single cross section. The lumen area change over the cardiac cycle was used to determine distension. For validation, a Bland-Altman analysis was used to compare the vessel wall and lumen areas measured by three-dimensional MRI volumes with those obtained by US scans.
  
  
  RESULTS
  Agreement between the two methods was found. The mean difference in distension between US and MRI was 1.2% (+/-5.1%). For the wall area measurements, good agreement was shown, but there was a systematic difference due to the visualization of the adventitia by MRI. Both techniques offer an easy way to objectively measure lumen indices. MRI can provide the complete circumference over the length of a vessel, while US is flexible and relatively inexpensive. The application of US is limited, however, when subjects are poorly echogenic. A difference between hypertensive and healthy subjects was found.
  
  
  CONCLUSIONS
  There was a good agreement between MRI and the clinically established two-dimensional US method. The MRI method has the advantage of providing increased vessel coverage, which permits one to assess localized abnormalities without assuming vessel uniformity.
authors.affiliation: Magnetic Resonance Unit, Imperial College/Royal Brompton Hospital, London, United Kingdom. Lindsey.crowe@talk21.com
authors.forename: Lindsey A
authors.initials: LA
authors.lastname: Crowe
authors.forename: Ben
authors.initials: B
authors.lastname: Ariff
authors.forename: Jennifer
authors.initials: J
authors.lastname: Keegan
authors.forename: Raad H
authors.initials: RH
authors.lastname: Mohiaddin
authors.forename: Guang Zhong
authors.initials: GZ
authors.lastname: Yang
authors.forename: Alun D
authors.initials: AD
authors.lastname: Hughes
authors.forename: Simon A
authors.initials: SA
authors.lastname: McG Thom
authors.forename: David N
authors.initials: DN
authors.lastname: Firmin
mesh_terms: D000328:Adult; D002339:Carotid Arteries / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000502:physiology*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012016:Reference Values; D015203:Reproducibility of Results; D014463:Ultrasonography / Q000379:methods*