title: Quantitative evaluation of high intensity signal on MIP images of carotid atherosclerotic plaques from routine TOF-MRA reveals elevated volumes of intraplaque hemorrhage and lipid rich necrotic core.
abstract: BACKGROUND
  Carotid intraplaque hemorrhage (IPH) and lipid rich necrotic core (LRNC) have been associated with accelerated plaque growth, luminal narrowing, future surface disruption and development of symptomatic events. The aim of this study was to evaluate the quantitative relationships between high intensity signals (HIS) in the plaque on TOF-MRA and IPH or LRNC volumes as measured by multicontrast weighted CMR.
  
  
  METHODS
  Seventy six patients with a suspected carotid artery stenosis or carotid plaque by ultrasonography underwent multicontrast carotid CMR. HIS presence and volume were measured from TOF-MRA MIP images while IPH and LRNC volumes were separately measured from multicontrast CMR.
  
  
  RESULTS
  For detecting IPH, HIS on MIP images overall had high specificity (100.0%, 95% CI: 93.0 - 100.0%) but relatively low sensitivity (32%, 95% CI: 20.8 - 47.9%). However, the sensitivity had a significant increasing relationship with underlying IPH volume (p = 0.033) and degree of stenosis (p = 0.022). Mean IPH volume was 2.7 times larger in those with presence of HIS than in those without (142.8 ± 97.7 mm(3) vs. 53.4 ± 56.3 mm(3), p = 0.014). Similarly, mean LRNC volume was 3.4 times larger in those with HIS present (379.8 ± 203.4 mm(3) vs. 111.3 ± 122.7 mm(3), p = 0.001). There was a strong correlation between the volume of the HIS region and the IPH volume measured from multicontrast CMR (r = 0.96, p < 0.001).
  
  
  CONCLUSIONS
  MIP images are easily reformatted from three minute, routine, clinical TOF sequences. High intensity signals in carotid plaque on TOF-MRA MIP images are associated with increased intraplaque hemorrhage and lipid-rich necrotic core volumes. The technique is most sensitive in patients with moderate to severe stenosis.
authors.affiliation: Department of Radiology, University of Washington, Seattle, WA 98109-4325, USA. cyuan@u.washington.edu
authors.forename: Kiyofumi
authors.initials: K
authors.lastname: Yamada
authors.forename: Yan
authors.initials: Y
authors.lastname: Song
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Hippe
authors.forename: Jie
authors.initials: J
authors.lastname: Sun
authors.forename: Li
authors.initials: L
authors.lastname: Dong
authors.forename: Dongxiang
authors.initials: D
authors.lastname: Xu
authors.forename: Marina S
authors.initials: MS
authors.lastname: Ferguson
authors.forename: Baocheng
authors.initials: B
authors.lastname: Chu
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Hatsukami
authors.forename: Min
authors.initials: M
authors.lastname: Chen
authors.forename: Cheng
authors.initials: C
authors.lastname: Zhou
authors.forename: Chun
authors.initials: C
authors.lastname: Yuan
mesh_terms: D002339:Carotid Arteries / Q000737:chemistry / Q000473:pathology*; D016893:Carotid Stenosis / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D003287:Contrast Media; D019786:Gadolinium DTPA; D006470:Hemorrhage / Q000473:pathology*; D006801:Humans; D016014:Linear Models; D008055:Lipids / Q000032:analysis*; D018810:Magnetic Resonance Angiography; D009336:Necrosis; D058226:Plaque, Atherosclerotic; D011237:Predictive Value of Tests; D012422:Rupture, Spontaneous; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
chemical_list: D003287:Contrast Media; D008055:Lipids; D019786:Gadolinium DTPA