title: Carotid plaque inflammation is associated with cerebral microembolism in patients with recent transient ischemic attack or stroke: a pilot study.
abstract: BACKGROUND
  Cerebral infarcts distal to carotid stenoses are thought to be caused by emboli from inflamed, destabilized plaques. We hypothesized that microembolic signals (MES) on transcranial Doppler will be associated with carotid plaque inflammation on (18)F fluorodeoxyglucose positron-emission tomography (FDG PET) in recently symptomatic patients.
  
  
  RESULTS
  Sixteen patients presenting with recent (47 ± 31 days) anterior circulation transient ischemic attack or minor stroke and 50% to 99% stenosis of the ipsilateral carotid bifurcation underwent FDG PET, high-resolution black-blood carotid MRI, and transcranial Doppler for detection of MES. Patients with potential cardiac sources of emboli or contralateral MES were excluded. Regions of interest defined on the coregistered MRI were used to measure FDG standardized uptake values (with Rousset partial volume correction) from the index and contralateral carotid plaques and artery. Ipsilateral MES were detected in 7 patients (MES+ group) and absent in 8 (MES- group). There was a significant difference in index-to-contralateral plaque standardized uptake value ratio between MES+ (median, 1.05; first to third quartile, 0.96 to 1.32) and MES- (median, 0.76; first to third quartile, 0.62 to 0.94) patients (P=0.005). The interval from symptom onset to PET and percent index carotid stenosis were not different between the 2 groups (P=0.68 and P=0.48, respectively).
  
  
  CONCLUSIONS
  In this sample of recently symptomatic patients with carotid stenosis, an association was found between in vivo measures of plaque inflammation detected by FDG PET and the presence of transcranial Doppler MES. These findings strengthen the notion that embolic events distal to carotid stenoses are related to plaque inflammation, and FDG PET may be useful in the investigation of culprit carotid lesions.
authors.affiliation: Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK. ramezm@msn.com
authors.forename: Ramez Reda
authors.initials: RR
authors.lastname: Moustafa
authors.forename: David
authors.initials: D
authors.lastname: Izquierdo-Garcia
authors.forename: Tim D
authors.initials: TD
authors.lastname: Fryer
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Graves
authors.forename: James H F
authors.initials: JH
authors.lastname: Rudd
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Gillard
authors.forename: Peter L
authors.initials: PL
authors.lastname: Weissberg
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Baron
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Warburton
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016893:Carotid Stenosis / Q000150:complications* / Q000000981:diagnostic imaging; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007249:Inflammation / Q000150:complications* / Q000000981:diagnostic imaging; D020766:Intracranial Embolism / Q000000981:diagnostic imaging / Q000209:etiology*; D002546:Ischemic Attack, Transient / Q000000981:diagnostic imaging / Q000209:etiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals; D020521:Stroke / Q000000981:diagnostic imaging / Q000209:etiology*; D013997:Time Factors; D017585:Ultrasonography, Doppler, Transcranial
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18