title: Pilot study of cardiac magnetic resonance imaging for detection of embolic source after ischemic stroke.
abstract: BACKGROUND
  Transesophageal echocardiography (TEE) is the standard for evaluating cardioembolic sources of stroke, although many strokes remain cryptogenic after TEE. Cardiac magnetic resonance (CMR) imaging may have advantages over TEE. We performed a prospective pilot study comparing CMR to TEE after stroke to assist in planning future definitive studies.
  
  
  METHODS
  Individuals with nonlacunar stroke within 90 days of undergoing clinical TEE were prospectively identified and underwent a 1.5 Tesla research CMR scan. Exclusion criteria included >50% relevant cervical vessel stenosis and inability to undergo nonsedated CMR. A descriptive comparison of cardioembolic source (intracardiac thrombus/mass, aortic atheroma ≥ 4 mm, or patent foramen ovale [PFO]) by study type was performed.
  
  
  RESULTS
  Twenty patients underwent CMR and TEE a median of 6 days apart. The median age was 51 years (interquartile range [IQR] 40, 63.5), 40% had hypertension, 15% had diabetes, 25% had a previous stroke/transient ischemic attack, 5% had atrial fibrillation, and none had coronary disease or heart failure. No patient had intracardiac thrombus or mass detected on either study. Aortic atheroma ≥ 4 mm thick was identified by TEE in 1 patient. CMR identified aortic atheroma as <4 mm in this patient (3 mm on CMR compared with 5 mm on TEE). PFO was identified in 6 of 20 patients on TEE; CMR found only 1 of these.
  
  
  CONCLUSIONS
  In this pilot study, TEE identified more potential cardioembolic sources than CMR imaging. Future studies comparing TEE and CMR after stroke should focus on older subjects at higher risk for cardiac disease to determine whether TEE, CMR, or both can best elucidate potential cardioembolic sources.
authors.affiliation: Stroke Program, University of Michigan, Ann Arbor, MI 48109-5855, USA. zdarin@umich.edu
authors.forename: Darin B
authors.initials: DB
authors.lastname: Zahuranec
authors.forename: Gisela C
authors.initials: GC
authors.lastname: Mueller
authors.forename: David S
authors.initials: DS
authors.lastname: Bach
authors.forename: Jadranka
authors.initials: J
authors.lastname: Stojanovska
authors.forename: Devin L
authors.initials: DL
authors.lastname: Brown
authors.forename: Lynda D
authors.initials: LD
authors.lastname: Lisabeth
authors.forename: Smita
authors.initials: S
authors.lastname: Patel
authors.forename: Rebecca M
authors.initials: RM
authors.lastname: Hughes
authors.forename: Anil K
authors.initials: AK
authors.lastname: Attili
authors.forename: William F
authors.initials: WF
authors.lastname: Armstrong
authors.forename: Lewis B
authors.initials: LB
authors.lastname: Morgenstern
mesh_terms: D000328:Adult; D000367:Age Factors; D001018:Aortic Diseases / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging; D002545:Brain Ischemia / Q000175:diagnosis* / Q000209:etiology; D017548:Echocardiography, Transesophageal; D004617:Embolism / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D054092:Foramen Ovale, Patent / Q000150:complications / Q000175:diagnosis / Q000000981:diagnostic imaging; D006331:Heart Diseases / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D058226:Plaque, Atherosclerotic / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012307:Risk Factors; D020521:Stroke / Q000175:diagnosis* / Q000209:etiology; D013927:Thrombosis / Q000150:complications / Q000175:diagnosis / Q000000981:diagnostic imaging; D013997:Time Factors