title: Comparison of magnetic resonance imaging and transesophageal echocardiography in detection of thrombus in the left atrial appendage.
abstract: OBJECTIVE
  A noninvasive technique of visualizing the left atrial appendage (LAA) and its thrombus in patients with atrial fibrillation would be of great interest. This study examined the utility of MRI for the assessment of thrombus in the LAA.
  
  
  METHODS
  We evaluated 50 subjects with nonrheumatic continuous atrial fibrillation and a history of cardioembolic stroke. Each patient received an MRI and a transesophageal echocardiography (TEE) on the same day for thrombus detection in the LAA. Both double- and triple-inversion recovery sequences were used for the MRI evaluations.
  
  
  RESULTS
  In all subjects, the LAA was readily visualized with MRI. High-intensity masses in the LAA were clearly distinguishable from the LAA wall in the triple-inversion recovery sequences. Concordance between detection of high-intensity mass with MRI and thrombus with TEE was high: no mass (MRI), no thrombus (TEE), 31 patients; mass (MRI), thrombus (TEE), 16 patients; and mass (MRI), no thrombus (TEE), 3 patients (overall kappa=0.876, SE=0.068).
  
  
  CONCLUSIONS
  MRI is a noninvasive and reproducible modality for thrombus detection in the LAA of patients with nonrheumatic continuous atrial fibrillation and previous cardioembolic stroke.
authors.affiliation: Second Department of Internal Medicine, Kagawa Medical University, 1750-1 Ikenobe, Miki-Cho, Kagawa 761-0793, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Ohyama
authors.forename: Naohisa
authors.initials: N
authors.lastname: Hosomi
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Takahashi
authors.forename: Katsufumi
authors.initials: K
authors.lastname: Mizushige
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Osaka
authors.forename: Masakazu
authors.initials: M
authors.lastname: Kohno
authors.forename: James A
authors.initials: JA
authors.lastname: Koziol
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D020517:Atrial Appendage / Q000000981:diagnostic imaging* / Q000473:pathology; D001281:Atrial Fibrillation / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging; D017548:Echocardiography, Transesophageal; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D055502:Secondary Prevention; D020521:Stroke / Q000209:etiology / Q000517:prevention & control; D013927:Thrombosis / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging