title: A computer-aided diagnostic algorithm improves the accuracy of transesophageal echocardiography for left atrial thrombi: a single-center prospective study.
abstract: OBJECTIVE
  We investigated whether transesophageal echocardiography (TEE) assisted with a computer-aided diagnostic (CAD) algorithm was superior to TEE in diagnosing left atrial (LA)/left atrial appendage (LAA) thrombi in patients with atrial fibrillation (AF) in a single prospective study.
  
  
  METHODS
  Transesophageal echocardiography was performed in patients with AF, and images were reconstructed. Gray level co-occurrence matrix-based features were calculated and then classified using an artificial neural network. The original data and processed images by the CAD system were studied by 5 radiologists independently in a blind manner. The diagnostic performance of each radiologist was evaluated.
  
  
  RESULTS
  One hundred thirty patients with AF were investigated. Thirty-one patients (23.9%) had a diagnosis of LA/LAA thrombi. The mean sensitivity ± SD of TEE for LA/LAA thrombi was 0.933 ± 0.027, which was noticeably improved by CAD (0.955 ± 0.021; P < .05). The specificity of TEE was 0.811 ± 0.055, which was markedly lower than that by TEE plus CAD (0.970 ± 0.009; P < .05). The positive predictive value of TEE was low (0.613 ± 0.073) compared to that of TEE plus CAD (0.908 ± 0.027; P < .001), whereas the negative predictive values were comparable for TEE, CAD, and TEE plus CAD. Diagnosis of an LA/LAA thrombus by TEE plus CAD had a higher accuracy rate (0.966 ± 0.011) than that by TEE (0.840 ± 0.047; P < .01). The mean area under the receiver operating characteristic curve (Az) for TEE was 0.834 ± 0.009 (95% confidence interval [CI], 0.815-0.852), which was markedly lower than the Az for TEE plus CAD (0.932 ± 0.005; 95% CI, 0.921-0.943). The use of CAD significantly improved the Az values for all 5 radiologists (P < .001).
  
  
  CONCLUSIONS
  The CAD algorithm significantly improves the diagnostic accuracy of TEE for LA/LAA thrombi in patients with AF.
authors.affiliation: Department of Cardiology, First Affiliated Hospital of Harbin Medical University, 23 Youzheng St, Nangang District, 150001 Harbin City, Heilongjiang Province, China. xiufenq@yahoo.com.cn.
authors.forename: Lin
authors.initials: L
authors.lastname: Sun
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Ying Tao
authors.initials: YT
authors.lastname: Zhang
authors.forename: Jing Xia
authors.initials: JX
authors.lastname: Shen
authors.forename: Feng Hua
authors.initials: FH
authors.lastname: Xue
authors.forename: Heng Da
authors.initials: HD
authors.lastname: Cheng
authors.forename: Xiu Fen
authors.initials: XF
authors.lastname: Qu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001281:Atrial Fibrillation / Q000150:complications / Q000000981:diagnostic imaging*; D017548:Echocardiography, Transesophageal / Q000379:methods*; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013927:Thrombosis / Q000000981:diagnostic imaging* / Q000209:etiology
keywords: computer-aided diagnosis; left atrial/left atrial appendage thrombus; morphologic analysis; texture analysis; transesophageal echocardiography; vascular ultrasound