title: Echocardiographic image tracker with a speckle adaptive noise reduction filter for the automatic measurement of the left atrial volume curve.
abstract: OBJECTIVE
  Since tracking accuracy in left atrial (LA) images decreases due to low image quality around the LA in the apical view, a practical tracking method for LA images has not yet been proposed. The aim of this study was to assess an accurate and high-speed LA volume tracking (LAVT) method for the automatic measurement of LA volume (LAV) curves.
  
  
  RESULTS
  We used three approved protocols in this study: (i) LAV curves were measured by LAVT on computer-simulated images; (ii) in 20 healthy volunteers, we assessed the feasibility and accuracy of this method compared with expert's measurements; and (iii) echocardiography and multi-detector row computed tomography (MDCT) imaging were performed on the same day in 20 patients with suspected coronary artery disease. On computer-simulated images, mean absolute percentage LAVT error in one cardiac cycle was 3% in filtered images and 16% in original images. In 20 healthy volunteers, there are strong correlations between LAVT and the expert's LA measurements (LA maximum volume; R = 0.93, P < 0.001). In 400 LA images with 20 patients, an excellent correlation was obtained between LAVs using echocardiography and MDCT (R = 0.98, P < 0.001), with a small bias (-14% of the mean) and narrow limits of agreement (+15% of the mean). The mean time required for the LAVT analysis was 1.8 min, for the MDCT analysis was 35.8 min, and for the manual echocardiographic analysis was 14.0 min.
  
  
  CONCLUSIONS
  This LAVT method is fast, valid, accurate, and reproducible for determining LAV in both simulated images and the clinical setting.
authors.affiliation: Department of Cardiovascular Medicine, University Hospital of Tokushima, 2-50-1, Kuramoto-cho, Tokushima 770-8504, Japan.
authors.forename: Kenya
authors.initials: K
authors.lastname: Kusunose
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Chono
authors.forename: Tomotsugu
authors.initials: T
authors.lastname: Tabata
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Yamada
authors.forename: Masataka
authors.initials: M
authors.lastname: Sata
mesh_terms: D000328:Adult; D000368:Aged; D016279:Atrial Function, Left; D016022:Case-Control Studies; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D004452:Echocardiography / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008875:Middle Aged; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D014057:Tomography, X-Ray Computed
keywords: Echocardiography; Image tracking; Left atrium; Noise reduction; Speckle