title: Enhancement of contrast echocardiography by image variability analysis.
abstract: BACKGROUND
  Although there have been recent advances in echocardiography, many studies remain suboptimal due to poor image quality and unclear blood-myocardium border. We developed a novel image processing technique, cardiac variability imaging (CVI), based on the variance of pixel intensity values during passage of ultrasound microbubble contrast into the left ventricle chamber, with the aim of enhancing endocardial border delineation and image quality.
  
  
  RESULTS
  CVI analysis was performed on simulated data to test and verify the mechanism of image enhancement. Then CVI analysis was applied to echocardiographic images obtained in two different clinical studies, and still images were interpreted by expert reviewers. In the first study (N = 15), using contrast agent EchoGen, the number of observable wall segments in end-diastolic images, for example, was significantly increased by CVI (4.93) as compared to precontrast (3.28) and contrast images (3.36), P < 0.001 for both comparisons to CVI. In the second study (N = 8), using contrast agent Optison, interobserver variability of manually traced end-diastolic volumes was significantly decreased using CVI (22.3 ml) as compared to precontrast (63.4) and contrast images (49.0), P < 0.01 for both comparisons to CVI.
  
  
  CONCLUSIONS
  CVI can substantially enhance endocardial border delineation and improve echocardiographic image quality and image interpretation.
authors.affiliation: Robin Medical, Inc., Baltimore, MD 21203, USA.
authors.forename: B J
authors.initials: BJ
authors.lastname: Fetics
authors.forename: E Y
authors.initials: EY
authors.lastname: Wong
authors.forename: T
authors.initials: T
authors.lastname: Murabayashi
authors.forename: G S
authors.initials: GS
authors.lastname: Nelson
authors.forename: M M
authors.initials: MM
authors.lastname: Cohen
authors.forename: C E
authors.initials: CE
authors.lastname: Rochitte
authors.forename: J L
authors.initials: JL
authors.lastname: Weiss
authors.forename: D A
authors.initials: DA
authors.lastname: Kass
authors.forename: E
authors.initials: E
authors.lastname: Nevo
mesh_terms: D000465:Algorithms; D004452:Echocardiography; D004699:Endocardium / Q000000981:diagnostic imaging; D005583:Fourier Analysis; D006352:Heart Ventricles / Q000000981:diagnostic imaging; D006801:Humans; D007089:Image Enhancement; D008962:Models, Theoretical; D015588:Observer Variation