title: Mechanical valve evaluation with four-dimensional computed tomography.
abstract: OBJECTIVE
  Echocardiography or cinefluoroscopy are standard modalities for evaluating implanted mechanical valve prostheses. The aim of the present study was to evaluate the validity of multidetector computed tomography (MDCT) with three-dimensional image reconstruction in a cine mode (four-dimensional (4D)-CT) for evaluating the functional and morphological findings of implanted mechanical valves.
  
  
  METHODS
  A total of 37 patients who had received 45 implanted mechanical valves was studied using electrocardiogram-gated (16- or 256-row) MDCT. The mean age of patients at the MDCT examination was 65.1 +/- 10.1 years (range: 0.5-85 years). The series included 18 aortic and 27 mitral mechanical valves, in addition to 36 bileaflet valves and nine monoleaflet valves. Fifteen patients had atrial fibrillation, and seven had permanent pacemaker implantation. Volume-rendering 3D and multiplanar reformations were obtained, and valve leaflet movement was evaluated using reformatted images in a cine mode (4D images). The quality of mechanical valve leaflet visualization was scored on a four-grade scale (Leaflet index), and the level of artifact was also scored (Artifact index).
  
  
  RESULTS
  There were two stuck-valve patients who required emergency surgery. Stuck mechanical leaflets could be visualized using 4D-CT. In all of the bileaflet mechanical valves the valve leaflet motions were visualized with 4D images. In contrast, in four of nine valves with monoleaflet valves the opening and closing angles could not be visualized because of radio-opacity of the leaflet. The median Leaflet index was 3.7 +/- 0.8, and the median Artifact index 3.0 + 0.8. The Leaflet and Artifact indices were significantly lower in monoleaflet valves (p < 0.0001, p = 0.0037, respectively). When using 256-row MDCT the Artifact index was superior to that achieved with 16-row MCDT, but was without statistical difference (p = 0.0654).
  
  
  CONCLUSIONS
  Functional and morphological evaluations of mechanical valves with 4D-MDCT is promising in patients with bileaflet mechanical valves. However, the evaluation of monoleaflet valves is limited.
authors.affiliation: Department of Cardiovascular Surgery, Fukui Cardiovascular Center, Fukui, Japan. snumat@yahoo.co.jp
authors.forename: Satoshi
authors.initials: S
authors.lastname: Numata
authors.affiliation: Department of Cardiovascular Surgery, Fukui Cardiovascular Center, Fukui, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Tsutsumi
authors.affiliation: Department of Cardiovascular Surgery, Fukui Cardiovascular Center, Fukui, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Monta
authors.affiliation: Department of Cardiovascular Surgery, Fukui Cardiovascular Center, Fukui, Japan.
authors.forename: Sachiko
authors.initials: S
authors.lastname: Yamazaki
authors.affiliation: Department of Cardiovascular Surgery, Fukui Cardiovascular Center, Fukui, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Seo
authors.affiliation: Department of Cardiovascular Surgery, Fukui Cardiovascular Center, Fukui, Japan.
authors.forename: Shohei
authors.initials: S
authors.lastname: Yoshida
authors.affiliation: Department of Cardiovascular Surgery, Fukui Cardiovascular Center, Fukui, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Samura
authors.affiliation: Department of Cardiovascular Surgery, Fukui Cardiovascular Center, Fukui, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Ohashi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000000981:diagnostic imaging / Q000601:surgery*; D016477:Artifacts; D055424:Cardiac-Gated Imaging Techniques; D016009:Chi-Square Distribution; D004562:Electrocardiography; D005260:Female; D056973:Four-Dimensional Computed Tomography; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation*; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000601:surgery*; D061330:Multidetector Computed Tomography; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000601:surgery; D011237:Predictive Value of Tests; D011474:Prosthesis Design; D011857:Radiographic Image Interpretation, Computer-Assisted; D012086:Reoperation; D015203:Reproducibility of Results; D012189:Retrospective Studies; D016896:Treatment Outcome