title: Dynamic four-dimensional computed tomography (4D CT) imaging for re-entry risk assessment in re-do sternotomy - first experience.
abstract: BACKGROUND
  Repeat cardiac surgeries are well known to have higher rates of complications, one of the important reasons being injuries associated with re-do sternotomy. Routine imaging with CT can help to minimise this risk by pre-operatively assessing the anatomical relation between the sternum and the underlying cardiovascular structures, but is limited by its inability to determine the presence and severity of functional tethering and adhesions between these structures. However, with the evolution of wide area detector MD CT scanners, it is possible to assess the presence of tethering using the dynamic four-dimensional CT (4D CT) imaging technique.
  
  
  METHODS
  Nineteen patients undergoing re-do cardiac surgery were pre-operatively imaged using dynamic 4D CT during regulated respiration. The datasets were assessed in cine mode for presence of differential motion between sternum and underlying cardiovascular structures which indicates lack of significant tethering.
  
  
  RESULTS
  Overall, there was excellent correlation between preoperative imaging and intraoperative findings. The technique enabled our surgeons to meticulously plan the procedures and to avoid re-entry related injuries.
  
  
  CONCLUSIONS
  Our initial experience shows that dynamic 4D CT is useful in risk stratification prior to re-do sternotomy by determining the presence or absence of tethering between sternum and underlying structures based on assessment of differential motion. Furthermore we determined the technique to be superior to non-dynamic assessment of retrocardiac tethering.
authors.affiliation: Department of Diagnostic Imaging, Monash Health, Melbourne, Vic, Australia. Electronic address: h4harishn@yahoo.co.in.
authors.forename: Harish
authors.initials: H
authors.lastname: Narayanan
authors.affiliation: Department of Cardiovascular Surgery, Monash Health, Melbourne, Vic, Australia.
authors.forename: Fabiano F
authors.initials: FF
authors.lastname: Viana
authors.affiliation: Department of Cardiovascular Surgery, Monash Health, Melbourne, Vic, Australia.
authors.forename: Julian A
authors.initials: JA
authors.lastname: Smith
authors.affiliation: Faculty of Science, University Of Melbourne, Melbourne, Vic, Australia.
authors.forename: Nicholas K
authors.initials: NK
authors.lastname: Roumeliotis
authors.affiliation: Faculty of Commerce, University Of Melbourne, Melbourne, Vic, Australia.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Troupis
authors.affiliation: Department of Diagnostic Imaging, Monash Health, Melbourne, Vic, Australia.
authors.forename: Marcus P
authors.initials: MP
authors.lastname: Crossett
authors.affiliation: Department of Diagnostic Imaging, Monash Health, Melbourne, Vic, Australia; Monash Cardiovascular Research Centre, Monash Health, Melbourne, Vic, Australia.
authors.forename: John M
authors.initials: JM
authors.lastname: Troupis
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D056973:Four-Dimensional Computed Tomography; D006801:Humans; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care; D012086:Reoperation; D018570:Risk Assessment / Q000379:methods; D056346:Sternotomy / Q000009:adverse effects*; D013249:Sternum; D000267:Tissue Adhesions / Q000000981:diagnostic imaging* / Q000209:etiology
keywords: Differential motion; Dynamic CT; Four-dimensional CT; Re-do sternotomy; Wide area detector CT