title: Quantification of pulmonary autograft characteristics using magnetic resonance imaging.
abstract: OBJECTIVE
  The diameters and distensibility of the native pulmonary root and their effect on pulmonary autograft performance were examined pre- and postoperatively using cardiac ultrasound and magnetic resonance imaging (MRI).
  
  
  METHODS
  Eight patients undergoing the Ross procedure were prospectively involved. The diameters of the native aortic, native pulmonary and autograft roots were measured at the level of the annulus, sinus, sinotubular junction and in the main root using MRI through the cardiac cycle. Ultrasound was also used to estimate the degree of regurgitation, both pre- and postoperatively.
  
  
  RESULTS
  The pulmonary root implanted into the systemic circulation increased in size but decreased in distensibility significantly at the sinus, sinotubular junction and main root, but not at the annulus. Postoperatively, the pulmonary autograft annulus showed a similar size and distensibility to that of the native aortic annulus. A wide range of aortic annular sizes (22-30 mm) produced clinically competent valves postoperatively. All undersized pulmonary valves showed only trivial regurgitation postoperatively. Although there was no clear correlation between root shape and valve insufficiency, two patients with mild and moderate autograft regurgitation both had divergent pulmonary roots (diameter at sinotubular junction > annulus diameter) preoperatively.
  
  
  CONCLUSIONS
  The pulmonary autograft using the root replacement technique functioned well in all but one case. The shape of the native pulmonary root may be a determinant of early autograft regurgitation, as well as the diameter and the size mismatch between the great arteries.
authors.affiliation: School of Mechanical Engineering, University of Leeds, Leeds, UK.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Reid
authors.forename: Peter G
authors.initials: PG
authors.lastname: Walker
authors.forename: John
authors.initials: J
authors.lastname: Fisher
authors.forename: Zsolt L
authors.initials: ZL
authors.lastname: Nagy
authors.forename: John P
authors.initials: JP
authors.lastname: Ridgway
authors.forename: Mohan U
authors.initials: MU
authors.lastname: Sivananthan
authors.forename: Kevin G
authors.initials: KG
authors.lastname: Watterson
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011446:Prospective Studies; D011664:Pulmonary Valve / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000637:transplantation*; D014463:Ultrasonography