title: In vivo variability in quantitative coronary ultrasound and tissue characterization measurements with mechanical and phased-array catheters.
abstract: BACKGROUND
  Both mechanical and phased-array catheters are used in clinical trials to assess quantitative parameters. Only limited evaluation of the in vivo agreement of volumetrical measurements between such systems has been performed, despite the fact that such information is essential for the conduction of atherosclerosis regression trials.
  
  
  RESULTS
  We prospectively evaluated the agreement in morphometric measurements and intravascular ultrasound (IVUS)-based plaque characterization between a 40 MHz rotating transducer (3.2 F Atlantis, Boston Scientific Corp.) and a 20 MHz phased-array catheter (2.9 F Eagle Eye, Volcano Therapeutics, Rancho Cordova, California) in 16 patients. Lumen (7.3+/-2.0 mm(2) vs. 6.7+/-1.8 mm(2), p=0.001) and vessel (11.8+/-3.3 mm(2) vs. 11.0+/-2.9 mm(2), p=0.02) cross-sectional areas (CSA) were significantly greater with the 20 MHz system. Plaque CSA measurements showed no significant difference between systems (4.4+/-2.3 mm(2) vs. 4.4+/-2.1). The relative differences were less than 10% for the three variables. On IVUS-based tissue characterization (13 patients), calculated percentage hypoechogenic volume was significantly higher for the 20 MHz system (96.7+/-2.38 vs. 88.4+/-5.53, p<0.0001).
  
  
  CONCLUSIONS
  Quantitative IVUS analyses display significant catheter type-dependent variability. It is unclear whether the variability reflects overestimation of measurements with the phased-array or underestimation with the mechanical system. Although plaque burden measurements did not differ significantly between systems, it appears prudent to recommend the use of a single system for progression/regression studies.
authors.affiliation: Thoraxcenter, Erasmus Medical Center, Bd406, Dr. Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands.
authors.forename: Gastón A
authors.initials: GA
authors.lastname: Rodriguez-Granillo
authors.forename: Eugène P
authors.initials: EP
authors.lastname: McFadden
authors.forename: Jiro
authors.initials: J
authors.lastname: Aoki
authors.forename: Carlos A G
authors.initials: CA
authors.lastname: van Mieghem
authors.forename: Evelyn
authors.initials: E
authors.lastname: Regar
authors.forename: Nico
authors.initials: N
authors.lastname: Bruining
authors.forename: Patrick W
authors.initials: PW
authors.lastname: Serruys
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014159:Transducers; D018084:Ultrasonography, Interventional / Q000379:methods*