title: Noninvasive determination of coronary blood flow velocity with cardiovascular magnetic resonance in patients after stent deployment.
abstract: BACKGROUND
  In patients with coronary artery stents, no direct noninvasive coronary artery imaging is possible with magnetic resonance (MR). A well-established method for the assessment of the functional significance of a coronary lesion is the measurement of coronary flow reserve by invasive intracoronary Doppler. The purpose of the study was to determine coronary flow velocity reserve (CFVR) with MR after stent deployment.
  
  
  RESULTS
  Thirty-eight patients after successful PTCA and stent deployment were included. CFVR was measured perpendicular to the artery distal to the stent using phase-contrast velocity quantification at rest and during adenosine-stimulated hyperemia with a 1.5T MR tomograph (ACS NT, Philips). Measurements were repeated after 3 months and compared with invasive coronary angiography. In 18 patients, additional invasive Doppler flow measurements were obtained. CFVR could be determined in 29 of 38 (76%) of the patients. After 3 months, significant differences were obtained between coronary arteries with and without restenosis. Using a threshold of 1.2, a sensitivity of 83% with a specificity of 94% was achieved for > or =75% stenoses. CFVR with CMR was similar to Doppler results (r=0.87), with a mean relative difference of 7.5%.
  
  
  CONCLUSIONS
  In patients with preserved coronary microcirculating vasoreactivity that are suitable for MR coronary angiography and flow assessments, CMR measures of coronary blood flow velocities reserve may be used to detect in-stent restenosis.
authors.affiliation: Internal Medicine/Cardiology, German Heart Institute, Augustenburger Platz 1, D-13353 Berlin, Germany. eike.nagel@dhzb.de
authors.forename: Eike
authors.initials: E
authors.lastname: Nagel
authors.forename: Thomas
authors.initials: T
authors.lastname: Thouet
authors.forename: Christoph
authors.initials: C
authors.lastname: Klein
authors.forename: Simon
authors.initials: S
authors.lastname: Schalla
authors.forename: Axel
authors.initials: A
authors.lastname: Bornstedt
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schnackenburg
authors.forename: Jürgen
authors.initials: J
authors.lastname: Hug
authors.forename: Ernst
authors.initials: E
authors.lastname: Wellnhofer
authors.forename: Eckart
authors.initials: E
authors.lastname: Fleck
mesh_terms: D001783:Blood Flow Velocity; D003326:Coronary Circulation; D023903:Coronary Restenosis / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology; D015150:Echocardiography, Doppler; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015607:Stents / Q000009:adverse effects*