title: Rapid left-to-right shunt quantification in children by phase-contrast magnetic resonance imaging combined with sensitivity encoding (SENSE).
abstract: BACKGROUND
  Parallel imaging by sensitivity encoding (SENSE) may considerably reduce scan time in MRI. For rapid flow quantification in children with congenital heart disease, we evaluated phase-contrast MRI (PC-MRI) techniques combined with SENSE.
  
  
  RESULTS
  In 22 pediatric patients (mean age, 7.2+/-6.2 years) with cardiac left-to-right shunt, blood flow rate in the pulmonary artery (Qp) and ascending aorta (Qs) and flow ratio Qp/Qs were determined by PC-MRI with SENSE reduction-factor 2 and 3 (SF-2 and SF-3). Additionally, we used PC-MRI with higher spatial in-plane resolution (1.6x2.1 versus 2.3x3.1 mm) with and without SF-3. Results were compared with a recently validated standard PC-MRI protocol and tested in vitro using a pulsatile flow phantom. Reduction of signal averages from 2 to 1 and application of SENSE accelerated flow measurements by a factor of 3.5 (5.2) using PC-MRI with SF-2 (SF-3) compared with standard PC-MRI. For blood flow rate through the pulmonary artery and aorta, as well as for the Qp/Qs ratio we found negligible differences of +/-3%, lower limits of agreement (mean+/-2 SD) of -7% to -18%, and upper limits of agreement (mean+/-2 SD) of +3 to +24%, demonstrating good agreement with standard PC-MRI. Mean Qp/Qs ratio by standard PC-MRI was 1.69+/-0.45 (range, 1.27 to 2.79). Interobserver variability was low, and high accuracy was confirmed in vitro for all protocols.
  
  
  CONCLUSIONS
  PC-MRI for flow quantitation may be combined with SENSE to achieve a substantive reduction of scanning time. In children with left-to-right shunt, Qp/Qs quantification is possible by PC-MRI+SF-3 in <60 seconds. Use of higher in-plane resolution did not improve measurement results.
authors.affiliation: Klinik für Angeborene Herzfehler, Herz- und Diabeteszentrum, Nordrhein-Westfalen, Ruhr-Universität Bochum, Germany. pbeerbaum@hdz-nrw.de
authors.forename: Philipp
authors.initials: P
authors.lastname: Beerbaum
authors.forename: Hermann
authors.initials: H
authors.lastname: Körperich
authors.forename: Jürgen
authors.initials: J
authors.lastname: Gieseke
authors.forename: Peter
authors.initials: P
authors.lastname: Barth
authors.forename: Matthias
authors.initials: M
authors.lastname: Peuster
authors.forename: Hans
authors.initials: H
authors.lastname: Meyer
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003326:Coronary Circulation; D005260:Female; D006330:Heart Defects, Congenital / Q000175:diagnosis*; D006801:Humans; D007223:Infant; D019028:Magnetic Resonance Imaging, Cine / Q000295:instrumentation* / Q000379:methods / Q000592:standards; D008297:Male; D015588:Observer Variation; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors