title: Magnetic resonance blood flow measurements in the follow-up of pediatric patients with aortic coarctation - a re-evaluation.
abstract: BACKGROUND
  Previous studies have suggested the feasibility of a non-invasive quantification of vascular trans-stenotic pressure gradients (DeltaP) by phase-contrast MR imaging (PC-MRI). Our purpose was to assess the value of MRI estimated pressure gradients as a screening tool for assessing hemodynamically significant (re-)coarctation of the aorta (CoA) in pediatric patients.
  
  
  METHODS
  Forty-three patients (median age (range), 16 (5-25) years) with CoA (38 postoperative and 5 native) and clinically suspected hemodynamically significant stenosis underwent quantitative and semi-quantitative PC-MRI blood flow measurements and 3D MR-angiography, Doppler ultrasound (US) and conventional catheter angiography (CCA, n=20). Estimated DeltaP for each modality was correlated with percent stenosis.
  
  
  RESULTS
  The percent stenosis correlated only moderately with DeltaP(MRI) (r=0.55, p<0.001) and DeltaP(CCA) (r=0.48, p<0.001). Only moderate correlations were observed between DeltaP(MRI) vs. DeltaP(CCA) (r=0.54, p=0.02) and vs. DeltaP(US) (r=0.40, p=0.01). In contrast, semi-quantitative analysis of PC-MRI flow profiles predicted with good sensitivity (88%) and specificity (88%) who would be operated on. Thirteen patients met hemodynamic and percent stenosis criteria by CCA for surgical intervention.
  
  
  CONCLUSIONS
  Measured pressure gradients using PC-MRI should be used cautiously when assessing patients for recoarctation of the aorta. The analysis of blood flow profiles by PC-MRI might be a promising alternative in assessing the hemodynamic significance of CoA.
authors.affiliation: Department of Paediatric Cardiology, University Children's Hospital, Im Neuenheimer Feld 153, 69120 Heidelberg, Germany. joachim_eichhorn@med.uni-heidelberg.de
authors.forename: Joachim G
authors.initials: JG
authors.lastname: Eichhorn
authors.forename: Christian
authors.initials: C
authors.lastname: Fink
authors.forename: Stefan
authors.initials: S
authors.lastname: Delorme
authors.forename: Siegfried
authors.initials: S
authors.lastname: Hagl
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Kauczor
authors.forename: Herbert E
authors.initials: HE
authors.lastname: Ulmer
mesh_terms: D000293:Adolescent; D000328:Adult; D001017:Aortic Coarctation / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011446:Prospective Studies; D011859:Radiography; D012008:Recurrence; D012039:Regional Blood Flow