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. CONCLUSION: 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.
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. CONCLUSION: 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.