Disparity between ratios of diameters and blood flows in central pulmonary arteries in postoperative congenital heart disease using MRI.
OBJECTIVE
To compare the relative severity of stenoses of right or left pulmonary arteries with differences in flow to each lung after repair of congenital heart disease (CHD).


METHODS
A total of 15 patients with postoperative congenital heart disease underwent MRI to evaluate branch pulmonary artery stenoses. Spin-echo images and MR angiography were used to assess morphology, and velocity-encoded cine (VEC) MRI was used to measure flow in the right and left pulmonary arteries. The ratios of the narrowest diameters of the right to left pulmonary arteries (R/L size) and right to left pulmonary arterial flow (R/L flow) were compared using Spearman's correlation. F test was used to assess the significance of the regression coefficients.


RESULTS
R/L size ratio varied from 0.50 to 2.66, while the R/L flow ratio varied from 0.36 to 12.02. There was an exponential relationship between R/L size and R/L flow, with r2=0.78 and P=0.001. However, severity of morphologic stenoses was not clinically useful for predicting flow reduction. Prediction residuals ranged from -136% to 54% of the true R/L flow.


CONCLUSIONS
Anatomical evaluation of the pulmonary arteries does not predict accurately differential blood flow in patients with pulmonary stenoses. Therefore, blood flow measurements are essential when considering the need for further surgical or interventional procedures.
Ordovás
Karen G
KG
Department of Radiology, University of California, San Francisco, San Francisco, California 94143-0628, USA.
Tan
Christopher
C
Reddy
Gautham P
GP
Weber
Oliver M
OM
Lu
Ying
Y
Higgins
Charles B
CB
D000293:Adolescent; D000328:Adult; D001783:Blood Flow Velocity; D002648:Child; D002675:Child, Preschool; D003251:Constriction, Pathologic; D005260:Female; D006330:Heart Defects, Congenital / Q000473:pathology* / Q000503:physiopathology / Q000628:therapy; D006801:Humans; D007223:Infant; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D011651:Pulmonary Artery / Q000473:pathology* / Q000502:physiology*; D012039:Regional Blood Flow; D012044:Regression Analysis