An 18-year-old patient, diagnosed with complex CHD in early
childhood presented with effort intolerance, NYHA class II;
SpO2 at 92%; single second-heart sound, continuous murmur
over right scapular region. Patient had not undergone an
operation for CHD.
Cine 2D FIESTA sequence showed a large conoventricular
septal defect with overriding aorta (Figure 1). Post contrast
MRA showed long segment pulmonary atresia with no
native pulmonary arteries. There was a large ( 22 mm)
aorto-pulmonary (AP) collateral (arising at T4 level), supplying
branches to all segments of the left lung. MRA also showed
a branch from the above collateral, stenotic close to its origin
( 6. 5 mm), supplying the right lung with branches to all segments
of right lung (Figure 2). MRA also showed excellent arborization
of the right pulmonary vasculature derived from the AP
collateral and rat-tailing and poor arborization of the left
pulmonary arterial vasculature (Figure 3).
Phase contrast sequences were used to study the blood
flows across the aorta, the AP collateral to left and right
lungs, the right and left pulmonary veins, and superior
and inferior vena cavae.
Systemic flows (Qs) Total pulmonary blood flow (Qp) Right pulmonary blood flow Left pulmonary blood flow Qp:Qs
4. 9 liters/minute
9. 6 liters/minute
7. 6 liters/minute
Flow pattern in the left lung showed lower peak velocity
and rapid descent as compared to the right pulmonary
flows (Figure 4).
Patient is clinically well-preserved with SpO2 greater than
90%, with an overall Qp:Qs of nearly 2:1. Anatomically looked
amenable to total correction with ventricular septal defect
closure and right-ventricle-to pulmonary artery conduit.
However flow studies (phase contrast) clearly showed that
right lung accounts for 80% of the total pulmonary blood
flow, despite being supplied by a stenotic collateral. The left
lung, supplied by an unrestrictive, large collateral, shows
low flows (20%) with flow-pattern suggestive of high
Severe pulmonary vascular disease (Eisenmengerization) of
the left lung with preservation of right lung resistances. CMR
flow studies clearly demonstrated unfavourable result for
total surgical correction.