•Congenital (0.002~0.044%)
•Partial > Complete
•Associate with VSD, PDA, MS, TOF…
•Partial absence
– Herniation of LA appendage or LV ➔ fatal myocardial strangulation
•Imaging findings
– Leftward displacement of the heart (more common in complete absence)
– Prominent PA and interposed lung tissue
➔ radiolucent zone btw MPA and the aorta
– Partial prominence of left heart border
– Accentuate in the left lateral position
Images from The International Journal of Cardiovascular Imaging 18: 67–73, 2002.