Congenital pulmonary airway malformation (CPAM) can be detected in utero with both ultrasound and MRI.

An important ratio when assessing a fetal CPAM is the ratio between the volume of the CPAM and the fetal head circumference (HC). The HC is essentially a surrogate for the fetal age.

A CVR >1.6 or a CPAM with a dominant cyst increases the fetal risk of fetal hydrops. In this case, the CVR <1.0.

Thanks to Steve Horii MD for this case.