Fig. 1

Fetal MRI and post-partum MRI/CT of complex vascular malformation. Fetal MRI using dedicated T2-weighted sequences reveal extensive venous malformation along the entire left leg (a) extending along the pelvis and lower back (b). c Large venous channel (arrow) raised suspicion of a large persistent marginal vein. d Healthy right leg in comparison. e Extension of the malformation in the retroperitoneal space. f Post-natal phlebography depicting large marginal vein together with extensive venous malformation of the lower and upper leg with extension into the pelvis (asterisk). Large blood volumes trapped in the marginal vein induced a localized consumptive coagulopathy in the child requiring immediate anticoagulation upon delivery. g Postnatal MRI revealing early arterial filling of an additional mesenteric arteriovenous malformation in the same patient, being asymptomatic at time of diagnosis. The course of the marginal vein, as depicted on MRI (h) and CT (i) showing large venous drainage into the pelvis (asterisk). j Transverse CT image in the arterial phase demonstrating multiple AV fistula paraspinal and along the left hip joint (arrows) together with the not yet contrasted marginal vein (asterisk). k Venous phase CT depicting the extension of intraabdominal, retroperitoneal, and paraspinal venous cavities with infiltration of the spinal canal (arrow) by the large slow-flow malformation, at time with contrast in the large marginal vein (asterisk). The large venous malformations required multiple rounds of image-guided embolization followed by stepwise surgery of the marginal vein