Case report

The following images demonstrate a case of the inferior vena cava interruption with azygos venous return and with a pseudo vena cava inferior which was represented by an abnormal venous return from the right fetal kidney.

Images 1, 2: Unusual aspect of the “three-vessel view” with a supernumerary arch corresponding to a dilated azygos arch (AA).

Images 3, 4: The images show a transverse section at the level of the aortic and azygos arches running by the both sides of the trachea (*).

Images 5, 6: The images show an axial section of the thorax. The descending aorta (Ao) and dilated azygos vein (arrow) behind the left atrium of the heart (LA) can be seen.

Images 7, 8: The images show transverse scan of the fetal abdomen demonstrating absence of the inferior vena cava and markedly visible azygos vein (arrow) positioned next to the aorta (*).

Images 9, 10: The images show coronal color Doppler scan of the abdominal aorta (Ao) which is crossed posteriorly by the azygos vein (AV).

Video 1: The video shows coronal color Doppler scan of the abdominal aorta (Ao) which is crossed posteriorly by the azygos vein (AV).

Images 11, 12: The images show similar color Doppler scan as the images 9 and 10 taken little bit more posteriorly. An "S" shape of the azygos vein (AV) crossing the aorta (Ao) from behind can be seen.

Image 13: The image shows a transverse scan of the fetal abdomen at the level of the normal confluence of the three hepatic veins.

Image 14: The image shows normal appearance of the four-chamber view of the heart.

Images 15, 16: The images show a short axis view of the heart with normal arrangement of the great vessels. Note the large superior vena cava (*).

Images 17, 18: Coronal section of the thorax showing the aorta (Ao) and azygos vein (arrows).

Images 19, 20: Transverse scans of the fetal abdomen showing normal position of the fetal stomach (S).

All the images above led us to the diagnosis of the inferior vena cava interruption with the azygos vein continuation and with normal visceral situs.

Images 21, 22, 23, and 24: The following images are confusing because of the presence of a vessel (arrows) coming from the caudal region of the fetus and joining the right atrium (RA). As the color Doppler images bellow show, the vessel turned out to be an aberrant venous return from the right fetal kidney connected directly to the right atrium of the heart.

Images 25, 26: The images show color Doppler views of the venous return of the right fetal kidney (RK). Note the upward direction of the vessel.

Video 2: The video shows color Doppler view of the venous return of the right fetal kidney (RK). Note the upward direction of the vessel.

Images 27, 28: The images demonstrate a 3D rendering of the vascularization showing the relationship of the aorta (Ao), azygos vein (AV), hepatic veins (HV) and renal vessels. The right renal artery arises normally from the descending aorta, but the venous return from the right kidney runs via a prolonged vessel (RRV) which courses directly to the right atrium (RA) of the heart.

Image 29: The image shows similar 3D rendering of the vessel"s arrangement as shown on the previous images 27 and 28. Ao - aorta, Av - azygos vein, RA - right atrium of the heart, RRV - right renal vein (in blue), RRA right renal artery (in red), HV - hepatic veins.

Images 15, 16: The images show 3D rendering of focused on the venous return from the right kidney (arrows) and on the hepatic veins (HV). Note the hepatic vein (HV) coming from the anterior part of the fetus, and the right renal venous return (arrows) coming from the posterior part of the fetus imitating the vena cava inferior (“pseudo inferior vena cava“) which was clearly seen on the images 21-24.

Teaching point: The visualization of the two vessels joining the right atrium on the bi-caval parasagittal view cannot rule out the interruption of the inferior vena cava all the time. The only aspect that should be attract our attention in this view, is the difference between the calibers of the superior vena cava and the “pseudo inferior vena cava" as was shown in our case. To confirm this observation would require a comparison of several similar cases of the vena cava inferior interruption. If you have such a case, feel free to send some images or videos to the author"s e-mail: manson.francois@gmail.com. Thank you very much for your collaboration.