Situs Inversus

  • Etiology: Congenital
  • Imaging CXR: Discordance between position of cardiac apex and stomach
    — Note: A CXR mislabeled left-right is more common than situs inversus on a CXR so all new diagnoses should be questioned
  • DDX:
  • Complications:
  • Treatment:
  • Clinical:

Radiology Cases of Situs Inversus

CT of interrupted aortic arch
Axial CT with contrast of the heart (above), obtained in a venous phase, shows discontinuity of the ascending and descending aorta while the sagittal image (below right) shows a dilated patent ductus arteriosus reconstituting the descending aorta and the coronal image (below left) shows dextrocardia.
CXR of heterotaxy syndrome and upper GI of malrotation without midgut volvulus
CXR AP (above) shows the cardiac apex to be in the right hemithorax and the gastric bubble to be in the left upper quadrant. AP image from an upper GI (below) shows the ligament of Treitz to be in the right upper quadrant. There is no evidence of duodenal obstruction. The proximal jejunum is also in the right upper quadrant.
CXR of Kartagener syndrome
CXR AP shows situs inversus with the cardiac apex in the right hemithorax, the stomach bubble in the right abdomen and mild thickening of the airways centrally.
US and upper GI of malrotation without midgut volvulus in heterotaxy syndrome
Transverse color doppler US of the abdomen (below left) shows an apparent reversal of the normal positions of the superior mesenteric artery and superior mesenteric vein. This is confirmed on the spectral doppler US of the aforementioned mesenteric vessels (above). AP image from an upper GI exam (below right) shows situs inversus with levocardia and the stomach in the right upper quadrant. The duodenum is redundant and the duodenal jejunal junction is over the right pedicle of the T11 vertebral body. The cecum was in the midline.
AXR of lower extremity peripherally inserted central catheter / PICC in a left-sided inferior vena cava in a patient with situs inversus
AXR AP shows a left lower extremity PICC and a right femoral venous catheter both of whose tips project over a left-sided inferior vena cava. An umbilical venous catheter tip projects over the ductus venosus. An umbilical arterial catheter tip projects at the level of T9. Nasogastric tube tip projects over the stomach in the right upper quadrant. Feeding tube tip projects transpylorically over the duodenal bulb. The cardiac apex is in the right chest.