Pictorial essay. Current evaluation of the patient with abnormal visceroatrial situs.

Patients suspected of having derangement of solitus asymmetry should be evaluated individually to determine abdominal visceral and vascular arrangement and to investigate associated problems. This evaluation should begin with plain films to assess cardiac and gastric positions and pulmonary vascularity. Assessment of the bronchial branching patterns should be attempted in all cases. Sonography will delineate the presence or absence of splenic tissue and the anatomy and relationships of the cava and the portal vein. When no spleen is found and the pulmonary vascularity appears congested, a subdiaphragmatic total anomalous pulmonary venous connection should be suspected and verified. If there are splenuli in the retrogastric area, particular attention should be paid to the status of the gallbladder, especially in children who do not have congenital heart disease. Selective spleen scans can confirm the presence of splenic tissue. The high cost and sedation requirement of MR would suggest that it be reserved for cases in which sonography is unable to answer the pertinent questions.