Anatomical associations and radiological characteristics of Scimitar syndrome on CT and MR

Purpose: To report the anatomical associations and radiological characteristics of Scimitar syndrome on CT and MR. Materials and methods: Retrospective review of the medical records between February 2001 and February 2016 was performed. To identify patients, radiological reports were queried for “Scimitar” or “partial anomalous pulmonary venous return.” Patients with radiological findings of Scimitar syndrome were included. Patients without cross-sectional imaging were excluded. Patients’ demographics, radiologic images, and medical notes were reviewed. Two radiologists re-read the available imaging studies. Images were reviewed for Scimitar syndrome confirmation, number and location of Scimitar vein drainage, number of lobes drained by the Scimitar vein, and right pulmonary artery and lung hypoplasia. In addition, the number of pulmonary veins draining into the left atrium, left sided anomalous pulmonary veins, congenital heart disease, aortic arch anomalies, cardiac dextroposition, right ventricular enlargement, pulmonary artery enlargement, and elevated QP:QS ratios were identified. Other associated anomalies including the presence of an anomalous feeding artery and pulmonary sequestration, abnormal lobar pattern, localized bronchiectasis, horseshoe lung, accessory diaphragm, diaphragmatic hernia, vertebral anomalies, and genitourinary tract anomalies were reviewed. Results: Sixteen patients (3 males, 13 females; mean age 39.5 years, range 14 days–72 years) with confirmed Scimitar syndrome on CT and MR imaging were identified. The Scimitar vein drained to the infra-diaphragmatic inferior vena cava (IVC) in ten patients and to the supra-diaphragmatic IVC in six patients. The most common associated anomalies were right ventricle enlargement (93.3%), variant lobar pattern of the right lung (92.9%), enlarged pulmonary arteries (60%), and cardiac dextroposition (50%). Conclusion: Recognizing the radiologic characteristics and anatomical associations of Scimitar syndrome is important as features of the primary condition and associated anomalies may have implications in surgical management.