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Chest Imaging

E3041. Thoracic Venous Anomalies: Pictorial Review, Associations, and Consequences

Mehta V,  Lowry J. Staten Island University Hospital, Staten Island, NY

Address correspondence to V. Mehta (v.mehipone@gmail.com)

Background Information: Cross-sectional imaging has allowed discovery of various venous anomalies involving the systemic and pulmonary veins. These anomalies can be isolated or associated with other anomalies and syndromes. Knowledge of these anatomic anomalies, their anatomic and syndromic associations, and any potential physiologic consequences should be familiar to all radiologists. This exhibit aims to review the various systemic and pulmonary venous anomalies within the thorax and their characteristics.

Educational Goals/Teaching Points: The goals of this exhibit are to review normal thoracic venous anatomy, present various examples of anatomic anomalies under the umbrella of systemic or pulmonary anomalies, and provide an embryologic basis of these anomalies. We will discuss each the anatomy of each anomaly with pictorial examples and illustrations. We will also discuss any additional anatomic variations and syndromes associated with the presented anomaly and any physiologic consequence of the anomaly. We will briefly discuss treatment options when appropriate.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques: Anomalies of the systemic veins are a consequence of variation in regression or persistence of certain venous structures during early fetal development. Similarly, pulmonary venous anomalies present in early fetal development as the primitive outpouching from the primitive left atrium incorporates with the developing lungs to form the pulmonary venous system. Most of these anomalies are discovered incidentally on cross-sectional imaging, often in adulthood. Some anomalies, however, may be acquired later in life as compensatory venous return. Examples of systemic venous anomalies include isolated left or duplicated superior vena cava (SVC), anomalous drainage of the right SVC, anomalous left brachiocephalic vein, absent azygos vein, azygos lobe, azygos and hemiazygos continuation of the inferior vena cava (IVC), and left IVC. Examples of pulmonary vein anomalies include variation in number of pulmonary veins, multiple different types of partial anomalous pulmonary venous connections (PAPVC), and total anomalous pulmonary venous return. Many of these can exist in isolation or in association with other abnormalities; for example, a left SVC may be isolated or associated with congenital heart disease. Physiologic consequences such as varying degrees of left to right shunting with PAPVCs or enlargement of hemizygous and intercostal veins with an absent azygos vein are examples of characteristic physiologic features of such anomalies. These can often demonstrate certain clues on radiographs like a prominent azygos arch associated with azygos continuation of IVC. CT remains an important tool that allows high-resolution anatomic understanding of such anomalies and their associated anatomic features.

Conclusion: Multiple anomalous pathways exist within the systemic and pulmonary venous circulation with varying degrees of anatomic and pathologic associations and physiologic alterations. Basic understanding of the normal anatomy, embryologic origin, and physiologic function of the venous vasculature is essential for all radiologists dealing with cross-sectional imaging of the thorax.