Truncus arteriosus

Truncus arteriosus is a cyanotic congenital heart anomaly where there is a single trunk supplying both the pulmonary and systemic circulation instead of a separate aorta and a pulmonary trunk 3. This can account for up to 2% of congenital cardiac anomalies and is almost always associated with a VSD to allow circulatory flow circuit completion1.

There is a lack of separation of the embryological truncus into a separate aorta and pulmonary trunk. This may result in a common truncal valve which can contain 2 - 4 cusps.

Sub types

* type I : both aorta and pulmonary arteries arise from common trunk
* type II : pulmonary arteries arise from posterior aspect of trunk
* type III : pulmonary arteries arise from either side of trunk

Radiographic features

Plain film

Often shows cardiomegaly with pulmonary plethora (mainly as result of collateral formation) and a narrow mediastinum 2.

Echocardiography / Ultrasound

Direct visualisation of a single trunk. colour doppler may additionally show flow across both ways through an associated VSD.


Direct visualisation of anomalous anatomy.


Direct visualisation of anomalous anatomy. SSFP sequences can offer additional functional assessment.


* right sided aortic arch
* persistence of primitive aortic arches
* DiGeorge syndrome


If left untreated approximately 80 % of infants die within the 1st year.

Differential diagnoses

  • aortopulmonary window / fenestration

Chest radiograph of a young patient with truncus arteriosus type 1

Article Source : Dr Yuranga Weerakkody, Radiopaedia


* 1. Barboza JM, Dajani NK, Glenn LG et-al. Prenatal diagnosis of congenital cardiac anomalies: a practical approach using two basic views. Radiographics. 22 (5): 1125-37. Radiographics (full text) - Pubmed citation
* 2. Hallerman, Persistant Truncus Arteriosus: A radiographic and angiographic study. American Journal of Roentgenology, Vol 107, 827-834:
* 3. Goo HW, Park IS, Ko JK et-al. CT of congenital heart disease: normal anatomy and typical pathologic conditions. Radiographics. 2003;23 Spec No (suppl 1): S147-65. doi:10.1148/rg.23si035501 - Pubmed citation
* 4. Felix Guenther, Persistent truncus arteriosus: a rare finding in adults, Eur Heart J (2009) 30 (9): 1154.
* 5. Sotiria C. Apostolopoulou, Original Report : "Absent" Pulmonary Artery in One Adult and Five Pediatric Patients: Imaging, Embryology, and Therapeutic Implications, AJR 2002; 179:1253-1260
* 6. Mark T. T. Takaki, Pictorial Essay : Nonatherosclerotic Cardiovascular Findings on MDCT Coronary Angiography: A Selection of Abnormalities, AJR 2008; 190:934-946

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