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.

CT / CTA

Direct visualisation of anomalous anatomy.

MRI

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

Associations

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

Prognosis

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

Differential diagnoses

  • aortopulmonary window / fenestration
truncus%20arteriosus%20type%201.jpg

Chest radiograph of a young patient with truncus arteriosus type 1

Article Source : Dr Yuranga Weerakkody, Radiopaedia

References

* 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 et.al, Persistant Truncus Arteriosus: A radiographic and angiographic study. American Journal of Roentgenology, Vol 107, 827-834: http://www.ajronline.org/cgi/content/abstract/107/4/827
* 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 et.al, Persistent truncus arteriosus: a rare finding in adults, Eur Heart J (2009) 30 (9): 1154.
* 5. Sotiria C. Apostolopoulou et.al, 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 et.al, Pictorial Essay : Nonatherosclerotic Cardiovascular Findings on MDCT Coronary Angiography: A Selection of Abnormalities, AJR 2008; 190:934-946

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