Type:
Educational Exhibit
Keywords:
Observational, Retrospective, Congenital, Contrast agent-intravenous, CT-Angiography, CT, Cardiac, Performed at one institution
Authors:
S. Kaushik1, P. Gupta2, R. AGARWAL3, S. K. Puri1; 1New Delhi/IN, 2New Delhi, De/IN, 3Amritsar/IN
DOI:
10.26044/ecr2020/C-05781
Background
SVP is characterized by admixture of pulmonary and systemic venous blood at the atrial or ventricular level with associated atresia/hypoplasia of a cardiac valve or chamber. As a result:
- Ventricular output is the sum of pulmonary blood flow and systemic blood flow
- Distribution of systemic and pulmonary blood flow is dependent on the relative resistances to flow into the two parallel circuits.1
This physiology can exist in patients with one well-developed ventricle as well as in patients with two well-formed ventricles (Fig.1) and is explained by the following scenarios:
- One well-developed ventricle and one hypoplastic ventricle -maintained by natural [patent ductus arteriosus (PDA) or aortopulmonary collaterals] or artificial systemic-to-pulmonary artery shunts.
- Two ventricles with obstructed pulmonary/systemic outflow -maintained by natural or artificial systemic-to-pulmonary artery shunts.
- Two ventricle anatomy with unobstructed pulmonary/systemic outflow, but with large, non-restrictive intra or extracardiac shunt2.
Patients with SVP having one hypoplastic ventricle are staged down to a single ventricle pathway. Patients with two well formed ventricles may be able to undergo a two-ventricle repair.
Role of CT in diagnostic evaluation of SVP: Echocardiography is the initial modality for assessment of SVP. However, it is operator dependent and may not be sufficient for evaluating extracardiac structures such as the pulmonary vessels,aortic arch,great vessels and coronary arteries.Despite its excellent anatomic and functional assessment capabilities, MRI is limited in the seriously ill or uncooperative patients. It is also time consuming and mostly requires patient sedation.
CT has multiple advantages over echocardiography and MRI, particularly with its high spatial resolution, multi-planar capabilities, good temporal resolution and short examination time.
CT can be used to systematically evaluate extra-cardiac vasculature, aortopulmonary collaterals, airways,mediastinum and pulmonary parenchyma. Its high resolution provides precise anatomical detail important for procedural planning.