Radiology – Integrated Training Initiative (R-ITI) | Paediatrics | Cardiac Shapes

Cardiac Shapes
Session Overview
Description
This session reviews which chambers contribute to the ‘normal cardiac outline’ and examines how specific chamber enlargement or absence alters the normal cardiac shape. It will describe the different diagnoses, which result in characteristic cardiac shapes that enable the diagnosis to be made from the chest radiograph (CXR). Associated features such as other mediastinal findings and changes in the lungs, for example right aortic arch, will be included where relevant.
 

Learning Objectives
By the end of this session you will be able to:

• Identify specific chamber enlargement
• Recognise specific cardiac shapes that suggest a specific diagnosis
• Describe the clinical significance of the diagnosis
• Identify the associated features on the CXR
   

Prerequisites
Before commencing this session you should have completed:

• Session in Module 5 Paediatrics/The Approach to the Chest Radiograph in Congenital Heart Disease (300-0462)

Although echocardiography and cardiac magnetic resonance imaging have replaced the CXR as the main diagnostic tools in congenital heart disease, the CXR can still provide a lot of useful information.

In some cases, it is still the first indicator that heart abnormalities may be present, so it is important to be able to recognise certain abnormalities of shape (Fig 1) which point towards the diagnosis.

Cardiac size and shape on CXR are often non-specific, but some cardiac shapes are typical of specific types of congenital heart disease:

• Egg-on side: transposition of the great arteries
• Boot: tetralogy of Fallot
• Sitting duck: truncus arteriosus
• Snowman: supracardiac total anomalous pulmonary venous drainage (TAPVD)