Cardiac MRI and cardiac CT are advanced imaging tests that produce highly detailed pictures of the heart, blood vessels and surrounding structures in the chest. Although they serve a similar purpose, they work in different ways, and Dr Giardini will recommend the most appropriate option based on your child's clinical needs.

Cardiac MRI uses strong magnets and radio waves to create both still and moving images of the heart. Because it does not use any ionising radiation (unlike X-rays or CT), it carries no radiation-related risks and is considered extremely safe. Cardiac MRI is particularly valuable because it can accurately measure the size and volume of the heart chambers, assess how well the heart muscle is squeezing, and measure blood flow within the circulation. This makes it one of the most comprehensive tools available for evaluating children with congenital heart defects, heart muscle disease and other complex cardiac conditions.

The test takes approximately 45 minutes. Your child will lie on a narrow bed that slides into the MRI scanner, which looks like a large tunnel. The machine can be noisy, so headphones or ear protection are provided. A small cannula (a thin plastic tube) is placed in a vein in the hand or arm so that a special contrast dye can be injected partway through the scan. This dye helps highlight the heart and blood vessels more clearly. Because it is essential to remain very still throughout, younger children who are unable to cooperate with the breathing instructions typically require a general anaesthetic. Dr Giardini will discuss this with you in advance if it applies to your child.

Cardiac CT (also called CT angiography) uses X-ray technology combined with a contrast dye to produce detailed three-dimensional images of the heart, blood vessels and other chest structures such as the airways and oesophagus. It is an excellent tool for assessing the relationship between different structures within the chest and can be completed in just a few minutes, making it much quicker than MRI. A cannula is placed in a vein for the dye injection and is removed as soon as the scan is finished. Cardiac CT does involve a small dose of ionising radiation, but modern scanners have reduced this dose significantly, and the clinical team always ensures that the lowest possible dose is used.

Dr Giardini has extensive expertise in both techniques and works closely with specialist radiology teams to ensure the highest quality imaging. In many cases, only one of these tests is needed. The choice depends on the clinical question being asked: MRI is often preferred when detailed measurements of heart function and blood flow are required, while CT may be chosen when three-dimensional anatomical detail is the priority or when a faster scan is more practical for a younger child.

Both tests require a cannula, but neither is otherwise painful. Results are reviewed by Dr Giardini and discussed with you at a follow-up appointment. If you have any questions about whether your child may need cardiac MRI or CT, please do not hesitate to contact Dr Giardini's team.