PET scanning (positron emission tomography) is a well-established technique used to identify areas of interest within the body. It involves injecting a radioactive tracer which highlights abnormal areas. It has recently been combined with CT (computed tomography) and MRI (magnetic resonance imaging) scanning to more accurately identify abnormalities within the heart. Cardiac amyloidosis, a condition which causes thickening of heart muscle due to abnormal protein deposits, is of particular interest. There are different forms of this condition and at present samples of tissue need to be taken and analysed in order to assess these accurately, which carries risks.

The study makes use of hybrid PET/MR scanning using a designated scanner which enables PET scanning combined with MRI scanning. The investigators will use a PET tracer which is widely used in cardiac imaging as it is hoped this will enable characterisation of abnormal areas within the heart in this condition in a way which hasn't been done before.

All participants will undergo PET scanning, where a radioactive tracer is injected into a vein before the scan. The radioactive substance only lasts for a short time and is safe, passed out of the body in urine. If successful, this imaging method will enable us to detect differences between different forms of cardiac amyloidosis in a non-invasive way, improving the diagnostic capabilities in this condition.

Inclusion Criteria:

• Aged over 40 years
• Completion of informed consent
• Established diagnosis of cardiac amyloidosis

Exclusion Criteria:

• Inability or unwilling to give informed consent
• Women who are pregnant, breastfeeding or of child-bearing potential (women who have experienced menarche, are pre-menopausal and have not been sterilised) will not be enrolled into the trial.
• Major intercurrent illness with life-expectancy <2 years.
• Renal dysfunction (eGFR less than or equal to 30ml/min/1.73m2)
• Adverse reaction or hypersensitivity to 18F-FDG PET tracer
• NYHA Class IV heart failure
• Patients with atrial fibrillation and poor rate control
• Contraindications to MRI scanning
• Previous history of contrast allergy of adverse reactions (Gadolinium-containing agents)

Patients attending the Edinburgh Heart Centre will be invited to participate. Inpatients and outpatients are eligible. Healthy volunteers will be invited to participate by local recruitment.