18F Sodium Fluoride PET/CT in Acute Aortic Syndrome

INCLUSION CRITERIA: Patients with Acute Aortic Syndrome or Chronic Aortic Disease: * A diagnosis of acute aortic syndrome as defined as per the European Society of Cardiology guidelines on the management of aortic disease a compatible clinical presentation with CT or magnetic resonance imaging confirming acute aortic syndrome. * Adults over the age of 25 years * Participants who have had previous open or thoracic endovascular aortic repair (TEVAR) are eligible to participate in the study. Healthy Controls: * No previous diagnosis of aortic disease * Over the age of 55 years EXCLUSION CRITERIA: * The inability of patients to undergo PET/CT scanning * Chronic kidney disease (eGFR ≤ 30 mL/min/1.73 m2) * Major or untreated cancer * Pregnancy * Allergy or contra-indication to iodinated contrast * Inability or unwillingness to give informed consent