Sodium Fluoride Imaging of Abdominal Aortic Aneurysms

Study Overview
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Brief Summary
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The purpose of this study is to determine whether Sodium Fluoride imaging (using Positron Emission Tomography-Computed Tomography - PET-CT) is able to help predict the rate of abdominal aortic aneurysm expansion.

Detailed Description
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Ruptured abdominal aortic aneurysms (AAAs) have a 90% mortality rate but there are currently no accurate methods of establishing the risk of rupture for an individual patient with an asymptomatic AAA. In vascular disease, microcalcification occurs in response to necrotic inflammation. Using computed tomography and positron emission tomography (PET-CT), early micro calcification can be identified using uptake of the radiotracer 18F-sodium fluoride. This can identify high risk-lesions in the aorta, coronary and carotid arteries, and appears to be indicative of necrotic and heavily inflamed tissue. The study investigators therefore propose to evaluate the ability of 18F-sodium fluoride to identify regions of necrotic inflammation in AAA and predict AAA expansion. The study investigators will explore its value as part of an ongoing clinical trial assessing the identification of macrophage activity using magnetic resonance imaging - the MA3RS Study (ISRCTN76413758). Patients already enrolled in the MA3RS Study will be recruited for the SoFIA3 study. Control patients with a normal calibre aorta will be recruited from the National AAA Screening Programme.

Official Title
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SoFIA3: Sodium Fluoride Imaging (18F-NaF PET-CT) in Abdominal Aortic Aneurysms

Conditions
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Abdominal Aortic Aneurysm

Intervention / Treatment
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* Radiation: 18F-NaF PET-CT


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria (AAA patients): Patients already enrolled in the MA3RS study (ISRCTN76413758) Patients with abdominal aortic aneurysm with AP diameter >40 mm on ultrasound >50 years of age Inclusion Criteria (control patients): Patients with abdominal aorta with AP diameter <30 mm on ultrasound >50 years of age Exclusion Criteria: Patients expected to undergo imminent AAA repair Patients who refuse or are unable to give informed consent Women of child-bearing potential without contraception Patients who are unable to undergo PET-CT scan Patients with collagen vascular disease Intercurrent illness, malignancy or comorbidity with life expectancy <1 year Renal dysfunction (eGFR <30ml/min/1.73m2) Contraindication to PET-CT or CTA Iodine allergy

Ages Eligible for Study
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Minimum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Aneurysm surveillance<br>Radiation: 18F-NaF PET-CT | Radiation: 18F-NaF PET-CT<br> <br> |
| Control patients<br>Radiation: 18F-NaF PET-CT | Radiation: 18F-NaF PET-CT<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in abdominal aortic aneurysm anteroposterior diameter over time at 6 and 12 months (mm) | The maximum AAA AP diameter on ultrasound will be obtained from time points below: At (or close to) the time of the study visit 6 months following the study visit 12 months following the study visit The maximum AP diameter will also be recorded on CTA performed at the time of study visit. | 0, 6, 12 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Co-localisation of 18F-NaF with USPIO uptake on MRI scanning | The data on USPIO uptake on MRI scanning will be derived from a separate study (MA3RS - MRI in AAA to predict Rupture or Survival, ISRCTN76413758). The proposed study described here (SoFIA3) will not involve any administration of USPIO. Regions of interest and uptake of 18F-NaF will be identified on PET-CT images acquired at baseline as part of this study (SoFIA3). These images will be co-registered to MRI data (uptake pre- and post-USPIO) which has already been obtained during the MA3RS Study. We will correlate the agreement between areas of significant 18F-NaF uptake on PET-CT (representing areas of active calcification) and areas of significant USPIO uptake on MRI (representing areas of active macrophage activity). This is an exploratory analysis which will take advantage of data already obtained through the MA3RS Study, which is a separate study. | At baseline | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Aortic aneurysm, abdominal, Sodium Fluoride, Positron Emission Tomography