Magnetic Resonance Imaging in Obesity
Condition: Obesity
MeSH terms: Obesity
Study type: Observational

Summary: 
      Obesity and its related conditions account for up to 5%of all health care spending in the UK
      and this is expected to double by 2030. Following weight loss, significant improvement in
      these obesity-related illnesses has been reported. However, there is limited understanding of
      how these improvements happen and in particular, little dedicated work has been done using
      imaging in the obese population to look at the effects of treatment.

      Magnetic resonance imaging (MRI) is an imaging technique that allows assessment of fat
      concentration and volume without the use of ionising radiation. It is safe, non-invasive and
      well-tolerated by most patients.

      There are several MRI imaging techniques that be can used for fat quantification. These
      include MR spectroscopy and Dixon methods with measurement of fat fraction. These techniques
      measure the fat in the body organs and also the fat in the abdomen and skin. Recent technical
      developments mean that the whole body can be scanned relatively quickly (typically 30-40
      minutes).
    

Detailed description: 
      Obesity and its related conditions are a significant cause of death and ill health. There
      have been a number of studies showing that weight loss, in particular that achieved by
      bariatric (weight-loss) surgery, results in improvement in obesity-related conditions such as
      type 2 diabetes mellitus. A large case-control study demonstrated a mean weight loss of 23.4%
      by 2 years and sustained mean weight loss of 16.1% compared to matched controls. 72% of
      patients with type 2 diabetes were in remission at 2 years and this was 36% at 10 years.
      Bariatric surgery also results in recovery from lipid disturbances with 62% of patients
      demonstrating normalisation of hypertriglyceridaemia (high fat levels in the blood) at 2
      years and 46% at 10 years. There is also a smaller cohort of patients who, despite
      significant weight loss, do not experience remission of their obesity-related comorbidities.

      The mechanisms for the improvement in obesity-related ill health are not well understood and
      little dedicated work has been undertaken on imaging in the obese population before and after
      treatment. For example, increased fat content in the liver, bone and pancreas is well
      described in obesity but it is unclear whether response to treatment is uniform across all
      these organs, or if there are specific patients who would benefit from additional or
      alternative interventions for hard to treat organ fat. The effect on remaining organ fat
      following treatment on clinical parameters such as body shape, and metabolism, is also
      unknown. Furthermore, it is not known if there are certain patterns of organ fat which may
      respond better to one type of therapy such as surgery compared to medical treatment for
      example, and choosing the best treatment for patients may be improved by a better
      understanding of organ fat. The effect of obesity on bone structure and strength, bone
      hormonal activity and metabolism is poorly understood. Finally, the link, if any, between
      patterns of organ fat and patients' genes, body shape and metabolism before and after
      treatment and is also unclear.

      Treatment options for obesity continue to develop. Several novel medical (non-surgical)
      treatments for obesity have become available and the number of patients undergoing bariatric
      surgery continues to increase. There is therefore need to understand the mechanisms behind
      both weight loss (and the contribution of individual organs to this) and the improvement in
      obesity-related conditions. By gaining greater understanding of this, we aim to better
      predict outcomes for individual patients and better select the most appropriate treatment for
      them.

      There has been recent research into MRI as a method of quantifying fat in abdominal organs
      such as the liver and pancreas. MRI has the advantages of being non-invasive (for example
      when compared to liver biopsy) and does not use ionising radiation unlike other imaging
      modalities.
    

Intervention name(s): MRI; Written Consent
Intervention type(s): Other; Other
Intervention description(s): MRI scan (not involving ionising radiation)
The MRI study will be conducted by a trained MR radiographer, supervised by the nominated researcher; Student researcher or research nurses to take consent. Consent will be taken in the obesity clinic or radiology departments.
Observational model: Case-Control
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Patients will be recruited by suitably trained members of the research team on the study
        delegation log including research fellows, nurses, surgeons and endocrinologists working in
        a tertiary bariatric referral centre at UCLH on a person-to-person basis.