Non-invasive Rapid Assessment of Patients With Liver Transplants Using Magnetic Resonance Imaging With LiverMultiScan.

Long-term survival after solid organ transplantation has increased during the last decade due to improvements in surgical technique, peri-operative care, and more efficient immunosuppression (IS) (1). However, transplant recipients still exhibit higher morbidity and mortality than the general population. One of the main causes are co-morbidities which are negatively influenced by chronic IS drug usage. It is however a very fine balance, as under-usage of IS can lead to transplant rejection (2). Therefore, many paediatric and some adult liver transplant recipients have regular liver biopsies as part of their serial evaluation, so-called 'routine liver biopsies'. Biopsy is performed if there is suspected rejection, as no current non-invasive tests are both sensitive and specific for rejection. Biopsy is used to identify early histological signs of rejection. However, there are some problems;

• There is a risk of complication due to biopsy(1 in 10,000)
• biopsies are painful
• sample only a tiny fraction of the liver and for children there is a need to sedate.

Therefore, they are less-than-perfect for serial evaluation. Optimisation of IS has become a priority goal in transplantation, but is hampered by the lack of diagnostic tests available for serial monitoring (3). There are potential benefits of IS minimization or withdrawal, however this need to be balanced with the risks, inconveniences and costs of prompting liver allograft rejection.

Identification of a reproducible and reliable non-invasive assessment tool for the transplanted liver, such as multiparametric quantitative MRI, would therefore substantially benefit the liver transplant population. In Europe, approximately 6000 liver transplants are performed every year (1). Under the current standard-of-care, indefinite pharmacological IS is prescribed to all of them. The cost of immunosuppressive drugs is €4200- €7000 per patient per year (£3000-£5000/patient/year). In addition to its cost, chronic IS may result in substantial side effects (hypertension, diabetes, renal insufficiency, hyperlipidaemia, cancer, infections) that contribute to patient morbidity and mortality (2). Rejection is a major concern with liver transplant recipients. At present, there is no clear non-invasive diagnostic pathway to identify early rejection. We would like to see if the implementation of LiverMultiScan (4) to monitor the transplant population and modify treatment can replace or equal the yield of invasive liver biopsies in the post-transplant population.

Therefore, the aim of this study is to determine whether there is concordance between using LiverMultiScan and liver biopsy in a post-liver transplant population.