Non-invasive diagnosis and monitoring of non-alcoholic fatty liver disease in bariatric surgical patients

MAGNETIC RESONANCE SPECTROSCOPY (MRS) This is an MRI scan, where the patient lies flat on a platform which is moved through the MRI tunnel. The procedure takes approximately 30 minutes and is carried out by the radiographer. The test is performed at baseline, and follow-up MRS is performed at 1 year after bariatric surgery. Patients will be seen in clinic prior to their scans to arrange a suitable time. Attendance will be checked by the study investigator and rescheduled if required. TRANSIENT ELASTOGRAPHY/FIBROSCAN This test looks at liver stiffness. Patients are scheduled for 3 scans during their year long follow-up (baseline, 3 and 12 months after bariatric surgery). The scan is performed in an outpatient clinic, with a probe on the right upper abdomen, similar to an ultrasound. The procedure takes approximately 10 minutes. It is not painful and there are no risks. The procedure is performed by trained Gastroenterologists. Attendance will be checked by the study investigator and rescheduled if required. SERUM BIOMARKERS Blood tests are taken from the patient at 0, 1, 3 and 12 months after bariatric surgery at their scheduled outpatient appointments. Approximately 20-30ml of blood will be taken at each time point. Tests of interest include routine blood tests, as well as the novel biomarker TNFSF14 (LIGHT) and other circulating cytokines. BARIATRIC SURGERY Surgery will occur as planned by their treating team.