Dyspeptic symptoms, such as pain after eating, bloating and nausea all have major impact on quality of life and health care costs. When no structural cause is identified, patients are diagnosed with functional dyspepsia. This trial aims to identify objective abnormalities of stomach function that explain patient's symptoms and establish diagnosis. Another group are diabetic patients who can often develop similar symptoms, labelled as diabetic gastroparesis. In some cases this is associated with delayed gastric emptying but not all.

24 patients with functional dyspepsia will be studied and 24 healthy controls (to establish normal ranges) and 24 diabetic patients with symptoms of functional dyspepsia.

The utility of 3 different non-invasive investigations will be assessed. At screening the nutrient drink test (NDT) asks the patient to drink 40ml of milkshake (0.75kcal/ml) every minute and score symptoms every 5 minutes. The patient continues until they reach the maximum tolerated volume.

Participants will then be randomized to undergo non-invasive imaging on two separate test days by magnetic resonance imaging (MRI) and gastric scintigraphy MRI will be completed with the patient ingesting 400ml of milkshake (identical to NDT) and 12 agar beads (no additional calories) of known breaking strength. The emptying of the stomach will be visualised with the MRI alongside symptom recording.

Gamma scintigraphy will ingest the same meal as for the MRI scan but radioactive labelling will allow the rate of liquid and solid meal emptying to be visualised alongside symptom recording.

Additionally, blood sugars will be recorded before nutrient drink test and at 15 and 30 minutes following ingestion of 400ml of milkshake and 12 agar beads.

Data will be analyzed to assess the association of objective abnormalities of gastric function and patient symptoms. Additionally the results of non-invasive imaging by MRI and GS will be compared to assess the optimal measurement of gastric function and emptying in this clinical scenario.

Inclusion Criteria:

1. Be an adult patient above 18 years old
2. Have a body mass index of >18 and <30kg.m2 and not exceed a waist circumference of 99cm at 5cm above ileal crest
3. Be able to give voluntary informed consent and from whom written consent to participate has been obtained.
4. Be able to understand the study, willing to co-operate with the study procedures and able to attend all study assessments.
5. Be willing to abstain from alcohol for 24 hours before and during the imaging appointment.
6. Be willing to fast from midnight prior to the screening and imaging appointment
7. Be able to ingest at least 400ml nutrient liquid (0.75kcal/ml at 40ml/min) during a Nutrient Drinking Test without experiencing more than moderate dyspeptic symptoms (no such restriction for patients with dyspeptic symptoms)
8. Be able to swallow a solid agar bead between 7.5 and 11.5 mm in diameter
9. Be willing to consent to their General Practitioner (GP) being informed of their participation.

Exclusion Criteria:

1. Have a history of gastrointestinal disease or surgery (other than appendicitis or hysterectomy)
2. Have ongoing disease requiring active management (including impaired renal clearance GFR <50 mL/min/1.73 m2)
3. Have a documented history of alcohol or drug abuse
4. Fail to satisfy the investigator's assessment of fitness to participate based on a survey of inclusion and exclusion criteria
5. Have consumed alcohol within 24 hours of start of study
6. Have participated in a similar study involving the use of radioisotopes in the previous 3 months such that participating in the current study would exceed the recommended yearly exposure limit (5mSv)
7. Take any medication which may affect oesophageal or gastric motility for a minimum 7 days
8. Have had previous history of gastric surgery
9. Have active upper gastrointestinal diseases
10. Have an active Eating Disorder
11. Have an allergy to milk protein (milk based, lactose free test meal)
12. Be a vegan
13. Be pregnant or breastfeeding
14. Have any contraindication to MRI scanning according to local guidelines