Evaluation of delayed gastric emptying in diabetic patients with autonomic neuropathy by a new magnetic resonance imaging technique and radio-opaque markers

OBJECTIVE. - Our objective was to validate a new noninvasive magnetic resonance imaging (MRI) technique for diagnosis of delayed gastric emptying by using radio-opaque mark markers (ROMs) in diabetic patients with and without cardiovascular autonomic (CAN) and peripheral sensomotoric neuropathy (PSN). RESEARCH DESIGN AND METHODS - Fifteen diabetic outpatients were recruited, eight with CAN and PSN (group A, age 28-61 years, mean diabetes duration 27 years) and seven without CAN (group B, age 28-60 years, mean diabetes duration 16 years). Gastric emptying and motility were assessed with ROMs and MRI in random order. After an overnight fast, either a lest meal (451 kcal) containing a capsule with 10 ROMs is eaten and a supine plain abdominal X ray is taken after 6 h or 500 ml Intralipid 10% (550 kcal) is swallowed for the MRI study, using a 1.5 Tesla Gyroscan ACS II (Philips, Eindhoven, The Netherlands). Computer-assisted segmentation of images was used to measure gastric emptying (T-1/2, min) over 125 min, contraction frequency (F, min(-1)), mean contraction amplitude (CA, % basal), and velocity (V, cm/s). Blood glucose was kept constant at 5.0-8.0 mmol/l. RESULTS - In group A, 6.1 +/- 1.36 ROMs (means +/- SE) were retained in the stomach after 6 h and 0 ROM in group B, indicating a significant delay of gastric emptying in patients with CAN. The MRI study revealed a significantly longer gastric emptying (P < 0.005) in group A (T-1/2 = 124 +/- 10 min) as compared with group B (T-1/2 = 85 +/- 18 min). There was no difference in F, CA, and V between the two groups: F 2.9 +/- 0.07 and 2.7 +/- 0.1 (min(-1)), CA 26.8 +/- 1.2 and 29.6 +/- 1.6 (% basal), V 0.43 +/- 0.02 and 0.40 +/- 0.02 (cm/s), respectively. CONCLUSIONS - MRI offers the possibility of visualizing and examining exactly the mechanisms responsible for gastric emptying and is characterized by a high specificity but a lower sensitivity as compared with ROMs, which proved to be an ideal screening test for diagnosis of gastroparesis in clinical practice.