SUBJECTS
20 patients were referred to the MRCP-S at our institution on a conventional 1,5T MRI scanner. The refferal diagnosis was as following:
- 4 patients (23.5 %) had clinical suspicion of early PEI,
- 1 patient (5.9 %) had known CP on enzyme substitution therapy, and
- in 12 patients (70.6 %) normal pancreatic exocrine function was suspected (healthy controls).
Patients were divided into three groups according to fecal elastase-1 (FE-1) levels:
- group 1 with FE-1 >200 µg/g (normal exocrine function),
- group 2 with FE-1 between 15-200 µg/g (suspected exocrine disfunction) and
- group 3 with FE-1 (CP on enzyme substitution therapy).
MR IMAGING PROTOCOL
Before the imaging, patients received intramuscular injection of an antiperistaltic agent glucagon and peroral negative contrast agent for stomach fluid signal suppression.
MRCP protocol was as following:
- axial and coronal T2-weighted sequence (TE 90 ms, slice thickness of 6 mm, a 1,2 mm gap between slices),
- axial T2-weighed sequence with fat-suppression (TE 90 ms, slice thickness of 6 mm, a 1,2 mm gap between slices),
- axial In-phase and Opposed-phase T1-weighted sequence (TR 135 ms, flip angle 80°, slice thickness of 6 mm, a 1,2 mm gap between slices),
- MRCP maximum intensity projection (MIP) 3D reconstruction in coronal plane (slice thickness of 1,8 mm, 50 slices reconstructed into 1 MIP),
- MRCP saggital and transverse rotation MIP reconstructions, and
- MRCP thick slab reconstruction (TE 1402 ms, TR minimal, slice thickness of 40 mm with zero spacing between slabs).
1 ml per 10 kg of body weight of secretin was then applied intravenously in the cubital vein slowly, over 1 minute, to avoid any possible side affects, flushed by additional 20 mL of 0,9% NaCl solution.
Additional 10 MRCP thick slab sequences were recorded after the application of secretin (1 per minute).
IMAGING PARAMETERS ANALYSIS:
MRCP images were evaluated first for the grade of duodenal filling according to Matos and colleagues' criteria [4], with grade 2 or less determining impaired pancreatic function (Table 1).
Grade of duodenal filling 10 minutes after secretin application
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Grade 0
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No fluid is observed in the duodenum
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Grade 1
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Fluid is limited to the duodenal bulb
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Grade 2
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Fluid partially fills the duodenum up to the genu
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Grade 3
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Fluid fills the duodenum beyond the genu
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Table 1: Grades of duodenal filling 10 minutes after secretin application; taken from Matos.
Images were also evaluated for indirect signs of main pancreatic duct (MPD) compliance: that is degree (in mm) and timing (in min) of maximum post-secretin dilatation and return to normal after secretin effect cessation (in min). Normal MPD was regarded when maximum dilatation of main pancreatic duct was 1-2 mm in < 3-5 min with returning to normal in < 5 min [2,6].
EVALUATION OF POSSIBLE SIDE AFFECTS AFTER SECRETIN ADMINISTRATION
All patients were assessed for any possible side affects of secretin application, such as acute pancreatitis, 5 to 14 days after the examination. In adition, blood levels of pancreatic amylase and lypase were determined after MRCP-S examination.
STATISTICAL ANALYSIS
Correlations beetween imaging parameters and different FE-1 groups were calculated with Spearman's correlation test (p value below 0.05 being statistically significant).