Endocrine Abstracts

Objective: A descriptive study to summarize the experience on diagnosis of NET using various imaging modalities.

Methods: Imaging was reviewed for 25 patients between 2002 and 2009 (22 MEN-1, 3 sporadic insulinoma). Of 13/25 had elevated fasting gut hormones. CT, MRI, endoscopic ultrasound (EUS), somatostatin receptor scintigraphy (SRS) and angiography were reviewed. (CT, MRI examined with arterial enhancement).

Results: Most frequently utilised tests were CT and EUS (16, 15). MRI, SRS and angiography were done in 13, 8 and 8 patients respectively. One test was done in 7 patients. Seven subjects were imaged with 2, >3 tests were performed in 10. All with biochemically confirmed insulinoma were imaged with at least CT and angiography.

Of 17/25 patients had tumours based on any test. EUS was positive in 11/15, CT 6/16, MRI 5/13, SRS 5/8 and angiography 8/8. EUS detected a minimum of 19 lesions whereas CT, MRI, SRS and angiogram 15, 7, 8 and 9 respectively. EUS and CT showed a minimum of 9 and 5 in the head of the pancreas respectively. Angiogram was positive in all with hyperinsulinaemia whereas CT only in 2. Minimum detection diameters for CT, MRI and EUS were 1.0, 0.4 and <0.3 cm respectively.

Of 6, 2 and 1 duodenal lesions were localized with EUS, SRS and CT respectively.

Three had liver metastasis. SRS showed multiple liver lesions in 1 patient while CT and MRI none.

Conclusion: Imaging plays a vital role in the pre-operative work-up of NET. Ascertaining the number, site and size of tumours in MEN-1 is important to determine the type of surgery. Angiography identified all lesions, but is invasive. EUS had a high rate of identifying lesions, but not all were detected. We advocate a multimodality strategy in tumour localization in MEN-1.