Endocrine Abstracts

Introduction: Insulinoma visualization is the most difficult stage of diagnosis of this disease. Currently, in most cases the contrast-enhanced multislice computer tomography of abdomen and retroperitoneal space (CE-MSCT) is the method of choice in topical diagnosis of insulinoma. This method is associated with radiation exposure and administration of contrast agents, so it is invasive. Thus, an alternative highly informative and safe method for initial topical diagnosis of insulinoma is necessary. In particular, the magnetic resonance imaging without contrast enhancement (MRI without CE) is a promising imaging method.

Materials and methods: In 24 patients aged 20–72 years with hypoglycemic syndrome the MRI without CE and CE-MSCT were performed.

Results: According to MRI, pancreatic neuroendocrine tumor was detected in 96% of patients (n=23). CE-MSCT revealed the pancreatic tumor in 100% of patients (n=24), among them the tumor in the head of pancreas in patient with negative result of MRI. According to CE-MSCT, there were 23 neuroendocrine and one solid pseudopapillary tumor. In all patients (n=24) the surgery was performed. Intraoperative revision confirmed the localization of pancreatic tumor in 100% of patients with positive result of MRI, and in patient with negative result of MRI the tumor in the tail of pancreas was revealed. Data of intraoperative revision were confirmed by the pathomorphological investigation in all patients. The immunomorphological features of insulin-producing tumor were revealed in 23 patients (96%) and in one patient the solid pseudopapillary tumor was diagnosed, in accordance with data of MSCT. Thus, the sensitivity of MRI without CE and CE-MSCT in detection of pancreatic tumors (reference is the localization according to intraoperative revision) is identical (96%), 95% confidence interval (79%; 100%). The sensitivity of methods in identifying the origin of tissue (reference is the result of histological investigation) is also not statistically different – 96% (79%; 100%) and 100% (86%; 100%) respectively.

Conclusion: MRI without CE and CE-MSCT are equivalent highly sensitive methods of topical diagnosis of insulin-producing neuroendocrine pancreatic tumors, but MRI without CE has additional advantages: the lack of ionizing radiation and necessity for contrast agents administration. Thus, for diagnosis of insulinoma it is advisable to use the MRI without CE as the first-line imaging modality, and the CE-MSCT should be used in difficult cases as additional method.

Funding: The work was supported by the state assignment ‘Hereditary tumor syndromes and multiple endocrine neoplasias: personalization of diagnostics and treatment, risk prediction, identification of nuclear families’ for 2018–2020 years.