Advances in the imaging of gastroenteropancreatic neuroendocrine neoplasms

Abstract

Gastroenteropancreatic neuroendocrine neoplasms comprise a heterogeneous group of tumors that differ in their pathogenesis, hormonal syndromes produced, biological behavior and consequently, in their requirement for and/or response to specific chemotherapeutic agents and molecular targeted therapies. Various imaging techniques are available for functional and morphological evaluation of these neoplasms and the selection of investigations performed in each patient should be customized to the clinical question. Also, with the increased availability of cross sectional imaging, these neoplasms are increasingly being detected incidentally in routine radiology practice. This article is a review of the various imaging modalities currently used in the evaluation of neuroendocrine neoplasms, along with a discussion of the role of advanced imaging techniques and a glimpse into the newer imaging horizons, mostly in the research stage.

The lesion detection rate of Ga‐68 DOTATATE PET/MR in multiple endocrine neoplasia type 1

“…The present data showed that the combination of PET and MRI had the highest detection rate for gastroenteropancreatic NETs. On the other hand, CT missed most lesions, which is consistent with previous findings that demonstrated that CT scans have a low sensitivity for detecting gastroenteropancreatic NETs 15 . Moreover, two additional lesions were detected by Ga‐68 DOTATATE but not CT or MRI, which may have been due to the predominance of low‐grade tumours in the patients in the present study, where the use of Ga‐68 DOTATATE PET is more advantageous.…”

“…On the other hand, CT missed most lesions, which is consistent with previous findings that demonstrated that CT scans have a low sensitivity for detecting gastroenteropancreatic NETs. 15 Moreover, two additional lesions were detected by Ga-68 DOTATATE but not CT or MRI, which may have been due to the predominance of low-grade tumours in the patients in the present study, where the use of Ga-68 DOTATATE PET is more advantageous. The majority of MEN1-relevant GEP NETs were at the G1 and G2 stages, while G3 NETs have only been reported in a small number of cases.…”

Defining the optimal segmentation method for measuring somatostatin receptor expressing tumor volume on 68Ga-DOTATATE positron emission tomography/computed tomography to predict prognosis in patients with gastroenteropancreatic neuroendocrine tumors

“…68 Ga-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-peptides can demonstrate SSTR expression, especially in well-differentiated NETs [3]. 68 Ga-DOTA-peptides uptake in NETs generally decreases with increasing tumor grade and a higher maximum standardized uptake value (SUVmax) has been associated with better progression-free survival (PFS) [4]. In fact, SUVmax reflects only the SSTR expression in the pixel with the highest uptake in a lesion and does not represent tumor heterogeneity.…”

Imaging of Neuroendocrine Neoplasms; Principles of Treatment Strategies. What Referring Clinicians Want to Know

“…Moreover, tumor primary site, grade at presentation and its changes over time (due to accumulation of mutations and lineage plasticity), presence and type of symptoms, 18-fluorodeoxyglucose (FDG), and SST agonist avidity on positron emission tomography/computed tomography (PET/CT) are all additional factors that may impact survival and treatment. 6,7 This review aims to convey the essential information and specific diagnostic challenges related to the available treatments that radiologists and nuclear medicine physicians need to be aware of as well as the information they need to provide to the referring clinicians for optimal management and treatment.…”

“…In fact, NENs are heterogeneous in clinical presentation and behavior over time. Moreover, tumor primary site, grade at presentation and its changes over time (due to accumulation of mutations and lineage plasticity), presence and type of symptoms, 18-fluorodeoxyglucose (FDG), and SST agonist avidity on positron emission tomography/computed tomography (PET/CT) are all additional factors that may impact survival and treatment 6,7 …”