Localization of Insulinoma Using 68Ga-DOTATATE PET/CT Scan

Abstract

Context. The reliable localization of insulinoma is critical for the successful surgical treatment.Objective. This study compared the accuracy of 68 Gallium (Ga)-DOTATATE PET/CT to anatomic imaging modalities, selective arterial secretagogue injection (SASI), and intraoperative ultrasound (IOUS) and palpation for localizing insulinoma in patients who were biochemically cured. Design, Setting, and Patients. We conducted a retrospective analysis of 31 patients who had an insulinoma confirmed on histology and were biochemically cured. The results of CT, MRI, transabdominal US, IOUS, 68 Ga-DOTATATE PET/CT, SASI, and operative findings were analyzed. Intervention, Main Outcome Measures, Results: The insulinomas were correctly localized in 17 out of 31 (55%) of patients by CT, in 17 out of 28 (61%) by MRI, in 6 out of 28 (21%) by US, and in 9 out of 10 (90%) by 68 Ga-DOTATATE. IOUS was performed in 31 patients, and 29 of them had an insulinoma successfully localized (93.5%). Thirty patients underwent SASI, and the insulinoma was regionalized in 28 out of 30 patients (93%). In 19 out of 23 patients (83%), manual palpation identified insulinoma. In patients who had all four noninvasive imaging studies, CT was concordant with 68 Ga-DOTATATE in 6 out of 9 patients (67%); MRI in 8 out of 9 (78%); US in 0 out of 9; and in 1 out of 9 patients (11%) the lesion was only seen by 68 Ga-DOTATATE. Conclusions:68 Ga-DOTATATE PET/CT identifies most insulinomas and may be considered as an adjunct imaging study when all imaging studies are negative and when a minimally invasive surgical approach is planned.PRECIS: We studied 68Ga-DOTATATE PET/CT imaging in patients with insulinoma and found it identifies most tumors and should be considered as an adjunct imaging study.

Diagnostic challenges in a patient with an occult insulinoma:68 Ga‐DOTA‐exendin‐4 PET/CT and 68Ga‐DOTATATE PET/CT

“…The sensitivity for detecting insulinomas has been reported to be approximately 75% for CT and 55–90% with MRI imaging . EUS has been reported to have excellent sensitivity (85–95%); however, insulinomas are often located in regions of the pancreas which makes them more difficult to visualize . SACST is the most invasive localizing procedure, however has been reported as the most sensitive modality (95–100%) .…”

Molecular imaging in the investigation of hypoglycaemic syndromes and their management

“…Conventional imaging modalities have variable success in localisation of insulinoma, with reported accuracy from a contemporary study demonstrating sensitivity of abdominal CT (64%) and magnetic resonance imaging (MRI) (75%) (Druce et al 2010). Endoscopic ultrasound (EUS) (65-94%) and SACST (63-94%) are highly operator dependent and the latter is particularly invasive and is only able to identify the pancreatic region of the tumour (McLean 2004, Guettier et al 2009, Druce et al 2010, Nockel et al 2017. The opportunity for biopsy confirmation of insulinoma is an advantage of EUS.…”

“…However, a recent retrospective review of pathologically confirmed insulinoma demonstrated successful localisation in 9/10 cases using this modality (Nockel et al 2017). Another retrospective review of 13 patients with histopathological correlation of hyperinsulinaemic hypoglycaemia (eight benign insulinoma, two malignant insulinoma and three nesidioblastosis) demonstrated positive SSTR PET/ CT ( 68 Ga-DOTATATE or 68 Ga-DOTA-TOC) in 11/13 patients (Prasad et al 2016, 8).…”

The future: surgical advances in MEN1 therapeutic approaches and management strategies

“…If these studies are negative, more invasive techniques, such as selective angiography with intra-arterial calcium stimulation and hepatic venous sampling for insulin levels, localize >80% of insulinomas (Brown et al 1997, Guettier et al 2009). Additionally, new somatostatin receptor (SSTR)-targeting PET modalities, such as 68Gallium-DOTATATE, are adjunct modalities for localization , Nockel et al 2017. As insulinomas express glucagon-like peptide 1 (GLP1) receptor more than SSTR, PET imaging with labeled GLP1 analogs might be a promising tool (Antwi et al 2015).…”