Review ArticleContinuing Education

Molecular Imaging of Gastroenteropancreatic Neuroendocrine Tumors: Current Status and Future Directions

Christophe M. Deroose, Elif Hindié, Electron Kebebew, Bernard Goichot, Karel Pacak, David Taïeb and Alessio Imperiale
Journal of Nuclear Medicine December 2016, 57 (12) 1949-1956; DOI: https://doi.org/10.2967/jnumed.116.179234

Article Figures & Data

Figures

  • FIGURE 1.
    FIGURE 1.

    Head-to-head comparison of 111In-pentetreotide SSTR scintigraphy (A) and 68Ga-DOTATATE (B) PET/CT in patient with metastatic low-grade cecal NET evaluated before PRRT. In liver, retroperitoneal and thoracic lymph nodes, and bones, PET/CT shows multiple metastases, many of which are undetectable on SSTR scintigraphy.

  • FIGURE 2.
    FIGURE 2.

    68Ga-DOTATATE PET/CT results (A: anterior PET maximum-intensity projection, B: axial CT scan, C: axial PET/CT scan) in patient referred for preoperative staging of low-grade duodenal NET (white arrows) appearing as nodular thickening of lateral wall of duodenum with contrast enhancement and intense radiotracer uptake. 68Ga-DOTATATE PET/CT also shows additional pathologic focal uptake in epigastric region corresponding to synchronous duodenal G1 NET (black arrow).

  • FIGURE 3.
    FIGURE 3.

    68Ga-DOTATATE PET/CT results (A: anterior PET maximum-intensity projection, B: coronal PET/CT scan) in patient with nonfunctional G1 NET of pancreatic head referred for primary staging. Tumor exhibited highly elevated uptake of 68G-DOTATATE (arrow) without locoregional or distant metastasis.

  • FIGURE 4.
    FIGURE 4.

    18F-FDOPA PET/CT results (A: anterior PET maximum-intensity projection, B: coronal PET/CT scan) in patient with carcinoid syndrome, retractile mesenteric lesions (curved arrow), and hepatic metastases of low-grade NET of unknown origin. Conventional imaging and 111In-pentetreotide SSTR scintigraphy failed to detect primary site. 18F-FDOPA PET/CT depicted 2 pathologic foci in ileum (straight arrows). Pathologic examination after surgery confirmed diagnosis of bifocal ileal G1 NET.

  • FIGURE 5.
    FIGURE 5.

    18F-FDOPA PET/CT after carbidopa premedication (A: anterior PET maximum-intensity projection, B: coronal PET/CT scan) in patient with hyperinsulinemic hypoglycemia. Insulinoma (arrow) was clearly identified by PET/CT. Normal pancreatic parenchyma has low uptake because of premedication by carbidopa.

  • FIGURE 6.
    FIGURE 6.

    Proposed diagnostic imaging algorithm for patients with GEP NETs. na = not available; SSRS = SSTR scintigraphy. *Based on presumption of origin and hormonal secretion if present.

  • FIGURE 7.
    FIGURE 7.

    Typical example of flip-flop phenomenon in molecular imaging of patient with hepatic metastasis from G3 NET of unknown origin and referred before therapeutic strategy planning. Shown are 111In-pentetreotide SSTR scintigram (A), anterior 18F-FDG PET maximum-intensity projection (B), and coronal PET/CT scan (C). 18F-FDG PET/CT showed intense uptake by hepatic lesions and allowed detection of primary rectal tumor (curved arrow) and retroperitoneal lymphatic metastasis (straight arrow). These high-grade lesions showed no uptake on SSTR scintigraphy.

Tables

  • TABLE 1

    Currently Available Endoscopic and Anatomic-Imaging Techniques for GEP NET Investigation

    CharacteristicTAUSEUSVideo capsuleCT*MRI*
    UseDetection of primary GI NET (solid organs only)Detection of gastric, duodenal and rectal primary NETs; diagnostic biopsyDetection of esophageal, gastric, duodenal, and small-bowel primary NETsStaging and follow-up (first-choice modality); identification of primary site; evaluation of local extent; assessment of metastasesDetection and assessment of liver metastases (first-choice modality)
    SensitivityLimited; high interoperator variabilityHighModerateCan be enhanced by enterography and enteroclysisHigh for bone marrow metastases; can be enhanced by enterography and enteroclysis
    Radiation exposureNoNoNoYesNo
    OtherIs widely availableIs invasiveCan analyze entire bowelIs widely availableUses gadolinium chelate, which is safer than CT iodine agents as regards allergic reactions and nephrotoxicity

    • ↵* Multiplanar contrast-enhanced images.

    • TAUS = transabdominal ultrasound; EUS = endoscopic ultrasound.

  • TABLE 2

    Currently Available Functional-Imaging Techniques for GEP NET Investigation

    Characteristic111In-pentetreotide SPECT/CT123I-MIBG SPECT/CT68Ga-SSA PET/CT18F-FDOPA PET/CT18F-FDG PET/CT
    UsePrimary staging; restaging; patient selection before PRRTPatient selection before 131I-MIBG radiometabolic treatmentPrimary staging; restaging; patient selection before PRRT; imaging when primary site is unknownPrimary staging; imaging when primary site is unknown (based on presumption of ileal origin); (restaging?)Prognostic stratification; imaging of high-grade G2/G3 NETs
    Spatial resolutionLow (>10 mm)Low (>10 mm)High (5 mm)High (5 mm)High (5 mm)
    Procedure length2 d2 d1 d1 d1 d
    Radiation exposureModerateMildMildMildMild
    OtherIs approved for NET imagingHas low sensitivity for GEP NETsWill soon replace conventional SSTR scintigraphyMay be less sensitive than 68Ga-SSA PET/CT for nonileal GEP NETsIs widely available
Back to top

In this issue

Print
Download PDF
Article Alerts
Email Article
Citation Tools
Bookmark this article

Jump to section

Keywords