Combined Quantification of 18F-FDG and 68Ga-DOTATATE PET/CT for Prognosis in High-Grade Gastroenteropancreatic Neuroendocrine Neoplasms

The potential application of MR-derived ADCmin values from 68Ga-DOTATATE and 18F-FDG dual tracer PET/MR as replacements for FDG PET in assessment of grade and stage of pancreatic neuroendocrine tumors

“…Signi cant differences in both 18 F-FDG uptake (MTV and TLG) and MR (ADCmin and ADCmean) parameters were observed when comparing PNETs of varying grades. Consistently, primary neuroendocrine tumors were shown to have a positive connection between MTV and TLG levels by Abdulrezzak et al [18] Moreover, Chan et al detected higher MTV values when assessing higher-grade tumors.…”

“…The LIFEx platform v5.1 [17] was used to extract all imaging parameters. Brie y, at the time this study was done, two nuclear medicine doctors, JG and SX, who had each worked with 18 F-FDG and 68 Ga-DOTATATAE PET/MR imaging for more than three years, hand-drew 3D volumes of interest (VOIs). Then, the 18 F-FDG PET FSUVmax, MTV, and TLG parameters, as well as the 68 Ga-DOTATATE PET maximum standardised uptake value (GSUVmax), somatostatin receptor density (SRD), and total lesion somatostatin receptor density (TLSRD) parameters, were taken from these primary tumors.…”

“…Currently, 68 Ga-DOTA peptide-based imaging approaches are the gold standard used for assessing welldifferentiated NETs exhibiting high levels of somatostatin receptor (SSTR) density, [5] However, since SSTR expression is lower on high-grade poorly differentiated NETs, 18 F-FDG PET imaging is more reliable for evaluating these tumors. [6] 68 Ga-DOTANOC PET-based SUVmax values can serve as a re ection of SSTR2 density, [7] whereas 18 F-FDG PET uptake values correspond to increases in metabolic activity at the cellular and tissue levels. Previous research efforts have demonstrated the complementary value of combining quantitative parameters derived from 68 Ga-DOTA-peptides and 18 F-FDG PET imaging analyses when evaluating PNET aggressiveness and conducting prognostic assessments.…”

“…[8,9] In contrast, apparent diffusion coe cient (ADC) values derived from diffusion-weighted imaging (DWI) from the MR sequence of PET/MR correlate with tumor cellularity such that they may offer value when evaluating tumor grading. [10,11] While DWI and 18 F-FDG PET offer insight into distinct molecular characteristics, glucose metabolic activity and tumor cellularity have also been reported to be positively correlated with one another. [12] When assessing tumor aggressiveness, the properties revealed by FDG and ADC are similar.…”

PET-CT in Clinical Adult Oncology—VI. Primary Cutaneous Cancer, Sarcomas and Neuroendocrine Tumors

“…Studies have demonstrated excellent correlation between SUV values for SSTR PET-CT and SSTR2 gene expression, suggesting that SUV quantification may help assess tumor characteristics and aid treatment decisions [ 119 , 120 , 121 , 122 ]. A number of studies have shown that the comparison of SSTR and FDG PET-CT systemically aided assessment of tumor grades and potential sites of higher-grade transformation [ 123 , 124 ]. This highlights the potential role multi-tracer PET-CT can play in better assessing the heterogeneous character of a patient’s disease as well as the limitations of the grading standard based upon a biopsy at a single site.…”