Jean-Noël Talbot

Introduction: The diagnosis and localization of insulinomas remain challenging. Imaging with contrast-enhanced CT, PET with somatostatin analogs, MRI, and endoscopic ultrasonography is often inconclusive. GLP1 receptor radioligands can specifically target insulinomas. A recent multicenter trial reported the superior performance of ⁶⁸ Ga-NODAGA-Exendin-4 (EX) PET/CT for the detection of benign insulinomas. Patients and Methods: Fifty EX-PET/CTs (individually authorized by the French Medicine Agency) were performed on 44 patients with a suspected sporadic insulinoma, based on biochemistry and clinical signs, but without a target lesion identified by imaging. A composite reference standard was based on postsurgical histology and/or follow-up data over 6–45 months after the EX-PET/CT. Results: The examination-based EX-PET/CT positivity rate was 62% (31/50), equivocal 0. Positive EX-PET/CTs were confirmed by the outcomes of all 29 EX-guided resections (PPV 100%), including 2 re-operations following partial resection. Furthermore, the suspected diagnosis of an insulinoma was abandoned in 12 patients after 14 of 19 negative EX-PET/CTs. Suspicion of occult insulinoma remained in 5 patients. EX-PET/CT performed similarly well in patients treated by antihypoglycemic drugs and/or younger than 18 years. Since no extra-pancreatic EX abnormal foci were observed, the EX-PET/CT field-of-view to the upper abdomen should be sufficient. Only 1 patient experienced symptomatic hypoglycemia after EX injection. Conclusions: In cases of suspected insulinomas with nondiagnostic imaging, the performance of EX-PET/CT for the detection of nonmalignant sporadic insulinomas was excellent, with a 29/50 (58%) rate of major impact on patients’ management. A negative EX-PET/CT appears to be a confident predictor to rule out the presence of sporadic insulinoma.

Introduction: Endometriosis is a common gynecologic condition that may be visualized on ¹⁸F-FDG PET/CT and mimic lesions of malignancy. We analyzed the interference of known or suspected endometriosis in reporting ¹⁸F-FDG PET/CT performed in another indication. Results: The PET/CT images of 18 women with known (n = 15) or suspected (n = 3) endometriosis were analyzed. Based on clinical follow-up and results of other imaging, biopsy, and/or postsurgical histology, the presence of lesions of endometriosis at the time of ¹⁸F-FDG PET/CT was confirmed in 13 of 18 patients (72%). The per-patient positivity rate of ¹⁸F-FDG PET/CT was 8/18 (44%; 95% confidence interval, 22%–69%). The patient-based detection rate of ¹⁸F-FDG PET/CT in patients with confirmed lesions of endometriosis was 8/13 (62%; confidence interval, 32%–86%). On per-lesion/site basis, ¹⁸F-FDG PET/CT detected 11 of 20 sites (55%) of endometriosis. The SUVmax of these lesions/sites ranged between 1.8 and 5.3 (median, 3.8). In 9 of 18 patients (50%), a total of 13 non–endometriosis-related lesions/sites were detected by ¹⁸F-FDG PET/CT; their SUVmax ranged between 2.7 and 23 (median, 9.4). Conclusion: The interference of known or suspected endometriosis in reporting ¹⁸F-FDG PET/CT performed in another indication was limited but possible and should be kept in mind, even in postmenopausal women, as the oldest patient with ¹⁸F-FDG–positive endometriosis was aged 63 years. The lesions of endometriosis showed inconstant ¹⁸F-FDG uptake with overlap of SUVmax with low-grade malignancies. In our series, the greatest SUVmax value of lesion of endometriosis was 5.3, somewhat higher than the threshold of 4 previously proposed for identification of malignant transformation of endometriosis.

Introduction Despite growing evidence of a superior diagnostic performance of ⁶⁸Ga-PSMA-11 over ¹⁸F-fluorocholine (FCH) PET/CT, the number of PET/CT centres able to label on site with gallium-68 is still currently limited. Therefore, patients with biochemical recurrence (BCR) of prostate cancer frequently undergo FCH as the 1st-line PET/CT. Actually, the positivity rate (PR) of a second-line PSMA-11 PET/CT in case of negative FCH PET/CT has only been reported in few short series, in a total of 185 patients. Our aims were to check (1) whether the excellent PR reported with PSMA-11 is also obtained in BCR patients whose recent FCH PET/CT was negative or equivocal; (2) in which biochemical and clinical context a high PSMA-11 PET/CT PR may be expected in those patients, in particular revealing an oligometastatic pattern; (3) whether among the various imaging protocols for PSMA-11 PET/CT used in France, one yields a significantly highest PR; (4) the tolerance of PSMA-11. Patients and methods Six centres performed ⁶⁸Ga-PSMA-11 PET/CTs during the first 3 years of its use in France. Prior to each PET/CT, the patient’s data were submitted prospectively for authorisation to ANSM, the French Medicine Agency. The on-site readings of 1084 PSMA-11 PET/CTs in BCR patients whose recent FCH PET/CTs resulted negative or equivocal were pooled and analysed. Results (1) The overall PR was 68%; for a median serum PSA level (sPSA) of 1.7 ng/mL, an oligometastatic pattern (1–3 foci) was observed in 31% of the cases overall; (2) PR was significantly related to sPSA (from 41% if < 0.2 ng/mL to 81% if ≥ 2 ng/mL), to patients’ age, to initial therapy (64% if prostatectomy vs. 85% without prostatectomy due to frequent foci in the prostate fossa), to whether FCH PET/CT was negative or equivocal (PR = 62% vs. 82%), and to previous BCR (PR = 63% for 1st BCR vs. 72% in case of previous BCR); (3) no significant difference in PR was found according to the imaging protocol: injected activity, administration of a contrast agent and/or of furosemide, dose length product, one single or multiple time points of image acquisition; (4) no adverse event was reported after PSMA-11 injection, even associated with a contrast agent and/or furosemide. Conclusion Compared with the performance of PSMA-11 PET/CT in BCR reported independently of FCH PET/CT in 6 large published series (n > 200), the selection based on FCH PET/CT resulted in no difference of PSMA-11 PR for sPSA < 1 ng/mL but in a slightly lower PR for sPSA ≥ 1 ng/mL, probably because FCH performs rather well at this sPSA and very occult BCR was over-represented in our cohort. An oligometastatic pattern paving the way to targeted therapy was observed in one fourth to one third of the cases, according to the clinico-biochemical context of the BCR. Systematic dual or triple acquisition time points or administration of a contrast agent and/or furosemide did not bring a significant added value for PSMA-11 PET/CT positivity and should be decided on individual bases.

The European Nuclear Medicine Guide offers a thorough overview of a wide variety of topics related to nuclear medicine for professionals in the field, including: Nuclear medicine-related basic science and technical procedures In vivo imaging with radiopharmaceuticals Hybrid/multimodality imaging Radionuclide-guided surgery Dosimetry Radionuclide therapy Techniques related to nuclear physics in medicine Medical applications of radiobiology and radiation protection

The aim of this study was to evaluate positron emission tomography (PET) imaging with [⁶⁸Ga]NODAGA-c(RGDfK) ([⁶⁸Ga]RGD), in comparison with 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG), for early monitoring of the efficacy of an antiangiogenic agent associated or not with chemotherapy, in a mouse model of glioblastoma (GB).

This Editorial Comment refers to the articles “Diagnostic evaluation of magnetization transfer and diffusion kurtosis imaging for prostate cancer detection in a re-biopsy population” by Barrett T et al., Eur Radiol. 2017 Dec 8 and “18F-Fluciclovine PET/MRI for preoperative lymph node staging in high-risk prostate cancer patients” by Selnæs KM et al., Eur Radiol. 2018 Jan 2.

Comparison and evaluation of two RGD peptides labelled with 68 Ga or 18 F for PET imaging of angiogenesis in animal models of human glioblastoma or lung carcinoma Comparison and evaluation of two RGD peptides labelled with 68Ga or 18F for PET imaging of angiogenesis in animal models of human glioblastoma or lung carcinoma