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Purpose: To evaluate organ-specific response to [177Lu]DOTATATE Peptide Receptor Radionuclide Therapy (PRRT) in patients with small intestine neuroendocrine tumor (SiNET) through [68Ga]DOTATOC PET/CT, and to analyze tumor uptake and functional volume variations at different metastatic sites in relation to disease progression during clinical follow-up after treatment. Methods: A retrospective analysis was conducted on 33 metastatic patients. PET/CT were performed pre-treatment (PET0), mid-treatment after two PRRT cycles (PET2), and post-treatment (PET4). SUVmax and somatostatin receptor-expressing tumor volume (SRETV) were measured in liver, lymph node, peritoneum/mesentery, and bone metastases. Results: Liver metastases showed significant reduction in both SUVmax and SRETV from PET0 to PET4, with early response evident after two PRRT cycles. Nodal lesions exhibited a delayed response, with significant reductions at PET4. Peritoneal and bone metastases showed a continuous decline in SUVmax, but no significant changes in SRETV. Objective response rates were highest in liver metastases after treatment completion with lesser responses in nodal, peritoneal, and bone lesions. At a median follow-up of 24.3 months, 70% of patients experienced disease progression, while 30% did not. Liver metastases showed no significant changes in SUVmax or SRETV regardless of progression. Conversely, in non-progressing patients, peritoneal/mesenteric lesions showed a significant reduction in SUVmax, with unchanged SRETV, and nodal metastases exhibited reduced SRETV. Bone lesions in non-progressing patients showed significant decreases in both SUVmax and SRETV. Conclusion: [177Lu]DOTATATE PRRT effectively reduces tumor functional activity in patients with SiNETs, with organ-specific responses highlighting the need for personalized treatment strategies to optimize efficacy and minimize toxicity. [ABSTRACT FROM AUTHOR]

Background Methods Results Conclusions 4D‐CT has garnered attention as complementary imaging for patients with primary hyperparathyroidism (pHPT). Herein we evaluated a diagnostic strategy using [18F]Fluorocholine Positron Emission Tomography/Computed Tomography (PET/CT), followed by 4D‐CT integrated into PET/4D‐CT after negative/inconclusive PET/CT results in a single‐center retrospective cohort of 166 pHPT patients who underwent parathyroidectomy after [18F]Fluorocholine PET/4D‐CT.PET/CT and 4D‐CT images were interpreted by three nuclear medicine physicians and one expert radiologist. Pathological findings were documented, and concordance rates were assessed. PET/CT results were categorized as positive/negative, with positive cases rated on a 3‐level certitude scale: low, moderate, high. Inconclusive cases included low/moderate positivity. The added value of PET/4D‐CT was assessed for negative/inconclusive cases through joint reading.PET/CT lesion‐based analysis showed almost perfect interobserver concordance (Cohen's kappa >.8). Across the cohort, PET/CT had a sensitivity of 83%, specificity of 97%, PPV of 90% and NPV of 94%. For 4D‐CT, these values were sensitivity: 53%, specificity: 84%, PPV: 56% and NPV: 82%. PET/CT was significantly more accurate than 4D‐CT. Among 44 patients with negative/inconclusive results, PET/CT had sensitivity: 60%, specificity: 91%, PPV: 71% and NPV: 86%. In the same patients, sensitivity and specificity of the sequential diagnostic algorithm increased to 80% and 97%, showing significantly better global accuracy (92% vs. 83%) than standard PET/CT.We support a personalized imaging algorithm for pHPT, placing [18F]Fluorocholine PET/CT at the forefront, followed by 4D‐CT integrated into PET/4D‐CT in the same imaging session for negative/inconclusive results. When PET/CT results are clearly positive, the additional sensitivity benefit of 4D‐CT is minimal. [ABSTRACT FROM AUTHOR]

Simple Summary: Preoperative 18F-FDG PET/CT is valuable in detecting colon lesions not visualized by conventional workup, especially in patients with incomplete colonoscopy. 18F-FDG PET/CT highlights distant metastases but exhibits limitations for N staging. The quantitative analysis of 18F-FDG uptake in the primary tumor did not reveal any association with recurrence or disease-free survival, adding no prognostic information. We analyzed whether preoperative 18F-FDG PET/CT adds to conventional primary staging in patients with presumed non-metastatic colonic cancer (CC). The prognostic role of 18F-FDG uptake in the primary tumor was evaluated after a mean follow-up of 15 years. Patients with a new diagnosis of presumed localized CC were prospectively enrolled and underwent presurgical 18F-FDG PET/CT. For each colon lesion, SUVmax, SUVpeak, TLG, and MTV were assessed and tested as prognostic factors. Forty-eight patients were included. Post-surgery pathology identified a total of 103 colon lesions, including 58 invasive adenocarcinomas, 4 in situ adenocarcinomas, 3 adenomas with high-grade dysplasia, and 38 adenomas with low-grade dysplasia. Per lesion sensitivity, specificity, positive (PPVs) and negative predictive values (NPVs) for colonic primary tumor detection were 78%, 97%, 98%, and 73% for conventional workup, and 94%, 87%, 92%, and 89% for 18F-FDG PET/CT. Only sensitivity was significantly different between 18F-FDG PET/CT and conventional workup. PET detected an additional ten pathological colonic lesions in seven patients. SUVmax, SUVpeak, and TLG showed significant differences between invasive adenocarcinomas, in situ adenocarcinomas, and high-grade dysplasia compared to low-grade dysplasia. There was a statistically significant difference between pT1-pT2 and pT3-pT4 adenocarcinomas. On patient-based analysis, sensitivity, specificity, PPV, and NPV for nodal staging were 22%, 84%, 44%, and 65% for CECT, and 33%, 90%, 67%, and 70% for 18F-FDG PET/CT, without a statistically significant difference. PET/CT also identified unknown metastatic spread and one synchronous lung cancer in four patients. Overall, 18F-FDG PETCT had an additional diagnostic value in 11 out of 48 patients (23%). 18F-FDG uptake of the primary tumor did not predict nodal or distant metastases. The difference in disease-free survival categorized by median SUVmax, SUVpeak, TLG, and MTV was not significant. Finally, preoperative 18F-FDG PET/CT is valuable in detecting potential colon lesions not visualized by conventional workups, especially in cases of incomplete colonoscopy. It effectively highlights distant metastases but exhibits limitations for N staging. Mainly due to the relatively small sample size, the quantitative analysis of 18F-FDG uptake in the primary tumor did not reveal any association with recurrence or disease-free survival, adding no significant prognostic information. [ABSTRACT FROM AUTHOR]

Hyperparathyroidism (HPT) in patients with chronic kidney disease (CKD) includes secondary (sHPT) and tertiary hyperparathyroidism (tHPT). Considering that the role of preoperative imaging in the clinical setting is controversial, in the present study we have retrospectively compared pre-surgical diagnostic performances of 18F-Fluorocholine (18F-FCH) PET/CT, cervical ultrasonography (US), parathyroid scintigraphy, and 4D-CT in a group of 30 patients with CKD and HPT (18/12 sHPT/tHPT), 21 CKD G5 including 18 in dialysis, and 9 kidney transplant recipients. All patients underwent 18F-FCH, and 22 had cervical US, 12 had parathyroid scintigraphy, and 11 had 4D-CT. Histopathology was the gold standard. Seventy-four parathyroids were removed: 65 hyperplasia, 6 adenomas, and 3 normal glands. In the whole population, in a per gland analysis, 18F-FCH PET/CT was significantly more sensitive and accurate (72%, 71%) than neck US (25%, 43%), parathyroid scintigraphy (35%, 47%), and 4D-CT (40%, 47%). The specificity of 18F-FCH PET/CT (69%) was lower than that of neck US (95%) and parathyroid scintigraphy (90%), without, however, achieving significance. 18F-FCH PET/CT was more accurate than all other diagnostic techniques when sHPT and tHPT patients were considered separately. 18F-FCH PET/CT sensitivity was significantly higher in tHPT (88%) than in sHPT (66%). Three ectopic hyperfunctioning glands (in three different patients) were all detected by 18F-FCH PET/CT, two by parathyroid scintigraphy, and none by cervical US and 4D-CT. Our study confirms that 18F-FCH PET/CT is an effective preoperative imaging option in patients with CKD and HPT. These findings may be of greater importance in patients with tHPT (who could benefit from minimally invasive parathyroidectomy) than in patients with sHPT, who often undergo bilateral cervicotomy. In these cases, preoperative 18F-FCH PET/CT may be helpful in locating ectopic glands and may guide the surgical choice for gland preservation. [ABSTRACT FROM AUTHOR]

Abstract: Spinal cord sarcoidosis (SCS) is an uncommon disease with estimated incidence of 0.4% in patients with systemic sarcoidosis. Spinal cord sarcoidosis typically manifests late in the disease course and significantly contributes to patient morbidity. Therefore, early SCS diagnosis and prompt initiation of therapy are crucial. Herein, we report the case of a 51-year-old man with symptomatic SCS managed by 18 F-FDG PET/MRI, allowing diagnosis and treatment efficacy evaluation of spine involvement. We believe that the increasing clinical availability of hybrid PET/MRI devices will offer new opportunities for optimal management of patients with uncommon severe sarcoidosis localizations, such as nervous system., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)