Bilateral Ovarian Metastases of Hepatocellular Carcinoma Diagnosed with 18F-Fluorocholine PET/CT in a Patient with Endometriosis.

A 47-year-old woman with history of hepatocellular carcinoma was referred for 18F-fluorocholine PET/CT evaluation due to elevated alpha-fetoprotein. The examination showed several peritoneal uptakes and two nodular pelvic foci. Coelioscopic exploration allowed confirmation and resection of multiple peritoneal metastases from hepatocellular carcinoma while pelvic biopsies revealed endometriosis and endosalpingiosis. However, alpha-fetoprotein kept rising: subsequent 18F-fluorodesoxyglucose PET/CT exploration found no pelvic uptake, while 18F-fluorocholine PET/CT revealed intense tracer accumulation in the two pelvic masses corresponding to bilateral ovarian metastases of hepatocellular carcinoma. We highlight the importance of 18F-fluorocholine PET/CT in hepatocellular carcinoma especially in patients with confounding comorbidities such as endometriosis.

18F-Fluorocholine PET/CT Compared with Current Imaging Procedures for Preoperative Localization of Hyperfunctioning Parathyroids in Patients with Chronic Kidney Disease.

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.

Cutting-Edge Imaging of Cardiac Metastases from Neuroendocrine Tumors: Lesson from a Case Series.

With the increasing availability of high-performance medical imaging for the management of patients with neuroendocrine tumors (NETs), a progressive growth of asymptomatic and incidentally detected cardiac metastases (CMs) has been observed in the recent years. In clinical practice, CMs of NENs are often incidentally detected by whole-body 68Ga-labeled somatostatin analogs or 18F-fluorodihydroxyphenylalanine positron emission tomography/computed tomography, and afterwards accurately characterized by cardiac magnetic resonance (CMR) and/or gated cardiac computed tomography when CMR is contraindicated or not available. The interpreting physician should familiarize with the main imaging features of CM, a finding that may be encountered in NETs patients more than previously thought. Herein, we present a case series of four patients with CMs from small-intestine NETs highlighting strengths and weaknesses of a multimodality imaging approach in clinical practice.

Pseudoprogression versus true progression in glioblastoma patients: A multiapproach literature review. Part 2 - Radiological features and metric markers.

After chemoradiotherapy for glioblastoma, pseudoprogression can occur and must be distinguished from true progression to correctly manage glioblastoma treatment and follow-up. Conventional treatment response assessment is evaluated via conventional MRI (contrast-enhanced T1-weighted and T2/FLAIR), which is unreliable. The emergence of advanced MRI techniques, MR spectroscopy, and PET tracers has improved pseudoprogression diagnostic accuracy. This review presents a literature review of the different imaging techniques and potential imaging biomarkers to differentiate pseudoprogression from true progression.

18F-FDG PET/CT Imaging of Peritoneal Fibrosis Mimicking Persistent Metastatic Ovarian Carcinoma.

A 65-year-old woman was addressed for clinical and biological suspicion of ovarian cancer relapse. 18F-FDG PET/CT revealed massive peritoneal carcinomatosis. Post-chemotherapy PET/CT showed complete metabolic response in initial localizations albeit three new 18F-FDG uptakes appeared in the mesentery and in the retro-hepatic space. Close follow-up (including PET/CT scan) and surgical examination of the abdominal cavity confirmed the absence of malignancy and the benign nature of these lesions, which appeared to be peritoneal fibrosis mimicking persistent carcinomatosis.

Lenograstim-Induced Nodal Extramedullary Hematopoiesis: A Challenging Diagnosis in Lymphoma Evaluation With 18F-FDG PET/CT.

We report the case of a 23-year-old man with nodal EMH (extramedullary hematopoiesis) occurring during treatment for a stage IIA "gray-zone" lymphoma. Although it is often related to myeloproliferative bone marrow disease, benign etiologies such as lenograstim treatment after chemotherapy can also induce EMH and be responsible for false-positive F-FDG PET/CT examinations. In this respect, GLUT overexpression in hematopoietic lineages and macrophages of the inflammatory environment are responsible for increased F-FDG uptake. Histopathologic confirmation of new hypermetabolic lesions on follow-up PET/CT may be required when the new lesions do not conform with the treatment responses in the preexisting lesions.

Early 18F-FDOPA PET/CT imaging after carbidopa premedication as a valuable diagnostic option in patients with insulinoma.

PURPOSE: Data on the diagnostic value of 18F-FDOPA PET/CT in patients with insulinoma are limited and are focused on small patient populations explored using different PET/CT protocols and the inconsistent use of carbidopa premedication. The aim of this study was to improve the current knowledge about the diagnostic value of 18F-FDOPA PET/CT combined with oral carbidopa premedication and early pancreatic imaging for tumour localization in patients with insulinoma-related hyperinsulinaemic hypoglycaemia (HH). The relationships among 18F-FDOPA quantitative uptake parameters, insulin secretion and tumour pathological features were also investigated. METHODS: Of 34 patients with suspicion of insulinoma-related HH examined by dual time-point carbidopa-assisted 18F-FDOPA PET/CT, 24 with histologically proven insulinoma were retrospectively included. One patient underwent two PET/CT examinations for relapsing insulinoma after surgical excision. Thus, 25 preoperative 18F-FDOPA PET/CT studies were finally retained and analysed. All studies were performed under carbidopa premedication (200 mg orally, 1-2 h prior to tracer injection). The PET/CT acquisition protocol included an early acquisition (5 min after 18F-FDOPA injection) over the upper abdomen and a delayed whole-body acquisition starting 20-30 min later. The cytological and/or histopathological diagnosis of insulinoma was the diagnostic standard of truth. RESULTS: 18F-FDOPA PET/CT localized insulinoma in 21 of the 25 studies, leading to a primary lesion detection rate of 84%. Four lesions (19%) were detected only on early acquisitions. The false-negative tumour detection rates were, respectively, 22% and 12.5% in patients receiving and not receiving treatment for hypoglycaemic symptoms at the time of PET/CT. In benign insulinomas, the early maximum standardized uptake value (SUVmax) was significantly higher than the delayed SUVmax. Compared to the 21 benign lesions, four malignant insulinomas showed significantly higher 18F-FDOPA uptake. Lesion size, fasting-end insulin and C-peptide levels correlated with tumour 18F-FDOPA uptake, dopaminergic tumour volume and metabolic burden. CONCLUSION: The present study showed that 18F-FDOPA PET/CT combined with carbidopa premedication and early pancreatic acquisitions is a valuable diagnostic option in patients with insulinoma when GLP1R-based imaging is not available. The results also provide new insights into the relationships between tumour secretion and imaging phenotype in insulinomas.

18F-FDOPA PET/CT of Nonfunctioning Paraganglioma of the Gastroepiploic Pedicle.

We report the case of a 54-year-old woman with a nonfunctioning paraganglioma arising from the gastroepiploic pedicle demonstrated by F-FDOPA PET/CT. Because gastroepiploic arcade can be assimilated to the gastric mesentery, this tumor has been classified as a mesenteric paraganglioma (PGL). Neural crest cells are a multipotent population of cells characterized by effective migratory properties potentially explaining PGL atypical localization as in the mesentery. Mesenteric PGLs are often nonfunctioning and can mimic gastric, colic, or pancreatic primary tumor because of their anatomical boundaries, making more difficult the diagnosis on preoperative imaging.