Aim In recent years, the clinical availability of scanners for integrated positron emission tomography (PET) and magnetic resonance imaging (MRI) has enabled the practical potential of multimodal, combined metabolic-receptor, anatomical, and functional imaging to be explored. The present systematic review and meta-analysis summarize the diagnostic information provided by PET/MRI in patients with prostate cancer (PCa). Materials and methods A literature search was conducted in three different databases. The terms used were “choline” or “prostate-specific membrane antigen - PSMA” AND “prostate cancer” or “prostate” AND “PET/MRI” or “PET MRI” or “PET-MRI” or “positron emission tomography/magnetic resonance imaging.” All relevant records identified were combined, and the full texts were retrieved. Reports were excluded if (1) they did not consider hybrid PET/MRI; or (2) the sample size was < 10 patients; or (3) the raw data were not enough to enable the completion of a 2 × 2 contingency table. Results Fifty articles were eligible for systematic review, and 23 for meta-analysis. The pooled data concerned 2104 patients. Initial disease staging was the main indication for PET/MRI in 24 studies. Radiolabeled PSMA was the tracer most frequently used. In primary tumors, the pooled sensitivity for the patient-based analysis was 94.9%. At restaging, the pooled detection rate was 80.9% and was higher for radiolabeled PSMA than for choline (81.8% and 77.3%, respectively). Conclusions PET/MRI proved highly sensitive in detecting primary PCa, with a high detection rate for recurrent disease, particularly when radiolabeled PSMA was used.

Aim The diagnosis, severity and extent of a sterile inflammation or a septic infection could be challenging since there is not one single test able to achieve an accurate diagnosis. The clinical use of 18F-fluorodeoxyglucose ([ 18 F]FDG) positron emission tomography/computed tomography (PET/CT) imaging in the assessment of inflammation and infection is increasing worldwide. The purpose of this paper is to achieve an Italian consensus document on [ 18 F]FDG PET/CT or PET/MRI in inflammatory and infectious diseases, such as osteomyelitis (OM), prosthetic joint infections (PJI), infective endocarditis (IE), prosthetic valve endocarditis (PVE), cardiac implantable electronic device infections (CIEDI), systemic and cardiac sarcoidosis (SS/CS), diabetic foot (DF), fungal infections (FI), tuberculosis (TBC), fever and inflammation of unknown origin (FUO/IUO), pediatric infections (PI), inflammatory bowel diseases (IBD), spine infections (SI), vascular graft infections (VGI), large vessel vasculitis (LVV), retroperitoneal fibrosis (RF) and COVID-19 infections. Methods In September 2020, the inflammatory and infectious diseases focus group (IIFG) of the Italian Association of Nuclear Medicine (AIMN) proposed to realize a procedural paper about the clinical applications of [ 18 F]FDG PET/CT or PET/MRI in inflammatory and infectious diseases. The project was carried out thanks to the collaboration of 13 Italian nuclear medicine centers, with a consolidate experience in this field. With the endorsement of AIMN, IIFG contacted each center, and the pediatric diseases focus group (PDFC). IIFG provided for each team involved, a draft with essential information regarding the execution of [ 18 F]FDG PET/CT or PET/MRI scan (i.e., indications, patient preparation, standard or specific acquisition modalities, interpretation criteria, reporting methods, pitfalls and artifacts), by limiting the literature research to the last 20 years. Moreover, some clinical cases were required from each center, to underline the teaching points. Time for the collection of each report was from October to December 2020. Results Overall, we summarized 291 scientific papers and guidelines published between 1998 and 2021. Papers were divided in several sub-topics and summarized in the following paragraphs: clinical indications, image interpretation criteria, future perspectivess and new trends (for each single disease), while patient preparation, image acquisition, possible pitfalls and

The aim of the present systematic review is to examine the role of fluorodeoxyglucose (FDG) positron emission tomography (PET) associated with computed tomography (CT) or magnetic resonance imaging (MRI) in assessing response to preoperative chemotherapy or chemoradiotherapy (CRT) for patients with borderline and resectable pancreatic ductal adenocarcinoma (PDAC). Three researchers ran a database query in PubMed, Web of Science and EMBASE. The total number of patients considered was 488. The most often used parameters of response to therapy were the reductions in the maximum standardized uptake value (SUVmax) or the peak standardized uptake lean mass (SULpeak). Patients whose SUVs were higher at the baseline (before CRT) were associated with a better response to therapy and a better overall survival. SUVs remaining high after neoadjuvant therapy correlated with a poor prognosis. Available data indicate that FDG PET/CT or PET/MRI can be useful for predicting and assessing response to CRT in patients with resectable or borderline PDAC.

Aim This mini-review aims to summarize the main findings on PET/MRI in patients with sarcomas. Materials and methods A literature search was carried out on MEDLINE databases, such as PubMed, Scopus, Web of Science and Google Scholar, using the search terms “PET”, “positron emission tomography”, “PET/MRI”, “positron emission tomography/magnetic resonance imaging”, and “sarcoma”. No restrictions (i.e. language, age, type of manuscript, or the like) were applied to the search strategy. Abstracts, reviews, letters to editors, and editorials were excluded. Results Eight studies were ultimately included. From 2013 to 2019, a total of 154 adult patients with sarcomas underwent 18F-fluorodeoxyglucose (18F-FDG) PET/MRI. Of these patients, 129 had soft tissue sarcomas (STS), 5 had bone sarcomas, and 20 had cardiac masses. Thirty-two patients had PET/MRI for early-stage disease, 45 for recurrences, and 57 for the assessment of response to treatment. For staging purposes, the studies suggest that PET/MRI can significantly improve the delineation of surgical margins. At restaging, PET/MRI can also detect sarcoma recurrences more accurately than conventional imaging. Conclusions 18F-FDG PET/MRI has promising indications in patients with sarcomas, from disease staging to the assessment of response to treatment. Further studies are warranted to confirm these results, especially in subgroups with specific histopathological features.

We present a case of neuroendocrine tumor localized in the gastric mucosa, incidentally detected by 18F-choline PET/CT in a 69-year-old man with prostate cancer. 18F-choline PET/CT scan showed an increased activity in the stomach, later diagnosed as a well-differentiated neuroendocrine tumor, at biopsy. A careful attention of reading 18F-choline PET/CT images should be made, in order to avoid the missing of potential concomitant neoplasia in patients with prostate cancer.

Objectives The aims of the study were (i) to examine the PCa detection rate of 18F-choline (FCH) PET/MRI and (ii) to assess the impact of PET/MRI findings in patients with PCa who develop OMD using PSA response as a biomarker. Methods We retrospectively analyzed a cohort of 103 patients undergoing FCH PET/MRI for biochemical recurrence of PCa. The inclusion criteria were (1) previous radical prostatectomy (RP) with or without adjuvant radiotherapy (RT); (2) PSA levels available at the time of PET; (3) OMD, defined as a maximum of 5 lesions on PET/MRI; and (4) follow-up data available for at least 6 months after PET. All images were reviewed by two nuclear medicine physicians and interpreted with the support of two radiologists. Results Seventy patients were eligible for the study: 52 patients had a positive FCH PET/MRI and 18 had a negative scan. The overall PCa detection rates for MRI, PET, and PET/MRI were 65.7%, 37.1%, and 74.3%, respectively. Thirty-five patients were treated with radiotherapy (RT), 16 received hormonal therapy (HT), 3 had a combined therapy (RT + HT), and 16 (23%) underwent PSA surveillance. At follow-up, PSA levels decreased in 51 patients (73%), most of whom had been treated with RT or RT + HT. Therapeutic management was guided by PET/MRI in 74% of patients, which performed better than MRI alone (68% of patients). Conclusion FCH PET/MRI has a higher detection rate than MRI or PET alone for PCa patients with OMD and PSA levels > 0.5 ng/mL, prompting a better choice of treatment.

We present a case of a chronic mass-forming pancreatitis (CMFP) detected by 18F-choline (FCH) PET/CT in a male affected by prostate cancer. FCH PET/CT scan showed a focal uptake in the uncinate process of the pancreas, later diagnosed as a CMFP at biopsy. Although the physiological distribution of FCH in the pancreas, a careful interpretation of the images in this area is warranted.