Purpose The present study hypothesised that whole-body [18F]FDG-PET/CT might provide insight into the pathophysiology of long COVID. Methods We prospectively enrolled 13 adult long COVID patients who complained for at least one persistent symptom for >30 days after infection recovery. A group of 26 melanoma patients with negative PET/CT matched for sex/age was used as controls (2:1 control to case ratio). Qualitative and semi-quantitative analysis of whole-body images was performed. Fisher exact and Mann-Whitney tests were applied to test differences between the two groups. Voxel-based analysis was performed to compare brain metabolism in cases and controls. Cases were further grouped according to prevalent symptoms and analysed accordingly. Results In 4/13 long COVID patients, CT images showed lung abnormalities presenting mild [18F]FDG uptake. Many healthy organs/parenchyma SUVs and SUV ratios significantly differed between the two groups (p ≤ 0.05). Long COVID patients exhibited brain hypometabolism in the right parahippocampal gyrus and thalamus (uncorrected p < 0.001 at voxel level). Specific area(s) of hypometabolism characterised patients with persistent anosmia/ageusia, fatigue, and vascular uptake (uncorrected p < 0.005 at voxel level). Conclusion [18F]FDG PET/CT acknowledged the multi-organ nature of long COVID, supporting the hypothesis of underlying systemic inflammation. Whole-body images showed increased [18F]FDG uptake in several “target” and “non-target” tissues. We found a typical pattern of brain hypometabolism associated with persistent complaints at the PET time, suggesting a different temporal sequence for brain and whole-body inflammatory changes. This evidence underlined the potential value of whole-body [18F]FDG PET in disclosing the pathophysiology of long COVID.

Purpose Several patients experience unexplained persistent symptoms after SARS-CoV-2 recovering. We aimed at evaluating if 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG) was able to demonstrate a persistent inflammatory process. Methods Recovered adult COVID-19 patients, who complained unexplained persisting symptoms for more than 30 days during the follow-up visits, were invited to participate in the study. Patients fulfilling inclusion criteria were imaged by [¹⁸F]FDG positron emission tomography/computed tomography ([¹⁸F]FDG-PET/CT). Whole-body [¹⁸F]FDG-PET/CT, performed according to good clinical practice, was qualitatively (comparison with background/liver) and semi-quantitatively (target-to-blood pool ratio calculated as average SUVmax artery/average SUVmean inferior vena cava) analyzed. Negative follow-up [¹⁸F]FDG-PET/CT images of oncologic patients matched for age/sex served as controls. Mann-Whitney test was used to test differences between groups. SPSS version 26 was used for analyses. Results Ten recovered SARS-CoV-2 patients (seven male and three females, median age 52 years, range 46–80) with persisting symptoms were enrolled in the study. Common findings at visual analysis were increased [¹⁸F]FDG uptake in bone marrow and blood vessels (8/10 and 6/10 cases, respectively). [¹⁸F]FDG uptake in bone marrow did not differ between cases and controls (p = 0.16). The total vascular score was similar in the two groups (p = 0.95). The target-to-blood pool ratio resulted higher in recovered SARS-CoV-2 patients than in controls. Conclusion Although the total vascular score was similar in the two groups, the target-to-blood pool ratio was significantly higher in three vascular regions (thoracic aorta, right iliac artery, and femoral arteries) in the recovered COVID-19 cohort than in controls, suggesting that SARS-CoV-2 induces vascular inflammation, which may be responsible for persisting symptoms.

Background: Contrast-enhanced mammography (CEM) and contrast-enhanced magnetic resonance imaging (CE-MRI) are commonly used in the screening of breast cancer. The present systematic review aimed to summarize, critically analyse, and meta-analyse the available evidence regarding the role of CE-MRI and CEM in the early detection, diagnosis, and preoperative assessment of breast cancer. Methods: The search was performed on PubMed, Google Scholar, and Web of Science on 28 July 2021 using the following terms “breast cancer”, “preoperative staging”, “contrast-enhanced mammography”, “contrast-enhanced spectral mammography”, “contrast enhanced digital mammography”, “contrast-enhanced breast magnetic resonance imaging” “CEM”, “CESM”, “CEDM”, and “CE-MRI”. We selected only those papers comparing the clinical efficacy of CEM and CE-MRI. The study quality was assessed using the QUADAS-2 criteria. The pooled sensitivities and specificity of CEM and CE-MRI were computed using a random-effects model directly from the STATA “metaprop” command. The between-study statistical heterogeneity was tested (I²-statistics). Results: Nineteen studies were selected for this systematic review. Fifteen studies (1315 patients) were included in the metanalysis. Both CEM and CE-MRI detect breast lesions with a high sensitivity, without a significant difference in performance (97% and 96%, respectively). Conclusions: Our findings confirm the potential of CEM as a supplemental screening imaging modality, even for intermediate-risk women, including females with dense breasts and a history of breast cancer.

Purpose: For several years, oncological positron emission tomography (PET) has developed beyond 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG). This umbrella review of meta-analyses aims to provide up-to-date, comprehensive, high-level evidence to support appropriate referral for a specific radiopharmaceutical PET/computed tomography (CT) or PET/magnetic resonance (MR) in the diagnosis and staging of solid cancers other than brain malignancies. Methods: We performed a systematic literature search on the PubMed/MEDLINE and EMBASE databases for meta-analyses assessing the accuracy of PET/CT and/or PET/MRI with [¹⁸F]FDG, somatostatin- receptor-targeting ⁶⁸Ga-DOTA-peptides, ¹⁸F-labelled dihydroxyphenylalanine ([¹⁸F]DOPA), prostate-specific membrane antigen (PSMA)-targeted radioligands, and fibroblast activation protein inhibitors (FAPI) in the diagnosis/disease characterisation and staging of solid cancers other than brain tumours. Results: The literature search yielded 449 scientific articles. After screening titles and abstracts and applying inclusion and exclusion criteria, we selected 173 meta-analyses to assess the strength of evidence. One article was selected from references. Sixty-four meta-analyses were finally considered. The current evidence corroborates the role of [¹⁸F]FDG as the main player in molecular imaging; PSMA tracers are useful in staging and re-staging prostate cancer; somatostatin-targeting peptides (e.g. [⁶⁸Ga]Ga- DOTA-TOC and -TATE) or [¹⁸F]DOPA are valuable in neuroendocrine tumours (NETs). FAPI has emerged in gastric cancer assessment. According to search and selection criteria, no satisfactory meta-analysis was selected for the diagnosis/detection of oesophageal cancer, the diagnosis/detection and N staging of small cell lung cancer and hepatic cell carcinoma, the diagnosis/detection and M staging of melanoma and Merkel cell carcinoma, cervical, vulvar and penis cancers, the N and M staging of lung and gastroenteropancreatic NET, testicular cancer, and chondrosarcoma, and the M staging of differentiated thyroid, bladder and anal cancers. Conclusion: The comprehensive high-level evidence synthesised in the present umbrella review serves as a guiding compass for clinicians and imagers, aiding them in navigating the increasingly intricate seascape of PET examinations.