The amyloid cascade hypothesis for Alzheimer’s disease is still alive, although heavily challenged. Effective anti-amyloid immunotherapy would confirm the hypothesis’ claim that the protein amyloid-beta is the cause of the disease. Two antibodies, aducanumab and lecanemab, have been approved by the U.S. Food and Drug Administration, while a third, donanemab, is under review. The main argument for the FDA approvals is a presumed therapy-induced removal of cerebral amyloid deposits. Lecanemab and donanemab are also thought to cause some statistical delay in the determination of cognitive decline. However, clinical efficacy that is less than with conventional treatment, selection of amyloid-positive trial patients with non-specific amyloid-PET imaging, and uncertain therapy-induced removal of cerebral amyloids in clinical trials cast doubt on this anti-Alzheimer’s antibody therapy and hence on the amyloid hypothesis, calling for a more thorough investigation of the negative impact of this type of therapy on the brain.

The introduction of total body (TB) PET/CT instruments over the past 2 years has initiated a new and exciting era in medical imaging. These instruments have substantially higher sensitivity (up to 68 times) than conventional modalities and therefore allow imaging the entire body over a short period. However, we need to further refine the imaging protocols of this instrument for different indications. Total body PET will allow accurate assessment of the extent of disease, particularly, including the entire axial and appendicular skeleton. Furthermore, delayed imaging with this instrument may enhance the sensitivity of PET for some types of cancer. Also, this modality may improve the detection of venous thrombosis, a common complication of cancer and chemotherapy, in the extremities and help prevent pulmonary embolism. Total body PET allows assessment of atherosclerotic plaques throughout the body as a systematic disease. Similarly, patients with widespread musculoskeletal disorders including both oncologic and nononcologic entities, such as degenerative joint disease, rheumatoid arthritis, and osteoporosis, may benefit from the use of TB-PET. Finally, quantitative global disease assessment provided by this approach will be superior to conventional measurements, which do not reflect overall disease activity. In conclusion, TB-PET imaging may have a revolutionary impact on day-to-day practice of medicine and may become the leading imaging modality in the future.

Alterations in cerebral glucose metabolism can be indicative of both normal and pathological aging processes. In this retrospective study, we evaluated global and regional neurological glucose metabolism in 73 healthy individuals (mean age: 35.8 ± 13.1 years; 82.5% female) using 18F-Fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT). This population exhibited a low prevalence of comorbidities associated with cerebrovascular risk factors. We utilized ¹⁸F-FDG-PET/CT imaging and quantitative regional analysis to assess cerebral glucose metabolism. A statistically significant negative correlation was found between age and the global standardized uptake value mean (SUVmean) of FDG uptake (p = 0.000795), indicating a decrease in whole-brain glucose metabolism with aging. Furthermore, region-specific analysis identified significant correlations in four cerebral regions, with positive correlations in the basis pontis, cerebellar hemisphere, and cerebellum and a negative correlation in the lateral orbital gyrus. These results were further confirmed via linear regression analysis. Our findings reveal a nuanced understanding of how aging affects glucose metabolism in the brain, providing insight into normal neurology. The study underscores the utility of ¹⁸F-FDG-PET/CT as a sensitive tool in monitoring these metabolic changes, highlighting its potential for the early detection of neurological diseases and disorders related to aging.

Rheumatoid Arthritis (RA) is a systemic inflammatory disorder that commonly presents with polyarthritis but can have multisystemic involvement and complications, leading to increased morbidity and mortality. The diagnosis of RA continues to be challenging due to its varied clinical presentations. In this review article, we aim to determine the potential of PET/CT to assist in the diagnosis of RA and its complications, evaluate the therapeutic response to treatment, and predict RA remission. PET/CT has increasingly been used in the last decade to diagnose, monitor treatment response, predict remissions, and diagnose subclinical complications in RA. PET imaging with [¹⁸F]-fluorodeoxyglucose ([¹⁸F]-FDG) is the most commonly applied radiotracer in RA, but other tracers are also being studied. PET/CT with [¹⁸F]-FDG, [¹⁸F]-NaF, and other tracers might lead to early identification of RA and timely evidence-based clinical management, decreasing morbidity and mortality. Although PET/CT has been evolving as a promising tool for evaluating and managing RA, more evidence is required before incorporating PET/CT in the standard clinical management of RA.

Castleman disease (CD) describes a group of rare hematologic conditions involving lymphadenopathy with characteristic histopathology and a spectrum of clinical abnormalities. CD is divided into localized or unicentric CD (UCD) and multicentric CD (MCD) by imaging. MCD is further divided based on etiological driver into human herpesvirus-8-associated MCD, POEMS-associated MCD, and idiopathic MCD. There is notable heterogeneity across MCD, but increased level of pro-inflammatory cytokines, particularly interleukin-6, is an established disease driver in a portion of patients. FDG-PET/CT can help determine UCD versus MCD, evaluate for neoplastic conditions that can mimic MCD clinico-pathologically, and monitor therapy responses. CD requires more robust characterization, earlier diagnosis, and an accurate tool for both monitoring and treatment response evaluation; FDG-PET/CT is particularly suited for this. Moving forward, future prospective studies should further characterize the use of FDG-PET/CT in CD and specifically explore the utility of global disease assessment and dual time point imaging.Trial registrationClinicalTrials.gov, NCT02817997, Registered 29 June 2016,https://clinicaltrials.gov/ct2/show/NCT02817997