Neuroimaging biomarkers and CSF sTREM2 levels in Alzheimer's disease: a longitudinal study.

Understanding the exact pathophysiological mechanisms underlying the involvement of triggering receptor expressed on myeloid cells 2 (TREM2) related microglia activation is crucial for the development of clinical trials targeting microglia activation at different stages of Alzheimer's disease (AD). Given the contradictory findings in the literature, it is imperative to investigate the longitudinal alterations in cerebrospinal fluid (CSF) soluble TREM2 (sTREM2) levels as a marker for microglia activation, and its potential association with AD biomarkers, in order to address the current knowledge gap. In this study, we aimed to assess the longitudinal changes in CSF sTREM2 levels within the framework of the A/T/N classification system for AD biomarkers and to explore potential associations with AD pathological features, including the presence of amyloid-beta (Aß) plaques and tau aggregates. The baseline and longitudinal (any available follow-up visit) CSF sTREM2 levels and processed tau-PET and Aß-PET data of 1001 subjects were recruited from the ADNI database. The participants were classified into four groups based on the A/T/N framework: A+ /TN+ , A+ /TN- , A- /TN+ , and A- /TN- . Linear regression analyses were conducted to assess the relationship between CSF sTREM2 with cognitive performance, tau and Aß-PET adjusting for age, gender, education, and APOE ε4 status. Based on our analysis there was a significant difference in baseline and rate of change of CSF sTREM2 between ATN groups. While there was no association between baseline CSF sTREM2 and cognitive performance (ADNI-mem), we found that the rate of change of CSF sTREM2 is significantly associated with cognitive performance in the entire cohort but not the ATN groups. We found that the baseline CSF sTREM2 is significantly associated with baseline tau-PET and Aß-PET rate of change only in the A+ /TN+ group. A significant association was found between the rate of change of CSF sTREM2 and the tau- and Aß-PET rate of change only in the A+ /TN- group. Our study suggests that the TREM2-related microglia activation and their relations with AD markers and cognitive performance vary the in presence or absence of Aß and tau pathology. Furthermore, our findings revealed that a faster increase in the level of CSF sTREM2 might attenuate future Aß plaque formation and tau aggregate accumulation only in the presence of Aß pathology.

Iron quantification in basal ganglia: quantitative susceptibility mapping as a potential biomarker for Alzheimer's disease - a systematic review and meta-analysis.

Introduction: Alzheimer's disease (AD), characterized by distinctive pathologies such as amyloid-ß plaques and tau tangles, also involves deregulation of iron homeostasis, which may accelerate neurodegeneration. This meta-analysis evaluated the use of quantitative susceptibility mapping (QSM) to detect iron accumulation in the deep gray matter (DGM) of the basal ganglia in AD, contributing to a better understanding of AD progression, and potentially leading to new diagnostic and therapeutic approaches. Methods: Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we systematically searched the PubMed, Scopus, Web of Sciences, and Google Scholar databases up to October 2023 for studies employing QSM in AD research. Eligibility criteria were based on the PECO framework, and we included studies assessing alterations in magnetic susceptibility indicative of iron accumulation in the DGM of patients with AD. After initial screening and quality assessment using the Newcastle-Ottawa Scale, a meta-analysis was conducted to compare iron levels between patients with AD and healthy controls (HCs) using a random-effects model. Results: The meta-analysis included nine studies comprising 267 patients with AD and 272 HCs. There were significantly higher QSM values, indicating greater iron deposition, in the putamen (standardized mean difference (SMD) = 1.23; 95% CI: 0.62 to 1.84; p = 0.00), globus pallidus (SMD = 0.79; 95% CI: 0.07 to 1.52; p = 0.03), and caudate nucleus (SMD = 0.72; 95% CI: 0.39 to 1.06; p = 0.00) of AD patients compared to HCs. However, no significant differences were found in the thalamus (SMD = 1.00; 95% CI: -0.42 to 2.43; p = 0.17). The sensitivity analysis indicated that no single study impacted the overall results. Age was identified as a major contributor to heterogeneity across all basal ganglia nuclei in subgroup analysis. Older age (>69 years) and lower male percentage (≤30%) were associated with greater putamen iron increase in patients with AD. Conclusion: The study suggests that excessive iron deposition is linked to the basal ganglia in AD, especially the putamen. The study underscores the complex nature of AD pathology and the accumulation of iron, influenced by age, sex, and regional differences, necessitating further research for a comprehensive understanding.

Imaging the post-treatment pelvis with gynecologic cancers.

Gynecological malignancies, such as ovarian cancers, cervical cancers, and endometrial cancers, have a significant global impact. Women with gynecologic malignancies may receive a single or a combination of treatments, including surgery, chemotherapy, and radiation-based therapies. Radiologists utilize various diagnostic imaging modalities to provide the surgeon with relevant information about the diagnosis, prognosis, optimal surgical strategy, and prospective post-treatment imaging. Computerized Tomography (CT) and magnetic resonance imaging (MRI) may be used initially to evaluate and detect post-treatment complications. Although CT is primarily used for staging, MRI is commonly used for a more accurate evaluation of a tumor's size and detection of local invasion. Complications such as hematoma, abscess, inclusion cyst, seroma, tumor thrombosis, anorectovaginal fistula, and gossypiboma may occur after the three primary treatments, and systems such as the genitourinary, gastrointestinal, neurological, and musculoskeletal may be affected. In order to distinguish between early-onset and late-onset complications following gynecological treatment, radiological findings of the most common post-treatment complications will be presented in this review.

Brain MRI findings in neurologically symptomatic COVID-19 patients: a systematic review and meta-analysis.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has been associated with nervous system involvement, with more than one-third of COVID-19 patients experiencing neurological manifestations. Utilizing a systematic review, this study aims to summarize brain MRI findings in COVID-19 patients presenting with neurological symptoms. METHODS: Systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) checklist. The electronic databases of PubMed/MEDLINE, Embase, Scopus, and Web of Science were systematically searched for literature addressing brain MRI findings in COVID-19 patients with neurological symptoms. RESULTS: 25 publications containing a total number of 3118 COVID-19 patients with neurological symptoms who underwent MRI were included. The most common MRI findings and the respective pooled incidences in decreasing order were acute/subacute infarct (22%), olfactory bulb abnormalities (22%), white matter abnormalities (20%), cerebral microbleeds (17%), grey matter abnormalities (12%), leptomeningeal enhancement (10%), ADEM (Acute Disseminated Encephalomyelitis) or ADEM-like lesions (10%), non-traumatic ICH (10%), cranial neuropathy (8%), cortical gray matter signal changes compatible with encephalitis (8%), basal ganglia abnormalities (5%), PRES (Posterior Reversible Encephalopathy Syndrome) (3%), hypoxic-ischemic lesions (4%), venous thrombosis (2%), and cytotoxic lesions of the corpus callosum (2%). CONCLUSION: The present study revealed that a considerable proportion of patients with COVID-19 might harbor neurological abnormalities detectable by MRI. Among various findings, the most common MRI alterations are acute/subacute infarction, olfactory bulb abnormalities, white matter abnormalities, and cerebral microbleeds.

Acute Necrotizing Encephalopathy in Adult Patients With COVID-19: A Systematic Review of Case Reports and Case Series.

BACKGROUND AND PURPOSE: Acute necrotizing encephalopathy (ANE) is a rare neurological disorder that is often associated with viral infections. Since the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a few COVID-19-associated ANE cases have been reported. Since very little is known about ANE, the present study aimed to determine the clinical, biochemical, and radiological characteristics of affected patients. METHODS: A search was conducted on PubMed, Scopus, Embase, and Web of Science databases for articles published up to August 30, 2022 using relevant keywords. Case reports and series in the English language that reported ANE in adult patients with COVID-19 confirmed by reverse transcription polymerase chain reaction were included in this study. Data on the demographic, clinical, laboratory, and radiological characteristics of patients were extracted and analyzed using the SPSS software (version 26). RESULTS: The study included 30 patients (18 males) with COVID-19 and ANE who were aged 49.87±18.68 years (mean±standard deviation). Fever was the most-prevalent symptom at presentation (66.7%). Elevated C-reactive protein was observed in the laboratory assessments of 13 patients. Computed tomography and magnetic resonance imaging were the most-common radiological modalities used for brain assessments. The most commonly prescribed medications were methylprednisolone (30%) and remdesivir (26.7%). Sixteen patients died prior to discharge. CONCLUSIONS: The diagnosis of COVID-19-associated ANE requires a thorough knowledge of the disease. Since the clinical presentations of ANE are neither sensitive nor specific, further laboratory and brain radiological evaluations will be needed to confirm the diagnosis. The suspicion of ANE should be raised among patients with COVID-19 who present with progressive neurological symptoms.