Systematic Review of Different Neuroimaging Correlates in Mild Cognitive Impairment and Alzheimer's Disease.

Alzheimer's disease (AD) is a heterogeneous progressive neurocognitive disorder. Although different neuroimaging modalities have been used for the identification of early diagnostic and prognostic factors of AD, there is no consolidated view of the findings from the literature. Here, we aim to provide a comprehensive account of different neural correlates of cognitive dysfunction via magnetic resonance imaging (MRI), diffusion tensor imaging (DTI), functional MRI (fMRI) (resting-state and task-related), positron emission tomography (PET) and magnetic resonance spectroscopy (MRS) modalities across the cognitive groups i.e., normal cognition, mild cognitive impairment (MCI), and AD. A total of 46 meta-analyses met the inclusion criteria, including relevance to MCI, and/or AD along with neuroimaging modality used with quantitative and/or functional data. Volumetric MRI identified early anatomical changes involving transentorhinal cortex, Brodmann area 28, followed by the hippocampus, which differentiated early AD from healthy subjects. A consistent pattern of disruption in the bilateral precuneus along with the medial temporal lobe and limbic system was observed in fMRI, while DTI substantiated the observed atrophic alterations in the corpus callosum among MCI and AD cases. Default mode network hypoconnectivity in bilateral precuneus (PCu)/posterior cingulate cortices (PCC) and hypometabolism/hypoperfusion in inferior parietal lobules and left PCC/PCu was evident. Molecular imaging revealed variable metabolite concentrations in PCC. In conclusion, the use of different neuroimaging modalities together may lead to identification of an early diagnostic and/or prognostic biomarker for AD.

Neurological Associations of COVID-19-Do We Know Enough: A Tertiary Care Hospital Based Study.

The neurotrophic potential of SARS-CoV-2 virus is manifesting as various neurological disorders in the present pandemic. Nervous system involvement can be due to the direct action of the virus on the brain tissue or due to an indirect action through the activation of immune-mediated mechanisms. This study will discuss the detailed systematically evaluated clinical profile and relevant investigations and outcome of 14 laboratory confirmed SARS-CoV-2 positive patients presenting with neurological signs and symptoms. The patients were further categorized into confirmed, probable, and possible neurological associations. The probable association was found in meningoencephalitis (n = 4), stroke (n = 2), Guillain-Barré syndrome (n = 1), and anosmia (n = 1). The other six patients had coexisting neurological diseases with SARS-CoV-2. One patient with a large artery stroke succumbed to the illness due to respiratory complication. Memory impairment as a sequela is present during follow up of one encephalitis patient. Presently the early recognition and diagnosis of neurological manifestations remains a challenge for clinicians as the SARS-CoV-2 related neurological manifestations are in evolution. A long-term correlation study of clinical profile, radiological and laboratory investigations, along with neuropathological studies is needed to further understand the pathophysiology behind the SARS-CoV-2 neurological manifestations. Further understanding will facilitate timely recognition, therapeutic intervention, and possible prevention of long-term sequalae.

Revisiting metastatic central nervous system tumors with unknown primary using clinicopathological findings: A single neurosciences institutional study.

BACKGROUND: Metastatic tumors are the most common central nervous system (CNS) tumors wherein the primary site remains unknown in most of the cases. Aim: The study was carried out to evaluate metastatic CNS tumors with unknown primary by using simplified diagnostic (clinico-histopathologic) approach. MATERIAL AND METHODS: A 2 years study was conducted on 32 cases of CNS metastases having unknown primary tumors in a neurosciences institute. STATISTICAL ANALYSIS: All the results were prepared using software version of SPSS 22. RESULTS: The most common metastatic site found in brain was cerebrum (59.3%) [frontal > frontoparietal > parieto-occipital > temporal] [left cerebrum > right cerebrum], followed by cerebellum (12.5%), spinal cord (9.3%), and leptomeninges (3.12%). Most of the metastatic tumors presented as ill-defined (34%) rather than well-defined (22%) lesions with ring enhancement seen only in 16% of the cases on magnetic resonance imaging (MRI).On histopathology findings with targeted immunohistochemistry, most common histological tumor type identified irrespective of site was adenocarcinoma (68.7%), followed by squamous cell carcinoma (15.6%) and poorly differentiated carcinoma (12.5%). Only one case of lymphoma was reported. Corroborating all the above findings along with clinical history and other relevant investigations, primary sites could be detected in 23 cases (71.8%).The most common primary site deduced was lungs (39.1%), followed by thyroid (17.3%), breast in females (13.0%), gastrointestinal tract (8.6%), and prostate in males (4.3%). Only in nine cases (28.1%) with mainly poorly differentiated histopathological type, primary site remained unknown. CONCLUSION: Detection of the primary site in metastatic CNS tumors is possible by adopting this simple and effective diagnostic approach at centers/hospitals having cost and other constraints.

Congenital Skull Anomaly with Multiple Brain Stones and Symptomatic Meningioma of Medial Sphenoid Wing.

Intracranial calcifications are not uncommon and are mostly seen with intracerebral hematomas, tuberculomas, and brain tumors. These lesions may be intra- or extra-axial and occasionally pose challenge in the diagnosis. We report a case of multiple intracranial extra-axial calcifications with congenital skull anomaly and multiple meningiomas. Authors could not find similar case reported in the literature and present their findings and discuss relevant literature.