Alzheimer’s disease (AD) is the most common cause of dementia and accounts for approximately 50% to 80% of all cases of dementia. The diagnosis of probable AD is based on clinical criteria and overlapping clinical features pose a challenge to accurate diagnosis. However, neuroimaging has been included as a biomarker in various published criteria for the diagnosis of probable AD, in the absence of a confirmatory diagnostic test during life. Advances in neuroimaging techniques and their inclusion in diagnostic and research criteria for the diagnosis of AD includes the use of positron emission tomography (PET) imaging as a biomarker in various therapeutic and prognostic studies in AD. The development and application of a range of PET tracers will allow more detailed assessment of people with AD and will improve diagnostic specificity and targeted therapy of AD. The aim of this review is to summarize current evidence on PET imaging using the non-specific tracer [18F]fluorodeoxyglucose and specific tracers that target amyloid and tau pathology in people with AD.

Alzheimer’s disease accounts for approximately 50% to 80% of all causes of dementia. Co-existence of AD with other diseases causing dementia poses a diagnostic challenge, as we are still far from diagnosing AD accurately in order to manage it appropriately. Neuroimaging techniques, not only help diagnose AD but also consistently feature in diagnostic and research criteria for AD as biomarkers. Molecular biomarkers including positron emission tomography (PET) and single-photon emission computed tomography (SPECT), and structural biomarkers including magnetic resonance imaging (MRI), have been used in various therapeutic and prognostic studies in AD. This review highlights the recent advances in neuroimaging biomarkers, including molecular biomarkers (PET and SPECT tracers) and structural biomarkers (MRI), for AD. For the purpose of this review, molecular biomarkers have been further subcategorized into non-specific radiotracers (FDG-PET and blood flow SPECT) and specific amyloid- and tau-related radiotracers. The aim of this review is to discuss the recent advances and evidence of molecular and structural biomarkers of AD.

There has not been extensive research into crossed cerebellar diaschisis (CCD) in neurodegenerative disorders. CCD is frequently detected using positron emission tomography (PET). However, advanced MRI techniques have come forth for the detection of CCD. The correct diagnosis of CCD is crucial for the care of neurological patients and those with neurodegenerative conditions. The purpose of this study is to determine whether PET can offer extra value over MRI or an advanced technique in MRI for detecting CCD in neurological conditions. We searched three main electronic databases from 1980 until the present and included only English and peer-reviewed journal articles. Eight articles involving 1246 participants met the inclusion criteria, six of which used PET imaging while the other two used MRI and hybrid imaging. The findings in PET studies showed decreased cerebral metabolism in the frontal, parietal, temporal, and occipital cortices, as on the opposite side of the cerebellar cortex. However, the findings in MRI studies showed decreased cerebellar volumes. This study concludes that PET is a common, accurate, and sensitive technique for detecting both crossed cerebellar and uncrossed basal ganglia as well as thalamic diaschisis in neurodegenerative diseases, while MRI is better for measuring brain volume. This study suggests that PET has a higher diagnostic value for diagnosing CCD compared to MRI, and that PET is a more valuable technique for predicting CCD.

Alzheimer’s disease accounts for approximately 50% to 80% of all causes of dementia. Co-existence of AD with other diseases causing dementia poses a diagnostic challenge as we are still far from diagnosing AD accurately and hence to manage it appropriately. Neuroimaging techniques, not only help diagnose AD but also consistently features in diagnostic and research criteria for AD as biomarkers. Molecular biomarkers including Positron emission tomography (PET) and Single Photon emission computed tomography (SPECT) and structural biomarkers including Magnetic Resonance Imaging (MRI) have been used in various therapeutic and prognostic studies in AD. This review highlights the recent advances in the neuroimaging biomarkers including molecular biomarkers (PET and SPECT) and structural biomarkers (MRI) for AD. For the purpose of this review, molecular biomarkers have been further subcategorized into non-specific radiotracers (FDG-PET and SPECT) and specific amyloid and tau related radiotracers. The aim of this review is to discuss the recent advances and evidences on molecular and structural biomarkers of AD.

Background: Geriatric depression is a prevalent mental health concern that impairs daily functioning, quality of life (QoL), and cognitive performance. Maladaptive metacognitive beliefs and executive dysfunction are hypothesized to contribute to depressive symptomatology in older adults. Methods: Participants were assessed using the Metacognitions Questionnaire-30 (MCQ-30), the Indian Council of Medical Research Neurocognitive Toolbox (verbal episodic memory, verbal fluency, and set-shifting), and World Health Organization Quality of Life–BREF (WHOQOL-BREF). Depression severity and suicidality were measured using the Geriatric Depression Scale-15 (GDS-15) and the Columbia-Suicide Severity Rating Scale (C-SSRS), respectively. Group differences were analyzed using Mann–Whitney U tests, associations using Spearman’s rho, and predictors using binary logistic regression (95% confidence interval). Results: Compared to controls, older adults with depression showed higher negative beliefs about uncontrollability and danger, which significantly predicted depression (OR = 1.81, p < .01), while need to control thoughts was protective (OR = 0.48, p < .01). The depression group demonstrated poorer verbal episodic memory, verbal fluency, and set-shifting ( p < .05–.01). Depression severity was positively correlated with suicidality ( r = 0.68) and negatively with QoL ( r = −0.54; p < .001). Conclusion: Maladaptive metacognitive beliefs and executive dysfunction are associated with geriatric depression. Interventions integrating metacognitive therapy (MCT) with cognitive flexibility and verbal fluency training may improve emotional well-being, functional independence, and QoL in older adults.