Article

Relevance of Magnetic Resonance Imaging for Early Detection and Diagnosis of Alzheimer Disease

University Medicine Rostock, Rostock, Germany
The Medical clinics of North America (Impact Factor: 2.61). 05/2013; 97(3):399-424. DOI: 10.1016/j.mcna.2012.12.013
Source: PubMed

ABSTRACT

Magnetic resonance imaging (MRI)-based indicators of regional and global brain atrophy and more advanced measures of cortical functional and structural connectivity are among the most promising imaging biomarkers for the characterization of preclinical and prodromal stages of Alzheimer disease (AD). This review presents the current status of available and evolving MRI-based technologies for the early asymptomatic and predementia diagnosis of AD, including high-resolution structural MRI of global and regional brain atrophy, diffusion tensor imaging of structural cortical connectivity, and functional MRI during rest and task performance. The selection of an appropriate technique needs to consider its suitability for specific applications.

Download full-text

Full-text

Available from: Michel Grothe, May 13, 2014
  • Source
    • "The underlying pathophysiological mechanisms contributing to neurocognitive deficit when sea-level residents are exposed to high altitude remain unknown, but may relate to impaired cerebrovascular function and/or neuronal apoptosis (evidenced by loss of gray and/or white matter tissue) even following return to sea level. For example, cognitive deficits are linked to structural brain alterations clinically, and magnetic resonance imaging (MRI) based measurements of regional gray matter volume are a close surrogate for neuronal loss (Teipel et al. 2013). Furthermore, impaired cerebral vascular reactivity can disturb oxygen delivery and is predictive of stroke risk in some clinical scenarios (Yonas et al. 1993). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Although high-altitude exposure can lead to neurocognitive impairment, even upon return to sea level, it remains unclear the extent to which brain volume and regional cerebral vascular reactivity (CVR) are altered following high-altitude exposure. The purpose of this study was to simultaneously determine the effect of 3 weeks at 5050 m on: (1) structural brain alterations; and (2) regional CVR after returning to sea level for 1 week. Healthy human volunteers (n = 6) underwent baseline and follow-up structural and functional magnetic resonance imaging (MRI) at rest and during a CVR protocol (end-tidal PCO2 reduced by −10, −5 and increased by +5, +10, and +15 mmHg from baseline). CVR maps (% mmHg−1) were generated using BOLD MRI and brain volumes were estimated. Following return to sea level, whole-brain volume and gray matter volume was reduced by 0.4 ± 0.3% (P < 0.01) and 2.6 ± 1.0% (P < 0.001), respectively; white matter was unchanged. Global gray matter CVR and white matter CVR were unchanged following return to sea level, but CVR was selectively increased (P < 0.05) in the brainstem (+30 ± 12%), hippocampus (+12 ± 3%), and thalamus (+10 ± 3%). These changes were the result of improvement and/or reversal of negative CVR to positive CVR in these regions. Three weeks of high-altitude exposure is reflected in loss of gray matter volume and improvements in negative CVR.
    Full-text · Article · Dec 2015
  • Source
    • "Such a specific pattern of atrophy aligns well with the topographic distribution of AD pathology such as neurofibrillary tangles (NFT)[10,11]and correlates strongly with the severity of cognitive decline[6,9,12131415. As reported previously[8,16], MRI-based neuronal injury biomarkers are becoming more widely used in clinical practice as probability of having AD in subjects who meet clinical diagnostic criteria of AD[1]is estimated to increase if MRI-based neuronal injury biomarker is positive or decrease if negative. In addition, interests on using MRI-based neuronal injury biomarker to reduce sample sizes required for a new drug trial or track disease progression as an outcome measure are also increasing currently[7,17,18]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: We aimed to identify and characterize subtypes of Alzheimer's disease (AD) exhibiting different patterns of regional brain atrophy on MRI using age- and gender-specific norms of regional brain volumes. AD subjects included in the Alzheimer's Disease Neuroimaging Initiative study were classified into subtypes based on standardized values (Z-scores) of hippocampal and regional cortical volumes on MRI with reference to age- and gender-specific norms obtained from 222 cognitively normal (CN) subjects. Baseline and longitudinal changes of clinical characteristics over 2 years were compared across subtypes. Whole-brain-level gray matter (GM) atrophy pattern using voxel-based morphometry (VBM) and cerebrospinal fluid (CSF) biomarkers of the subtypes were also investigated. Of 163 AD subjects, 58.9% were classified as the "both impaired" subtype with the typical hippocampal and cortical atrophy pattern, whereas 41.1% were classified as the subtypes with atypical atrophy patterns: "hippocampal atrophy only" (19.0%), "cortical atrophy only" (11.7%), and "both spared" (10.4%). Voxel-based morphometric analysis demonstrated whole-brain-level differences in overall GM atrophy across the subtypes. These subtypes showed different progression rates over 2 years; and all subtypes had significantly lower CSF amyloid-β1-42 levels compared to CN. In conclusion, we identified four AD subtypes exhibiting heterogeneous atrophy patterns on MRI with different progression rates after controlling the effects of aging and gender on atrophy with normative information. CSF biomarker analysis suggests the presence of Aβ neuropathology irrespective of subtypes. Such heterogeneity of MRI-based neuronal injury biomarker and related heterogeneous progression patterns should be considered in clinical trials and practice with AD patients.
    Full-text · Article · Nov 2015 · PLoS ONE
  • Source
    • "The deposition of neurofibrillary tangles begins primarily in the limbic system structures, initially in the entorhinal cortex and the medial temporal regions, then progressively spread across the cerebral cortex. Hippocampal and entorhinal cortical atrophy assessed with MRI is well documented in patients with AD (Teipel et al., 2013), and in many with MCI (Pihlajamaki et al., 2009). Furthermore, this observation has extended the investigation of all limbic structures in relation to disease progression and cognitive performance. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The fornix is a part of the limbic system and constitutes the major efferent and afferent white matter tracts from the hippocampi. The underdevelopment of or injuries to the fornix are strongly associated with memory deficits. Its role in memory impairments was suggested long ago with cases of surgical forniceal transections. However, recent advances in brain imaging techniques, such as diffusion tensor imaging have revealed that macrostructural and microstructural abnormalities of the fornix correlated highly with declarative and episodic memory performance. This structure appears to provide a robust and early imaging predictor for memory deficits not only in neurodegenerative and neuroinflammatory diseases, such as Alzheimer’s disease and multiple sclerosis, but also in schizophrenia and psychiatric disorders, and during neurodevelopment and “typical” aging. The objective of the manuscript is to present a systematic review regarding published brain imaging research on the fornix, including the development of its tracts, its role in various neurological diseases, and its relationship to neurocognitive performance in human studies.
    Full-text · Article · Jan 2015 · Frontiers in Aging Neuroscience
Show more