Relative Capability of MR Imaging and FDG PET to Depict Changes Associated with Prodromal and Early Alzheimer Disease

Department of Radiology, University of California, San Diego, La Jolla, CA 92093, USA.
Radiology (Impact Factor: 6.21). 09/2010; 256(3):932-42. DOI: 10.1148/radiol.10091402
Source: PubMed

ABSTRACT To quantify the effect sizes of regional metabolic and morphometric measures in patients with preclinical and mild Alzheimer disease (AD) to aid in the identification of noninvasive biomarkers for the early detection of AD.
The study was conducted with institutional review board approval and in compliance with HIPAA regulations. Written informed consent was obtained from each participant or participant's legal guardian. Fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) and magnetic resonance (MR) imaging data were analyzed from 80 healthy control (HC) subjects, 68 individuals with AD, and 156 with amnestic mild cognitive impairment (MCI), 69 of whom had single-domain amnestic MCI. Regions of interest (ROIs) were derived after coregistering FDG PET and MR images by using high-throughput, subject-specific procedures. The Cohen d effect sizes were calculated for 42 predefined ROIs across the brain. Statistical comparison of the largest overall effect sizes for MR imaging and PET was performed. Metabolic effect sizes were determined with and without accounting for regional atrophy. Discriminative accuracy of ROIs showing the largest effect sizes were compared by calculating receiver operating characteristic curves.
For all disease groups, the hippocampus showed the largest morphometric effect size and the entorhinal cortex showed the largest metabolic effect size. In mild AD, the Cohen d effect size for hippocampal volume (1.92) was significantly larger (P < .05) than that for entorhinal metabolism (1.43). Regression of regional atrophy substantially reduced most metabolic effects. For all group comparisons, the areas under the receiver operating characteristic curves were significantly larger for hippocampal volume than for entorhinal metabolism.
The current results show no evidence that FDG PET is more sensitive than MR imaging to the degeneration occurring in preclinical and mild AD, suggesting that an MR imaging finding may be a more practical clinical biomarker for early detection of AD.

Download full-text


Available from: Carl Hoh, Sep 03, 2015
1 Follower
  • Source
    • "For example, right hippocampus volume in our AD sample reached a Cohen's d of 1.64. Karow et al. reported a d of 1.94 in a sample of mild AD patients [79], and Fennema-Notestine et al. found a value of 1.62 for the right hippocampus and 1.80 for the left one in the ADNI sample [74]. With respect to MCI, Desikan and colleagues reported effect size calculations by splitting their sample on the basis of progression (converters versus non converters) [80]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study was to characterize the neuropsychological and neuroimaging profiles of mild cognitive impairment (MCI) and Alzheimer's disease (AD) patients, and to study the magnitude of the differences by comparing both outcomes with healthy subjects in a cross-sectional manner. Five hundred and thirty-five subjects (356 cognitively normal adults (CONT), 79 MCI, and 100 AD) were assessed with the NEURONORMA neuropsychological battery. Thirty CONT, 23 MCI, and 23 AD subjects from this sample were included in the neuroimaging substudy. Patients' raw cognitive scores were converted to age and education-adjusted scaled ones (range 2-18) using co-normed reference values. Medians were plotted to examine the cognitive profile. MRIs were processed by means of FreeSurfer. Effect size indices (Cohen's d) were calculated in order to compare the standardized differences between patients and healthy subjects. Graphically, the observed cognitive profiles for MCI and AD groups produced near to parallel lines. Verbal and visual memories were the most impaired domains in both groups, followed by executive functions and linguistic/semantic ones. The largest effect size between AD and cognitively normal subjects was found for the FCSRT (d = 4.05, AD versus CONT), which doubled the value obtained by the best MRI measure, the right hippocampus (d = 1.65, AD versus CONT). Our results support the notion of a continuum in cognitive profile between MCI and AD. Neuropsychological outcomes, in particular the FCSRT, are better than neuroimaging ones at detecting differences among subjects.
    Journal of Alzheimer's disease: JAD 04/2014; 41(3). DOI:10.3233/JAD-132186 · 4.15 Impact Factor
  • Source
    • "The anteromedial temporal atrophy was described even in cognitively normal individuals later converting to MCI (Smith et al., 2007). The posterior part of the gyrus, the parahippocampal cortex , is affected later in the course of AD (Karow et al., 2010; Spulber et al., 2012), followed by atrophy of the fusiform gyrus (McDonald et al., 2009). A number of neuroimaging studies have also shown structural and metabolic changes in the parietal lobe, early in the course of AD. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Although the memory impairment is a hallmark of Alzheimer's disease (AD), AD has also been characterized by spatial disorientation, which is present from its early stages. Spatial disorientation in AD manifests itself in getting lost in familiar and unfamiliar places and have been characterized more specifically using spatial navigation tests in both real space and virtual environments as an impairment in multiple spatial abilities, including allocentric and egocentric navigation strategies, visuo-spatial perception, or selection of relevant information for successful navigation. Patients suffering mild cognitive impairment (MCI), who are at a high risk of development of dementia, show impairment in a subset of these abilities, mainly connected with allocentric and egocentric processing. While spatial disorientation in typical AD patients probably reflects neurodegenerative changes in medial and posterior temporal, parietal, and frontal lobes, and retrosplenial cortex, the impairment of spatial navigation in MCI seem to be connected mainly with the medial temporal and also parietal brain changes. In this review, we will summarize the signs of brain disease in most MCI and AD patients showing in various tasks of spatial memory and navigation.
    Frontiers in Behavioral Neuroscience 03/2014; 8:89. DOI:10.3389/fnbeh.2014.00089 · 4.16 Impact Factor
  • Source
    • "Moreover, PET proved to be a reliable tool for the identification of MCI patients bound to become AD, with a diagnostic accuracy which has been proposed to be better than SPECT and MRI in a recent meta-analysis [16]. On the other hand, a recent study found no evidence that FDG- PET is more sensitive than MRI to quantify the degeneration present in preclinical and mild AD, in specific brain regions [17]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Alzheimer's Disease (AD) is the most frequent form of dementia and represents one of the main causes of disability among older subjects. Up to now, the diagnosis of AD has been made according to clinical criteria. However, the use of such criteria does not allow an early diagnosis, as pathological alterations may be apparent many years before the clear-cut clinical picture. An early diagnosis is even more valuable to develop new treatments, potentially interfering with the pathogenetic process. During the last decade, several neuroimaging and cerebrospinal fluid (CSF) parameters have been introduced to allow an early and accurate detection of AD patients, and, recently, they have been included among research criteria for AD diagnosis. However, their use in clinical practice suffers from limitations both in accuracy and availability. The increasing amount of knowledge about peripheral biomarkers will possibly allow the future identification of reliable and easily available diagnostic tests.
    International Journal of Alzheimer's Disease 12/2010; 2011:342980. DOI:10.4061/2011/342980
Show more