This page contains a Flash digital edition of a book.
PET correlates of cognition deficits in Alzheimer’ disease


were determined and were shown to be below 110 mg/dL in all patients. From 15 minutes before injection until 45 minutes after, patients were rested in a quiet room with dimmed light. Patients were told to keep their eyes closed but their ears were left unplugged, in order to avoid frontal activation as reported in total sensory deprivation studies. Then, emission scans over 20 minutes were acquired, followed by the transmission scans over 5 minutes using three68 Ge line sources. Measurements were obtained with a whole-body PET system (ECAT EXACT HR, CTI, Knoxville, TN, USA) covering 155 mm in the axial field of view (63 transversal slices, thickness of each slices 2.4 mm). The scanner consisted of four rings each with 72 bismuth germanate detector blocks. Data were acquired in themore sensitive 3D mode without interslice tungsten septa, which was found to be equivalent to the 2D mode for quantification of radioactivity used in the clinical setting. The matrix size was 128128 pixels. In 3D mode, the transaxial resolution is between 4.1 and 4.8 mm.Iterative image reconstruction used the ordered subsets-expectation maximization (OSEM) algorithm, implemented in the ECAT V7.1 software (Siemens Medical Systems Inc., Knoxville, TN, USA).


Image Analysis and Statistics


Basic image processing was done by MEDx 3.0 (Sensor 3 Systems, Inc.) including statistical parametric mapping (SPM) routines (Wellcome Department of Cognitive Neurology, London) on a Silicon Graphics station. All data were spatially normalized by affine 12-parameter transformation to stan- dard stereotactic space using the Montreal Neurological Institute (MNI) template.22 Normalized images were repre- sented on a 787685 matrix and smoothed by a Gaussian filter of 12 mm full width of half maximum (FWHM). Resting brain glucose metabolism reflects synaptic dysfunction as well as neuronal lesions but all studies that performed voxel- based correction of resting brain glucose metabolism for cerebral atrophy could exclude artifacts due to cerebral atrophy.9,2325


Using a multisubject design, age-corrected positive correla-


tions significant at pB0.005 (uncorrected for multiple comparisons) were generated to assess the association of cerebral glucose metabolism and neuropsychological test performance (clusters size 40 voxels) within the patient


–1.5 –1


–2.5 –2


–3


group. Cerebral glucose metabolism was regressed on the cognitive test performance. The resulting cerebral structures were identified by their coordinates according to the Talairach atlas.26 Data were derived from the MNI template and had to be transformed to Talairach atlas coordinates using appro- priate algorithms (http://www.mrc-cbu.cam.ac.uk).


RESULTS The mean age of the patients was 70.598.4 years (Table 1).


Patients had at least 8 years of education and the mean MMSE scorewas 23.395.1 points. According to the CERAD neurop- sychological test battery, patients showed the following results: word list memory scores (9standard deviation):  2.691.8; word list recall scores: 2.391.5; word recogni- tion scores: 2.893.5; correct rejection scores: 2.897.2; verbal fluency scores: 1.691.2; naming scores: 1.392.1; constructional praxis scores: 1.292.0; and constructional praxis recall scores: 1.891.9 (Figure 1).


Between CERAD test scores and cerebral glucose metabo-


lism, significant correlations occurred. For the word list memory test scores, significant correlations concerned the left temporal, and the right frontal and cingulate cortex (Figure 2). Peak data as revealed by SPM procedures are shown in Table 2. Word list recall test scores were significantly correlated with left temporal and frontal cortex bilaterally (Figure 2; Table 2). Word list recognition (subtest correct recognition) test scores were significantly correlated with principally the right frontal cortex, the left insula, and the cingulate gyrus bilaterally (Figure 2; Table 2). Word list rejection (subtest correct rejection) test scores showed a significant correlation with the frontal cortex bilaterally, left limbic structures such as parahippocampal gyrus and uncus, and the left temporal cortex (Figure 2; Table 2).


Verbal fluency test scores were significantly correlated with predominantly left-side fronto-temporo-parietal cortices (Fig- ure 2; Table 2). Naming test score showed significant correlations with more left than right temporal cortices, and left limbic structures such as parahippocampal gyrus and uncus (Figure 2; Table 2).


Constructional praxis test scores were significantly corre-


lated with left fusiform gyrus and middle temporal cortex, and right frontal cortex (Figure 2; Table 2). Constructional


Figure 1. Neuropsychological test performance of the patients (n75) as indicated by zscores. www.slm-psychiatry.com 3 M&B 2011; 2:(1). July 2011


Word list memory Word list recall Word list recognition Word list rejection Verbal fluency Naming Constructive praxis Constructive praxis recall


z Score


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89