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ABSTRACT: Malignant meningiomas are uncommon intracranial tumors. The metastasis of malignant meningiomas to distant extracranial sites are well known. However, dissemination of the tumours in the cerebrospinal fluid (CSF) is rare and few cases have been reported. We present a case of histologically proven malignant meningioma with CSF dissemination at the remote intracranial area and into the spinal canal detected with magnetic resonance imaging.
Chinese medical journal 05/2011; 124(10):1597-9. · 0.86 Impact Factor
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ABSTRACT: To investigate the feature brain damage and clinical manifestations in neuromyelitis optica (NMO) patients; To investigate the relationship between serum NMO-IgG antibody and NMO brain damage.
Clinical data of 37 NMO patients and their head and spinal cord MRI by 1.5T superconducting MR scanner, were analyzed; serum NMO-IgG antibody were measured by immunofluorescence.
17 cases were found to have abnormal signals on MRI, which were mainly in the white matter, pons, medulla, ventricle, aqueduct, and around the corpus callosum; According to pathological changes, brain damage can be divided into scattered irregularity (13 cases), fusion (3 cases), multiple sclerosis-like (1 case), with scattered irregularity more common, 5 cases had clinical manifestations of brain damage: somnolence, vomiting, diplopia, visual rotation, 11 cases patients with brainstem damage show positive serum NMO-IgG antibodies.
Brain damage can be seen in half of NMO patients, they often located in the high expression area of AQP4: brain white matter, periventricular, brainstem and so on. Clinical symptoms has nothing to do with the size of lesions but the location, they often occur when brainstem was involved. Serum NMO-IgG is helpful in differentiating NMO with brain damage and MS.
Zhonghua nei ke za zhi [Chinese journal of internal medicine] 03/2011; 50(3):193-6.
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ABSTRACT: Dysembryoplastic neuroepithelial tumor (DNT) is a rare benign neoplasm of the central nervous system affecting young people. A correct preoperative diagnosis is helpful for planning surgical strategies and improving prognosis. The purpose of this study was to characterize DNTs using magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) and to analyze the value of these two techniques in the diagnosis of DNTs.
MR images of 13 patients with DNTs were reviewed retrospectively; and five of the patients also underwent MRS. Tumors were confirmed by surgery. The distribution, extension and signal features of the lesions were assessed, and the MRS results were analyzed.
All tumors were supratentorial. The cortex was the main area involved, with nine tumors located in the temporal lobe, three in the frontal lobe, and one on the boundary between the temporal and occipital lobes. All cases had decreased signal intensity on T1-weighted MR images and increased signal intensity on T2-weighted images. On fluid attenuated inversion recovery weighted images, the hyperintense "ring sign" and internal septation of the lesion were seen in 9 cases. Eight tumors had well-demarcated borders. Peritumoral edema or mass effect was absent in all cases. A contrast enhancement examination was performed in 9 cases. Contrast enhancement was absent in five cases, and four cases showed significant enhancement. The MRS showed a low N-acetylaspartate peak and a lack of elevated choline-containing component (Cho) or Cho-Cr ratio (Cho/Cr) in five patients.
The MRI findings of DNTs were stereotypical. The combination of MRI and MRS techniques were helpful in making a correct presurgical diagnosis.
Chinese medical journal 10/2009; 122(20):2433-7. · 0.86 Impact Factor
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ABSTRACT: To investigate the value of 64-detector spiral computed tomography versus MRI in the assessment of right ventricular function.
Thirty healthy volunteers (15 males, 15 females, 48 +/- 24 years) underwent 64-detector spiral computed tomography CT and breath-hold MRI. With semiautomatic contour detection software, the parameters of end-diastolic volume, end-systolic volume, stroke volume and ejection fraction were determined from short-axis CT reformations (MPR) created at every 5% of RR-interval. The results from CT were compared with those from MRI using Pearson correlation test and Bland-Altman plot.
The CT values of mean end-diastolic volume (146 +/- 27) ml, end-systolic volume (70 +/- 20) ml, stroke volume (75 +/- 12) ml and ejection fraction (52% +/- 5%) correlated well with those by MRI [146 +/- 25 ml (r = 0.959), 66 +/- 17 ml (r = 0.914), 80 +/- 15 ml (r = 0.706), 55% +/- 7% (r = 0.612)]. A strong correlation between MSCT and MRI was also found in the Bland-Altman plot.
64-detector spiral CT can accurately assess the right ventricular function. It is a valuable method for evaluating cardiac function.
Zhonghua yi xue za zhi 07/2009; 89(27):1926-9.
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ABSTRACT: To introduce multilevel binomial logistic prediction model-based computer-aided diagnostic (CAD) method of small solitary pulmonary nodules (SPNs) diagnosis by combining patient and image characteristics by textural features of CT image.
Describe fourteen gray level co-occurrence matrix textural features obtained from 2171 benign and malignant small solitary pulmonary nodules, which belongs to 185 patients. Multilevel binomial logistic model is applied to gain these initial insights.
Five texture features, including Inertia, Entropy, Correlation, Difference-mean, Sum-Entropy, and age of patients own aggregating character on patient-level, which are statistically different (P<0.05) between benign and malignant small solitary pulmonary nodules.
Some gray level co-occurrence matrix textural features are efficiently descriptive features of CT image of small solitary pulmonary nodules, which can profit diagnosis of earlier period lung cancer if combined patient-level characteristics to some extent.
European journal of radiology 03/2009; 74(1):124-9. · 2.65 Impact Factor
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ABSTRACT: The aim was to investigate the effects of echo time (TE) on diffusion quantification of brain white matter. Seven rhesus monkeys (all males; age, 4-6 years; weight, 5-7 kg) underwent diffusion tensor imaging (DTI) with a series of TEs in 1.5 T and 3.0 T MR scanners. The mean diffusivity (MD), fractional anisotropy (FA), primary (lambda(1)), and transverse eigenvalues (lambda(23)) were measured in a region of interest at the bilateral internal capsule. Pearson correlation showed that the FA and lambda(1) increased and lambda(23) decreased with TE both at 1.5 T and 3.0 T except for the MD. Repeated measurement analysis of variance (ANOVA) also showed significantly higher FA and lower MD and lambda(23) at 3.0 T than those at 1.5 T (P<0.01), but no statistical differences were found in lambda(1) between these two field strengths (P=0.709). These findings implied that TE and field strength might influence diffusion quantification in brain white matter.
Magnetic Resonance in Medicine 02/2009; 61(4):755-60. · 2.96 Impact Factor
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ABSTRACT: Using magnetic resonance imaging, diagnosis of malignant meningioma from benign meningioma with atypical features is uncertain. We evaluated the value of lipid signal in differentiating intracranial meningiomas.
1H-magnetic resonance spectroscopy (MRS) using a point resolved spectroscopy (TR/TE 1000/144 ms) sequences were performed on 34 patients on a 3.0 T scanner. Lipid peak located at 1.3 ppm was evaluated. MRS data from these tumours were compared with histopathological findings (including hematoxylin and eosin staining and KP-1 staining).
Twenty-nine meningiomas were histologically benign (eleven meningothelial, thirteen fibrous, four transitional and one microcystic), three were atypical, and two were anaplastic. Lipid signal was detected in ten cases: two anaplastic, three atypical, two fibrous and three meningothelial meningiomas. All voxels with lipid peak in the spectrum from the tumour were evaluated. With creatinine peak in the normal white matter chosen as internal standard, lipid/creatinine ratios of anaplastic, atypical and benign meningiomas were 0.844 +/- 0.027 (range from 0.725 to 0.994), 0.465 +/- 0.023 (range from 0.239 to 0.724), and 0.373 +/- 0.016 (range from 0.172 to 0.571) respectively. Highly significant differences were noted between anaplastic and the other two subtypes. Patchy necrosis was observed in anaplastic meningioma, while focal necrosis was noted in atypical meningioma with HE stain. However, no necrosis was found in benign group. KP-1 stain demonstrated histocytes containing lipids in the necrotic region of anaplastic and atypical meningioma.
The lipid signal at 1.3 ppm is a useful marker in evaluating the malignancy of intracranial meningiomas, especially in the differential diagnosis of anaplastic meningioma.
Chinese medical journal 01/2009; 121(23):2415-9. · 0.86 Impact Factor
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ABSTRACT: Stimulation of acupuncture points (acupoints) located on meridians has been proven to activate specific areas of the human brain, as evidenced by functional imaging studies. To date, the specificity of acupoints located on different meridians has been investigated with functional magnetic resonance image (fMRI). The present fMRI study explored the effects of stimulating 4 acupoints on 2 different meridians for the purpose of researching the characteristic response of acupoints on the same meridian.
The acupoints studied were LR3 (Taichong) and LR6 (Zhongdu), which belong to the Liver meridian of Foot-Jueyin; ST36 (Zusanli) and ST43 (Xiangu), which belong to the Stomach meridian of Foot-Yangming; and 2 nearby sham acupoints. Fifty-three (53) healthy right-handed subjects were divided randomly into 6 groups. Each group only received acupuncture at one acupoint. All the acupoints in this study were stimulated only on the right side of the subject's body. Through analysis of fMRI data from all subjects, we obtained the activation patterns in the central nervous system (CNS) evoked by acupuncture.
In contrast to the CNS activation by sham acupoint, the results showed that all 4 real acupoints under consideration had the common effect of activating 2 specific areas of the brain: the bilateral primary somatosensory area and the ipsilateral cerebellum. Acupuncture stimulation of both acupoints LR3 and LR6 evoked activation at the ipsilateral superior parietal lobe (BA7). Acupuncture stimulation of both acupoints ST36 and ST43 evoked activation at the ipsilateral middle frontal gyrus (BA10).
These results suggest that different acupoints on the same meridian may activate certain similar areas of the brain. In addition, acupoints that are commonly used in clinical practice might modulate a greater extent of cortical areas than uncommonly used acupoints.
Journal of alternative and complementary medicine (New York, N.Y.) 08/2008; 14(6):673-8. · 1.69 Impact Factor
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Xiang-Yu Long,
Xi-Nian Zuo,
Vesa Kiviniemi,
Yihong Yang,
Qi-Hong Zou,
Chao-Zhe Zhu,
Tian-Zi Jiang,
Hong Yang,
Qi-Yong Gong,
Liang Wang, Kun-Cheng Li,
Sheng Xie,
Yu-Feng Zang
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ABSTRACT: Recently, human brain activity during a resting-state has attracted increasing attention. Several studies have found that there are two networks: the default mode network and its anti-correlation network. Some studies have subsequently showed that the functions of brain areas within the default mode network are crucial in human mental activity. To further discern the brain default mode network as well as its anti-correlation network during resting-state, we used three methods to analyze resting-state functional magnetic resonance imaging (fMRI) data; regional homogeneity analysis, linear correlation and independent component analysis, on four groups of dataset. Our results showed the existence of these two networks prominently and consistently during a resting- and conscious-state across the three methods. This consistency was exhibited in four independent groups of normal adults. Moreover, the current results provided evidences that the brain areas within the two anti-correlated networks are highly integrated at both the intra- and inter-regional level.
Journal of Neuroscience Methods 07/2008; 171(2):349-55. · 1.98 Impact Factor
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ABSTRACT: Temporal clustering analysis (TCA) has been proposed as a method for detecting the brain responses of a functional magnetic resonance imaging (fMRI) time series when the time and location of activation are completely unknown. But TCA is not suitable for treating the time series of the whole brain due to the existence of many inactive pixels. In theory, active pixels are located only in gray matter (GM). In this study, SPM2 was used to segment functional images into GM, white matter and cerebrospinal fluid, and only the pixels in GM were considered. Thus, most of inactive pixels are deleted, so that the sensitivity of TCA is greatly improved in the analysis of the whole brain. The same set of acupuncture fMRI data was treated using both conventional TCA and modified TCA (MTCA) for comparing their analytical ability. The results clearly show a significant improvement in the sensitivity achieved by MTCA.
Magnetic Resonance Imaging 11/2007; 25(8):1190-5. · 1.99 Impact Factor
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ABSTRACT: The purposes of our study were to employ diffusion tensor imaging (DTI)-based histogram analysis to determine the presence of occult damage in clinically isolated syndrome (CIS), to compare its severity with relapsing-remitting multiple sclerosis (RRMS), and to determine correlations between DTI histogram measures and clinical and MRI indices in these two diseases.
DTI scans were performed in 19 CIS and 19 RRMS patients and 19 matched healthy volunteers. Histogram analyses of mean diffusivity and fractional anisotropy were performed in normal-appearing brain tissue (NABT), normal-appearing white matter (NAWM) and gray matter (NAGM). Correlations were analyzed between these measures and expanded disability status scale (EDSS) scores, T(2)WI lesion volumes (LV) and normalized brain tissue volumes (NBTV) in CIS and RRMS patients.
Significant differences were found among CIS, RRMS and control groups in the NBTV and most of the DTI histogram measures of the NABT, NAWM and NAGM. In CIS patients, some DTI histogram measures showed significant correlations with LV and NBTV, but none of them with EDSS. In RRMS patients, however, some DTI histogram measures were significantly correlated with LV, NBTV and EDSS.
Occult damage occurs in both NAGM and NAWM in CIS, but the severity is milder than that in RRMS. In CIS and RRMS, the occult damage might be related to both T2 lesion load and brain tissue atrophy. Some DTI histogram measures might be useful for assessing the disease progression in RRMS patients.
European Journal of Radiology 11/2007; 68(2):328-34. · 2.61 Impact Factor
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ABSTRACT: To prospectively assess sensitivity and specificity of diffusion indexes of the corpus callosum (CC) for differentiating relapsing neuromyelitis optica (RNMO) from relapsing-remitting multiple sclerosis (RRMS), by using final clinical diagnosis as the reference standard.
Participants provided informed consent; the study was approved by the institutional review board. Forty-six consecutive patients with RRMS (18 men, 28 women; mean age, 37.7 years; range, 18-58 years) and 26 consecutive patients with RNMO (two men, 24 women; mean age, 38.6 years; range, 19-59 years) underwent diffusion-tensor magnetic resonance imaging. Mean diffusivity (MD) and fractional anisotropy (FA) of the region of interest (ROI) of the CC in the midsagittal plane were measured and used as discriminative indexes. Bayesian classification with leave-one-out cross-validation was used to determine diagnostic accuracy. Differences in diffusion indexes of ROIs among groups were evaluated by using the Kruskal-Wallis test, followed by the Mann-Whitney U test for multiple comparisons and Bonferroni correction.
Mean MD (8.48 x 10(-4) mm(2)/sec) and FA (0.729) of the ROI in patients with RNMO were significantly (P<.001) different from those (MD=10.64 x 10(-4) mm(2)/sec, FA=0.599) in patients with RRMS. Sensitivity and specificity for differentiation were 92.3% (24 of 26 patients with RNMO) and 93.5% (43 of 46 patients with RRMS) for FA and 88.5% (23 of 26 patients with RNMO) and 89.1% (41 of 46 patients with RRMS) for MD, respectively.
Measurement of diffusion indexes of the CC may be useful for distinguishing patients with RNMO from those with RRMS.
Radiology 08/2007; 244(1):249-56. · 5.73 Impact Factor
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ABSTRACT: Temporal clustering analysis (TCA) has been proposed as a method to detect the brain responses of an fMRI time series when the time and location of the activation are completely unknown. But TCA is still incompetent in dealing with the time series of the whole brain due to the existence of many inactive pixels. If only active pixels are considered, the sensitivity of TCA will be improved greatly and it could be applied to the whole brain. In this study, some modifications were made to TCA to remove inactive pixels, and the applicability of the modified TCA to the whole brain was validated with a set of visual fMRI data. Based on the time series of the modified TCA, activations of the whole brain corresponding to the visual stimulation were detected. Compared with the previous TCA, the modified TCA method shows a significant improvement in the sensitivity to detect activation peaks of the whole brain.
Magnetic Resonance Imaging 02/2007; 25(1):57-62. · 1.99 Impact Factor
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ABSTRACT: Diffusion tensor imaging (DTI) is a noninvasive imaging technique for the assessment of the integrity of cerebral tissues. This study was undertaken to assess the changes of diffusion indices of hippocampal formation (HF) in patients with medial temporal lobe epilepsy (MTLE).
Fourteen patients with MTLE and 14 healthy subjects were evaluated. Mean diffusivity (MD) and fractional anisotropy (FA) from the symmetrical-voxel sampling regions of the anterior HF were calculated in all subjects. The MD and FA values were compared across the groups.
No significant differences of MD and FA values were noted between right and left HF in the controls. In the patient group, MD significantly increased in the HF ipsilateral to the lesioned side [(9.27 +/- 1.09) x 10(-4) mm(2)/s], compared with the values in the contralateral HF [(8.20 +/- 0.59) x 10(-4) mm(2)/s] (t = 4.479, P = 0.001) and healthy subjects [(7.58 +/- 0.51) x 10(-4) mm(2)/s] (P < 0.001), but no significant differences were found in FA. When compared with the controls, patients had a significantly higher MD in the contralateral HF (P < 0.05), but the difference in FA was not statistically significant.
DTI could detect hippocampal abnormality in patients with MTLE. This technique may be helpful for preoperative evaluation of such patients.
Chinese medical journal 08/2006; 119(15):1237-41. · 0.86 Impact Factor
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ABSTRACT: To investigate whether normal-appearing brain tissue (NABT) on conventional MRI has occult damage in patients with relapsing-remitting multiple sclerosis (RRMS) by using diffusion tensor imaging (DTI) histogram analysis, and to determine the correlations between DTI histogram-derived measures of the NABT and expanded disability status scale (EDSS) scores, disease durations, T2WI lesion volumes and brain tissue volumes in RRMS patients.
Conventional MRI and DTI scans were performed in 24 patients with RRMS and 24 sex- and age-matched healthy controls. After segmentation of the NABT, the mean diffusivity (MD) and fractional anisotropy (FA) histograms of the NABT were created and analyzed.
In patients with RRMS, the average MD (1.014 x 10(-3) mm2 x s(-1)) of the NABT was higher than that (0.910 x 10(-3) mm2 x s(-1)) of control subjects (t = 7.238, P < 0.001); the MD histogram peak height (8.858 per thousand) of the NABT was lower than that (0.767 per thousand) of control subjects (t = 6.161, P < 0.001); the MD histogram peak location (0.809 x 10(-3) mm2 x s(-1)) of the NABT was higher than that (0.767 x 10(-3) mm2 x s(-1)) of control subjects (t = 5.324, P < 0.001); the average FA (0.231) of the NABT was lower than that (0.254) of control subjects (t = 6.217, P < 0.001); the FA histogram peak height (4.502 per thousand) of the NABT was higher than that (4.107 per thousand) of control subjects (t = 4.198, P < 0.001); no significant difference was found in the FA histogram peak location of the NABT between these two groups (t = 1.223, P = 0.227); none of the DTI histogram-derived measures correlated with EDSS scores or disease durations (P > 0.05); the average MD and all the FA histogram-derived measures correlated with T2WI lesion volumes (P < 0.05); and the average MD, the MD histogram peak height and all the FA histogram-derived measures correlated with brain tissue volumes (P < 0.05). In healthy controls, however, only the average FA of the NABT correlated with brain tissue volumes.
Patients with RRMS had occult damage in the NABT and the extent of NABT damage was related to the lesion load of brain and to the extent of brain tissue atrophy.
Zhonghua yi xue za zhi 06/2006; 86(18):1260-4.
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ABSTRACT: To develop an improved temporal clustering analysis (TCA) method for detecting multiple active peaks by running the method once.
Two cases of simulation data and a set of actual fMRI data from nine subjects were used to compare the traditional TCA method with the new method, termed extremum TCA (ETCA). The first case of simulation data simulated event-related activation and block activation in one cerebral area, and the second case simulated event-related activation and block activation in two cerebral areas. An in vivo visual stimulating experiment was performed on a 1.5T MR scanner. All imaging data were processed using both traditional TCA and the new method.
The results of both the simulated and actual fMRI data show that the new method is more sensitive and exact than traditional TCA in detecting multiple response peaks.
The new method is effective in detecting multiple activations even when the timing and location of the brain activation are completely unknown.
Journal of Magnetic Resonance Imaging 04/2006; 23(3):285-90. · 2.70 Impact Factor
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ABSTRACT: The functional connectivity of the resting state, or default mode, of the human brain has been a research focus, because it
is reportedly altered in many neurological and psychiatric disorders. Among the methods to assess the functional connectivity
of the resting brain, independent component analysis (ICA) has been very useful. But how to choose the optimal number of separated
components and the best-fit component of default mode network are still problems left. In this paper, we used three different
numbers of independent components to separate the fMRI data of resting brain and three criterions to choose the best-fit component.
Furthermore, we proposed a new approach to get the best-fit component. The result of the new approach is consistent with the
default-mode network.
03/2006: pages 175-182;
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ABSTRACT: To demonstrate the role of diffusion tensor tractography (DTT) in preoperative mapping of eloquent tracts in relation to cerebral tumors and to determine whether it is helpful for neurosurgical planning and postoperative assessment.
Sixteen patients with brain tumors underwent diffusion tensor imaging (DTI). The pyramidal tract, corpus callosum and optic radiation were reconstructed and the exact location of a lesion with respect to these tracts was observed to design a reasonable surgical plan for preserving vital tracts while maximizing tumor resection. After surgery, DTI was performed again and these tracts were evaluated to investigate the surgical outcomes. Twenty-four patients with suspicion of pyramidal tract involvement were also evaluated as a control group.
The relationship between tracts and tumors was classified as three types: type I is simple displacement, type II is displacement with disruption and type III is simple disruption. Twelve cases involved in pyramidal tract (DTT group), one was type I with reduction of displacement after surgery, nine were type II with reduction of displacement and other two were type III without any improvement. The extent of tumor resection (p = 0.045) and postoperative improvement of locomotive function (p = 0.015) of DTT group were significantly higher than those of control group. Corpus callosum was involved in seven cases, three were type II with reduction of displacement and four were type III without any improvement. Optic radiation was involved in three cases, all were type I with reduction of displacement.
DTT allowed for visualization of the exact location of tumors relevant to eloquent tracts and was found to be beneficial in the neurosurgical planning and postoperative assessment.
European Journal of Radiology 12/2005; 56(2):197-204. · 2.61 Impact Factor
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ABSTRACT: Although transient ischemic attacks (TIA) is a clinical diagnosis, imaging findings are important for its diagnosis and treatment. This study evaluated the value and limitations of conventional CT, CT cerebral perfusion imaging and transcranial Doppler sonography (TCD) in patients with TIA.
Conventional CT, CT cerebral perfusion imaging and TCD were performed in 20 patients with TIA. After regular CT examination, 40-second dynamic scans were performed on selected slice, while 40 ml of non-ionic contrast materials was bolus-injected through antecubital vein with power injector. These dynamic images were processed with the perfusion software package on workstation. Cerebral blood flow (CBF) and time to peak (TTP) were measured in specific regions of the brain. TCD was also performed in 20 patients with TIA. Comparative analysis was made on the basis of the results of conventional CT, CT cerebral perfusion imaging and TCD.
In the 20 patients with TIA, conventional CT turned out to be normal. However, persisting abnormal perfusion changes corresponding to clinical symptoms were found in 13 cases with the prolonged TTP. The other 7 cases were normal. TTP of the affected side (11.6 +/- 3.0) s was significantly prolonged (t = 4.782, P < 0.01) in comparison with the contralateral side (8.8 +/- 1.5) s. The difference in CBF was not statistically significant (t = 1.912, P = 0.073) between the affected side [(223.9 +/- 19.6) ml.min(-1).L(-1)] and the contralateral side [(227.7 +/- 19.8) ml.min(-1).L(-1)]. TCD revealed severe stenosis or occlusion of the carotid artery in 10 patients, arteriosclerosis in 6 patients, blood speed decrease in 2 patients, vasospasm in 1 patient.
Conventional CT can exclude intracerebral diseases. Perfusion CT provides valuable hemodynamic information and shows the extent of perfusion disturbances. TCD can demonstrate abnormalities of the involved arteries in patients with TIA. The combination of these three imaging methods can provide more diagnostic information.
Chinese medical journal 12/2005; 118(21):1812-6. · 0.86 Impact Factor
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ABSTRACT: To investigate the functional activation patterns during two types of visual search tasks in Alzheimer's disease (AD) with functional MRI, and probe the neuro-anatomic basis of visual attention.
13 patients with AD and 13 sex and age-matched healthy subjects participated in the experiment designed with two visual search tasks. The first was a "pop-out" single feature task, detecting a vertical target among horizontal distrators, and the second was a conjunction task where the target was defined by conjunction of feature (color and orientation) and the performance depended on some shifting of attention. The fMRI data were collected by Siemens 1.5 T Sonata magnetic resonance imaging (MRI) system and analyzed by Statistical Parametric Mapping software (SPM 99) to generate the activation map.
AD patients had a particular impairment in the conjunction task but not in the single-feature task. Although both groups revealed overlapping networks engaged in the conjunction tasks including the superior parietal lobule (SPL), frontal and occipitotemporal cortical regions (OTC), primary visual cortex and some subcortical structures, the most pronounced difference between them was found in bilateral SPL (more activities in the controls) and right OTC (more activities in the patients). The difference between the 2 groups was small in the pop-out condition.
AD particularly affects those mechanisms controlling spatial shifts of attention. Some additional remote activation (ventral visual stream and temporal lobe) can be interpreted as dynamic reallocating of brain functional resource.
Zhonghua yi xue za zhi 09/2005; 85(33):2349-53.
