Multi Modal Study On Brain Function Impairment In Patients With Early AIDS Based On MRI

Part Ⅰ Preliminary observation on cerebral white matter of AIDS patient with diffusion tensor imaging at early stageObjective:To evaluate the changes of water diffusion in different cerebral white matter regions of AIDS patients with magnetic resonance diffusion tensor imaging (DTI).Materials and methods:65 AIDS patients with positive HIV were collected from Henan Provincial People’s Hospital from January 2011 to August 2013, all of whom were confirmed by the national assigned laboratory. CD4+ T lymphocytes of all the patients were< 200/mm3.18 cases with suspicious opportunistic intracranial infection, malignant tumor or other lesions and 8 cases with brain atrophy were excluded according to head MRI and other related inspections. The rest of the 39 patients without exception in conventional MRI scan were selected as the research object; Montreal cognitive scores were normal in 11 cases and dropped in 28 cases; among the 39 cases,8 cases showed mild dementia,6 cases showed headache and 3 cases showed epilepsy, so these 17 cases formed AIDS symptomatic group; the rest 22 cases without symptoms were as AIDS asymptomatic group; in addition,30 age- and gender- matched healthy volunteers were as the control group. All the subjects were given conventional head MRI and DTI scan with Discovery MR 750 (USA, GE,8 channel phased-array head coil). Syngo workstation was used for post-processing of all raw DTI data to obtain diagram of fractional anisotropy (FA) and diagram of directionally encoded color (DEC) respectively. DEC diagram set direction code as: green for anterior-posterior direction of nerve fiber bundle, red for horizontal direction and blue for superior-inferior direction.9 areas (genu, body and splenium of corpus callosum; anterior and posterior limb of internal capsule; periventricular, frontal, parietal and occipital white matter) at the same level were selected as the regions of interest (ROI) in AIDS group and the control group.3 ROIs (ROI area of 3 mm2 each) were randomly measured in each white matter region for FA and ADC, and the average values were taken as statistics. To avoid the partial volume effect, selection of ROI is given priority to axial DEC diagram; furthermore, coronal and sagittal DEC diagrams were combined for auxiliary positioning to ensure the accuracy of selected location. SPSS 13.0 was adopted for variance analysis on FA and ADC statistics of the 3 groups, and then t-test of independent sample was performed separately; P=0.05 referred to index of significance.Results:FAs were significantly decreased while ADC were significantly increased in genu, body and splenium of corpus callosum, and periventricular, frontal and parietal white matter regions, and there were differences compared with the control group (P<0.05); while the changes of FA and ADC were not obvious in anterior and posterior limb of internal capsule and occipital white matter region, and there were no significant differences compared with the control group (P>0.05). FA values of all the 9 white mass regions were significantly decreased in AIDS symptomatic group, ACD values were all significantly increased, and there were differences with the asymptomatic group (P<0.05). FA values of all the 9 white mass regions were significantly decreased in AIDS symptomatic group, ACD values were all significantly increased, and there were differences with the asymptomatic group (P<0.05).Conclusion:Abnormal diffusion of cerebral white matter in AIDS is area-related. DTI can early find abnormal cerebral white matter.PartⅡ Prospective study on regional homogeneity changes of local brain function of AIDS patients at early stageObjective:To preliminarily discuss the changes of regional homogeneity of local brain function in AIDS patients at resting state and its relationship with cognitive impairment.Materials and methods:65 AIDS patients with positive HIV were collected from Henan Provincial People’s Hospital from January 2011 to August 2013,all of whom were confirmed by the national assigned laboratory.CD4+ T lymphocytes of all the patients were<200/mm3.18 cases with suspicious opportunistic intracranial infection, malignant tumor or other lesions and 8 cases with brain atrophy were excluded according to head MRI and other related inspections.The rest of the 39 patients without exception in conventional MRI scan were selected as the research object; Montreal cognitive scores[13]were normal in 11 cases and dropped in 28 cases;28 cases with declined Montreal cognitive scores (MoCA<26 points)were as the AIDs cognitive impairment group；and the rest 11 cases with normal Montreal cognitive scores(MoCA≥26 points)were as the AIDS non-cognitive impairment group；in addition,30 healthy volunteers were as the control group.Cognitive impairment group,non-cognitive impairment group and the health control group were not signficantly different in age and gender. There was no metal in any subject.All the subjects were right-handed and signed informed consent.The research was approved by hospital ethics committee.Discovery MR 750 (USA,GE) was adopted for imaging. The subjects were awake with closed eyes and fixed head at supine position quietly, and no special task was performed.8 channel cerebral coils were adopted.Scanning sequence included 3D T1-FSPGR and Resting Bold.Statistical parametric mapping (SPM) was used for data preprocessing.ReHo fMRI 1.0 was adopted to compute ReHo value of each pixel in brain.Therefore,each subject obtained a ReHo diagram. Standardized ReHo diagram was statistically analyzed. SPM software was used for One-way ANOVA and pairwise comparison for ReHo diagrams of the cognitive impairment group, non-cognitive impairment group and healthy control group. P<0.005 and voxel range (K)>10 referred to significant difference.Results:Ⅰ. Comparison between AIDS cognitive impairment group and healthy control groupCompared with the healthy control group, brain areas where the ReHo were reduced in AIDS cognitive impairment group included bilateral superior and middle frontal gyrus, left middle and inferior temporal gyrus, bilateral anterior cingulate, left hippocampus and left parahippocampal gyrus. There was no cerebral area with increased ReHo value.II. Comparison between AIDS non-cognitive impairment group and healthy control groupCompared with the healthy control group, brain areas where the ReHo were reduced in AIDS non-cognitive impairment group included left superior frontal gyrus, left temporal gyrus, right anterior cingulate, and left hippocampus. There was no cerebral area with increased ReHo value.III. Comparison between AIDS cognitive impairment group and AIDS non-cognitive impairment groupCompared with the AIDS non-cognitive impairment group, brain areas where the ReHo were reduced in AIDS cognitive impairment group included bilateral superior and middle frontal gyrus, left middle temporal gyrus, left anterior cingulate, and left parahippocampal gyrus. There was no cerebral area with increased ReHo value.Conclusion:1. Brain regions related with the early cognitive impairment of AIDS patients included frontal lobe and temporal lobe, anterior cingulate, hippocampus and parahippocampal gyrus;2. The declined degree of the regional homogeneity of local brain function in AIDS patients was closely associated with the degree of cognitive impairment;3. Brain function of AIDS patients with cognitive impairment changed earlier than the emergence of clinical symptoms.Part IIIBlood perfusion changes in local brain region of AIDS patients at early stage and its relationship with cognitive function changesObjective:To further explore the relationship between abnormal cerebral perfusion of AIDS patients and the related clinical symptoms through combination with the scores of Montreal cognitive scale and abnormal perfusion in related regions of AIDS patients.Materials and methods65 AIDS patients with positive HIV were collected from Henan Provincial People’s Hospital from January 2011 to August 2013, all of whom were confirmed by the national assigned laboratory. CD4+ T lymphocytes of all the patients were< 200/mm3.18 cases with suspicious opportunistic intracranial infection, malignant tumor or other lesions and 8 cases with brain atrophy were excluded according to head MRI and other related inspections. The rest of the 39 patients without exception in conventional MRI scan were selected as the research object; Montreal cognitive scores [11] were normal in 11 cases and dropped in 28 cases, where 23 cases were male and 16 cases were female, with the average age of 36.7±4.3 years. The disease course varied from 1 to 8 years, with an average of 4.3 years. Montreal cognitive scores were dropped in 28 cases; 28 cases (male:17, female:11, average age:36.4±3.7 years) with declined Montreal cognitive scores (MoCA <26 points) were as the AIDs experiment group; and 30 healthy volunteers (male:18, female:12, average age:36.4±4.1 years) were as the control group. Experimental group and the health control group were not significantly different in age and gender. There was no metal in any subject. All the subjects were right-handed and signed informed consent. The research was approved by hospital ethics committee. Discovery MR 750 (USA, GE) was adopted for imaging. The subjects were awake with closed eyes and fixed head at supine position quietly, and no special task was performed. The patients were fixed with sponge pad for their heads and nano sponge ball in the ears.8 channel cerebral coils were adopted. Scanning sequence included 3D Tl-FSPGR and ASL. GE ADW 4.5 workstation was used for calculating diagram of cerebral reperfusion. Statistical parametric mapping (SPM8) was used for statistical analysis and data preprocessing. Voxel-to-voxel paired t test was used for comparison of figures of cerebral perfusion between the experimental group and the control group. FWE corrected P<0.05 was selected to get corresponding distribution of cerebral perfusion difference. SPSS 17.0 was used for paired t test on scores of MoCA scale between the two groups. Pearson correlation analysis was performed between CBF value at the brain area of maximize difference of rCBF and total scores of patients’MoCA scale as well as each factor. Inspection standard was p=0.05.Results:I. Brain area with different rCBF between the two groupsAIDS patients’rCBFs in left superior and middle frontal gyrus, right superior frontal gyrus, left superior temporal gyrus, left cingulate gyrus, left thalamus and left lentiform nucleus were all smaller than the control group (p<0.05). AIDS patients’ local rCBF was not greater than the brain area of the control group.II. Correlation between abnormal brain region and clinical symptoms of AIDS patient group.There was no correlation between rCBF and total scores of MoCA scale in seven different brain regions (p>0.05). In-depth analysis found that rCBF in the left frontal gyrus was separately correlated with factor scores of attention, concentration and abstract thinking (r=0.52,p<0.05;r=0.53,p<0.05); rCBF in the left middle frontal gyrus was separately correlated with factor scores of executive function and abstract thinking (r=0.54,p<0.05;r=0.57,p<0.05); rCBF in the right superior frontal gyrus was separately correlated with factor scores of abstract thinking (r=0.58,p<0.05); rCBF in the left superior temporal gyrus was separately correlated with factor scores of memory and visual spatial skills (r=0.52,p<0.05;r=0.57,p<0.05); No related MoCA factor scores were seen in rCBF of the left cingulate cortex, thalamus and lentiform nucleus.Conclusion:1. Local area of the AIDS patients where blood perfusion generally dropped was concentrated in the frontal and temporal lobe, cingulate and thalamus area.2. Distribution of brain regions with abnormal local blood perfusion in AIDS patients was partial laterality.3. Brain regions with abnormal perfusion of the AIDS patients were closely correlated with the corresponding cognitive impairment.