| Objective: Cognitive impairment refers to the damage of multiple cognitive area, which include orientation, memory, calculate, executive function, understand, judgement and others. Dementia was one of a type with a wide range of damage and severe clinical symptoms, which had been paid attention as a disease with high morbidity and disability rate. Alzheimer disease(AD) is the most common type of dementia, memory decline was the only symptom in the early time, the latter performance was comprehensive cognitive dysfunction. AD had a serious impact on patients quality of life in advanced period, and there is no effective treatment currently, therefore, the early detection and intervention of AD become the focus of today’s medical research. Previous studies had found that a certain degree of pathological changes had appeared before performed dementia of AD patients. Following this discovery, the concept of mild cognitive impairment(MCI) was proposed. MCI refers to cognitive deficits but do not fulfill the criteria for dementia, which is the transition state between AD and normal people. Early pathological changes were seen in the hippocampus of MCI patients, which can cause changes in the structure of hippocampal volume(HV) when damage to a certain extent. Research have shown that the hippocampus was closely related to memory, especially on significant recent memory. Therefore, the value of HV in diagnosis of cognitive impairment was caused the people’s attention. Our research analyzed the differences of HV among AD patients, MCI patients and normal subjects and the relationship of HV and clinical indicators through using 3.0T magnetic resonance imaging(MRI), and explored the clinical application value of HV measurement in diagnosis of cognitive impairment.Methods: A total of 90 patients with right-handed(48men, 42women),average age was 72.34±3.95 years(ranging from 65 to 80 years) admitted in neurology department of our hospital in March 2013 to December 2014. According to clinical examination and neuropsychological screening,the 90 subjects were divided into 30 patients diagnosed with AD and 30 patients with MCI, 30 healthy controls who were without cognitive impairment. AD patients were diagnosed according to NINCDS-ADRDA criteria, MCI diagnosis was made in accordance with Petersen’s criteria(1999). We collected dementia factors and brain magnetic resonance imaging(including T1 weighted image, T2 weighted image, fluid attenuated inversion recovery and diffusion weighted imaging) were performed if there is no prohibition, in order to exclude intracranial tumor, hydrocephalus and multi infarct and then hippocampal oblique coronal scan were performed by the Siemens Tim-avanto3.0T superconductance magnetic resonance. The segmentation followed the description of Watson. Laid out the hippocampus boundaries manually on the reconstructed image, then calculate HV, which need to be standardized. Each patients’ HV was complete by one imaging technology surveyors, in order to ensure the accuracy of the results. HV and clinical general information(Mini-Mental State Examination score(MMSE), blood lipids, blood glucose, homocysteine(Hcy), etc) were comprehensive analyzed, and evaluation the applications of HV measurement in cognitive impairment. The data was analyzed with SPSS 13.0 statistic software. The comparison of three groups, measurement data use the ANOVA and non-parament test, and correlation analysis used Spearman correlation.Results:1 General information: 90 patients were divided three groups, and each group had 30 subjects. There were no significant difference in age, sex and the level of education during each group(P >0.05). 2 MMSE score: The MMSE scores of AD group, MCI group and NC group were 19.97±4.27 score, 27.30±2.32 score, 29.10±1.12 score respectively. There were significant differences during different groups(P <0.05). 3 Standardized HV: The total volume of standardized HV in the patients of AD was 6.141±0.791cm3, which left was 3.005±0.417cm3 and the right was 3.135±0.376cm3; The total volume of standardized HV in the patients of MCI was 6.515±0.394cm3, which left was 3.202±0.193cm3 and the right was 3.313±0.203cm3; The total volume of standardized HV in the patients of NC was 6.854±0.619cm3, which left was 3.377±0.302cm3 and the right was 3.477±0.318cm3.There were significant difference between AD and NC groups, AD and MCI groups, MCI and NC groups in terms of normalized bilateral and total HV(P <0.05).4 the relationship of standardized HV with MMSE score: The standardized HV of all subjects had positive correlation with MMSE scores.(left: r=0.520, P<0.05; right: r=0.510, P<0.05; total HV: r =0.519, P<0.05)5 biochemical index: There were no significant difference of blood lipids level, blood glucose level and other index between AD group and NC group, AD group and MCI group, MCI group and NC group(P>0.05); But there were significant difference of Hcy between AD group and NC group, AD group and MCI group, MCI group and NC group(P<0.05).The relationship of standardized HV with the level of Hcy: There were no relativity of bilateral and total standardized HV with Hcy level of all subjects, but there was positive correlation of MMSE score with Hcy level(r=-0.438, P <0.05).Conclusions: 1 MRI is one of the best tools for HV measurement as a non-invasive diagnostic technique.2 The study find that HV change can reflect the change of cognitive function of patients with early state, and can be used as an important evidence for evaluating the degree of cognitive impairment of patients.3 Combine HV measurement with MMSE score can more accurately provide evidence of early diagnosis and treatment for MCI and AD patients.4 Hcy may be one of the risk factors of cognitive impairment. |
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