Evalution Of Brain Atrophy And Lesion Index In Aging And Alzheimer's Disease

Objective:To collectively evaluate multiple common brain changes and their additive effect on brain function,a semi-quantitative rating scale,the Brain Atrophy and Lesion Index(BALI)has been validated.In this study,based on the previous T1 WI and T2 WI BALI,the developed BALI which contained the T2*-gradient-recalled echo(T2*GRE)and T2 fluid-attenuation inversion recovery(T2-FLAIR)was established.We compared the Alzheimer's disease(AD),mild cognitive impairment(MCI)and healthy contral using the BALI rating scale.Combined with the above experiments,the application of magnetic resonance imaging(MRI)based BALI evaluation index in the assessment of normal brain aging and Alzheimer's disease was discussed.Materials and Methods:The data were from two databases,the database of Tianjin Medical University General Hospital(n=169;female=56.8%;age=62.7±13.02)and the Alzheimer's disease Neuroimaging Initiative database(ADNI)(n=136;female =55.9 %,age=74.84±8.25).The healthy aging subjects need to be excluded other brain organic diseases and cognitive decline.They were divided into 5 groups at an interval of 10 years,40-49,50-59,60-69,70-79,80-89 years old respectively.GE 3.0T magnetic resonance scanner was used for T1 WI,T2WI,T2-weighted fluid attenuated inversion recovery(T2-FLAIR),and T2* weighted gradient-recalled echo(T2*GRE)data acquisition.Data were evaluated according to the BALI rating scale.Participants in the cognitive abnormalities and healthy control group were from the ADNI database.Finally,41 AD,50 MCI,and 45 HC were included.In this database,only T1 WI,T2-FLAIR,T2*GRE were collected.The BALI rating scale was used to evaluate lesions in different regions: Depending on the extent of the lesion,0-3 points were assigned to gray matter lesions and subcortical dilated perivascular spaces,lesions in the peri-ventricular white matter,lesions in the infratentorial regions,lesions in basal ganglia and its surrounding areas,microbleeds,and "other lesions".While,the deep white matter lesions and global atrophy need to be given 0-5 minutes.Finally,combining the values of the subscores obtained to get the total score of the whole brain.SPSS 22.0 software was used for statistical analysis of the demographic data and BALI scores and sub-score categeries for each group of subjects.Results:There was a significant correlation between age and BALI total score in healthy aging patients(r?0.70;P<0.001).With the increase of age,the BALI total score of the four sequences increased as well(F?36.601,P<0.001).T2-FLAIR was more sensitive to periventricular white matter lesions(?2=26.81,P<0.001)and deep white matter(?2=53.47,P<0.001)lesions at different age groups than other sequences while T2 WI was more sensitive with the dilated perivascular space(?2=55.45,P<0.001).The incidence of microbleeds in the subjects was 17%,which was detected in the T2*GRE sequence.There existed differences in both BALI subscores and total scores of the three sequences in AD,MCI and healthy patients,with the highest subscore(?2?6.50,P?0.039)and total score in the AD group(?2?24.39,P?0.001).T1 WI,T2-FLAIR and T2*GRE-based BALI scores showed comparable accuracy at classifying people with AD at the individual level.At its point of 10,the BALI score with a sensitivity of 75.6%,78.0%,85.4%,a specificity of 75.6%,84.4%,80.0%.The area under the curve(AUC)ranged between 0.77 and 0.83.Conclusions:The BALI total scores based on T1 WI,T2WI,T2-FLAIR,and T2*GRE sequences in each BALI category reflecting the burden of age-related and disease-related whole-brain structural changes in older adults.It may provide an alternative method of identifying brain structual changes in aging and AD.T2-weighted fluid-attenuation inversion recovery(T2-FLAIR)and T2*-weighted gradient-recalled echo(T2*GRE)MRI testing can improve the assessment and are more sensitive to early detection of white matter lesions and microbleeds.The new sequence may also quantify the brain structure of abnormal cognitive function and help summarize the structural changes related to AD.Further research will integrate these MRI tests as clinical diagnostic tools to support brain aging diagnosis.