The atrophy pattern in the subtypes of frontotemporal lobar degeneration and Alzheimer disease by structural MRI / 中华放射学杂志

ABSTRACT

Objective To analyze the patterns of cortical atrophy of the two subtypes of frontotemporal lobar degeneration (FTLD ),behavioural-vsriant frontotemporal dementia (bvFTD ) and primary progressive aphasia (PPA).And to compare them with that of Alzheimer disease (AD) to provide an objective basis for early diagnosis and differential diagnosis.MethodsA total of 83 patients were enrolled in this study and there were 30 patients with cognitively normal controls (CN),30 with AD and 23 with FTLD (10 with bvFTD,13 with PPA).Philips 3.0 T TX scanner and 8 channel head coil was employed.Three dimensional turbo fast echo(3D-TFE)T1WI sequence with high resolution was used to collect the volume data of gray matter.3D-TFE T1 WI images were normalized and segmented into gray matter map for statistical analysis by SPM 8 and VBM 8.The false discovery rate (FDR) was adopted in P value adjustment,P ＜ 0.001,and the cluster size was set at 5.The full width at half maximum (FWHM ) was set at 4 mm for the smoothing.Paired t test was used for statistics.ResultsIn bvFTD,PPA and AD groups,there were diffuse regions with reduced volume in cerebral cortex and subcortical structures (such as the hippocampus,the amygdala,the caudate nuclei,et al).The most obvious atrophic region in bvFTD and PPA group was found in the frontotemporal.Compared with AD,gray matter atrophy in bvFTD was found in brain regions including bilateral temporal lobes,bilateral superior temporal pole gyri,bilateral middle temporal pole gyri,right fusiform gyrus and bilateral frontal lobes.Among them,temporal and frontal lobes atrophy had obvious right partial lateralizing,with 14 301 voxels in right temporal lobe and 5105 in left (t =-5.03,P＜0.05).The number of atrophy voxels in right and left frontal lobe were 1344 and 125 (t =3.45,P ＜0.05).The left temporooccipital lobe atrophy was more obvious than the right in PPA,with 15 637 voxels in left and 10 723 in right ( t =- 2.65,P ＜ 0.05 ).ConclusionsThere are different brain gray matter atrophy patterns in bvFD,PPA and AD.Among them,bvFTD has asymmetric right frontal and temporal lobe atrophy,which may be related to characteristic personality changes.On the other hand,the asymmetric atrophy in left temporooccipital lobe may be responsible for the aphasis of patients with PPA.