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Objective To investigate the morphological changes of the brainstem in patients with Alzheimer's disease (AD) and their relationship with hippocampal morphological changes.Methods Sixty AD patients (AD group) and sixty age-and gender-matched normal elderly (normal control group) were selected from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database.The hippocampus and the brainstem of each subject were segmented and their normalized volumes were calculated.According to the hippocampal volume standard value (Z-score),AD patients were divided into two subgroups (hippocampal atrophy group (n=51) and hippocampal spared group (n=9)).A voxel-based morphology (VBM) study was also performed to investigate the morphological differences of the brainstem between the normal control group and the AD group,as well as between the AD subgroups.Results Compared with the normal control group,the brainstem volume in the AD group decreased significantly (16 741.31±1 739.11 vs 15 609.67±1 451.60,t=3.870,P=0.001).In AD subgroups,the volume of the brainstem in the hippocampal atrophy group was significantly smaller than that in the hippocampal spared group (16 556.30 ± 1 514.86 vs 15 442.62 ± 1 389.05,t=2.189,P=0.033).Pearson correlation analysis showed that Mini-Mental State Examination scores were positively correlated with the hippocampal and the brainstem volumes (r=0.590,P＜0.01;r=0.234,P＜0.05),and there was a positive correlation between the hippocampal and the brainstem volume changes in patients with AD (r=0.315,P=0.014).VBM results showed that both the bilateral midbrain and the bilateral pons in the AD group had significant atrophy compared with the normal control group (P＜0.05).In the AD subgroups,the bilateral midbrain and the left pons in the hippocampal atrophy group were significantly atrophied compared with the hippocampal spared group (P＜0.05).Conclusion The brainstem showed morphological changes in patients with AD,and the morphological changes of the brainstem in AD patients with different degrees of hippocampal atrophy were different,indicating the morphological changes of the hippocampus and the brainstem may have an interrelated relationship.
RESUMO
PURPOSE: To obtain a series of parameters describing the shape and bone thickness of the fixation route along the superior border of the arcuate line, so as to provide references for pelvic and acetabular surgery and design pelvic anatomic internal fixators. METHOD: A total of 175 complete pelvic computed tomography (CT) scans of normal adult pelvises were collected. Each person's CT scans were reconstructed to create a three-dimensional pelvic model. A curve of the fixation route was delineated and divided into 11 equal parts. The total length of the curve, the radius of curvature, and the bone thickness at each decile point were all measured. The position of the pelvic inlet, the anterior and posterior sagittal diameter were measured. RESULTS: The radius of curvature at each decile point were 29.18 ± 15.53, 55.27 ± 29.48, 43.04 ± 14.42, 59.62 ± 21.02, 91.67 ± 52.01, 78.9 ± 38.66, 75.76 ± 25.87, 61.75 ± 16.68, 54.62 ± 14.88, and 43.61 ± 19.10 mm, respectively. The anterior and posterior sagittal diameter of the pelvic inlet was 66.01 ± 9.15 and 41.36 ± 8.19 mm, respectively. For all groups divided by the ratio of the posterior and the anterior sagittal diameter, the decile points 1, 3, and 10 had smaller radii of curvature than the before and after points, respectively. CONCLUSIONS: The curve of the fixation route along superior border of arcuate line has a relatively greater bending degree at the pubic tubercle, iliopubic eminence and close to the sacroiliac joint. With the transition of the pelvic inlet shape from android to gynecoid and platypelloid type, the bone surface at the iliopubic eminence becomes flatter. Pelvic and acetabular surgery could be more accurate by referring to the previous key bending points and the change of the pelvic inlet shape.
