Volumetric measurement of the hippocampus in a series of patients with Alzheimer disease

Cuantificación volumétrica del hipocampo en una serie de sujetos con la enfermedad de Alzheimer

Background

Hippocampal volume is recognised as a surrogate imaging biomarker for the study of Alzheimer's disease (AD). However, in Cuba there are no antecedents of its use. The objective of this research was to establish an automatic hippocampal segmentation procedure to study a sample of Cuban subjects diagnosed with possible mild or moderate AD.

Methodology

A total of 104 subjects with mean ages of 73.77 ± 6.74 years participated. Imaging for the calculation of hippocampal volumes and asymmetry index (AI) was performed with a Siemens Magnetom Allegra 3T scanner using an MP-RAGE sequence. Volumes were obtained manually and automatically using Amira 5.3 and FreeSurfer 6.0 software, respectively. The results of both methods were statistically compared.

Results

The steps for hippocampal volumetric quantification were established for these methods. Comparison between them showed high concordance (ICC = 0.95) for both hippocampi. Therefore, there were no significant differences between them. The mean right (2961.84 ± 552.70 mm3) and left (2892.68 ± 536.6 mm3) volumes of the subjects were obtained. These volumes and the asymmetry index were significantly different with respect to a sample of healthy subjects with (p = 0.00001) and (p = 0.003) respectively; and similar to those obtained in a sample of subjects with AD in Latin America.

Conclusions

A procedure for automated volumetric quantification of the hippocampus was established. This allowed the study of a Cuban sample with possible AD. This constitutes a previous step to longitudinally evaluate the effectiveness of new Cuban drugs.

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