Several methods offer free volumetry services for MR data that adequately quantify volume differences in the hippocampus and its subregions. These methods are frequently used to assist in clinical ...diagnosis of suspected hippocampal sclerosis in temporal lobe epilepsy. A strong association between severity of histopathological anomalies and hippocampal volumes was reported using MR volumetry with a higher diagnostic yield than visual examination alone. Interpretation of volumetry results is challenging due to inherent methodological differences and to the reported variability of hippocampal volume. Furthermore, normal morphometric differences are recognized in diverse populations that may need consideration. To address this concern, we highlighted procedural discrepancies including atlas definition and computation of total intracranial volume that may impact volumetry results. We aimed to quantify diagnostic performance and to propose reference values for hippocampal volume from two well-established techniques: FreeSurfer v.06 and volBrain-HIPS.
Volumetry measures were calculated using clinical T1 MRI from a local population of 61 healthy controls and 57 epilepsy patients with confirmed unilateral hippocampal sclerosis. We further validated the results by a state-of-the-art machine learning classification algorithm (Random Forest) computing accuracy and feature relevance to distinguish between patients and controls. This validation process was performed using the FreeSurfer dataset alone, considering morphometric values not only from the hippocampus but also from additional non-hippocampal brain regions that could be potentially relevant for group classification. Mean reference values and 95% confidence intervals were calculated for left and right hippocampi along with hippocampal asymmetry degree to test diagnostic accuracy.
Both methods showed excellent classification performance (AUC:> 0.914) with noticeable differences in absolute (cm
) and normalized volumes. Hippocampal asymmetry was the most accurate discriminator from all estimates (AUC:1~0.97). Similar results were achieved in the validation test with an automatic classifier (AUC:>0.960), disclosing hippocampal structures as the most relevant features for group differentiation among other brain regions.
We calculated reference volumetry values from two commonly used methods to accurately identify patients with temporal epilepsy and hippocampal sclerosis. Validation with an automatic classifier confirmed the principal role of the hippocampus and its subregions for diagnosis.
El estudio de las propiedades estructurales y funcionales del cerebro en Homo sapiens, así como en otros primates no-humanos, constituye un tema fundante en la tradición de investigación de la ...antropología biológica. Sin embargo, el cuestionamiento temprano a la perspectiva tipológico-racial condujo al abandono de los análisis intraespecíficos, limitando fuertemente su integración a las neurociencias. En este trabajo se realiza un análisis histórico crítico de las investigaciones sobre el cerebro, enfatizando en las poblaciones humanas actuales, realizadas desde la antropología biológica y las neurociencias -particularmente en biomedicina-. Finalmente, se discuten líneas de diálogo que podrían fortalecer a ambas áreas. Se concluye que el corpus ontológico y teórico-metodológico empleado por la antropología biológica para la generación de conocimientos sobre los patrones de variación espaciotemporal en rasgos fenotípicos y genéticos, así como de los procesos evolutivos y factores ambientales que los modelaron resulta un aporte significativo para los estudios desarrollados por las neurociencias.
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