Automated versus manual segmentation of brain region volumes in former football players

Abstract

ObjectivesTo determine whether or not automated FreeSurfer segmentation of brain regions considered important in repetitive head trauma can be analyzed accurately without manual correction.Materials and methods3 T MR neuroimaging was performed with automated FreeSurfer segmentation and manual correction of 11 brain regions in former National Football League (NFL) players with neurobehavioral symptoms and in control subjects. Automated segmentation and manually-corrected volumes were compared using an intraclass correlation coefficient (ICC). Linear mixed effects regression models were also used to estimate between-group mean volume comparisons and to correlate former NFL player brain volumes with neurobehavioral factors.ResultsEighty-six former NFL players (55.2 ± 8.0 years) and 22 control subjects (57.0 ± 6.6 years) were evaluated. ICC was highly correlated between automated and manually-corrected corpus callosum volumes (0.911), lateral ventricular volumes (right 0.980, left 0.967), and amygdala-hippocampal complex volumes (right 0.713, left 0.731), but less correlated when amygdalae (right −0.170, left −0.090) and hippocampi (right 0.539, left 0.637) volumes were separately delineated and also less correlated for cingulate gyri volumes (right 0.639, left 0.351). Statistically significant differences between former NFL player and controls were identified in 8 of 11 regions with manual correction but in only 4 of 11 regions without such correction. Within NFL players, manually corrected brain volumes were significantly associated with 3 neurobehavioral factors, but a different set of 3 brain regions and neurobehavioral factor correlations was observed for brain region volumes segmented without manual correction.ConclusionsAutomated FreeSurfer segmentation of the corpus callosum, lateral ventricles, and amygdala-hippocampus complex may be appropriate for analysis without manual correction. However, FreeSurfer segmentation of the amygdala, hippocampus, and cingulate gyrus need further manual correction prior to performing group comparisons and correlations with neurobehavioral measures.

Longitudinal change in regional brain volumes with exposure to repetitive head impacts

“…However, we speculate that the statistical effects due to lack of manually editing those minor imperfections on brain regions utilized in this study should be minimal. 34 In addition, we have processed the longitudinal data with cross-sectional analysis in FreeSurfer. To minimize the effect of brain volume at different time points, this study utilized intracranial volume as a nuisance regressor.…”

MRI‐Based Manual versus Automated Corpus Callosum Volumetric Measurements in Multiple Sclerosis

“…A study by Guenette et al. showed that a previous version of FreeSurfer provided reliable corpus callosum measurements without the need for manual corrections . Due to this, we decided to omit any manual intervention in FreeSurfer's segmentation outputs, which also increases the generalizability of the results when no rater‐bias is introduced.…”

Increased Nucleus Accumbens Volume in College Binge Drinkers - Preliminary Evidence From Manually Segmented MRI Analysis

“…Automated methods can in part counter some of these limitations by, for example, reducing the rater's subjectivity and increasing segmentation accuracy, but they largely depend on the parcellation/segmentation packages selection and preprocessing steps applied (e.g., 44). In this sense, manual tracing has some advantages in relation to the automated segmentation procedures such as more rigorous control of inter-subject variability of the brain's size and shape, superior accuracy in volume's estimation, and increased segmentation precision, especially when the ROIs' anatomical boundaries are more difficult to determine as in the subcortical regions (37,44,45). However, despite its potential for detecting structural alterations in addictive behaviors including alcoholism (46)(47)(48) to the best of our knowledge no study so far has manually segmented the striatal nuclei in BDs.…”