Automatic analysis of skull thickness, scalp-to-cortex distance and association with age and sex in cognitively normal elderly

Abstract

Transcranial brain stimulation has been a potential treatment for many brain diseases. The skull compartment exerts a strong influence on the delivery of stimulation, implying the need to accurately examine its geometry and alterations in the population. Here, we developed an open source efficient pipeline BrainCalculator based on BrainSuite Skullfinder for automatically computing the skull thickness map to locate the position of minimum thickness, scalp to cortex distance (SCD), and brain volume based on structural T1-weighted MRI 3T data. We examined the influence of age and sex cross-sectionally in 407 cognitively normal older adults (71.93±7.98 years, 60.2% female) from the ADNI on the minimum skull thickness, SCD and brain volume of the whole-head MR data. We demonstrated the compatibility of BrainCalculator with available preprocessing toolboxes, including FSL Brain Extraction Tool (BET) 2 and Statistical Parametric Mapping (SPM)12-based unified segmentation, and compared their performance. We found that the sphenoid bone and temporal bone were thinnest among the skull regions. There was no increase in minimum skull thickness at different regions with increasing age except in the female sphenoid bone. No sex difference in minimum skull thickness or SCD in different age groups was observed. Positive correlations between age and SCD in both males and females were observed, and the slope was higher in the temporal cortex SCD in females (0.307%/y) than in males (0.216%/y) but comparable in other regions. A negative correlation between age and whole brain volume computed based on brain surface in both males and females was observed, and the slope was slightly higher in females (-1.031%/y) than in males (-0.998%/y). In conclusion, we developed a pipeline for MR-based skull thickness and SCD brain volume analysis and demonstrated the sex-dependent association between minimum regional skull thickness, SCD and brain volume with age.

Simulation-based dosimetry of transcranial and intranasal photobiomodulation of the human brain: the roles of wavelength, power density and skin colour

“…Skin colour varies widely across each racial category and throughout different seasons, emphasizing the importance of precise measurements rather than relying on broad racial categorizations. Moreover, we did not include sex-related or age-related differences, such as that in cranial thickness [46], into our modeling consideration.…”

The Application of Forensic Imaging to Sex Estimation: Focus on Skull and Pelvic Structures

“…The application of this specific imaging technology is more common in cases involving living. The representative studies [52,53,55] on skulls regarding sex estimation were based on living individuals' MRI images. Another non-invasive and non-radiation imaging technique that utilizes the soft tissue characteristic and applies to living individuals' sex estimation is ultrasound [68].…”

“…Head MRI was performed on healthy living individuals to estimate sex by measuring the width, height, and depth of the maxillary sinus; the results showed that males had a statistically significant difference in both the volume and dimensions of their maxillary sinus compared to females and the left maxillary sinus volume had the highest percentage of sexual dimorphism in the studied population [53]. Skull thickness and scalp-to-cortical distance measurements on MRI images from the open-source Alzheimer's Disease Neuroimaging-Initiative [54] were studied to estimate sex, the results suggested male participants tended to have thicker skulls than female participants, albeit this difference was not statistically significant [55]. To the author's best knowledge, the application of the MRI imaging method to sex estimation based on pelvic structure has not been reported.…”