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Updated: Jun 26, 2026

How to Measure Cortical Folding from MR Images: a Step-by-Step Tutorial to Compute Local Gyrification Index
Published on: January 2, 2012
[Relationship between the gray level of X-ray photograph and the cortical thickness]
Hong-gang Zhong1, Hai-bin Bu, Fu-hui Dong
1College of Life Science & Bioengineering, Beijing University of Technology, Beijing 100022, China.
Objective:
In order to get three dimensional measurements simply an plain X-ray photographs.
Methods:
The multi-layers of bone pieces were made by use of bone saw, and piled up to spiral ladder, which was used as a calibrating module for to living bone in clinics. The relationship between the cortical thickness and gray level of the X-ray photographs was obtained.
Results:
The correlation can be described with a cubic regression curve, and it can be simplified to a linear regression equation when cortical thickness is small than 3.8 mm.
Conclusion:
It can be realized to get three dimensional measures of the bone on plain X-ray photographs, by use of the bony spiral ladder described here.
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