Deformation field morphometry
Deformation field morphometry: Quantification of structural differences
Deformation field morphometry is a technique which is used to capture and measure structural differences between individual brains. This technique is based on the analysis of images of the human brain, which were acquired by magnetic resonance tomography (MRT). Deformation fields are calculated by means of image registration procedures. They encode local differences in volume and shape of single brains.
This technique is used in order to identify structural characteristics of the brain which e.g. are related with neurological or psychiatric diseases in patients’ brains, or which occur during normal aging.
Deformation field morphometry can be used for cross-sectional studies (= comparisons of different groups at one time point), as well as for longitudinal studies (= examination of individual temporal course). Longitudinal studies enable to visualize e.g. progredient atrophy in the brains of patients which suffer from certain neurodegenerative diseases. To this end MRT images are acquired serially from the brain of each patient with intervals of several months. Then the follow-up images are registered with the initial image in order to detect the atrophic changes which emerged between the time points.
Example: Local volume changes occuring in corticol-basal degeneration after 16 (left) and 20 (right) months.
The colour coding indicates the length of the vectors of a deformation field (red means a length of 2 mm).
Local changes of brain volume, which were calculated based on the deformation fields shown above. The progredient volume loss of brain tissue is marked in red to yellow colour shades (red=5 %, yellow ≥ 20 %).