Jianchun He | PubMed Health

PubMed2003

Large deformation inverse consistent elastic image registration.

This paper presents a new image registration algorithm that accommodates locally large nonlinear deformations. The algorithm concurrently estimates the forward and reverse transformations between a pair of images while minimizing the inverse consistency error between the transformations. It assumes that the two images to be registered contain topologically similar objects and were collected using the same imaging modality. The large deformation transformation from one image to the other is accommodated by concatenating a sequence of small deformation transformations. Each incremental transformation is regularized using a linear elastic continuum mechanical model. Results of ten 2D and twelve 3D MR image registration experiments are presented that tested the algorithm's performance on real brain shapes. For these experiments, the inverse consistency error was reduced on average by 50 times in 2D and 30 times in 3D compared to the viscous fluid registration algorithm.

Algorithms↗

PubMed2003

Automatic measurement of the labyrinth using image registration and a deformable inner ear atlas.

RATIONALE AND OBJECTIVES: This article presents a new method for measuring the shape of the cochlea, vestibule, semi-circular canals, and internal auditory canal using image registration and a deformable inner ear atlas. MATERIALS AND METHODS: Computed tomography images of the inner ear are analyzed by placing them into a common orientation and then registering a digital atlas of the inner ear to the data set. The atlas is deformed from its original shape to match the shape of the inner ear in the computed tomography data set using inverse consistent elastic image registration. This process produces an individualized inner ear atlas containing subject-specific measurements and segmentations of the inner ear anatomy in the target computed tomography data set. The shape measurements include the volume and length of the cochlea, vestibule, semi-circular canals, and internal auditory canal; and the angles between the semi-circular canals. RESULTS: A simulated population of inner ear shapes were generated based on the shape of a real population of inner ear shapes and were used to characterize the measurement error of this method. The deformable atlas was used to measure the shape of the left and right inner ear of six individuals. CONCLUSION: Measurement error for 15 of the 24 measurements of our simulated population had an average error of less than 1% and only one measurement had an average error greater than 2.54%. The deformable human inner ear atlas shows promise as a new method for automatically measuring the shape of the labyrinth.

Adult↗