MRI / PET nonrigid breast-image registration using skin fiducial markers
Date
2006Author
Krol, Andrzej
Unlu, Mehmet
Baum, Karl
Mandel, James
Lee, Wei
Coman, Ioana
Lipson, Edward
Feiglin, David
Metadata
Show full item recordAbstract
We propose a finite-element method (FEM) deformable breast model that does not require elastic breast data for nonrigid PET/
MRI breast image registration. The model is applicable only if the stress conditions in the imaged breast are virtually the same
in PET and MRI. Under these conditions, the observed intermodality displacements are solely due the imaging/reconstruction
process. Similar stress conditions are assured by use of an MRI breast-antenna replica for breast support during PET, and use
of the same positioning. The tetrahedral volume and triangular surface elements are used to construct the FEM mesh from the
MRI image. Our model requires a number of fiducial skin markers (FSM) visible in PET and MRI. The displacement vectors of
FSMs are measured followed by the dense displacement field estimation by first distributing the displacement vectors linearly
over the breast surface and then distributing them throughout the volume. Finally, the floating MRI image is warped to a fixed
PET image, by using an appropriate shape function in the interpolation from mesh nodes to voxels. We tested our model on
an elastk breast phantom with simulated internal lesions and on a small number of patients imaged with FSM using PET and
MRI. Using simulated lesions (in phantom) and real lesions (in patients) visible in both PET and MRI, we established that the
target registration error (TRE) is below two pet voxels.