A nonrigid registration of MR breast images using complex-valued wavelet transform.
In this paper, a fast, slice-by-slice, nonrigid registration algorithm of dynamic magnetic resonance breast images is presented. The method is based on a multiresolution motion estimation of the breast using complex discrete wavelet transform (CDWT): the pyramid of oriented complex subimages is used to implement a hierarchical phase-matching-based motion estimation algorithm. The resulting motion estimate is nonrigid and pixel-independent. To assess the method performance, we computed the correlation coefficient and the normalized mutual information between pre- and postcontrast images with and without realignment. The indices increased after using our approach and the improvement was superior to rigid or affine registration. A set of clinical scores was also evaluated. The clinical validation demonstrated an increased readability in the subtraction images. In particular, CDWT registration allowed a best definition of breast and lesion borders and greater detail detectability.
Mainardi
L
L
Department of Biomedical Engineering, Polytechnic University of Milan, Piazza Leonardo da Vinci 32, 20133, Milan, Italy. luca.mainardi@biomed.polimi.it
Passera
K M
KM
Lucesoli
A
A
Vergnaghi
D
D
Trecate
G
G
Setti
E
E
Musumeci
R
R
Cerutti
S
S
D000465:Algorithms; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging; D003287:Contrast Media; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D011859:Radiography
D003287:Contrast Media