@article{Itti_etal97hbm2,
  author = {L. Itti and L. Chang and T. Ernst and F. S. Mishkin},
  title = {Improved 3D correction for partial volume effects in brain SPECT},
  journal = {Human Brain Mapping},
  volume = {5},
  number = {5},
  pages = {379-388},
  year = {1997},
  keywords = {partial volume effects ; MRI ; SPECT ; brain atrophy ; image processing},
  abstract = {An improved method for correction of partial volume effects (PVE) in brain SPECT is proposed. It is fully three-dimensional, does not require particular patient positioning, and works with scans only partially covering the brain. The location of functionally inactive brain regions (primarily cerebrospinal fluid) is extracted from high-resolution MRI. An automatic 3D registration algorithm then determines the geometric transformation between MRI and SPECT. Correction consists of: 1) counting the volumetric active/inactive ratio in each volume element of the functional scan using the measured SPECT point spread function; 2) correcting the functional measures according to these ratios; 3) fusing functional and anatomical information at the resolution of MRI. Quantitative validation was performed using a phantom containing a test region in which multiple parallel acrylic plates thinner than SPECT resolution created high PVE, as well. as a large reference region not suffering from PVE. Reference activity was recovered in the test region with an accuracy of 1-3 percent. The method was applied to clinical images demonstrating a combination of hypoperfusion and cortical atrophy. The composite anatomical-functional corrected images, in which the main sulci are visible, yield better differentiation between decreased function and focal atrophy.},
  file = {http://iLab.usc.edu/publications/doc/Itti_etal97hbm2.pdf},
  type = {mip},
  if = {1998 impact factor: 4.738}
}