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L. Itti, L. Chang, T. Ernst, F. S. Mishkin, Improved 3D correction for partial volume effects in brain SPECT, Human Brain Mapping, Vol. 5, No. 5, pp. 379-388, 1997. [1998 impact factor: 4.738] (Cited by 21)
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.
Keywords: partial volume effects ; MRI ; SPECT ; brain atrophy ; image processing
Themes: Medical Image Processing
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