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Abstract:
Abstract: This project was designed to determine the
reproducibility of brain SPECT-MR volume co-registration using a
semi-automated computer program developed by Picker International.
SPECT images were acquired using a triple-headed Picker 3000 gamma
camera with a 20-minute acquisition starting 10 minutes after
intravenous injections of 99mTc-HMPAO. Image reconstruction used
simultaneous transmission-emission protocol. MR images were
obtained with a Picker Edge 1.5 tesla MR scanner. SPECT and MR
images for six subjects were volume co-registered on six separate
occasions using a semi-automated Picker program and workstation by
three operators. The co- registration program initially brings an
individual's SPECT and MR images to the screen in the same relative
position each time, with pre-registration values of '0' assigned to
three axes and three angles. These coordinate values are derived
from image pixel addresses assigned during acquisition. As the
structural and functional images are manipulated simultaneously in
transverse, coronal, and sagittal views, the registration
coordinates change accordingly and are expressed in millimeters and
degrees. Post-registration coordinate and angle values were
compared across operators, registrations, subjects, axes, and
angles to determine the degree of variability inherent in the
co-registration process. The results were highly reproducible, with
spatial variations smaller than the 3.56 mm thickness of a SPECT
slice.
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