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PubMedDate not supplied

Image filtering in single-photon emission computed tomography: principles and applications.

Among the factors contributing to optimal image quality in single-photon emission computed tomography (SPECT), image filtering is an important, though mostly subjectively applied, image-processing parameter. We have aimed at giving an overview of current available SPECT filtering options. Current SPECT applications are discussed and practical guidelines to choose optimal filter parameters for a given situation are provided. It is shown that Hann and Butterworth filters allow accurate approximations to most filter types. The authors support the use of limited filter types in an attempt to standardise image-processing approaches, which may lead to better diagnostic compatibility and interpretation of interdepartmental results.

Bone and Bones↗

PubMedDate not supplied

Regional brain perfusion in 10 normal dogs measured using Technetium-99m ethyl cysteinate dimer spect.

Single photon emission computed tomography (SPECT) of the brain using perfusion tracers allows estimation of regional brain perfusion. This allows in vivo examination of brain function in the setting of neuropsychologic and pathophysiologic changes. However functional imaging data on brain perfusion in dogs are limited. Hence, the aim of this study was to determine the scintigraphic regional perfusion pattern of the normal canine brain. Ten healthy shepherd type dogs were injected with 925 MBq Technetium-99m ethyl cysteinate (ECD) 20 minutes before the examination. Acquisition was performed using a triple head gamma camera equipped with fanbeam collimators. Uniform attenuation correction and triple energy window correction were applied. Computed tomographic images were obtained from the same dogs, reoriented along the orbito-meatal axis and SPECT perfusion data were coregistered to the CT-volume data. Based on morphological and suggested brain divisions, regions-of-interest (ROIs) were defined for the bilateral frontocerebral, temporocerebral, parietocerebral, occipitocerebral, cerebellar, thalamic, and striatal area. Regional count density was normalized on total counts. All dogs had the highest uptake in the thalamic/striatal area compared to a rather homogeneous cerebral uptake. No significant left/right count differences were found, but a rostro-caudal gradient (+12-13%) was present. In this group, age and gender did not influence the perfusion pattern.

Animals↗