Document Detail

Nonlinear partial volume artifacts in x-ray computed tomography.
MedLine Citation:
PMID:  7393149     Owner:  NLM     Status:  MEDLINE    
Dark streaks connecting the petrous bones are often observed in cranial transverse section CT reconstructions. These artifacts are usually only slightly diminished by two-pass beam hardening corrections. However, it is found that by narrowing the slice thickness the artifacts are substantially reduced. In this paper, it is shown that axial partial volume effects can account for the presence of the artifacts. These axial partial volume effects occur when, at any point in the slice, the object has axial variations in attenuation. In such cases the logarithm of the integrated intensity measured by the detector is not a linear function of the integrated attenuation (even for monochromatic beams). This nonlinearity causes inconsistencies in the data set which in turn can cause streaks in the image. We have studied the partial volume effect using computer simulation. Algorithms are presented whose purpose is to correct for these effects by estimating the axial variation using neighboring slices. These correction algorithms are successful in computer simulation cases but failed with clinical data. It is concluded that no practical correction method is viable unless overlap scanning is employed. However, thin-slice scanning for sections where these artifacts are common is perhaps a more preferable solution.
G H Glover; N J Pelc
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Medical physics     Volume:  7     ISSN:  0094-2405     ISO Abbreviation:  Med Phys     Publication Date:    1980 May-Jun
Date Detail:
Created Date:  1980-09-23     Completed Date:  1980-09-23     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  0425746     Medline TA:  Med Phys     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  238-48     Citation Subset:  IM    
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MeSH Terms
Brain / radiography*
Petrous Bone / radiography
Radiographic Image Enhancement
Scattering, Radiation
Tomography, X-Ray Computed / methods*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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