Search PubMed⌕ Search
Home/Archive/PubMed

PubMed · 2488037

Image processing in digital radiography: basic concepts and applications.

G T Barnes·K Lauro
View original source ↗Export metadata ↓

Abstract

Digital x-ray images are routinely processed to enhance diagnostic information and to suppress irrelevant detail, and also to extract quantitative information. The basic concepts and terminology of image processing as it applies to x-ray projection radiography are discussed and defined. In general, the processing of an image involves one or more point, local, and/or global operations. Clinical examples of linear and nonlinear gray-scale and algebraic point operations are presented. Examples are also given of local operations. Included in the latter group are distortion corrections, misregistration corrections, linear filtering, and nonlinear filtering.

Explore related subjects

Angiography, Digital SubtractionColorFourier AnalysisHumansMathematicsModels, TheoreticalRadiographic Image EnhancementRadiography, Dual-Energy Scanned ProjectionSubtraction TechniqueTomography, X-Ray ComputedJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

G T Barnes, K Lauro. 1989. Image processing in digital radiography: basic concepts and applications.. https://doi.org/10.1007/bf03168032

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed1997

Common carotid artery bifurcation: preliminary results of CT angiography and color-coded duplex sonography compared with digital subtraction angiography.

OBJECTIVE: The purpose of this study was to compare the abilities of color-coded duplex sonography, CT angiography, and selective digital subtraction angiography to reveal disease requiring surgery in patients with occlusive disease of the carotid bifurcation. MATERIALS AND METHODS: Fifty-six carotid arteries in 28 patients who had 48 carotid stenoses and symptomatic cerebrovascular disease were prospectively studied by selective digital subtraction angiography, color-coded duplex sonography, and CT angiography. CT data were displayed in maximum intensity projection. The degree of stenoses revealed were graded as mild, moderate, severe, and occluded according to North American Symptomatic Carotid Endarterectomy Trial criteria. The results of CT angiography and color-coded duplex sonography were correlated with the gold standard of digital subtraction angiography. RESULTS: Grading of stenoses on CT angiography agreed with grading of stenoses on digital subtraction angiography in 89% of cases. All high-grade stenoses and occlusions revealed on CT angiography were correctly interpreted by all observers. For stenoses revealed by color-coded duplex sonography and digital subtraction angiography, observers' agreement was 75%. Two severe stenoses were incorrectly graded as occluded by the interpreter of the color-coded duplex sonograms. Also, one occluded carotid artery was misdiagnosed as moderate stenosis. CONCLUSION: Our results indicate that CT angiography is superior to color-coded duplex sonography for evaluating carotid disease and determining disease requiring surgery. CT angiography warrants further investigation in a larger group of patients.

Angiography, Digital Subtraction↗
PubMed1997

Long-term angiographic and histopathologic findings in experimental aneurysms of the carotid bifurcation embolized with platinum and tungsten coils.

PURPOSE: To evaluate the long-term outcome of endovascular occlusion of arterial aneurysms effected with metal coils. METHODS: Microsurgical methods were used to produce carotid bifurcation aneurysms in 20 rabbits and the radiologic and histologic changes were examined. Eight of these aneurysms were occluded with electrically detachable platinum coils (Guglielmi detachable coils [GDCs] and nine were treated with mechanically detachable tungsten coils (mechanical detachable system [MDS]). Three aneurysms remained untreated and served as controls. One animal died of embolic complications 12 hours after endovascular treatment. After observation periods of 3 to 6 months, the remaining animals were examined by intraarterial digital subtraction angiography and subsequent fixation and light and electron microscopy. RESULTS: Large open spaces without signs of thrombosis were found between the loops of the coil baskets in 12 aneurysms (six treated with GDCs and six treated with MDS) regardless of the observation period. In very densely packed aneurysms (four cases with complete occlusion as determined by angiographic criteria), the coil surfaces were for the most part covered by thin cell layers; however, complete endothelialization was never seen. In aneurysms with an initial partial occlusion of 70% to 90%, coil compaction and/or recanalization was a consistent finding. A comparison of the radiologic findings with the histologic aspect revealed that the degree of occlusion was often overrated on the radiographs (in eight of 17 cases). In general, the fibrous tissue reaction appeared to be slightly more pronounced in aneurysms occluded with tungsten coils. CONCLUSIONS: Platinum and tungsten coils were not always effective in causing endoluminal thrombosis leading to long-term occlusion by organized thrombus.

Angiography, Digital Subtraction↗