Document Detail


Dispersive Transport of Angiographic Contrast During Antegrade Arterial Injection.
MedLine Citation:
PMID:  23139732     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
PURPOSE: Angiography is commonly used during endovascular procedures to navigate catheters into a target artery and for evaluation of the arterial luminal geometry. X-ray attenuating contrast material is injected into the arteries and transported into pathologies such as aneurysms or arteriovenous malformations. Images of the transported contrast are used to guide therapeutic decisions. Experience and intuition of the interventionalist are often serving as guide for the injection force, and hence, the speed and volume of the bolus. Forceful injections of small boluses can evoke local turbulence and dispersive mixing in the zone immediately distal to the catheter tip. Turbulence by its nature acts as a strong agitating mechanism such that the bolus of contrast quickly mixes with the flowing blood to occupy the entire lumen so the artery can be visualized. The aims of the present study are (a) to determine the distance from catheter tip beyond which contrast can consider to be fully mixed with the blood during antegrade injection and (b) to determine the thickness of the boundary layer in which contrast concentration is poor, which can contribute to underestimation of vascular diameter using this method. METHODS: We performed in silico experiments to describe blood and angiographic contrast transport in a straight artery model. The conditions investigated are derived from clinical contrast injection rates typically found in cerebral angiography. RESULTS: A recirculation flow exists in the mixing zone distal to the catheter tip issuing the contrast and convective mixing rather than diffusion is dominating the rapid mixing process. In the vicinity of the arterial wall in the mass transfer boundary layer, however, transport is dominated by molecular diffusion. For lower molecule diffusion coefficient, the mass transfer boundary layer contains a lower concentration of contrast than for a higher molecular diffusion coefficient. CONCLUSIONS: These findings imply that contrast visibility near the arterial wall is poor such that arterial dimensions derived from angiograms may be underestimated and consequently sizing of potential implants inaccurate. Outside the mass transfer boundary layer contrast can be considered as fully mixed with the carrying flow in about 10 arterial diameters distal to the injection port.
Authors:
Qing Hao; Baruch B Lieber
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-4-13
Journal Detail:
Title:  Cardiovascular engineering and technology     Volume:  3     ISSN:  1869-4098     ISO Abbreviation:  Cardiovasc Eng Technol     Publication Date:  2012 Jun 
Date Detail:
Created Date:  2012-11-9     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101531846     Medline TA:  Cardiovasc Eng Technol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  171-178     Citation Subset:  -    
Affiliation:
Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI.
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