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ULTIMO FASCICOLOINTERNATIONAL ANGIOLOGY

Rivista di Angiologia

Official Journal of the International Union of Angiology, the International Union of Phlebology and the Central European Vascular Forum
Indexed/Abstracted in: BIOSIS Previews, Current Contents/Clinical Medicine, EMBASE, PubMed/MEDLINE, Science Citation Index Expanded (SciSearch), Scopus
Impact Factor 0,899

Periodicità: Bimestrale

ISSN 0392-9590

Online ISSN 1827-1839

 

International Angiology 2004 Settembre;23(3):276-83

 TECHNICAL NOTES

Non spiral and spiral (helical) flow patterns in stenoses. In vitro observations using spin and gradient echo magnetic resonance imaging (MRI) and computable fluid dynamic modeling

Stonebridge P. A. 1, Buckley C. 2, Thompson A. 3, Dick J. 4, Hunter G. 5, Chudek J. A. 5, Houston J. G. 3, Belch J. J. F. 4

1 Depart­ment of Sur­gery, The Insti­tute of Car­di­o­vas­cu­lar ­Research, Nine­wells Hos­pi­tal and Med­i­cal ­School, Dund­ee, Scot­land, UK
2 Mag­net­ic Res­o­nance ­Research Cen­tre, Depart­ment of Chem­i­cal Engi­neer­ing, Uni­ver­sity of Cam­bridge, Cam­bridge, UK
3 Depart­ment of Radiol­o­gy, The Insti­tute of Car­di­o­vas­cu­lar ­Research, Nine­wells Hos­pi­tal and Med­i­cal ­School, Dund­ee, Scot­land, UK
4 Depart­ment of Vas­cu­lar Med­i­cine, The Insti­tute of Car­di­o­vas­cu­lar ­Research, Nine­wells Hos­pi­tal and Med­i­cal ­School, Dund­ee, Scot­land, UK
5 Depart­ment of Chem­is­try, Dund­ee Uni­ver­sity, Dund­ee, Scot­land, UK

Aim. Phys­io­log­i­cal blood flow pat­terns are them­selves poor­ly under­stood ­despite their ­impact on arte­ri­al dis­ease. ­Stable spi­ral (hel­i­cal) lam­i­nar flow (SLF) has been ­observed in nor­mal sub­jects. The pur­pose of the ­present study is to devel­op a meth­od of mag­net­ic res­o­nance (MR) flow pat­tern vis­u­al­iza­tion and to ana­lyze spi­ral and non-spi­ral flow pat­terns with and with­out lumi­nal nar­row­ing in vitro. The flow con­di­tions were then mod­eled using com­pu­ta­tion­al fluid dynam­ics (Star-CD).
Meth­ods. Lam­i­nar integ­rity was exam­ined in a flow-rig using spin and gra­di­ent echo mag­net­ic res­o­nance imag­ing (MRI) in non-ste­nosed and ste­nosed con­duits in the pres­ence of non-spi­ral and spi­ral flow.
­Results. No dif­fer­ence was ­observed in a non-ste­nosed con­duit ­between non-spi­ral and spi­ral flow. In the pres­ence of a sten­o­sis spi­ral flow pre­serves flow veloc­ity coher­ence where­as non-spi­ral flow increas­ing­ly lost coher­ence begin­ning prox­i­mal to the sten­o­sis. Com­pu­ta­tion­al fluid dynam­ic mod­el­ing of the in vitro experi­ment ­showed ­marked dif­fer­enc­es ­between the 2 flow pat­terns. Non-spi­ral flow pro­duced great­er inward­ly direct­ed forc­es just ­beyond the sten­o­sis and great­er out­ward pres­sures at more dis­tal sites. The near wall tur­bu­lent ener­gy was up to 700% less with spi­ral flow over non-spi­ral flow ­beyond the sten­o­sis.
Con­clu­sion. Spi­ral flow ­appears to offer clear flow pro­file sta­bi­liz­ing advan­tag­es over non-spi­ral flow, by sig­nif­i­cant­ly reduc­ing the tur­bu­lence ­caused by a sten­o­sis. Spi­ral flow also pro­duc­es lower forc­es act­ing on the ves­sel wall.

lingua: Inglese


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