Switch to
| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
5
|
| pubmed:dateCreated |
1991-5-1
|
| pubmed:abstractText |
Previously described Doppler color flow mapping methods for estimating the severity of valvular regurgitation have focused on the distal jet. In this study, a newer Doppler color flow technique, focusing on the flow proximal to an orifice, was used. This method identifies a proximal isovelocity surface area (PISA) by displaying an aliasing interface. Volume flow rate (cm3/s) can be calculated as PISA (cm2) x aliasing velocity (cm/s). For planar circular orifices, a hemi-elliptic model accurately approximated the shape of PISA. Clinically, however, orifice shapes may be noncircular. In vitro flow experiments (n = 226) using orifices of various shapes (ellipse, square, triangle, star, rectangle) were performed. Volume flow rate calculated using a hemi-elliptic model for PISA was accurate, with average percent differences from actual flow rate = +4.3% for a square, -4.2% for a triangle, -4.7% for a star, -4.5% for an ellipse and -2.8% for a rectangle. However, average percent differences for calculated volume flow rates using a hemispheric model for PISA shape ranged from -11.6% (square) to -34.8% (rectangle). In addition, to evaluate whether PISA is influenced by machine factors, in vitro studies (n = 83) were performed.(ABSTRACT TRUNCATED AT 250 WORDS)
|
| pubmed:commentsCorrections | |
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
AIM
|
| pubmed:status |
MEDLINE
|
| pubmed:month |
Apr
|
| pubmed:issn |
0735-1097
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
17
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
1103-11
|
| pubmed:dateRevised |
2007-11-15
|
| pubmed:meshHeading | |
| pubmed:year |
1991
|
| pubmed:articleTitle |
Doppler color flow "proximal isovelocity surface area" method for estimating volume flow rate: effects of orifice shape and machine factors.
|
| pubmed:affiliation |
Department of Medicine, University of California, Irvine.
|
| pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
|