Factor | Relation to or effect on colour jet size | |
---|---|---|
LA, left atrium, LV, left ventricle. | ||
Direct, jet size increases as factor increases; Inverse, jet size decreases as factor increases. | ||
Effects on measured or displayed flow velocities | ||
Haemodynamic effects | LA compliance | Direct |
LA pressure | Inverse | |
LV systolic function | Direct | |
LV pressure | Direct | |
Instrument settings | Colour gain | Direct |
Wall filter | Inverse | |
Transducer frequency | Direct | |
Pulse repetition frequency | Inverse | |
Other factors affecting colour jet size | ||
Transducer position | Relative to direction of flow | Doppler angle effects |
Inadequate alignment to jet | Underestimation of true jet size | |
Jet eccentricity | Coanda effect (see text) | Reduced jet dimensions |