BORDER DETECTION METHOD AND SYSTEM

Vessel border detection is provided. A top border or border closer to a transducer of a vessel is detected using Doppler data. Since little flowing fluid is provided between the top border of the vessel and the transducer, reverberation artifacts are minimized. A bottom border or border of the vessel farther from the transducer is detected from B-mode data. Since few tissue layers are provided immediately adjacent the bottom border between the bottom border and the transducer, reverberation artifacts are minimized. The detected borders are used for further calculation or display, such as automatically estimating vessel diameter for endothelial function assessment. In alternate embodiments, different techniques for identifying fluid or tissue data are used, such as magnetic resonance imaging, CAT scan, x-ray or other techniques for imaging interior portions of a patient. Borders for other fluid regions in a patient may be detected, such as a heart border or other organ borders.