От медицинския речник
Hyperechoic: 1. In ultrasonography, pertaining to material that produces echoes of higher amplitude or density than the surrounding medium. 2. Denoting a region in an ultrasound image in which the echoes are stronger than normal or than surrounding structures.

There is an abruptive missing of color flow and spectral duppler signals along the middle and distal part of the superficial femoral artery and hypo to anechoic material within the occluded artery with a rised hyperechoic atherosclerotic plaque just befor the occlution.
http://radiopaedia.org/cases/acute-arterial-occlusion

За nonstenotic в Гугъл могат да се намерят прекалено много примери, за да ги цитирам тук.

аа - артерии (в мн.число), напр. aa. tibiales anteriores


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Note added at 3 hrs (2014-07-04 08:01:01 GMT)
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ЕДС-каротидни аа = екстракраниална Доплерова сонография на каротидните артерии
Extracranial Doppler sonography of the carotid arteries