DUPLEX SCANNING IN THE EVALUATION OF NON-CAROTID VASCULAR DISEASE.

High resolution duplex imaging (7. 5-10 MHz real time B-mode, coupled with a 3-5 MHz pulsed Doppler) has been proven to be sensitive and specific in grading degrees of stenosis at the common cartoid bifurcation. Duplex scanning can evaluate arterial venous dialysis fistulas (particularly Gortex shunts) with both imaging and flow analysis. Duplex systems can now measure the diameter of the graft and then convert frequency to velocity (cm. per second) when the angle of flow is known. Flow is then converted to ccs per minute. The internal jugular vein can be easily imaged and flow documented when neck masses are evaluated. Peripheral emboli in the upper extremities, particularly in the brachial, radial, ulnar arteries can be readily imaged and the degree of thrombosis documented.