ARDMS (American Registry for Diagnostic Medical Sonography) Practice Test

In vascular ultrasound, what does "triphasic" waveform indicate?

1. Abnormal arterial blood flow

2. Normal arterial blood flow

3. Decreased blood circulation

4. Vein thrombosis

The correct answer is: Normal arterial blood flow

A triphasic waveform in vascular ultrasound is indicative of normal arterial blood flow. This type of waveform exhibits three distinct phases during a single cardiac cycle, which reflects the normal pulsatile flow of blood in healthy arteries. The presence of a triphasic waveform suggests that there is adequate arterial compliance and that the peripheral resistance is functioning correctly, which is essential for maintaining optimal blood circulation. In contrast, abnormalities in the waveform, such as becoming biphasic or monophasic, signal changes in the vascular condition, possibly indicating conditions like stenosis, occlusion, or other forms of arterial compromise. This differentiates it significantly from the answers related to decreased blood circulation or vein thrombosis, which typically do not present with a triphasic pattern. Instead, those conditions may exhibit altered waveforms due to impaired blood flow dynamics or unsatisfactory venous return. Therefore, the presence of the triphasic waveform serves as a reliable marker for assessing the health of arterial flow and vascular function.