This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Contrast Agents, Subject name: Radiology
All are features of a normal venous doppler except? 
Select and explain. 
A. Triphasic pattern, B. Flow Ceases with Valsalva, C. Flow Augmentation with Distal Compression, D. Compressibility
A: Triphasic pattern
Answer: A: Triphasic pattern 
Explanation: Normal Venous doppler is Monophasic with Respiratory and Cardiac Phasicity. High Resistance Peripheral Aeries show a Triphasic pattern.