In a venous Doppler study, what is the term for abnormal flow patterns due to obstruction?

In a venous Doppler study, the term for abnormal flow patterns due to obstruction is referred to as "reversal flow." This term describes a situation where blood flow changes direction, indicating a pathological state, often resulting from a blockage or obstruction in the venous system.

Under normal circumstances, venous flow should be continuous and unidirectional towards the heart. However, in cases of obstruction, various compensatory mechanisms or increased venous pressure may cause significant changes, leading to reversal of flow. This reversal is critical in diagnosing venous insufficiency or identifying thrombus presence within the vessel.

Other options do not accurately describe the abnormal flow patterns caused by obstruction. The absence of flow indicates a complete stop, rather than a direction change. Continuous flow signifies normal unobstructed venous return. Intermittent flow suggests variations in flow that can occur under normal physiological conditions and does not specifically denote abnormality due to obstruction. Thus, reversal flow is the most accurate term for abnormal flow patterns caused by obstruction in a venous Doppler study.