Which statement is NOT true regarding carotid bruit?

The statement regarding the absence of carotid bruit ruling out significant stenosis is not true because a carotid bruit is not always present in patients with significant stenosis. The presence of a bruit suggests some degree of turbulence in blood flow likely due to stenosis, but its absence does not mean there is no significant narrowing. In fact, significant stenosis can occur without producing an audible bruit in certain cases, particularly if the stenosis is in the distal segments of the internal carotid artery or if collateral circulation compensates for the narrowed area. Therefore, the presence or absence of a carotid bruit should be interpreted in conjunction with other diagnostic findings rather than as a definitive indicator of the degree of stenosis.

To add context for clarity, the presence of a bruit might indicate severe stenosis, but it is not a foolproof measure since many patients with significant carotid artery disease may lack an audible bruit. Similarly, while cervical bruits can arise from external carotid artery (ECA) stenosis, it is important to evaluate the hemodynamics in conjunction with imaging studies. Lastly, a bruit that extends into diastole is typically associated with more severe stenosis, suggesting that the turbulence in blood flow is significant throughout the cardiac cycle.