What is the common appearance of the spectrum of a severely stenosed ICA?

The spectrum of a severely stenosed internal carotid artery (ICA) typically shows a specific appearance due to the presence of disturbance in blood flow caused by the narrowing of the vessel. When an ICA is severely stenosed, the waveform often presents with a filled-in systolic window, which indicates that the blood flow is turbulent and the velocity is significantly increased. In this case, the filling in of the systolic window shows a reduction in the normal diastolic flow pattern due to the obstruction, making it appear more continuous.

This characteristic matches the typical hemodynamic changes that occur in severe stenosis, where resistance increases and flow becomes more disturbed, leading to a lack of a clear spectral window that is commonly seen in normal flow or less stenotic arteries. Such a filled-in systolic window is a strong indicator of significant arterial narrowing and assists clinicians in diagnosing the severity of the stenosis.

Understanding this appearance is crucial for vascular specialists, as it aids in the assessment and management of patients with carotid artery disease, enhancing the overall interpretation of Doppler studies in clinical practice.