1. What is a CCA ICA Ratio Calculator?

Definition: This calculator determines the carotid artery stenosis ratio by comparing peak systolic velocities in the internal carotid artery (ICA) and common carotid artery (CCA).

Purpose: It helps vascular specialists assess the severity of carotid artery stenosis, which is crucial for stroke risk evaluation.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Ratio \) — Stenosis ratio (unitless)
• \( PSV_{ICA} \) — Peak systolic velocity in internal carotid artery (cm/s)
• \( PSV_{CCA} \) — Peak systolic velocity in common carotid artery (cm/s)

Explanation: The ratio compares blood flow velocities to identify potential narrowing in the carotid arteries.

3. Clinical Significance

Details: Higher ratios indicate more severe stenosis. Common interpretation thresholds:

• Ratio < 2.0: Normal or <50% stenosis
• Ratio 2.0-4.0: 50-69% stenosis
• Ratio > 4.0: ≥70% stenosis

4. Using the Calculator

Tips: Enter PSV measurements obtained from Doppler ultrasound. Both values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a normal CCA ICA ratio?
A: Typically less than 2.0, indicating no significant stenosis.

Q2: How accurate is this ratio for stenosis assessment?
A: While useful, it should be combined with other criteria (ICA PSV, EDV, visual assessment) for complete evaluation.

Q3: What affects PSV measurements?
A: Technical factors (angle correction), patient factors (cardiac output, contralateral disease), and equipment settings.

Q4: When is this ratio most useful?
A: Particularly helpful when absolute PSV values are borderline or affected by systemic factors.

Q5: Are there limitations to this method?
A: Yes, it may be less reliable with very high or low CCA velocities, or with tandem lesions.