1. What is ICA/CCA PSV Ratio?

The ICA/CCA PSV (Internal Carotid Artery/Common Carotid Artery Peak Systolic Velocity) Ratio is a dimensionless value used in carotid ultrasound to assess the degree of stenosis in the internal carotid artery.

2. How Does the Calculator Work?

The calculator uses the simple formula:

Where:

• ICA PSV — Peak systolic velocity in the internal carotid artery (cm/s)
• CCA PSV — Peak systolic velocity in the common carotid artery (cm/s)

Explanation: The ratio compares the blood flow velocity in the narrowed internal carotid artery to the normal common carotid artery.

3. Importance of ICA/CCA Ratio

Details: This ratio helps in grading carotid stenosis and is particularly useful when absolute velocity measurements might be affected by systemic factors like cardiac output.

4. Using the Calculator

Tips: Enter both ICA PSV and CCA PSV values in cm/s. The calculator will automatically compute the ratio. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a normal ICA/CCA PSV ratio?
A: Normally, the ratio is less than 1.5. Ratios above 2.0 suggest significant stenosis (>50%).

Q2: When is this ratio particularly useful?
A: It's especially helpful in cases with low cardiac output where absolute velocities might be misleading.

Q3: How should measurements be taken?
A: PSV should be measured at the point of maximum stenosis for ICA and in the mid-CCA segment.

Q4: Are there limitations to this ratio?
A: The ratio may be less reliable with very tortuous vessels or when there's CCA disease.

Q5: How does this compare to NASCET criteria?
A: The ratio complements NASCET criteria and can help confirm degree of stenosis when used with other parameters.