Calculate Ica Cca Ratio

ICA/CCA Velocity Ratio Calculator

Enter the Peak Systolic Velocity of the Internal Carotid Artery.
Enter the Peak Systolic Velocity of the Common Carotid Artery.

Calculated Ratio:

Understanding the ICA/CCA Ratio

The ICA/CCA ratio is a critical metric used in medical sonography, specifically during Carotid Doppler ultrasounds. It evaluates the severity of carotid artery stenosis (narrowing). This ratio is calculated by dividing the Peak Systolic Velocity (PSV) of the Internal Carotid Artery (ICA) by the PSV of the Common Carotid Artery (CCA).

The Formula

Ratio = ICA PSV / CCA PSV

Standard Interpretation Guidelines

While specific laboratory standards may vary, the general consensus for interpreting the ICA/CCA ratio is as follows:

  • Normal: Ratio < 2.0 (and ICA PSV < 125 cm/s)
  • < 50% Stenosis: Ratio < 2.0 (and ICA PSV < 125 cm/s)
  • 50% to 69% Stenosis: Ratio between 2.0 and 4.0
  • ≥ 70% Stenosis (to near occlusion): Ratio > 4.0 (and ICA PSV > 230 cm/s)

Why is this ratio used?

The ratio is used alongside absolute velocity measurements because it helps account for physiological variations. Factors like cardiac output, blood pressure, or contralateral disease can affect absolute velocities. Using the ratio provides a more standardized assessment of the degree of narrowing relative to the patient's baseline flow in the common carotid artery.

Disclaimer: This tool is for educational purposes only. Medical decisions should be based on comprehensive clinical evaluation and interpreted by qualified healthcare professionals.

function calculateIcaCcaRatio() { var ica = parseFloat(document.getElementById('ica_psv').value); var cca = parseFloat(document.getElementById('cca_psv').value); var resultDiv = document.getElementById('ratioResult'); var finalVal = document.getElementById('finalRatioValue'); var interpretation = document.getElementById('ratioInterpretation'); if (isNaN(ica) || isNaN(cca) || cca <= 0) { alert('Please enter valid positive numbers for both velocities.'); return; } var ratio = ica / cca; var roundedRatio = ratio.toFixed(2); finalVal.innerText = roundedRatio; resultDiv.style.display = 'block'; if (ratio < 2.0) { resultDiv.style.backgroundColor = '#d4edda'; resultDiv.style.color = '#155724'; interpretation.innerText = 'Ratio < 2.0: Typically associated with = 2.0 && ratio 4.0: Typically associated with ≥ 70% stenosis.'; } }

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