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ICA/CCA Ratio Formula:
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The ICA/CCA (Internal Carotid Artery/Common Carotid Artery) ratio is a measurement used in vascular ultrasound to assess carotid artery stenosis. It compares the peak systolic velocity in the internal carotid artery to that in the common carotid artery.
The calculator uses the ICA/CCA ratio formula:
Where:
Explanation: This ratio helps in grading carotid stenosis, with higher ratios typically indicating more severe narrowing of the internal carotid artery.
Details: The ICA/CCA ratio is an important parameter in carotid duplex ultrasound for evaluating and monitoring carotid artery disease, which is a major risk factor for stroke.
Tips: Enter PSV values in cm/s for both ICA and CCA. Ensure measurements are taken correctly during Doppler ultrasound examination.
Q1: What is a normal ICA/CCA ratio?
A: A normal ICA/CCA ratio is typically less than 1.5. Ratios above this may indicate varying degrees of carotid stenosis.
Q2: How does the ICA/CCA ratio help in stenosis grading?
A: Higher ratios generally correlate with more severe stenosis. Specific cutoff values may vary between institutions but typically: 1.5-2.0 suggests 50-69% stenosis, 2.0-4.0 suggests 70-79% stenosis, and >4.0 suggests 80% or greater stenosis.
Q3: Are there limitations to using the ICA/CCA ratio?
A: Yes, the ratio should be interpreted in conjunction with other Doppler parameters and clinical context. It may be less reliable in certain conditions like contralateral high-grade stenosis or tandem lesions.
Q4: Why is this specifically for Malaysia?
A: While the ICA/CCA ratio is used globally, this calculator may incorporate measurement standards or reference values commonly used in Malaysian clinical practice.
Q5: Can this calculator be used for treatment decisions?
A: This calculator provides a ratio value but should not be used alone for clinical decisions. Always consult with a vascular specialist for proper diagnosis and treatment planning.