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ASI Formula:
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The Ascending Aorta Index (ASI) is a normalized measurement of aortic diameter relative to body surface area. It provides a more accurate assessment of aortic size by accounting for patient body size, making it particularly useful for evaluating aortic dimensions in individuals of different sizes.
The calculator uses the ASI formula:
Where:
Explanation: The index normalizes aortic diameter to body size, allowing for better comparison across patients of different sizes and more accurate assessment of aortic dilation.
Details: ASI is crucial for diagnosing aortic dilation, monitoring progression of aortic diseases, assessing surgical timing, and managing patients with connective tissue disorders or genetic syndromes affecting the aorta.
Tips: Enter aortic diameter in centimeters and body surface area in square meters. Both values must be positive numbers. BSA can be calculated using various formulas (Mosteller, Du Bois, etc.) based on height and weight.
Q1: What is a normal ASI value?
A: Normal ASI values typically range from 1.3-2.1 cm/m². Values above 2.1 cm/m² may indicate aortic dilation, but interpretation should consider clinical context.
Q2: Why use ASI instead of absolute aortic diameter?
A: ASI accounts for body size, providing a more accurate assessment of aortic dimensions, especially in smaller or larger individuals where absolute measurements may be misleading.
Q3: How is BSA calculated?
A: BSA is commonly calculated using formulas like Mosteller (√[height(cm)×weight(kg)/3600]) or Du Bois (0.007184×height(cm)^0.725×weight(kg)^0.425).
Q4: When is ASI particularly useful?
A: ASI is especially valuable in pediatric patients, athletes, obese individuals, and patients with Marfan syndrome or other connective tissue disorders.
Q5: What are the limitations of ASI?
A: ASI may not account for all body composition variations and should be interpreted alongside clinical findings and other imaging parameters.