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Left ventricular volume calculation using a count-based ratio method applied to first-pass radionuclide angiography
R A Gal1, R P Grenier, S C Port
1Cardiovascular Disease Section, University of Wisconsin Medical School, Milwaukee.
Insights
A new method simplifies left ventricular volume calculation using first-pass radionuclide angiography without blood samples or distance measurements. This approach offers accurate and clinically applicable results for assessing cardiac function.
Area of Science:
- Nuclear Cardiology
- Medical Imaging Analysis
- Cardiovascular Physiology
Background:
- Traditional radionuclide methods for left ventricular volume calculation require peripheral blood samples and ventricle-to-collimator distance measurements.
- These requirements can be invasive and add complexity to the first-pass radionuclide angiography procedure.
Purpose of the Study:
- To develop and validate a novel, simplified method for calculating left ventricular volume.
- To assess the applicability of this method in first-pass radionuclide angiography, eliminating the need for blood samples and distance measurements.
Main Methods:
- A new equation was developed using pixel area, total left ventricular counts, and maximum pixel count.
- The method was applied to resting first-pass radionuclide angiography data from 50 patients.
- Calculated volumes were compared against contrast ventriculography measurements.
Main Results:
- High correlation coefficients (r ranging 0.93-0.98) were observed for end-diastolic and end-systolic volumes.
- Standard errors of estimate were 23-35 ml for end-diastolic volume (14%-17% of mean) and 16-23 ml for end-systolic volume (18%-21% of mean).
- The method is compatible with generally available nuclear medicine imaging software and requires minimal additional calculation time.
Conclusions:
- The developed radionuclide method provides reasonably accurate and clinically applicable left ventricular volume calculations.
- This simplified approach enhances the utility of first-pass radionuclide angiography by removing the need for blood samples and distance measurements.
Abstract:
Most count-based radionuclide methods for calculating left ventricular volume rely on measurement of radioactivity in a peripheral blood sample and a measurement of ventricle to collimator distance. We have developed a method which requires neither a blood sample nor a distance measurement and which is applicable to first-pass radionuclide angiography. The parameters used to calculate volume are the area of pixel, the total counts in the left ventricle and the maximum pixel count. The equation was used to calculate the volumes in 50 patients who had both resting first-pass radionuclide angiography (25 patients with a single crystal and 25 patients with a multicrystal camera) and contrast ventriculography on the same day. Correlation coefficients for end-diastolic and end-systolic volumes showed r ranging 0.93-0.98 and standard error of estimate ranging 23-35 ml for end-diastolic volume (14%-17% of mean end-diastolic volume) and 16-23 ml for end-systolic volume (18%-21% of mean end-systolic volume). Image processing software for extracting the needed values is generally available on most commercial nuclear medicine imaging systems and the additional time for the calculations is short. Although the theory is based on multiple assumptions, the volume calculation appears to be reasonably accurate and clinically applicable.