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Quantitation of intracardiac shunts by cine-CT
J S Garrett1, W Jaschke, T Aherne
1Department of Radiology, University of California, San Francisco 94143.
Insights
Contrast-enhanced cine-CT offers a precise, noninvasive method for quantifying right-to-left shunts. This advanced technique improves upon oximetry and radionuclide angiography for evaluating congenital and acquired heart diseases.
Area of Science:
- Cardiology
- Medical Imaging
- Diagnostic Techniques
Background:
- Intracardiac shunt quantitation is crucial for congenital heart disease and post-myocardial infarction ventricular septal defects.
- Current methods like oximetry (invasive) and radionuclide angiography (limited spatial resolution) have drawbacks.
- There is a need for accurate, noninvasive shunt quantitation with detailed anatomical information.
Purpose of the Study:
- To evaluate a novel noninvasive technique using cine-CT for quantifying right-to-left shunts.
- To assess the accuracy and reproducibility of cine-CT indicator dilution curve analysis.
- To compare cine-CT shunt quantitation with oximetry in a canine model.
Main Methods:
- Development and validation of an indicator dilution curve analysis algorithm using cine-CT.
- Evaluation in a phantom model for accuracy and reproducibility.
- In vivo testing in postoperative dogs with surgically created shunts, comparing with oximetry.
Main Results:
- The cine-CT technique accurately estimated right-to-left shunt fraction (r = 0.91) compared to oximetry.
- Cine-CT demonstrated higher sensitivity than oximetry in detecting small shunts.
- Phantom and canine models confirmed the accuracy and reproducibility of the cine-CT method.
Conclusions:
- Contrast-enhanced cine-CT provides a precise and noninvasive method for measuring intracardiac shunts.
- This technique is superior to oximetry and radionuclide angiography for shunt quantitation.
- Cine-CT is a valuable tool for evaluating congenital and acquired heart diseases involving shunts.
Abstract:
Quantitation of intracardiac shunts is important in the evaluation of congenital heart disease and ventricular septal defects postmyocardial infarction. Shunt detection and quantitation is currently performed by either oximetry or radionuclide angiography. Oximetry is an invasive technique and radionuclide angiography, although noninvasive, does not have sufficient spatial resolution to provide detailed anatomic information. The present study evaluated a new technique for quantitating right-to-left shunts by analysis of indicator dilution curves acquired noninvasively using cine-CT. This technique was evaluated in a phantom and in postoperative dogs with a surgically created variable shunt. The phantom model demonstrated the accuracy and reproducibility of the curve analysis algorithm, and the canine model permitted the comparison of oximetry with cine-CT for shunt quantitation. Cine-CT accurately estimated right-to-left shunt fraction when compared with oximetry (r = 0.91) and is more sensitive than oximetry in detecting small shunts. The results of this study suggest that contrast enhanced cine-CT provides a precise noninvasive technique for measuring shunt lesions in congenital and acquired heart diseases.