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Conventional computerized tomography of the heart
K Lackner1, P Landwehr, P Thurn
1Institut für Röntgendiagnostik, Universität Würzburg, BRD.
Insights
Cardiovascular computed tomography (CT) offers valuable morphological insights into various heart conditions. While ECG-gated cardio-CT provides quantitative functional data, its time resolution limits accuracy for ejection fraction calculations.
Area of Science:
- Cardiovascular Imaging
- Radiology
- Cardiac CT
Background:
- Ungated cardiac computed tomography (CT) is useful for assessing cardiac morphology in conditions like congenital heart disease, cardiac masses, and calcifications.
- It allows qualitative evaluation of myocardial thickness and coronary bypass graft perfusion.
Purpose of the Study:
- To evaluate the capabilities of ECG-gated cardiac CT for quantitative assessment of cardiac function and morphology.
- To compare the diagnostic performance of cardiac CT with other imaging modalities.
Main Methods:
- Utilized ECG-gated cardiac CT for quantitative analysis of myocardial thickness, cardiac cavity volumes, and functional parameters.
- Compared left ventricular ejection fraction derived from ECG-gated cardiac CT with laevocardiography.
- Assessed regional wall motion analysis using cardiac CT.
Main Results:
- ECG-gated cardiac CT enables quantitative assessment of systolic and diastolic function and cardiac volumes.
- Correlation between left ventricular ejection fraction from ECG-gated cardiac CT and laevocardiography was poor (r=0.7) due to limited temporal resolution of CT.
- Quantitative analysis of regional wall motion demonstrated 80.5% specificity, 73.9% sensitivity, and 75.7% accuracy for diagnosing pathological wall motion.
Conclusions:
- Cardiac CT, particularly ECG-gated protocols, provides comprehensive morphological and functional information about the heart.
- Limitations in temporal resolution affect quantitative functional assessments like ejection fraction.
- Potential side effects include fluid retention and cardiac volume loading from contrast media, necessitating careful patient selection.
Abstract:
Ungated cardio-CT provides good morphologic information in the case of congenital heart disease, volume or pressure loading, left ventricular aneurysm, tumours, thrombi, cardiac calcifications and pericardial diseases. It allows qualitative assessments of myocardial thickness and perfusion of coronary bypass grafts. ECG-gated cardio-CT allows a quantitative assessment of systolic and diastolic myocardial thickness, volume calculation of cardiac cavities and evaluation of functional parameters. The correlation of the calculated left ventricular ejection fraction comparing laevocardiography and ECG-gated cardio-CT was poor (r = 0.7) mainly due to the comparable poor time resolution on the side of cardio-CT (approximately 0.1s). The quantitative analysis of regional wall motion based on cardio-CT showed for the diagnosis of pathologic wall motion a specificity of 80.5%, sensitivity of 73.9% and accuracy of 75.7%. Side effects must be taken into account following the injection of 200-250 ml hyperosmolar contrast medium during 5-10 minutes which causes intravascular fluid retention and cardiac volume loading. Patients prone to cardiac decompensation should be excluded from cardio-CT examinations.