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Diagnostic value of technetium-99m radionuclide angiography for detecting thrombosis in left atrial appendage
T Uehara1, T Nishimura, K Hayashida
1Department of Radiology, Osaka University Hospital, Japan.
Insights
Radionuclide angiography (RNA) can detect left atrial thrombi in mitral valve disease. A clearly visualized left atrial appendage via RNA suggests the absence of thrombi, aiding treatment decisions.
Area of Science:
- Cardiovascular Imaging
- Nuclear Cardiology
- Diagnostic Accuracy Studies
Background:
- Left atrial thrombi in mitral valve disease necessitate accurate detection for treatment planning.
- The left atrial appendage is the common site for thrombus formation.
Observation:
- Radionuclide angiography (RNA) using 99mTc-labeled red blood cells can visualize the left atrial appendage.
- A hypothesis was formed that non-visualization of the left atrial appendage by RNA indicates the presence of thrombi.
Findings:
- Retrospective analysis of 60 mitral valve disease patients evaluated RNA's diagnostic accuracy for left atrial thrombi.
- First-pass RNA showed 83% sensitivity and 80% accuracy; equilibrium RNA showed 67% sensitivity and 57% accuracy.
- High negative predictive value indicates a visualized left atrial appendage reliably excludes thrombi.
Implications:
- RNA is a valuable tool for ruling out left atrial thrombi in mitral valve disease.
- Clear visualization of the left atrial appendage by RNA can guide clinical management and treatment strategies.
- Further investigation may refine RNA protocols for improved thrombus detection and characterization.
Abstract:
In mitral valve disease, it is important to know whether thrombi are present in the left atrium when deciding upon a course of treatment. The left atrial thrombus usually locates in the left atrial appendage. In most cases of mitral valve disease, the left atrial appendage is clearly demonstrated by radionuclide angiography using 99mTc-labeled red blood cells and it can be speculated that the cases in which left atrial appendage are not demonstrated by RNA have left atrial thrombi. On the basis of this hypothesis, the diagnostic accuracy of radionuclide angiography to detect left atrial thrombi was evaluated retrospectively in 60 patients with mitral valve disease who had undergone surgery. The sensitivity of first-pass and equilibrium radionuclide angiography to detect left atrial thrombi was 83% and 67%, the specificity 79% and 54%, and the accuracy 80% and 57%, respectively. Although there were two false-negative cases in which the left atrial thrombi did not locate in the appendage and 10 false-positive cases in which left atrial appendages were not dilated, the negative predictive value was so high that a clearly demonstrated left atrial appendage can be translated into the absence of left atrial thrombi.