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Published on: February 26, 2013
Diagnostic Value of Delayed Contrast-Enhanced Cardiac Computed Tomography for Detecting Left Atrial Appendage
Xiang-Nan Li1, Jing-Xi Wang1, Qing Wei2
1State Key Laboratory of Cardiovascular Disease, Department of Radiology, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Insights
Delayed enhancement cardiac CT effectively detects left atrial appendage thrombus. Including 1 and 3-minute delay phases significantly improves diagnostic accuracy for thrombus detection and risk stratification.
Area of Science:
- Cardiovascular Imaging
- Radiology
- Medical Diagnostics
Background:
- Left atrial appendage thrombus is a critical concern in cardiovascular disease.
- Delayed enhancement cardiac CT is a key imaging modality, but its effectiveness can be limited by scanning heterogeneity.
Purpose of the Study:
- To evaluate the diagnostic improvement offered by 1-minute and 3-minute delay phases in cardiac CT for detecting left atrial appendage thrombus.
- To establish an optimized CT scanning protocol for thrombus detection.
Main Methods:
- Retrospective analysis of 329 patients who underwent cardiac CT (arterial, 1-min, and 3-min delay phases) and Transesophageal echocardiography (TEE).
- Independent assessment of CT images by three radiologists.
- Logistic regression for high-risk stratification.
Main Results:
- All CT phases demonstrated 100% sensitivity and negative predictive value for thrombus detection.
- Specificity and positive predictive values (PPV) increased with delay: 3-min phase achieved 100% specificity and PPV.
- Area Under Curve (AUC) improved from 0.75 (arterial phase) to 0.95 (1-min) and 0.98 (3-min).
- High-risk factors like reduced cardiac function and left atrial enlargement were better assessed with delayed phases.
Conclusions:
- Early contrast-enhanced CT scanning with 1-min and 3-min delay phases is essential for accurate left atrial appendage thrombus diagnosis.
- The 3-min delay phase provides optimal diagnostic efficiency.
- Patients identified as high-risk can benefit from direct 3-min delayed scanning.
Objective:
Delayed enhancement cardiac CT is a reliable tool for the diagnosis of left atrial appendage thrombus but limited for scanning heterogeneity. We aimed to explore the improvement of the 1 and 3-min delay phase at the diagnostic level to detect left atrial appendage thrombus, in order to set up a reasonable CT scanning scheme.
Materials And Methods:
A total of 6,524 patients were continuously retrieved from January 2015 to September 2020 retrospectively. The patients had undergone Transesophageal echocardiography (TEE) and cardiac CT with complete period include the arterial enhancement phase, 1 and 3-min delay phase, TEE were used as the reference standard. The final study included 329 patients. Three experienced radiologists independently assessed each phase of the cardiac CT images for thrombus diagnosis. We explored the improvement of the diagnostic ability of different delayed contrast-enhanced phases for left atrial appendage thrombus detection. Multiple logistic regression analysis were used for further high-risk stratification to avoid an additional 1-min delayed scan.
Results:
In total, 29 thrombosis were detected at TEE. For all cardiac CT phases, sensitivity and negative predictive were 100%. The specificity were 0.54, 0.93, and 1.00, respectively; The positive predictive values (PPV) were 0.17, 0.57, and 1.00, respectively; Area under curve (AUC) were 0.75, 0.95, and 0.98, respectively. High risk factors that cannot be clearly diagnosed with 1-min delay phase included reduced cardiac function, increased CHA2DS2-VAScscore and left atrial enlargement. Compared with the arterial enhanced phase, increased radiation doses in the 1 and 3-min delay phases were 1.7 ± 1.3 msv and 1.5 ± 0.8 msv (mean ± standard deviation).
Conclusion:
Using TEE as the reference standard, early contrast-enhanced CT scanning with 1 and 3-min delay is necessary for the diagnosis of left appendage thrombus, which could significantly improve the diagnostic efficiency. Patients with high-risk stratification are suitable for direct 3-min delayed scanning.
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