Rationale and Objectives
To determine the diagnostic accuracy of 64-row multidetector cardiac computed tomography (MDCT) in detecting aortic regurgitation (AR) on prospectively acquired images with trans-thoracic echocardiography (TTE) as a reference standard.
Materials and Methods
Forty-three consecutive patients underwent MDCT and TTE. AR was defined on MDCT images acquired at 75% phase of R-R interval as the lack of aortic cusps coaptation. The maximum regurgitant orifice area (ROA) was planimetered and compared to TTE.
Results
All 29 patients with AR on TTE were correctly identified by MDCT. The sensitivity, specificity, positive predictive value, and negative predictive value of MDCT were 100%, 85.7%, 93.5%, and 100%, respectively. Sixteen, nine, and four patients were found to have mild, moderate, and severe AR on TTE, respectively. The corresponding ROA by MDCT were 3.25 ± 1.04 mm 2 , 4.16 ± 1.19 mm 2 , and 11.30 ± 6.13 mm 2 , respectively.
Conclusion
MDCT data acquired for the coronary artery evaluation can be used for the detection of aortic regurgitation with high diagnostic accuracy without additional scanning or radiation and can support appropriate referral for TTE.
Aortic regurgitation (AR) is a common clinical condition, with increasing prevalence as the population ages. The overall prevalence of AR was 4.9% in the Framingham Heart study and 10% in the Strong Heart Study . Clinically, patients with AR can remain asymptomatic and undetected for a long time . Significant left ventricular decompensation may accompany the initial diagnosis. Cardiac auscultation can reveal the characteristic murmur and patients can be referred for echocardiography for confirmation. Trans-thoracic echocardiography (TTE) not only confirms the presence of AR, but also determines its etiology, severity, and the effects of the regurgitant lesion on left ventricular size and function .
Currently the utilization of multidetector cardiac computed tomography (MDCT) has increased for the detection of coronary artery disease . With increased temporal and spatial resolution, it is now possible to perform detailed evaluation of various noncoronary cardiac structures. Multiple clinical studies have shown the role of MDCT in detecting mitral regurgitation as well as aortic stenosis .
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Materials and methods
Study Population
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MDCT Image Acquisition and Postprocessing
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MDCT Image Reconstruction and Analysis
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TTE
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Statistical Analysis
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Results
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Table 1
Patient Characteristics
Characteristics ( n = 43) Mean ± SD OR No. (%) Age (y) 64.5 ± 16 Male 25 (58.14) Hypertension 16 (55.17) Diabetes mellitus 5 (13) Hyperlipidemia 17 (42.5) AVC score on CT(AU) ( n = 16) 30.56 ± 93.45 History of CAD 20 (51.28) Ejection fraction on TTE 54.26 ± 12.71 Prevalence of AR by echo 29 (67.44) Aortic root diameter on CTA (mm) 3.45 ± 0.391 Aortic valve morphology Tricuspid 41 (95.35) Bicuspid 1 (2.33) Quadricuspid 1 (2.33) AR jet position Central 30 (96.7) Eccentric 1 (3.3) Heart rate at the time of CTA (beats/min) 55 ± 7.5 (range, 38–73) Time duration between TTE and CTA (days) 59.3 ± 55.4 (range, 0–180)
TTE, trans-thoracic echocardiography; CTA, computed tomography angiogram; AU, Agatston units; AR, aortic regurgitation; AVC, aortic valve calcium; CAD, coronary artery disease.
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Table 2
Correlation of Severity of AR on Echo with Aortic Regurgitation Orifice Area on CTA
Severity of AR on TTE No. of Patients Mean ROA on CTA (mm 2 ) Range (mm 2 ) Standard Deviation 95% Confidence Interval Mild 16 3.25 1.3–5.1 1.04 2.69–3.80 Moderate 9 4.16 1.9–5.92 1.19 3.24–5.08 Severe 4 11.30 5.2–19.45 6.13 1.53–21.07
TTE, trans-thoracic echocardiography; ROA, regurgitation orifice area; AR, aortic regurgitation; CTA, computed tomography angiography.
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Discussion
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Limitations
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Conclusion
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