18F-FDG-PET/CT-Angiography in Infective Endocarditis
Is there added value associated with 18F-FDG-PET/CT (positron emission tomography/computed tomography [PET/CT]) or 18F-FDG-PET/CT-angiography (PET/CTA) in diagnosing infective endocarditis (IE) among patients with a prosthetic valve or an intracardiac device?
A cohort of 92 patients admitted to a referral center with a multidisciplinary IE unit with suspected prosthetic valve or cardiac device IE between November 2012 and November 2014 were prospectively included. All patients underwent echocardiography (echo) and PET/CT, and 76 underwent cardiac CTA. PET/CT and echo findings were evaluated and compared, with concordant results in 54% of cases (kappa: 0.23). Initial diagnoses with Duke criteria at admission, PET/CT, and Duke criteria plus PET/CT were compared with the final diagnostic consensus reached by the IE unit.
Duke criteria plus PET/CT enabled reclassification of 90% of cases initially classified by Duke criteria alone as possible IE, and provided a conclusive diagnosis (definite/rejected) in 95% of cases. Sensitivity, specificity, and positive and negative predictive values were 52%, 94.7%, 92.9%, and 59.7% for Duke criteria alone; 87%, 92.1%, 93.6%, and 84.3% for PET/CT alone; and 90.7%, 89.5%, 92%, and 87.9% for Duke criteria plus PET/CT. Use of PET/CTA yielded even better diagnostic performance values than PET/non-enhanced CT (PET/NECT) (sensitivity, specificity, and positive and negative predictive values were 91%, 90.6%, 92.8%, and 88.3% vs. 86.4, 87.5, 90.2, and 82.9) and substantially reduced the rate of doubtful cases from 20% to 8% (p < 0.001). Duke criteria plus PET/CTA reclassified an additional 20% of cases classified by Duke criteria plus PET/NECT as possible IE. In addition, PET/CTA enabled detection of a significantly larger number of anatomical lesions associated with active endocarditis compared to PET/NECT (p = 0.006) or echo (p < 0.001).
The authors concluded that 18F-FDG-PET/CT improves the diagnostic accuracy of the modified Duke criteria in patients with suspected IE and a prosthetic valve or cardiac device. PET/CTA yielded the highest diagnostic performance and provided additional diagnostic benefits.
The diagnosis of IE can be clinically challenging in general; and even more so in the setting of a patient with a prosthetic heart valve or intracardiac device, owing to limitations associated with the echocardiographic detection of vegetations in the setting of prosthetic material. This study suggests that the use of 18F-FDG-PET/CT or 18F-FDG-PET/CT-angiography can improve on the ability to reliably diagnose IE in this challenging patient population.
Clinical Topics: Cardiac Surgery, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Valvular Heart Disease, Cardiac Surgery and Heart Failure, Cardiac Surgery and VHD, Mechanical Circulatory Support, Interventions and Imaging, Interventions and Structural Heart Disease, Angiography, Computed Tomography, Echocardiography/Ultrasound, Nuclear Imaging
Keywords: Angiography, Echocardiography, Endocarditis, Fluorodeoxyglucose F18, Heart-Assist Devices, Heart Valve Prosthesis, Heart Valve Diseases, Positron-Emission Tomography, Tomography, X-Ray Computed
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