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Imaging Echocardiography Transthoracic echocardiography (TTE) has much higher sensitivity in children (>85%) than in adults Two-dimensional (2D) images have high spatial resolution and high quality and diagnostic yield The interplay between 2D and color Doppler (CD) imaging for visualization of structures and flow, respectively, are of greatest significance Pulsed wave Doppler and continuous wave Doppler have importance in assessing stenosis and gradients between cavities Tissue harmonic imaging provides improved image quality Currently, the negative predicted value of the absence of echo signs of IE even in adults can reach 97%.30 Transesophageal echocardiography (TEE) may only occasionally be indicated in technical difficulties in acquisition of transthoracic images, abscesses, or negative TTE in strong clinical suspicion of IE Unlike adults, TEE is only rarely required and is usually not necessary because the sensitivity of TTE is greater than 90% for vegetations and greater than 85% in total.31 A summary of echocardiography findings and rules and indications for TEE are summarized in Box 56.3 Echocardiography images of signs of IE as well as matching intraoperative findings are shown in Videos 56.1 to 56.43 Box 56.3 Echocardiogrphy in Infective Endocarditis Echocardiography Signs of IE: ■ Vegetation: mobile hyperechogenic mass attached to valve, device, or wall (2D) ■ Regurgitation due to: ■ perforation: regurgitant jet (CD) across an interruption of leaflet echo (2D) ■ fistula: communication (CD) between neighboring cavities through perforation (2D) ■ chordal rupture of AV valve: central regurgitant jet (CD) with gap, free floating chord prolapsing to the atrium, leaflet prolapse (2D) ■ dehiscence of prosthetic mechanical valve: paravalvar leak (CD) with/without rocking motion of the prosthesis ■ aneurysm: saccular bulging (2D) ■ Abscess: perivalvar thickened, nonhomogeneous, hyperechogenic (echodense), or hypoechogenic (echolucent) area (2D) not communicating with any cavity (CD) ■ Pseudoaneurysm: pulsatile perivalvar echolucent area (2D) with flow communicating with lumen (CD) ■ Intracardiac fistula: communication between a vessel and a cardiac chamber ■ Blocked shunt or stented vessel Echocardiography rules of IE: ■ Neither sensitivity nor specificity of echocardiography is 100% and therefore negative echocardiogram does not 100% exclude IE ■ Echogenicity does not differ significantly between vegetation, thrombus, and tumor ■ Compare to previous images, if available, as dysplasia myxomatous changes may imitate vegetations ■ Do not rely on still images, review loops of at least one complete cycle at low speed ■ If the initial echocardiography was negative and the clinical suspicion remains high, repeated echo in 7–10 days or earlier if S aureus infection ■ Serial examinations have significance for guiding the management Echocardiography report should include: ■ Location and size of vegetation, perforation, abscess, aneurysm ■ Severity of stenosis or regurgitation ■ Hemodynamic consequences of stenosis or regurgitation including cavity size, ventricular function, and pulmonary artery pressure assessment ■ Relation to presumed underlying cause: valvar abnormality, ventricular septal defect, prosthetic material etc ■ In case of multisite IE, proximity each location to each other TEE may be indicated in: ■ Negative transthoracic echo in high clinical suspicion of IE ■ Prosthetic valve endocarditis ■ Suspected paravalvar abscess ■ Children and adolescents with inadequate transthoracic imaging because of overweight/obesity and chest wall deformities 2D, Two-dimensional; CD, color Doppler; IE, infective endocarditis; TEE, transesophageal echocardiography The added value of three-dimensional echocardiography remains to be established: it might remain low due to the currently low spatial resolution Targeted emergency echo may be lifesaving It is becoming increasingly important to have a timely diagnosis and manage the emergency conditions related to embolic complications of IE or to heart failure related to acute valvar regurgitations Guidelines for urgent targeted echo have been adopted.32 Intracardiac echo may have added value for visualizing intrastent vegetations It has been shown to be useful for visualizing vegetations in IE related to transcatheter implanted pulmonary valves,33 as up to 50% remain not visualized with TTE and TEE It is rarely used because of the rare indications and relatively high price Computed Tomography High-resolution multislice gated cardiac computed tomography (CT) with contrast is one of the added major IE criteria in the new 2015 IE guidelines.1 The newest third-generation dual source turboflash CT equipment not only has superior spatial resolution but also allows the acquisition of images in minimal amounts of time, thus enabling the investigation to be performed without general anesthesia and at very low radiation exposure CT has high added value for diagnosing IE in the following:
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