Diagnosing Endocarditis: Get the Picture?!

Abstract

Infective endocarditis (IE), an infection of the endocardium, initially was described in 1646 and may affect native heart valves and/or chordae tendineae, prosthetic valves, and/or implanted cardiac devices. A definitive diagnosis of IE oftent is quite challenging because of the wide variability patients exhibit regarding clinical history, physical presentation, laboratory analysis, and imaging techniques.1Hubers SA DeSimone DC Gersh BJ et al.Infective endocarditis: A contemporary review.Mayo Clin Proc. 2020; 95: 982-997Abstract Full Text Full Text PDF PubMed Scopus (18) Google Scholar,2Rajani R Klein JL. Infective endocarditis: A contemporary update.Clin Med (Lond). 2020; 20: 31-35Crossref PubMed Scopus (23) Google Scholar Traditionally, a diagnosis of IE is determined via the Modified Duke Criteria (Table 1), originally described in 1994 and modified in 2000, which encompass clinical history, physical presentation, laboratory analysis (primarily blood cultures), and transthoracic echocardiography (TTE) and/or transesophageal echocardiography (TEE).3Li JS Sexton DJ Mick N et al.Proposed modifications to the Duke criteria for the diagnosis of infective endocarditis.Clin Infect Dis. 2000; 30: 633-638Crossref PubMed Scopus (2740) Google Scholar “Definite IE” requires 2 major criteria OR 1 major/3 minor criteria OR 5 minor criteria. “Possible IE” requires 1 major criteria/1 minor criteria OR 3 minor criteria. IE also is classified as “acute” (symptoms for days and up to 6 weeks), “subacute” (symptoms between 6 weeks and 3 months), and “chronic” (symptoms longer than 3 months). The Incidence of IE (approximately 15 cases/100,000 population) and subsequent hospitalization have increased progressively over the years. It is unfortunate that physicians often continue to struggle definitively diagnosing IE because of its profound effect on morbidity and mortality.Table 1Modified Duke CriteriaMAJOR Criteria1Typical microorganisms consistent with IE obtained from 2 separate blood cultures in absence of a primary focus2Microorganisms consistent with IE from persistently positive blood cultures, defined as 2 positive cultures of blood samples drawn more than 12 hours apart or all of 3 or a majority of 4 separate cultures of blood (first and last drawn 1 hour apart)3Coxiella burnetti detected or antiphase-1 IgG antibody titer greater than 1:8004Positive echocardiographic findingsMINOR Criteria1Predisposing heart disease or history of drug injection2Fever: temperature greater than 38˚C3Clinical vascular phenomenon (arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial hemorrhage, conjunctival hemorrhages, and Janeway lesions)4Immunologic phenomenon (Osler nodes, Roth spots, rheumatoid factor, or glomerulonephritis)5Microbiologic evidence not fitting major criteria6Positive blood culture not fitting major criteriaAbbreviations: IE, infective endocarditis; IgG, immunoglobulin G Open table in a new tab Abbreviations: IE, infective endocarditis; IgG, immunoglobulin G Traditionally, echocardiography has been the imaging technique of choice and usually is performed as soon as IE is suspected.4Xie P Zhuang X Liu M Zhang S Liu J Liu D Liao X. An appraisal of clinical practice guidelines for the appropriate use of echocardiography for adult infective endocarditis – the timing and mode of assessment (TTE or TEE).BMC Infectious Diseases. 2021; 21: 92Crossref PubMed Scopus (3) Google Scholar, 5Sordelli C Fele N Mocerino R et al.Infective endocarditis: Echocardiographic imaging and new imaging modalities.J Cardiovasc Echography. 2019; 29: 149-155Crossref PubMed Scopus (10) Google Scholar, 6Afonso L Kottam A Reddy V et al.Echocardiography in infective endocarditis: State of the art.Curr Cardiol Rep. 2017; 19: 127Crossref PubMed Scopus (34) Google Scholar Typical findings meeting the major criteria include vegetation, abscess, and/or new dehiscence of a prosthetic valve. Echocardiography can identify number, size, shape, location, echogenicity, and mobility of vegetations, perhaps predicting embolic risk. TTE usually is performed first, followed by TEE when either TTE is positive (further characterize lesions, identify local complications) or nondiagnostic in a case of suspected complications and when intracardiac device leads are present.5Sordelli C Fele N Mocerino R et al.Infective endocarditis: Echocardiographic imaging and new imaging modalities.J Cardiovasc Echography. 2019; 29: 149-155Crossref PubMed Scopus (10) Google Scholar When an initial TEE is negative yet there exists high suspicion for IE, a repeat TEE is recommended.5Sordelli C Fele N Mocerino R et al.Infective endocarditis: Echocardiographic imaging and new imaging modalities.J Cardiovasc Echography. 2019; 29: 149-155Crossref PubMed Scopus (10) Google Scholar While TTE may be useful in the settings of native left-sided valve IE with excellent echogenicity, tricuspid valve IE, and/or the detection of anterior aortic abscess (especially prosthetic valve IE), it remains inferior to TEE, especially for the detection of vegetations and size measurements, which have a major impact on embolism risk and indication for early surgery (prosthetic valve and/or intracardiac device). The sensitivity of TTE in patients with prosthetic valves is only approximately 50%, likely because of shadowing from structural components of the prosthetic valve. Despite TEE's superiority to TTE, its sensitivity and specificity for suspected native valve endocarditis are only 90%- to-100% and 90%, respectively.5Sordelli C Fele N Mocerino R et al.Infective endocarditis: Echocardiographic imaging and new imaging modalities.J Cardiovasc Echography. 2019; 29: 149-155Crossref PubMed Scopus (10) Google Scholar The low specificity of TEE relates to distinguishing valvular vegetation from other intracardiac masses and from ultrasound artifacts. Echocardiographic findings that may be mistaken for vegetation include papillary fibroelastoma, myxomatous mitral valve disease, nonbacterial thrombotic endocarditis, thrombus, and/or normal valve variants (Lambl excrescence). Although the roles of 3-dimensional (3D) echocardiography and intracardiac echocardiography are increasing, they still are regarded as supplements to standard echocardiography in most cases.5Sordelli C Fele N Mocerino R et al.Infective endocarditis: Echocardiographic imaging and new imaging modalities.J Cardiovasc Echography. 2019; 29: 149-155Crossref PubMed Scopus (10) Google Scholar,7Perez-Garcia CN Olmos C Islas F et al.Morphological characterization of vegetation by real-time three-dimensional transesophageal echocardiography in infective endocarditis: Prognostic impact.Echocardiography. 2019; 36: 742-751Crossref PubMed Scopus (7) Google Scholar Not surprisingly, numerous guidelines have been published over the years recommending a wide variety of approaches in the timing and mode of TTE and/or TEE assessment in patients with suspected or real IE.4Xie P Zhuang X Liu M Zhang S Liu J Liu D Liao X. An appraisal of clinical practice guidelines for the appropriate use of echocardiography for adult infective endocarditis – the timing and mode of assessment (TTE or TEE).BMC Infectious Diseases. 2021; 21: 92Crossref PubMed Scopus (3) Google Scholar Thus, to enhance a physician's ability to definitively diagnose and/or treat IE, new imaging modalities now are supplementing information from echocardiography, including computed tomography (CT), magnetic resonance imaging (MRI), and nuclear molecular imaging.5Sordelli C Fele N Mocerino R et al.Infective endocarditis: Echocardiographic imaging and new imaging modalities.J Cardiovasc Echography. 2019; 29: 149-155Crossref PubMed Scopus (10) Google Scholar,8Saeedan MB Wang TKM Cremer P et al.Role of cardiac CT in infective endocarditis: Current evidence, opportunities, and challenges.Radiol Cardiothorac Imaging. 2021; 3e200378Crossref Scopus (8) Google Scholar Cardiac CT (CCT) has gained traction as an adjunct to echocardiography when the echocardiogram is unable to offer diagnostic clarity or if invasive testing is undesirable. CT coronary angiography is used to evaluate coronary artery disease, coronary artery stenosis, or coronary artery anatomy prior to cardiac surgery, in some cases in place of invasive angiography.8Saeedan MB Wang TKM Cremer P et al.Role of cardiac CT in infective endocarditis: Current evidence, opportunities, and challenges.Radiol Cardiothorac Imaging. 2021; 3e200378Crossref Scopus (8) Google Scholar, 9Entrikin DW Gupta P Kon ND et al.Imaging of infective endocarditis with cardiac CT angiography.J Cardiovasc Comput Tomogr. 2012; 6: 399-405Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar, 10Villines TC Al'Aref SJ Andreini D et al.The Journal of Cardiovascular Computed Tomography: 2020 year in review.J Cardiovasc Comput Tomogr. 2021; 15: 180-189Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar, 11Taylor AJ Cerqueira M Hodgson JM et al.ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 Appropriate Use Criteria for Cardiac Computed Tomography. A Report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance.J Cardiovasc Comput Tomogr. 2010; 4 (e1-33): 407Abstract Full Text Full Text PDF PubMed Google Scholar The ability to obtain thin slices (0.65-0.75 mm), the usage of echocardiogram gating, and postprocessing multiplanar reconstruction allow for the creation of a 3D image of the heart that can be viewed at various angles, all of which contribute to the excellent spatial resolution seen with CCT.8Saeedan MB Wang TKM Cremer P et al.Role of cardiac CT in infective endocarditis: Current evidence, opportunities, and challenges.Radiol Cardiothorac Imaging. 2021; 3e200378Crossref Scopus (8) Google Scholar,12Khalique OK Veillet-Chowdhury M Choi AD et al.Cardiac computed tomography in the contemporary evaluation of infective endocarditis.J Cardiovasc Comput Tomogr. 2021; 15: 304-312Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar Additionally, CCT provides excellent temporal resolution (although not superior to 2D echocardiography), with the ability to capture the heart at various points in the cardiac cycle.8Saeedan MB Wang TKM Cremer P et al.Role of cardiac CT in infective endocarditis: Current evidence, opportunities, and challenges.Radiol Cardiothorac Imaging. 2021; 3e200378Crossref Scopus (8) Google Scholar,12Khalique OK Veillet-Chowdhury M Choi AD et al.Cardiac computed tomography in the contemporary evaluation of infective endocarditis.J Cardiovasc Comput Tomogr. 2021; 15: 304-312Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar All of this has contributed to the increased usage of CCT in the diagnosis of IE, such was incorporated into the 2015 European Society of Cardiology modified diagnostic criteria.13Habib G Lancellotti P Antunes MJ et al.2015 ESC Guidelines for the management of infective endocarditis: The Task Force for the Management of Infective Endocarditis of the European Society of Cardiology (ESC). Endorsed by: European Association for Cardio-Thoracic Surgery (EACTS), the European Association of Nuclear Medicine (EANM).Eur Heart J. 2015; 36: 3075-3128Crossref PubMed Scopus (2483) Google Scholar CCT can be used when TTE images are suboptimal, and there is a contraindication to TEE, such as esophageal pathology (surgery, stricture and/or stenosis, or active bleeding and/or ulcers). In the setting of the current coronavirus disease 2019 pandemic, CCT can be utilized when one wants to avoid the risk of possible aerosolization of viral particles while performing TEE.12Khalique OK Veillet-Chowdhury M Choi AD et al.Cardiac computed tomography in the contemporary evaluation of infective endocarditis.J Cardiovasc Comput Tomogr. 2021; 15: 304-312Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar The presence of extensive valve calcifications, prosthetic valves, or other prosthetic material can cause a lot of image artifacts and make visualization with TEE challenging (particularly for the presence of valvular vegetations), and, thus, adding CCT may improve diagnostic accuracy.8Saeedan MB Wang TKM Cremer P et al.Role of cardiac CT in infective endocarditis: Current evidence, opportunities, and challenges.Radiol Cardiothorac Imaging. 2021; 3e200378Crossref Scopus (8) Google Scholar,13Habib G Lancellotti P Antunes MJ et al.2015 ESC Guidelines for the management of infective endocarditis: The Task Force for the Management of Infective Endocarditis of the European Society of Cardiology (ESC). Endorsed by: European Association for Cardio-Thoracic Surgery (EACTS), the European Association of Nuclear Medicine (EANM).Eur Heart J. 2015; 36: 3075-3128Crossref PubMed Scopus (2483) Google Scholar, 14Feuchtner GM Stolzmann P Dichtl W et al.Multislice computed tomography in infective endocarditis: Comparison with transesophageal echocardiography and intraoperative findings.J Am Coll Cardiol. 2009; 53: 436-444Crossref PubMed Scopus (286) Google Scholar, 15Habets J Tanis W van Herwerden LA et al.Cardiac computed tomography angiography results in diagnostic and therapeutic change in prosthetic heart valve endocarditis.Int J Cardiovasc Imaging. 2014; 30: 377-387Crossref PubMed Scopus (56) Google Scholar Far-field structures, such as the pulmonic or tricuspid valves, can be difficult to visualize with TEE, making the ability to generate a full 3D reconstruction of the heart with CCT valuable as one can better pinpoint the exact anatomic location of vegetations on these valves.12Khalique OK Veillet-Chowdhury M Choi AD et al.Cardiac computed tomography in the contemporary evaluation of infective endocarditis.J Cardiovasc Comput Tomogr. 2021; 15: 304-312Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar CCT can be used to determine the size and anatomy of the valve or perivalvular structures to help with surgical planning, particularly with the aortic valve and root, as demonstrated by Gahide et al.16Gahide G Bommart S Demaria R et al.Preoperative evaluation in aortic endocarditis: Findings on cardiac CT.AJR Am J Roentgenol. 2010; 194: 574-578Crossref PubMed Scopus (74) Google Scholar CT coronary angiography can be used to detect possible cardioembolic coronary artery occlusion, which also may be important for surgical planning. Common CCT findings for IE can be characterized as valvular or perivalvular. Valvular findings include vegetation and leaflet perforation, whereas perivalvular findings include fistulae, pseudoaneurysms, abscesses, and prosthetic valve dehiscence.8Saeedan MB Wang TKM Cremer P et al.Role of cardiac CT in infective endocarditis: Current evidence, opportunities, and challenges.Radiol Cardiothorac Imaging. 2021; 3e200378Crossref Scopus (8) Google Scholar, 9Entrikin DW Gupta P Kon ND et al.Imaging of infective endocarditis with cardiac CT angiography.J Cardiovasc Comput Tomogr. 2012; 6: 399-405Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar,12Khalique OK Veillet-Chowdhury M Choi AD et al.Cardiac computed tomography in the contemporary evaluation of infective endocarditis.J Cardiovasc Comput Tomogr. 2021; 15: 304-312Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar Although the confirmation of vegetations certainly is important, perivalvular extension is quite common, occurring in 10%-to-40% of cases of native valve endocarditis, and 56%-to-100% of prosthetic valve endocarditis, with very high morbidity and mortality.17Prendergast BD Tornos P. Surgery for infective endocarditis: Who and when?.Circulation. 2010; 121: 1141-1152Crossref PubMed Scopus (250) Google Scholar With TEE, vegetations often are seen as mobile (but occasionally immobile) echogenic structures commonly attached to valve leaflets, but can be found anywhere on the valvular apparatus. On CCT, vegetations can be seen as low-to-intermediate attenuation structures or can appear as focal thickening (Figs. 1 and 2) of the valve leaflets.8Saeedan MB Wang TKM Cremer P et al.Role of cardiac CT in infective endocarditis: Current evidence, opportunities, and challenges.Radiol Cardiothorac Imaging. 2021; 3e200378Crossref Scopus (8) Google Scholar Abscesses are very well-visualized on CCT due to excellent tissue-contrast differentiation.12Khalique OK Veillet-Chowdhury M Choi AD et al.Cardiac computed tomography in the contemporary evaluation of infective endocarditis.J Cardiovasc Comput Tomogr. 2021; 15: 304-312Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar They can appear as low-attenuation structures or heterogeneous collections of fluid adjacent to the valve, and also can possess a hyper-enhancing rim, also referred to as a capsule, which is more indicative of an acute abscess.12Khalique OK Veillet-Chowdhury M Choi AD et al.Cardiac computed tomography in the contemporary evaluation of infective endocarditis.J Cardiovasc Comput Tomogr. 2021; 15: 304-312Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar Evidence of soft tissue infiltration and attenuation, especially near a valve of interest, also may represent an abscess (Fig. 3). Additionally, CCT allows for visualization of the wall of the aorta and aortic root where the loss of the normal periaortic lipid layer or the presence of inflammatory soft tissue and fat stranding may be indicative of possible periaortic abscess.12Khalique OK Veillet-Chowdhury M Choi AD et al.Cardiac computed tomography in the contemporary evaluation of infective endocarditis.J Cardiovasc Comput Tomogr. 2021; 15: 304-312Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar Pseudoaneurysm often appears as a cavity near the valve, and communicates with the surrounding structures. The use of contrast during CCT helps distinguish a pseudoaneurysm from an abscess, as the contrast agent will fill the aneurysm cavity.12Khalique OK Veillet-Chowdhury M Choi AD et al.Cardiac computed tomography in the contemporary evaluation of infective endocarditis.J Cardiovasc Comput Tomogr. 2021; 15: 304-312Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar The use of contrast also may help distinguish a fistula or the communication between normally isolated cavities, as one can visualize contrast flowing through a fistulous tract.12Khalique OK Veillet-Chowdhury M Choi AD et al.Cardiac computed tomography in the contemporary evaluation of infective endocarditis.J Cardiovasc Comput Tomogr. 2021; 15: 304-312Abstract Full Text Full Text PDF PubMed Scopus (5) Google ScholarFig. 2Thickening of the noncoronary cusp of the aortic valve along with evidence of an independently mobile density located on the ventricular side of the valve (arrow).View Large Image Figure ViewerDownload Hi-res image Download (PPT)Fig. 3Soft tissue attenuation adjacent to aortic valve representative of inflammation, possible perivalvular abscess (arrow).View Large Image Figure ViewerDownload Hi-res image Download (PPT) As stated above, TEE is considered the best imaging method for IE, with sensitivity ranging from 85%-to-100%.5Sordelli C Fele N Mocerino R et al.Infective endocarditis: Echocardiographic imaging and new imaging modalities.J Cardiovasc Echography. 2019; 29: 149-155Crossref PubMed Scopus (10) Google Scholar,8Saeedan MB Wang TKM Cremer P et al.Role of cardiac CT in infective endocarditis: Current evidence, opportunities, and challenges.Radiol Cardiothorac Imaging. 2021; 3e200378Crossref Scopus (8) Google Scholar In several studies, CCT has shown to have near-equivalent diagnostic accuracy to TEE, and has helped to further elucidate findings when TEE images are suboptimal. In a study by Feuchtner et al, CT identified 97% of patients who had valve abnormalities first identified by TEE, and correctly had identified 96% of patients who had vegetations that were intraoperatively proven. Additionally, CT helped to identify a vegetation attached to a mechanical valve that previously was missed by TEE and helped to distinguish valve calcifications from vegetations. In this same study, CCT identified the presence of abscess and pseudoaneurysm, as well as the extent of these findings (for example, abscess extension into the coronary sinus), which helped with surgical planning.14Feuchtner GM Stolzmann P Dichtl W et al.Multislice computed tomography in infective endocarditis: Comparison with transesophageal echocardiography and intraoperative findings.J Am Coll Cardiol. 2009; 53: 436-444Crossref PubMed Scopus (286) Google Scholar Habets et al found that when CCT was added to TTE, the sensitivity for detecting vegetations went from 63% to 100%.15Habets J Tanis W van Herwerden LA et al.Cardiac computed tomography angiography results in diagnostic and therapeutic change in prosthetic heart valve endocarditis.Int J Cardiovasc Imaging. 2014; 30: 377-387Crossref PubMed Scopus (56) Google Scholar In terms of perivalvular extension, CCT also seems to corroborate positively both TEE and intraoperative findings. Oliveira et al reported that CCT detected pseudoaneurysm and abscess with a higher sensitivity than TEE (78% v 69%).18Oliveira M Guittet L Hamon M Hamon M. Comparative value of cardiac CT and transesophageal echocardiography in infective endocarditis: A systematic review and meta-analysis.Radiol Cardiothorac Imaging. 2020; 2e190189Crossref PubMed Scopus (5) Google Scholar Hryniewiecki et al found that the sensitivity and specificity of TTE and TEE to be 63% and 90%, respectively, for detecting abscess or pseudoaneurysm, which increased to 100% for both when CCT was added to the diagnostic algorithm.19Hryniewiecki T Zatorska K Abramczuk E et al.The usefulness of cardiac CT in the diagnosis of perivalvular complications in patients with infective endocarditis.Eur Radiol. 2019; 29: 4368-4376Crossref PubMed Scopus (25) Google Scholar In a large retrospective cohort study of 255 adults who underwent surgery for IE, Sims et al found that TEE performed superiorly in the detection of vegetations and perforation, but was equivocal for the detection of perivalvular extensions, such as an abscess or pseudoaneurysm.20Sims JR Anavekar NS Chandrasekaran K et al.Utility of cardiac computed tomography scanning in the diagnosis and pre-operative evaluation of patients with infective endocarditis.Int J Cardiovasc Imaging. 2018; 34: 1155-1163Crossref PubMed Scopus (20) Google Scholar Prosthetic valve endocarditis has a very poor prognosis; perivalvular extension occurs more frequently than in native valve endocarditis, with incidence ranging from 5%-to-100%.21Fagman E Perrotta S Bech-Hanssen O et al.ECG-gated computed tomography: A new role for patients with suspected aortic prosthetic valve endocarditis.Eur Radiol. 2012; 22: 2407-2414Crossref PubMed Scopus (129) Google Scholar This extension can lead to the destruction of the annulus, with resultant valve dehiscence and perivalvular leaks. Although TEE remains the imaging gold standard for prosthetic valves, CCT can be useful when acoustic shadowing caused by prosthetic material (similar to what occurs with calcifications) makes visualization difficult. With CCT, valve leaflets themselves, as well as leaflet motion, can be better-visualized, where focal thickening or restricted motion may be indicative of IE if clinical suspicion is high (Fig 4, A and B). In addition to the pathologies described above, CCT can help to diagnose prosthetic valve dehiscence, which can be visualized as misalignment between the prosthesis and the annulus, as well as rocking motion seen on cine images.8Saeedan MB Wang TKM Cremer P et al.Role of cardiac CT in infective endocarditis: Current evidence, opportunities, and challenges.Radiol Cardiothorac Imaging. 2021; 3e200378Crossref Scopus (8) Google Scholar Most studies showed that CCT and TEE had comparable ability to detect valve dehiscence, with TEE being slightly superior in all cases due to the ability to utilize color Doppler to detect perivalvular regurgitation and more subtle rocking of the valve not picked up by CCT cine imaging.18Oliveira M Guittet L Hamon M Hamon M. Comparative value of cardiac CT and transesophageal echocardiography in infective endocarditis: A systematic review and meta-analysis.Radiol Cardiothorac Imaging. 2020; 2e190189Crossref PubMed Scopus (5) Google Scholar,21Fagman E Perrotta S Bech-Hanssen O et al.ECG-gated computed tomography: A new role for patients with suspected aortic prosthetic valve endocarditis.Eur Radiol. 2012; 22: 2407-2414Crossref PubMed Scopus (129) Google Scholar, 22Koneru S Huang SS Oldan J et al.Role of preoperative cardiac CT in the evaluation of infective endocarditis: Comparison with transesophageal echocardiography and surgical findings.Cardiovasc Diagn Ther. 2018; 8: 439-449Crossref PubMed Scopus (21) Google Scholar Limitations to CCT include those that are related to the actual image generated, as well as the methods used to obtain the image. While CCT has an excellent temporal resolution, it is not superior to TEE and, thus, may not detect smaller vegetations (<4 mm) or be able to fully assess valvular dysfunction.8Saeedan MB Wang TKM Cremer P et al.Role of cardiac CT in infective endocarditis: Current evidence, opportunities, and challenges.Radiol Cardiothorac Imaging. 2021; 3e200378Crossref Scopus (8) Google Scholar By using color Doppler, TEE is better able to detect perivalvular leaks and leaflet perforation. CCT has limited use in patients with arrhythmias, particularly atrial fibrillation, as they can cause misalignment artifacts.9Entrikin DW Gupta P Kon ND et al.Imaging of infective endocarditis with cardiac CT angiography.J Cardiovasc Comput Tomogr. 2012; 6: 399-405Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar,14Feuchtner GM Stolzmann P Dichtl W et al.Multislice computed tomography in infective endocarditis: Comparison with transesophageal echocardiography and intraoperative findings.J Am Coll Cardiol. 2009; 53: 436-444Crossref PubMed Scopus (286) Google Scholar The administration of iodinated contrast puts patients at risk for contrast nephropathy from acute kidney injury, which can be problematic for patients with preexisting renal dysfunction, as is commonly seen in patients with IE. Lastly, CCT does result in significant radiation exposure (9-11 mSv for a 64-slice CT).23Hausleiter J Meyer T Hadamitzky M et al.Radiation dose estimates from cardiac multislice computed tomography in daily practice: Impact of different scanning protocols on effective dose estimates.Circulation. 2006; 113: 1305-1310Crossref PubMed Scopus (626) Google Scholar Data regarding the usage of cardiac MRI (cMRI) are very limited. Similar to CCT, vegetations can be visualized on valve leaflets, although not as well as with CCT or TEE, and perivalvular involvement can be indicated by the presence of delayed contrast enhancement of the valve itself or surrounding structures. A small study conducted by Dursun et al, utilizing cMRI on patients with a preliminary diagnosis of IE, found that cMRI detected vegetations in only 68% of those patients, but was able to display delayed contrast enhancement of either the valves or other cardiac structures, which helped to corroborate echocardiography or clinical findings.24Dursun M Yilmaz S Yilmaz E et al.The utility of cardiac MRI in diagnosis of infective endocarditis: Preliminary results.Diagn Interv Radiol. 2015; 21: 28-33Crossref PubMed Scopus (55) Google Scholar An assessment of valvular regurgitation, as well as myocardial damage that could be caused by the embolization of vegetations, can be well-assessed by cMRI, which may not aid in diagnosis but may assist with guiding surgical management.12Khalique OK Veillet-Chowdhury M Choi AD et al.Cardiac computed tomography in the contemporary evaluation of infective endocarditis.J Cardiovasc Comput Tomogr. 2021; 15: 304-312Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar,24Dursun M Yilmaz S Yilmaz E et al.The utility of cardiac MRI in diagnosis of infective endocarditis: Preliminary results.Diagn Interv Radiol. 2015; 21: 28-33Crossref PubMed Scopus (55) Google Scholar One of the major limitations to cMRI is that prosthetic valves cause significant imaging artifacts, making it very difficult to assess IE in this subset of patients. Similar to cMRI, literature regarding the use of fluorodeoxyglucose positron emission tomography (FDG-PET) in IE is limited. Studies have shown its utility in detecting infectious processes in the body, as well as infections in vascular prostheses.25Meller J Sahlmann CO Gurocak O et al.FDG-PET in patients with fever of unknown origin: the importance of diagnosing large vessel vasculitis.Q J Nucl Med Mol Imaging. 2009; 53: 51-63PubMed Google Scholar,26Bruggink JL Slart RH Pol JA et al.Current role of imaging in diagnosing aortic graft infections.Semin Vasc Surg. 2011; 24: 182-190Crossref PubMed Scopus (49) Google Scholar Since FDG-PET identifies areas of hypermetabolic activity, it has been postulated that it would help identify areas of infection within the heart, particularly in settings where TEE visualization is difficult, such as prosthetic valves. One study by Saby et al found the sensitivity and specificity of FDG-PET to be 73% and 80%, respectively, for detecting prosthetic valve endocarditis, and, in some patients, showed damage caused by infection even before it would have appeared on echocardiography, indicating it may have some value if applied early in the course of suspected infection.27Saby L Laas O Habib G et al.Positron emission tomography/computed tomography for diagnosis of prosthetic valve endocarditis: Increased valvular 18F-fluorodeoxyglucose uptake as a novel major criterion.J Am Coll Cardiol. 2013; 61: 2374-2382Crossref PubMed Scopus (357) Google Scholar There is little utility for FDG-PET in the diagnosis of native valve endocarditis; although, in these patients, it can be used to detect the source of infection.28Granados U Fuster D Pericas JM et al.Diagnostic accuracy of 18F-FDG PET/CT in infective endocarditis and implantable cardiac electronic device infection: A cross-sectional study.J Nucl Med. 2016; 57: 1726-1732Crossref PubMed Scopus (102) Google Scholar Considerations regarding FDG-PET include needing to ensure a diet rich in fat and low in carbohydrates prior to imaging to reduce physiologic uptake of FDG by the myocardium, as well as decreased usefulness in detecting infection in the first months after cardiac surgery, when early postoperative inflammation can confound results.27Saby L Laas O Habib G et al.Positron emission tomography/computed tomography for diagnosis of prosthetic valve endocarditis: Increased valvular 18F-fluorodeoxyglucose uptake as a novel major criterion.J Am Coll Cardiol. 2013; 61: 2374-2382Crossref PubMed Scopus (357) Google Scholar Untreated IE has very high morbidity and mortality, and, due to the breadth of patient presentation, diagnosis can be very challenging. The patient history, presentation, and laboratory findings, along with usage of the Duke criteria, can help guide clinicians, but imaging often is needed for a definitive diagnosis. While echocardiography remains the gold standard, certain limitations exist. These limitations include patient comorbidities, such as esophageal dysfunction, cardiac, anatomic, or structural issues like calcifications or prosthetic valves, and the concern regarding aerosolization of respiratory particles during the coronavirus disease 2019 pandemic. In these patients, noninvasive imaging, such as CCT, cMRI, and FDG-PET, often are useful. CCT, in particular, is able to identify large vegetations, perivalvular complications of IE, and the involvement of other structures (such as coronary arteries), which can help with surgical planning. CCT often confirms what was visualized with TEE, and, as such, appears to be most valuable when used in a multimodality approach in conjunction with TEE, either when TEE results are equivocal or with negative TEE results when clinical suspicion is high. The changing landscape of cardiac imaging in IE presents an exciting new frontier, with the potential for improving diagnosis and, thus, clinical outcomes for patients. None. Diagnosing Endocarditis: Get the Picture?!Journal of Cardiothoracic and Vascular AnesthesiaVol. 36Issue 2PreviewInfective endocarditis (IE), an infection of the endocardium, initially was described in 1646 and may affect native heart valves and/or chordae tendineae, prosthetic valves, and/or implanted cardiac devices. A definitive diagnosis of IE often is quite challenging because of the wide variability patients exhibit regarding clinical history, physical presentation, laboratory analysis, and imaging techniques.1,2 Traditionally, a diagnosis of IE is determined via the Modified Duke Criteria (Table 1), originally described in 1994 and modified in 2000, which encompass clinical history, physical presentation, laboratory analysis (primarily blood cultures), and transthoracic echocardiography (TTE) and/or transesophageal echocardiography (TEE). Full-Text PDF Erratum to ‘Diagnosing Endocarditis: Get the Picture?!’ [Journal of Cardiothoracic and Vascular Anesthesia (2022) 358-361]Journal of Cardiothoracic and Vascular AnesthesiaVol. 36Issue 7PreviewThe publisher regrets that the printed version of the above article did not contain the article's figures. The correct and final version follows. The publisher would like to apologise for any inconvenience caused. Full-Text PDF