Cardiac multidetector computed tomography in infective endocarditis: a pictorial essay

Tip of the iceberg: extracardiac CT findings in infective endocarditis

Infective endocarditis (IE) is a disease with high morbidity and mortality rate, but diagnosis is confounded by diverse clinical presentations, which mimic other pathologies. A history of illicit intravenous drug use, previous cardiac valve surgery, and indwelling intracardiac devices increases the risk for developing infective endocarditis. The modified Duke criteria serve as the standard diagnostic tool, though its accuracy is reduced in certain cases. Radiologists in the Emergency Room setting reading body CT may be the first to identify the secondary extra-cardiac complications and facilitate expeditious management by considering otherwise unsuspected infective endocarditis. This review highlights common extracardiac complications of IE and their corresponding CT findings in the chest, abdomen, pelvis, and brain. If IE is suspected radiologists should suggest further investigation with echocardiography.

Imaging in Infective Endocarditis-Current Opinions and Trends in Cardiac Computed Tomography

Infective endocarditis is a rare disease with an increasing incidence and an unaltered high mortality rate, despite medical development. Imaging plays an integrative part in the diagnosis of infective endocarditis, with echocardiography as the initial diagnostic test. Research data in the utility of cardiac computed tomography (CCT) in the diagnostic algorithm of IE are rising, which indicates its importance in detection of IE-related lesion along with the exclusion of coronary artery disease. The latest 2023 European Society of Cardiology Guidelines in the management of IE classified CCT as class of recommendation I and level of evidence B in detection of both valvular and paravalvular lesions in native and prosthetic valve endocarditis. This review article provides a comprehensive and contemporary review of the role of CCT in the diagnosis of IE, the optimization of acquisition protocols, the morphology characteristics of IE-related lesions, the published data of the diagnostic performance of CCT in comparison to echocardiography as the state-of-art method, as well as the limitations and future possibilities.

Cardiac Computed Tomography of Native Cardiac Valves

Valvular heart disease (VHD) is a significant clinical problem associated with high morbidity and mortality. Although not being the primary imaging modality in VHD, cardiac computed tomography (CCT) provides relevant information about its morphology, function, severity grading, and adverse cardiac remodeling assessment. Aortic valve calcification quantification is necessary for grading severity in cases of low-flow/low-gradient aortic stenosis. Moreover, CCT details significant information necessary for adequate percutaneous treatment planning. CCT may help to detail the etiology of VHD as well as to depict other less frequent causes of valvular disease, such as infective endocarditis, valvular neoplasms, or other cardiac pseudomasses.

Multimodality Imaging of Infective Endocarditis

Infective endocarditis (IE) is a complex multisystemic disease resulting from infection of the endocardium, the prosthetic valves, or an implantable cardiac electronic device. The clinical presentation of patients with IE varies, ranging from acute and rapidly progressive symptoms to a more chronic disease onset. Because of its severe morbidity and mortality rates, it is necessary for radiologists to maintain a high degree of suspicion in evaluation of patients for IE. Modified Duke criteria are used to classify cases as "definite IE," "possible IE," or "rejected IE." However, these criteria are limited in characterizing definite IE in clinical practice. The use of advanced imaging techniques such as cardiac CT and nuclear imaging has increased the accuracy of these criteria and has allowed possible IE to be reclassified as definite IE in up to 90% of cases. Cardiac CT may be the best choice when there is high clinical suspicion for IE that has not been confirmed with other imaging techniques, in cases of IE and perivalvular involvement, and for preoperative treatment planning or excluding concomitant coronary artery disease. Nuclear imaging may have a complementary role in prosthetic IE. The main imaging findings in IE are classified according to the site of involvement as valvular (eg, abnormal growths [ie, "vegetations"], leaflet perforations, or pseudoaneurysms), perivalvular (eg, pseudoaneurysms, abscesses, fistulas, or prosthetic dehiscence), or extracardiac embolic phenomena. The differential diagnosis of IE includes evaluation for thrombus, pannus, nonbacterial thrombotic endocarditis, Lambl excrescences, papillary fibroelastoma, and caseous necrosis of the mitral valve. The location of the lesion relative to the surface of the valve, the presence of a stalk, and calcification or enhancement at contrast-enhanced imaging may offer useful clues for their differentiation. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Multimodality Imaging Diagnosis in Infective Endocarditis

Imaging is an important tool in the diagnosis and management of infective endocarditis (IE). Echocardiography is an essential examination, especially in native valve endocarditis (NVE), but its diagnostic accuracy is reduced in prosthetic valve endocarditis (PVE). The diagnostic ability is superior for transoesophageal echocardiography (TEE), but a negative test cannot exclude PVE. Both transthoracic echocardiography (TTE) and TEE can provide normal or inconclusive findings in up to 30% of cases, especially in patients with prosthetic devices. New advanced non-invasive imaging tests are increasingly used in the diagnosis of IE. Nuclear medicine imaging techniques have demonstrated their superiority over TEE for the diagnosis of PVE and cardiac implantable electronic device infective endocarditis (CIED-IE). Cardiac computed tomography angiography imaging is useful in PVE cases with inconclusive TTE and TEE investigations and for the evaluation of paravalvular complications. In the present review, imaging tools are described with their values and limitations for improving diagnosis in NVE, PVE and CIED-IE. Current knowledge about multimodality imaging approaches in IE and imaging methods to assess the local and distant complications of IE is also reviewed. Furthermore, a potential diagnostic work-up for different clinical scenarios is described. However, further studies are essential for refining diagnostic and management approaches in infective endocarditis, addressing limitations and optimizing advanced imaging techniques across different clinical scenarios.

Computed Tomography and Magnetic Resonance Imaging Findings of Bicuspid Aortic Valve and Related Abnormalities of the Heart and Thoracic Aorta

The bicuspid aortic valve (BAV) is the most common congenital cardiovascular malformation. Patients with BAV are at higher risk of other congenital cardiovascular malformations and valvular dysfunction, including aortic stenosis/regurgitation and infective endocarditis. BAV may also be related to aortic wall abnormalities such as aortic dilatation, aneurysm, and dissection. The morphology of the BAV varies with the presence and position of the raphe and is associated with the type of valvular dysfunction and aortopathy. Therefore, accurate diagnosis and effective treatment at an early stage are essential to prevent complications in patients with BAV. This pictorial essay highlights the characteristics of BAV and its related congenital cardiovascular malformations, valvular dysfunction, aortopathy, and other rare cardiac complications using multimodal imaging.

Radionuclide Imaging of Infective Endocarditis

Infective endocarditis (IE) is associated with high morbidity and mortality. Early diagnosis is crucial for adequate patient management. Due to difficulties in the diagnosis, a multidisciplinary discussion in addition to the integration of clinical signs, microbiology data, and imaging data is used. Imaging, including echocardiography, molecular imaging techniques, and coronary CT angiography (CTA) is central to detect infections involving heart valves and implanted cardiovascular devices, also allowing for early detection of septic emboli and metastatic. This article describes the main clinical application of white blood cell SPECT/CT and [¹⁸F]FDG-PET/CT and CTA in IE and infections associated with cardiovascular implantable electronic devices.

Expanding utility of cardiac computed tomography in infective endocarditis: A contemporary review

There is increasing evidence on the utility of cardiac computed tomography (CCT) in infective endocarditis (IE) to investigate the valvular pathology, the extra-cardiac manifestations of IE and pre-operative planning. CCT can assist in the diagnosis of perivalvular complications, such as pseudoaneurysms and abscesses, and can help identify embolic events to the lungs or systemic vasculature. CCT has also been shown to be beneficial in the pre-operative planning of patients by delineating the coronary artery anatomy and the major cardiovascular structures in relation to the sternum. Finally, hybrid nuclear/computed tomography techniques have been shown to increase the diagnostic accuracy in prosthetic valve endocarditis. This manuscript aims to provide a contemporary update of the existing evidence base for the use of CCT in IE.

Tricuspid valve endocarditis: Cardiovascular imaging evaluation and management

Right-sided infective endocarditis is an increasingly recognized disease entity, with tricuspid valve being most frequently involved. Risk factors for tricuspid valve endocarditis (TVIE) include intravenous drug use, cardiac implantable electronic devices and indwelling catheters. Staphylococcus aureus is the predominant causative organism in TVIE. The diagnosis of infective endocarditis (IE) is based on clinical manifestations, blood cultures, and the presence of valvular vegetations detected by echocardiography. Complementary imaging is helpful when there is ongoing clinical suspicion for IE following initially negative echocardiography. Multislice computed tomography allows for assessment of extra-cardiac complications in TVIE, including pulmonary septic emboli. 18F-fluorodeoxyglucose positron emission tomography/computed tomography and radiolabelled white blood cell, single-photon emission computed tomography provide important clinical information concerning the presence of IE in right-sided prosthetic valves or cardiac implantable electronic devices. The aim of this review is to provide an update on TVIE, discussing the role of multimodality imaging in TVIE and the management of these patients.

Role of Cardiac CT in Infective Endocarditis: Current Evidence, Opportunities, and Challenges

Infective endocarditis (IE) can present with variable clinical and imaging findings and is associated with high morbidity and mortality. Substantial improvement of CT technology, most notably improved temporal and spatial resolution, has resulted in increased use of this modality in the evaluation of IE. The aim of this article is to review the potential role of cardiac CT in evaluating IE. Supplemental material is available for this article. © RSNA, 2021.

Infective endocarditis - A review of current therapy and future challenges

Etiological, microbiological and epidemiological factors changed over time, but mortality rates remain high in infective endocarditis (IE). Healthcare-associated IE is nowadays responsible for a significant proportion of cases due to increasing numbers of cardiac devices. Cardiac implantable electronic devices, transcatheter aortic valve replacement, and percutaneous valve repair are meanwhile used, especially in old and sick patients. In suspected IE modified Duke criteria, integrating clinical results, imaging, and biomarkers are traditionally applied. Newer imaging technologies such as multi-slice computed tomography, photon-emission computed tomography, and magnetic resonance imaging might add value to conventional echocardiography in diagnosis and management of IE. Treatment consists of long-term antibiotic therapy, infectiological source control and/or cardiac surgery. Recently, antibiotic parenteral outpatient regimens and partial oral treatment strategies were shown to shorten hospital stays in patients suffering from IE. However, it remains unclear how to best select patients for partial oral therapy. This review describes new trends in diagnosing, imaging, and treating IE in a changing patient collective with particular focus on patients with implantable cardiac devices.

Multimodality Imaging in the Diagnostic Work-Up of Endocarditis and Cardiac Implantable Electronic Device (CIED) Infection

Infective endocarditis (IE) is a serious cardiac condition, which includes a wide range of clinical presentations, with varying degrees of severity. The diagnosis is multifactorial and a proper characterization of disease requires the identification of the primary site of infection (usually the cardiac valve) and the search of secondary systemic complications. Early depiction of local complications or distant embolization has a great impact on patient management and prognosis, as it may induce to aggressive antibiotic treatment or, in more advanced cases, cardiac surgery. In this setting, the multimodality imaging has assumed a pivotal role in the clinical decision making and it requires the physician to be aware of the advantages and disadvantages of each imaging technique. Echocardiography is the first imaging test, but it has several limitations. Therefore, the integration with other imaging modalities (computed tomography, magnetic resonance imaging, nuclear imaging) becomes often necessary. Different strategies should be applied depending on whether the infection is suspected or already ascertained, whether located in native or prosthetic valves, in the left or right chambers, or if it involves an implanted cardiac device. In addition, detection of extracardiac IE-related lesions is crucial for a correct management and treatment. The aim of this review is to illustrate strengths and weaknesses of the various methods in the most common clinical scenarios.

Multimodality Imaging in Infective Endocarditis: An Imaging Team Within the Endocarditis Team

Infective endocarditis (IE) is a complex disease with cardiac involvement and multiorgan complications. Its prognosis depends on prompt diagnosis that leads to an aggressive therapeutic management combining antibiotic therapy and early cardiac surgery when indicated. However, IE diagnosis always poses a challenge, and echocardiography remains diagnostically imperfect in cases of prosthetic valve IE or cardiac implantable electronic device infection. In recent years, other imaging modalities (computed tomography, magnetic resonance imaging, nuclear imaging) have experienced significant technical improvements, and their application to the detection of cardiac and extracardiac IE-related lesions seems to be a strategic way forward in the management of patients with suspected IE. However, the scientific evidence in the literature remains limited; current guidelines address the use of the multimodality imaging in the field of IE with caution; the incremental value of each technique and their combinations is debated; and their use varies across countries. Despite these limitations, healthcare providers and surgeons should be aware of the possibilities offered by the multimodal imaging approach when appropriate. Here, we emphasize the value of a multidisciplinary heart valve team, the endocarditis team, underlining the importance of cardiac and extracardiac imaging experts in playing a key role in informing the diagnosis and management of patients with IE. Illustrative cases, critical appraisal of contemporary data, and conceptual and practical suggestions for clinicians that may help to improve the prognosis of patients with IE are provided in this review article.

Caseous Calcification of the Mitral Annulus

Soft-tissue masses or mass-like lesions involving the mitral valve include a wide range of diseases such as tumors, abscesses, vegetations, thrombus and, rarely, caseous calcifications of the mitral annulus. Caseous calcifications of the mitral annulus is a rare variant of mitral annular calcification that is usually asymptomatic and diagnosed incidentally. Echocardiography is the first-choice imaging modality. Cardiac computed tomography is an ideal tool to confirm the presence of calcifications and caseous necrosis. In cases where there is doubt, cardiac magnetic resonance imaging may be used. We present the case of a 62-year-old patient with an intra-cardiac mass diagnosed by echocardiography. Imaging modalities to achieve a correct diagnosis and avoid unnecessary surgical intervention are discussed.

The usefulness of cardiac CT in the diagnosis of perivalvular complications in patients with infective endocarditis

Objectives

The aim of the study was to compare the usefulness of cardiac CT to transthoracic (TTE) and transesophageal (TEE) echocardiography in the diagnosis of infective endocarditis (IE) and perivalvular complications using surgical inspection as the gold standard.

Material and methods

Fifty-three consecutive patients (42 men, mean age 58.3 ± 12.5) with IE requiring surgical procedures were enrolled in the study. All patients underwent preoperative TTE, TEE, and CT. The presence of vegetations, perivalvular abscess/pseudoaneurysm, leaflet perforation, inflammatory infiltration, and prosthesis dehiscence was assessed.

Results

We analyzed 71 affected valves (58 native, 13 prosthetic). Intraoperative assessment revealed 11 abscesses/pseudoaneurysms. Sensitivity and specificity of echocardiography (TTE + TEE) and CT were 63%, 90% and 81%, 90%, respectively. The combination of CT and echocardiography allowed diagnosing all abscesses/pseudoaneurysms. Inflammatory infiltration was found intraoperatively in 15 patients. Sensitivity and specificity of TEE and CT were 53%, 94% and 46%, 100%, respectively. Intraoperative assessment revealed leaflet perforation in 16 patients. Sensitivity and specificity of TEE and CT were 75%, 79% and 43%, 89%. The sensitivity of the combination of TTE + TEE + CT was 81%. Perivalvular leakage was found in eight patients with a prosthetic valve. Sensitivity and specificity of echocardiography and CT were 100%, 100% and 88%, 100%, respectively. TEE showed higher sensitivity (97%) than CT (89%) in the diagnosis of vegetations.

Conclusions

The combination of TTE, TEE, and CT increased the sensitivity for the detection of valvular and perivalvular complications of IE.

Key Points

• CT is a useful modality in the diagnosis of IE and its local complications in addition to echocardiography.

• For the detection of abscesses and pseudoaneurysms, CT is superior to echocardiography. Combining these two modalities can increase the sensitivity of diagnosing abscess/pseudoaneurysm up to 100%.

• Adding CT to TEE increases the sensitivity for detection of inflammatory infiltrate. CT is not superior to echocardiography in diagnosing vegetations, valvular leaflet perforations, and perivalvular leaks, but it can be a useful tool when echocardiography is indeterminate.

Demonstration of infective endocarditis by cardiac CT and transoesophageal echocardiography: comparison with intra-operative findings

Aims

We aimed to compare imaging findings of infective endocarditis between computed tomography (CT) and transoesophageal echocardiography (TEE) using surgical inspection as a reference standard.

Methods and results

Forty-nine patients (aged 54 ± 17 years, 69% men) who underwent pre-operative CT and TEE for infective endocarditis were included. Twelve of these patients had prosthetic valve endocarditis. Imaging findings of infective endocarditis were classified as vegetation, leaflet perforation, abscess/pseudoaneurysm, and paravalvular leakage. Diagnostic performances of CT and TEE were evaluated using surgical inspection as a reference standard. Interobserver agreements for CT findings were obtained using Cohen's κ test. The detection rates of infective endocarditis per patient with CT and TEE were 93.9% (46/49) and 95.9% (47/49), respectively. In per-imaging analysis, the sensitivities of CT and TEE were not significantly different for both native and prosthetic valve infective endocarditis (sensitivity: vegetation, 100% in TEE and 90.9% in CT; leaflet perforation, 87.5% in TEE and 50.0% in CT; abscess/pseudoaneurysm, 40.0% in TEE and 60.0% in CT; paravalvular leakage, 100% in TEE and 50.0% in CT). Interobserver agreements for CT findings were substantial or excellent (0.79-0.88).

Conclusion

Cardiac CT can accurately demonstrate infective endocarditis in pre-operative patients with a similar diagnostic accuracy to TEE. The interobserver agreements for the CT findings of infective endocarditis were excellent.

Complications of Intravenous Substance Use Disorders (SUDs): A Multimodality Pictorial Essay for Cardiothoracic Radiologists

With the growing substance use disorders epidemic in the United States, a wide range of complications may be seen in both the acute and chronic clinical setting. This article will use a multimodality approach to review complications of intravenous substance use that cardiothoracic radiologists are likely to encounter. Radiologists should be aware of these multisystem complications that can affect the cardiovascular, respiratory, and musculoskeletal systems in order to make an accurate and timely diagnosis, which can drastically alter the management of these patients.

Management of Septic emboli in patients with infectious endocarditis

BACKGROUND AND AIM

Septic emboli (SE) associated with infectious endocarditis (IE) can result in splenic abscesses and infectious intracranial aneurysms (IIA). We investigated the impact of SE on patient outcomes following surgery for IE.

METHOD

From January-2000 to October-2015, all patients with surgical IE (n = 437) were evaluated for incidence and management of SE.

RESULTS

Overall SE was found in 46/437 (10.52%) patients (n = 17 spleen, 13 brain, and 16 both). No mortality was seen in the brain emboli groups, but in the splenic abscess group the in-hospital mortality was 8.69% (n = 4); and was associated with Age >35 (OR = 2.63, 1.65-4.20) and congestive heart failure (OR = 14.40, 1.23-168.50). Patients with splenic emboli had excellent mid-term outcome following discharge (100% survival at 4-years). Splenic emboli requiring splenectomy was predicted by a >20 mm valve vegetation (OR = 1.37, 1.056-1.77) and WBC >12000 cells/mm (OR = 5.58, 1.2-26.3). No patient with streptococcus-viridians infection had a nonviable spleen (OR = 0.67, 0.53-0.85). Postoperative acute-kidney-injury was higher in the splenectomy group (45.45% vs 9%) (p = 0.027). There were 6 patients with symptomatic IIAs that required coiling/clipping which was associated with age <30 years, (OR = 6.09, 1.10-33.55). Survival in patients with cerebral emboli decreased to 78% at 3-4 years. Patients with both splenic and brain emboli had a 92% survival rate at 1-year and 77% at 2-4 years.

CONCLUSION

Septic emboli is common in endocarditis patients. Patients with high preoperative WBC level and large valve vegetations require CT imaging of the spleen. Both spleen and brain interventions in the setting of IE can be performed safely with excellent early and mid-term outcomes.

Cross-sectional imaging of aortic infections

Aortic infections are uncommon clinical entities, but are associated with high rates of morbidity and mortality. In this review, we focus on the cross-sectional imaging appearance of aortic infections, including aortic valve endocarditis, pyogenic aortitis, mycotic aneurysm and aortic graft infections, with an emphasis on CT, MRI and PET/CT appearance. Teaching Points • Aortic infections are associated with high morbidity and mortality. • CT, MRI and FDG PET/CT play complementary roles in aortic infection imaging. • Radiologists should be vigilant for aortic infection manifestations to ensure timely diagnosis.

Aortocavitary fistula as a complication of infective endocarditis and subsequent complete heart block in a patient with severe anemia

Infective endocarditis has different presentations depending on the involvement of valvular and perivalvular structures, and it is associated with high morbidity and mortality. Aortocavitary fistula is a rare complication. We introduce the case of a 48-year-old female with native valve endocarditis, complicated by aortocavitary fistula to the right atrium, and consequently presented with syncope.