Assessment of Infective Endocarditis and Valvular Tumors






  • Key Points



  • There have been few studies of the yield and contribution of CCT to the evaluation of infective endocarditis, but vegetations can be imaged, and several structural complications of endocarditis have been well described.



  • The use of CCT to establish the absence of significant coronary artery disease in patients with complicated cases of aortic valve endocarditis who are to undergo surgery is appealing because it obviates the need for catheter-based coronary angiography.



  • Fibroelastomas of the aortic valve also can be depicted by CCT.




Infectious Endocarditis


Although it is still early in the process of validating cardiac CT (CCT), this test may have a role to play in the assessment of aortic valve endocarditis—less to assess vegetations than to assess the aortic root for abscesses. The erratic oscillatory motion of many vegetations, and their irregular surfaces, render the lesions underrepresented, principally due to partial volume averaging effects.


Complications of endocarditis such as vegetations, abscesses, and fistulas can be imaged by CCT ( Table 18-1 ). Although cardiac MR (CMR) previously was better validated for the detection of root complications of endocarditis, current CCT technology appears considerably more promising. Root abscess lesions can be imaged by CCT if they are not seen by transesophageal echocardiography (TEE), but metallic prosthetic valve material may impart image artifact in the vicinity of a ring abscess. CMR suffers from the same effect, probably to a greater degree.



TABLE 18-1

64-CT for the Detection of Valvular Lesions and Abscesses of Endocarditis



































































SENSITIVITY (%) SPECIFICITY (%) PPV (%) NPV (%) INTERMODALITY AGREEMENT
Valvular abnormalities 97 98 97 88 κ = 0.84
Vegetations 96
Abscesses 100
Perforations ≤ 2 mm 0
Mobility of vegetations 96
Correlation of size versus TEE r = 0.95, P < .001
Per-valve basis for the detection of vegetations, abscesses/ pseudoaneurysms 96 97 96 97
TEE 100 100 100 100

IE, infective endocarditis; NPV, negative predictive value; PPV, positive predictive value; TEE, transesophageal echocardiography.

Data from Feuchtner 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(5):436-444.

n = 37 patients with suspected IE; TEE versus CCT, 29 cases proven to have definite IE



Transthoracic echocardiography (TTE) and TEE remain the principal tests for assessing the presence of vegetations, abscesses, and fistulas. These tests do have limitations, however, especially in the presence of aortic valve prostheses, where the prosthesis is imaged edge-on and the sewing ring, in particular, may acoustically shadow the far side structures or cover them in reverberation artifact, thus obscuring relevant findings. Minor degrees of perivalvular insufficiency, while commonly seen in endocarditis, are not specific for this condition. It may be difficult to distinguish postoperative inflammatory changes and hematomas from infectious changes by TEE and probably by any modality. When compared with surgical findings, incorrect echocardiographic diagnosis was found in 7% of mitral mechanical valve cases and in 15% of aortic valve mechanical prosthesis cases.


The predictive value of CCT for the diagnosis of all anatomic echocardiographic findings of endocarditis has been published ( Table 18-2 ).



TABLE 18-2

Positive Predictive Value of the Echocardiographic Findings of Prosthetic Value Endocarditis






















































TRUE POSITIVES FALSE POSITIVES PPV (%)
Vegetations 17 1 94
Abscesses 19 1 96
Dehiscences 4 0 100
Pseudoaneurysms 3 0 100
Fistulas 2 0 100
Perivalvular leaks
Mild regurgitation 1 1 6
Moderate to severe regurgitation 15 0 100
All echocardiographic findings 61 16 94

PPV, positive predictive value.

Data from Ronderos RE, Portis M, Stoermann W, Sarmiento C. Are all echocardiographic findings equally predictive for diagnosis in prosthetic endocarditis? J Am Soc Echocardiogr. 2004;17(6):664-669.




Vegetations


Valvular vegetations can be imaged by CCT ( Figs. 18-1 through 18-5 ; ).




Figure 18-1


A 48-year-old man presented with chest pain, fever, and chills, and a 20-pound weight loss over 6 weeks following prostatectomy. His troponins were elevated. A, Transthoracic echocardiography revealed a shaggy soft tissue mass on the aortic valve, which appeared to dome. B, Transesophageal echocardiography revealed the shaggy mass in detail. C, A chest CT showed the large mass on the aortic valve (and no pulmonary embolism). An ECG-gated cardiac CT scan ( D ), performed to assess CT coronary angiography, revealed in clear detail the shaggy aortic valve lesion. Blood cultures were heavily positive for Enterococcus faecalis . These images illustrate the relative spatial resolution/image clarity of the four different modalities for detection of large vegetations. E, The surgically excised vegetation fragments.



Figure 18-2


Same patient as Figure 18-1 . Contrast-enhanced cardiac CT short-axis axial images at the level of the aortic root. Variation in the attenuation of the soft tissue is seen at the root and lower ascending aortic valve level, suggestive of inflammation.



Figure 18-3


Same patient as Figure 18-1 and 18-2 . Intraoperative images during resection of a large aortic valve vegetation. A 5-mm abscess/false aneurysm was seen at the root level, corroborating the impression of the CT scan obtained 4 days earlier that the aortic wall was inflamed.



Figure 18-4


Mitral valve endocarditis (vegetation and abscess) likely secondary to empyema. Composite images from a cardiac CT study demonstrate small-to-moderate bilateral pleural effusions with a mild amount of pleural reaction (thickening and enhancement) involving the right pleural reflection. A small amount of pleural gas also is noted. No pleural tap had been performed. Inverted CT cine images demonstrate a soft tissue mass larger than 1 cm along the free edge of the posterior mitral valve leak, consistent with a vegetation. An extension of the blood pool (an abscess) also is seen on the medial aspect of the mitral annulus. See



Figure 18-5


Contrast-enhanced ECG-gated CT scans of a 23-year-old patient with a prior Ross procedure, presenting with fevers and Staphylococcus aureus bacteremia. Transthoracic and transesophageal echocardiography suggested the presence of pulmonic valve vegetations but were inconclusive. Cardiac CT imaging revealed and confirmed vegetations on the pulmonic valve. A and B, Long-axis/outflow views. C and D, Cross-sectional/short-axis views of the pulmonic valve.




Structural Complications of Endocarditis



Apr 10, 2019 | Posted by in COMPUTERIZED TOMOGRAPHY | Comments Off on Assessment of Infective Endocarditis and Valvular Tumors

Full access? Get Clinical Tree

Get Clinical Tree app for offline access