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.

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 ).

Vegetations

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

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.

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.

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 Video 18-1.

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

• □
  

  Abscesses and fistulas can be imaged by CCT.

  
  
• □
  

  For images of valvular endocarditic perforations, see Figures 18-6 through 18-8 ;

  
  

  
  

  
  

  

  
  

  
  

  Oblique multiplanar reformatted images show a cross section through the aortic valve in the open position ( A ) and immediately below the valve in the closed position ( B ). C and D , The corresponding thin-slab three-dimensional (3D) volumetric reconstructions with the blood pool inverted to better display valvular anatomy. Note the functionally bicuspid valve in A and C. With the valve closed ( D ) there is clear delineation of the commissural fusion of the right and left cusps, the median raphe, and a 5-mm perforation of the noncoronary cusp, all best shown on the 3D volumetric reconstruction. E, Operative specimen showing a 5-mm perforation of the noncoronary cusp of the bicuspid aortic valve.

  Only gold members can continue reading. Log In or Register to continue

  Share this:

  • Click to share on Twitter (Opens in new window)
  • Click to share on Facebook (Opens in new window)

  Related posts:

  Overview of the Process, Exclusions and Risks, and Preparation CTA Assessment of Saphenous Vein Grafts and Internal Thoracic (Mammary) Arteries Determination of Coronary Calcium Assessment of Left Ventricular Structural Abnormalities Cardiac and Paracardiac Masses Caval Anatomy: Variants and Lesions

  

  Stay updated, free articles. Join our Telegram channel

  Join