Case of the month header
 March 2010

Dear SCCT Member:

As you know, the SCCT is the only professional medical membership organization dedicated to ensuring patient access to the appropriate use of cardiovascular CT. The SCCT Board of Directors thought that it would be beneficial to our members to create a Case of the Month series that showcases cardiac CTA in various clinical scenarios. Please provide feedback or forward any questions to info@scct.org.

Sincerely,
John R Lesser, MD, FSCCT
Suhny Abbara, MD, FSCCT
Jeff Carr, MD, FSCCT
Daniel Entrikin, MD
Cardiac CTA is Useful in Suspected Prosthetic Paravalvular Abscess
B Williams, R Schwartz, B Flygenring, T Knickelbine, T Longe, J Lesser
  Minneapolis Heart Institute
History

A 31 y/o female presented to the Minneapolis Heart Institute with chills, fever, and dyspnea for one week. Initial blood cultures were positive for Streptococcus mitis. She had a history of aortic valve endocarditis in 2006, bioprosthetic AVR (7/06), and repeat AVR with ascending aorta replacement with homograft (10/06) due to recurrent endocarditis. TEE now showed normal LV size and function, severe aortic regurgitation, mobile density of the right aortic leaflet, and and one echo-free space suspicious for abscess. Cardiac and proximal aortic CTA was performed (with function, radiation dose 5 mSv).
Findings

The prosthetic valve had a 1.1 cm mobile vegetation which flipped from the ascending aorta to the LV outflow tract (yellow arrow). Beneath the AVR were 2 separate pseudoaneurysms (blue arrows) connecting the LV chamber and a 6 mm inflammatory mass surrounding the aortic tube graft and AoV (red arrows). She then underwent successful high risk redo AVR/ascending aorta graft surgery which confirmed the CT findings.
 Image 2 Image 3Graphic 1
Discussion

Cardiac valves are typically best imaged with echocardiography.  However, when full visualization of both aortic and cardiac structures is required, gated CT angiography is an excellent option. CT angiography can assess many prosthetic valve complications, such as thrombus or pannus, valve dehiscence, pseudoaneurysm, infectious endocarditis, and paravalvular abscess (1,2).  A recent study compared multidetector CT with TEE in endocarditis and showed a good correlation.  Vegetation size correlated with CT as did mobility of vegetations. As in our patient, CT provided more accurate information about pseudoaneurysm and abscesses than TEE (3).
References

1. Chen JJ, et al. "CT Angiography of the Cardiac Valves: Normal, Diseased, and Postoperative Appearances." Radiographics 2009;29(5):1393-412.
2. Gaztanaga et al. "Evaluation of Cardiac Valves Using Multidetector CT." Cardiol Clin 2009;27:633-644.
3. Feuchtner GM, et al. "Multislice Computed Tomography in Infective Endocarditis." J Am Coll Cardiol 2009;53:436-44.
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If you would like to submit a Case of the Month for publication, please contact Debra Fernandez at dfernandez@scct.org for specifications and instructions.