Troy LaBounty, Presenter: Nothing to Disclose

Prachi Agarwal MD, Abstract Co-Author: Nothing to Disclose

Aamer Rasheed Chughtai MBBS, Abstract Co-Author: Nothing to Disclose

David Bach, Abstract Co-Author: Nothing to Disclose

Eric Wizauer, Abstract Co-Author: Nothing to Disclose

Ella A. Kazerooni MD, Abstract Co-Author: Consultant, General Electric Company Consultant, Vital Images, Inc Research funded, General Electric Company

Echocardiography can assess elevated valvular peak velocities, but is limited in its visualization of mechanical valves because of shadowing. We sought to determine the feasibility of mechanical aortic valve functional assessment using retrospectively gated 64-slice multidetector computed tomography (MDCT).

Data from 64-detector retrospectively gated MDCT and transthoracic echocardiography (TTE) was retrospectively evaluated in 33 patients with mechanical aortic valves [n=20 for Medtronic-Hall (MH) valves and n=13 for St. Jude (SJ) valves]. Two MDCT readers independently and blindly determined annulus diameter (AD) and opening angles (OA); one TTE reader blindly measured peak velocity. AD was measured on CT in a plane parallel to the valve using electronic calipers and the OA was measured in a plane vertical to the valve using an electronic protractor on images showing the least motion artifact. The AD and OA were compared between MDCT readers, and between MDCT and manufacturer specifications. The OA was compared in patients with elevated (>3.0 m/s) versus normal peak velocities on TTE.

OA and AD could be determined in all patients on MDCT. There was high correlation between MDCT readers for OA (SJ: r=0.87; MH: r=0.93) and AD (SJ: r=0.93; MH: r=0.94). For valves with normal peak velocities on TTE, the OA with MDCT was slightly lower than specifications provided by the manufacturer (SJ: 83.4±4.4 versus 90°, p<0.01; MH: 69.4±6.5 versus 75°, p<0.01). OA was lower in patients with elevated (n=6) versus normal (n=27) peak velocities (p<0.05). When known, valve size with MDCT was similar to specifications for SJ (n=6; AD=25.7±4.3 versus 25.3±2.3mm, p=0.65, r=0.98) and MH valves (n=17; AD=27.6±2.2 versus 28.8±2.6mm, p=0.02, r=0.71).

MDCT has high interobserver agreement for AD and OA. In comparison to manufacturer specifications, the AD is similar, and the OA is slightly smaller using MDCT. In patients with MH or SJ valves and elevated velocities, MDCT may be useful in evaluating valve function.

Computed tomography may be useful to identify valve malfunction or patient-prosthesis mismatch by measuring valve size and opening angles in patients with high gradients on echocardiography.

LaBounty, T, Agarwal, P, Chughtai, A, Bach, D, Wizauer, E, Kazerooni, E, Assessment of Mechanical Aortic Valves with 64-Detector Computed Tomography and Echocardiography: A Feasibility Study.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6011764.html