Assessment of a transcatheter heart valve prosthesis with multidetector computed tomography: in vitro and in vivo imaging characteristics

Multidetector-row computed tomography (MDCT) image quality (IQ) of the commonly implanted Sapien prosthesis was assessed both in vitro and in vivo. The prosthesis was imaged in an in vitro model with a 256-slice CT system under pulsatile conditions using three protocols (1) retrospectively ECG-gating at 120 kV/600 mAs and (2) 140 kV/406 mAs, and (3) prospective triggering at 120 kV/210 mAs (10 acquisitions per protocol). After reconstruction in three perpendicular planes, IQ of the supra-,peri-,sub-,and intraprosthetic as well as leaflet regions was scored on a four-point scale (1 = non-diagnostic, 2 = moderate, 3 = good and 4 = excellent) by two observers. IQ was also assessed for twenty-one post-operative scans. The in vitro scans of the two retrospective protocols and twenty-one in vivo scans were analyzed during systole and diastole. The prospectively triggered scans were analyzed during diastole. Except for the valve leaflets in 5 systolic reconstructions, the in vitro scores were moderate to excellent. In vivo, 7 systolic and 3 diastolic reconstructions of the valve leaflets were non-diagnostic as well as 3 peri-prosthetic regions in diastole. All other scores were moderate to excellent. The Sapien prosthesis surrounded by a radiopaque stainless steel stent can be visualized with MDCT with moderate to good IQ, except for the valve leaflet region that has generally non-diagnostic or moderate IQ.