Vascularization of hydroxyapatite orbital implants: Comparison between ultrasonic contrast and enhanced MRI / 中国组织工程研究

ABSTRACT

BACKGROUND: It is very important to evaluate vascularization of postoperative hydroxyapatite (HA) orbital implants in human eyes. Recently, methods for evaluating vascularization of HA orbital implants are limited; however, ultrasonic contrast is a novel technique to high-precisely measure blood flow.OBJECTIVE: To investigate the feasibility of ultrasonic contrast to evaluate the vascularization of HA orbital implants, and to compare with enhanced MRI.DESIGN, TIME AND SETTING: The comparative observation was performed at Departments of Ophthalmology and Ultrasound,Jiangyin People's Hospital between January 2008 and January 2009.PARTICIPANTS: Ten patients including 8 males and 2 females were treated with eye ball extirpation and HA orbital implants. The patients were aged 24-61 years, with the mean age of (45.0±10.2) years. HA orbital implants were crossly coated using anterior part of pedicle scleral flap.METHODS: PHILIPS IU22 color Doppler ultrasound was used in this study, and SonoVue (59 mg) was the major contrast medium. Sulphur hexafluoride was dissolved in saline to make suspension. A 2.4-mL suspension was injected through peripheral vein of elbow. Enhanced MRI was additionally used in this study Siemens Magnetom Avanto 1.5T, standard head coil, horizontal axis, 2.0-3.0 mm thickness, no interval, FOV 160 mmxi80 mm, 256x256 matrix, and SE sequence T1WI (TR 500 ms, TE 12 ms).Dimeglumine gadopentetate injection was used as a contrast medium.MAIN OUTCOME MEASURES: Vascularization characteristics and degrees between ultrasonic contrast and enhanced MRI at different time points after implantation.RESULTS: Ultrasonic contrast showed a well dynamic contrast-enhanced image of the anterior part of HA in early stage of post-operation, and showed distributing instance and density of blood vessel. Later stage of post-operation (about 3-6 months),contrast-enhanced image was unconspicuous. The enhanced MRI showed a clear vascularization of HA orbital implants at the stage of post-operation.CONCLUSION: Ultrasonic contrast is a effective investigative way to evaluate vascularization of HA orbital implants in early stage of implantation, and it is limited at the later stage of post-operation than enhanced MRI.