Kalitzeos, A; (2006) The use of contrast agents for the visualisation of ocular blood flow by means of Doppler ultrasound. Masters thesis , University of Crete.

Abstract

Ultrasonography and Doppler ultrasound have undergone an impressive metamorphosis since their appearance and now occupy a pivotal role at the forefront of radiological imaging, as qualitative or quantitative tools for functional characterization of the vascular system. Ultrasonic methods that have developed throughout the years are used routinely in the investigation and treatment of many pathologic situations. One of the numerous medical branches that ultrasonography has been applied to is ophthalmology, being a fundamental choice for non-invasive ocular examination for the evaluation of a possible eye disease. The ultrasound revolution has mainly been due to technological advances in electronics and computing and is responsible for the diversity of imaging modes at the sonographer�s disposal. Microbubble contrast agents have dramatically extended the clinical and research applications of ultrasound and allow the microcirculation to be imaged as well as providing functional data, being safe and effective vascular echo enhancers. The aim of our study was to identify and evaluate possible differences between two separate conditions in the retrobulbar vascular system of our group of patients, using Doppler ultrasound in conjunction with the use of microbubble contrast agents. For the complete comprehension of the experimental part of this project, we present extensively the indicated theoretical background of ultrasound in general and of course the fundamental properties of Doppler ultrasound and microbubble contrast agents, that are closely related to the subject of this work. Each one of the patients that participated in this study had undergone vitrectomy for various pathologic reasons. We inserted the appropriate gas inside the vitreous cavity of each study eye for the treatment of the pathologic eyes. The study was conducted when there was 20-30% repletion of gas in the vitreous cavity and it was repeated when the vitreous cavity took up with aqueous humour. After the Colour Doppler analysis there was not found any statistical differences between PI or RI, neither between study eyes, nor between control eyes in both conditions (before-after). On the contrary, we found a statistical significant difference (p=0.0145) in blood perfusion rate between the bulbar vascular regions of the two different conditions in the Power Doppler part of our study. Finally, there was no statistical significant difference between the retrobulbar vascular regions (p=0.759).

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