Improving the analysis of arteriovenous passage times.

Abstract

This study evaluated the effect of two techniques, time-based correction (TBC) and de-interlacing, on the quality of an image sequence from a scanning laser ophthalmoscope (SLO), and their impact on subsequent analysis for the determination of arteriovenous passage (AVP) times. Fluorescein angiograms obtained from one patient participating in a concurrent study approved by an institutional review board (IRB) were analyzed before and after the serial connection of a TBC, and before and after de-interlacing of the images. Informed consent was obtained, and all tenets of the Declaration of Helsinki were followed. AVP times were determined and the variance in time per 100 frames was calculated. The average error in the determination of AVP times was significantly less after the application of these techniques ( p<0.05). Also, the coefficient of variance in the time elapsed per 100 frames was reduced after TBC and de-interlacing of the video sequence. The study showed that in addition to the subjective improvement in image quality after de-interlacing and TBC, quantitative parameters are improved. This leads to a more accurate analysis of the angiogram.