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The accurate assessment of changes in retinal vessel diameter using multiple frame electrocardiograph synchronised
M J Dumskyj1, S J Aldington, C J Dore
1Department of Medicine and Department of Medical Statistics, Royal Postgraduate Medical School, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK.
Insights
Electrocardiograph synchronized fundus photography reliably detects small changes in retinal vessel diameter. This method improves accuracy for detecting subtle alterations, crucial for research and clinical applications.
Area of Science:
- Ophthalmology
- Medical Imaging
- Cardiovascular Research
Background:
- Retinal vessel diameter changes are significant in various research fields.
- Pulse-related diameter fluctuations necessitate accounting for them in studies.
- Accurate measurement of retinal vessels is key for understanding ocular and systemic health.
Purpose of the Study:
- To evaluate the impact of electrocardiograph (ECG) synchronization on detecting retinal vessel diameter changes.
- To compare the effectiveness of multiple fundus photographs with and without ECG synchronization.
- To determine the optimal number of synchronized images for reliable detection of small diameter variations.
Main Methods:
- Acquired 12 ECG-synchronized fundus photographs throughout the cardiac cycle in 10 volunteers.
- Measured vessel diameters using computer-assisted image analysis.
- Modeled smaller sample sizes with and without ECG synchronization from existing data.
Main Results:
- Six or more ECG-synchronized photographs reliably detected 1.4% diameter changes in 10 subjects.
- Unsynchronized methods or fewer images were unreliable for detecting small changes.
- Larger changes (5.4%) were detectable with any method, including a single unsynchronized photograph.
Conclusions:
- Multiple-frame ECG-synchronized fundus photography enhances the accuracy of detecting small retinal vessel diameter changes.
- This advanced imaging technique is superior for identifying subtle vascular alterations.
- ECG synchronization is vital for precise quantification of retinal vessel dynamics.
Purpose:
Detection and precise quantification of changes in retinal vessel diameter by image analysis techniques is important in a number of fields of research. The retinal vessels have been shown to exhibit pulse related changes in diameter. These may need to be taken into account when studying diameter changes due to other causes. This study examined the effect of using multiple fundus photographs with and without electrocardiographic synchronisation on the size and statistical significance of changes in mean retinal vessel diameter.
Methods:
Twelve fundus photographs spaced throughout the cardiac cycle by electrocardiographic synchronisation were taken in 10 normal volunteers: (a) at rest, (b) during isometric exercise, and (c) during oxygen inhalation. Vessel diameters were measured using a computer assisted image analysis system. Subsequently smaller sample sizes, with and without electrocardiograph synchronisation were modeled from the available data.
Results:
With a group of ten subjects six or more electrocardiograph synchronised photographs enable reliable detection of small diameter changes (1.4%) induced by isometric exercises while other methods either failed to detect change or were unreliable at doing so. With six subjects twelve synchronised photographs were required to reliably detect a change of the same magnitude. Larger diameter changes (5.4%) were detected by any method including a single unsynchronised photograph.
Conclusions:
Multiple frame electrocardiograph synchronized fundus photography permits more accurate detection of small changes in retinal vessel diameter.