Hindawi Publishing Corporation ISRN Ophthalmology Volume 2013, Article ID 865834, 9 pages http://dx.doi.org/10.1155/2013/865834 Clinical Study A Method for Visualization of Fine Retinal Vascular Pulsation Using Nonmydriatic Fundus Camera Synchronized with Electrocardiogram Dinesh Kant Kumar, 1 Behzad Aliahmad, 1 Hao Hao, 1 Mohd Zulfaezal Che Azemin, 1,2 and Ryo Kawasaki 3 1 School of Electrical and Computer Engineering, RMIT University, 124 Latrobe Street, Melbourne, VIC 3000, Australia 2 Department of Allied Health Sciences, International Islamic University Malaysia, 25200 Kuantan, Pahang, Malaysia 3 Department of Public Health, Faculty of Medicine, Yamagata University, Yamagata 990-9585, Japan Correspondence should be addressed to Dinesh Kant Kumar; dinesh.kumar@rmit.edu.au Received 9 January 2013; Accepted 14 February 2013 Academic Editors: J. O. Croxatto and U. U. Inan Copyright © 2013 Dinesh Kant Kumar et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Pulsatile changes in retinal vascular geometry over the cardiac cycle have clinical implication for diagnosis of ocular and systemic vascular diseases. In this study, we report a Vesselness Mapping of Retinal Image Sequence (VMRS) methodology to visualize the vessel pulsation and quantify the pulsatile motions in the cardiac cycle. Retinal images were recorded in an image sequence corresponding to 8 segments of the cardiac cycle using a nonmydriatic fundus camera (Canon CR45, Canon Inc., Japan) modifed with ECG-synchronization. Individual cross-sectional vessel diameters were measured separately and the signifcance of the variations was tested statistically by repeated measures analysis of variance (ANOVA). Te graders observed an improved quality of vessel pulsation on a wide region around the optic disk using the VMRS. Individual cross- sectional vessel diameter measurement afer visualization of pulsatile motions resulted in the detection of more signifcant diameter change for both arterioles (3.3 m,  = 0.001) and venules (6.6 m,  < 0.001) compared to individual measurement without visualization of the pulsatile motions (all P values > 0.05), showing an increase of 2.1 m and 4.7 m for arterioles and venules, respectively. 1. Introduction Retinal imaging has enabled direct and in vivo assessment of human’s body circulation system and is applied for the detection of major systemic vascular diseases, including ischemia [1], coronary heart diseases [2] and diabetes mellitus [3] and its complications [4–6]. A number of studies [7, 8] have also reported the clinical application of dynamic retinal image processing for the investigation of pulsatile properties infuenced by cardiac rhythm over time. Tis pulsatility is expected as a result of change in blood volumetric fow entering the ophthalmic vascular system under certain level of intraocular pressure during the peak systolic and diastolic phases of cardiac cycle, which can serve as a potential feature to rule out some clinical signs. An example of pulsatile property observable from the retina is the spontaneous venous pulsation (SVP), which is available in approximately 90% of the patients [9, 10]. It is caused by the variation in the pressure gradient between the intraocular retinal veins and the retrolaminar portion of the central retinal vein (CRV) [11], visible as rhythmic changes the in diameter of one or more veins near or on the optic nerve head. Its clinical relevance is for diferentiating early papilledema from pseudopapilledema, detection of elevated intracranial pressure (≥14 mmHg), and other pathological conditions [8]. In addition to SVP, pulsation of veins outside the optic disk (OD), such as the serpentine movement of principal arteries, pulsatile motion of small arterioles, and movement of optic nerve head are other features that can be visualized with the help of dynamic fundoscopy [8].