Table of Contents - WOC 2012

Computer-Aided Diagnosis, Novel Image Processing and Analysis
Sat 18 Feb 13:30 - 15:00 Conference Room B2
IS-TEL-SA 213 (1)
Low Cost Fundus Camera-System for Telemedical Applications
Hoeher Bernhard (1, 3, 5) , Schmauss Bernhard (1, 3, 4, 5) (2, 3, 4)
, Michelson Georg
1. Microwave Engineering, University of Erlangen-Nuremberg
2. Department of Ophthalmology, University of Erlangen-Nuremberg
3. Graduate School in Advanced Optical Technologies (SAOT)
4. Interdisciplinary Center for Ophthalmological Preventive Medicine and Imaging
5. Medical Valley EMN, Leading-Edge Cluster
Medical examinations in ophthalmology often require expensive devices.
Therefore many people living in regions with insufficient health care facilities
cannot be treated for eye diseases due to missing medical equipment and for
lack of qualified eye doctors. Hence we design a low cost, robust and highly
automated non-mydriatic fundus camera-system with a telemedical interface.
Thereby fundus images can be taken even by less qualified people and
the diagnosis is done by specialists located elsewhere. The fundus images
are transmitted by the local mobile phone network. We take advantage
of low prices in three high-tech sectors: Optics for amateur astronomy and
photography, computer hardware and mobile phone technology. We embed
technology from all three sectors in one powerful system. We found that even
cheap eyepieces together with a one mega pixel camera give fundus images
of sufficient quality. In addition we increased performance by applying image
processing technologies. The fundus camera will be capable to screen a large
number of people. For the eye doctors this means an immense time saving by
just clicking through fundus images quickly. Thus many people can effectively
be examined, even though there is no expert on site.
IS-TEL-SA 213 (2)
The Erlangen Glaucoma Matrix
Hornegger Joachim (1,2) , Meier Jörg (1,2) , Bock Rüdiger (1,2) ,
Michelson Georg (2,3,4)
1. School of Advanced Optical Technologies, University Erlangen-Nuremberg
2. Pattern Recognition Lab, University Erlangen-Nuremberg
3. Online Journals of Ophthalmology
4. Interdisciplinary Center of Ophthalmic Preventive Medicine and Imaging, University
Erlangen-Nuremberg
Background and Purpose: Glaucoma is one of the most common causes for
blindness worldwide. The early and reliable diagnosis of glaucoma is important
to slow down the progression of this particular disease. Efficient, effective
and low-cost screening methods are required but still do not exist. Research
focuses both on concepts for low-cost fundus cameras, and algorithmic tools
for computer aided diagnosis of fundus images. In this contribution a twodimensional
visualization tool is introduced that allows for the comparison of
the current image with pre-diagnosed image data. The automated computation
of a glaucoma risk index on color fundus photographs is used to spatially
assign an undiagnosed image to a point in the two-dimensional space of
reference data.
Methods: The chosen two-stage approach computes in the first step the
probability for glaucoma disease based on a single color fundus image, and
in a second step the acquired image is visualized in a matrix where the matrix
components are pre-diagnosed reference images. The matrix separates, for
instance, different papilla sizes (columns) and varying stages of the glaucoma
disease (rows), but any other feature types can be used for the visualization
of topological structures of image similarities in two dimensions. The reference
image database holds papilla-centered color fundus photographs (Kowa nonmyd,
FOV 22.5°) from the Erlangen Glaucoma Registry (EGR). The gold
standard for glaucoma diagnosis is defined by the diagnosis of experienced
ophthalmologists using in addition to the fundus image the following tools:
ophthalmoscopy, visual field test, IOP, FDT and HRT II.
Results: SVM-based glaucoma classification of PCA-transformed pixel
intensities leads to an accuracy of 0.83 (specificity: 0.72, sensitivity: 0.94,
ROC area: 0.90). Using coefficients of spline functions instead of PCA features
leads to a recognition rate of 0.86 (specificity: 0.78, sensitivity: 0.94, ROC
area: 0.88). The combination of both features increases the area under the
ROC curve to 0.93. Also specificity slightly increased to 0.82, and sensitivity
lead to 0.92. The proposed visualization allows evaluating an image in the
context of given pre-diagnosed reference samples. Due to the two-dimensional
presentation, non-disease- dependent variations (papilla size, illumination,
etc.) and glaucomatous changes are shown separately.
Conclusions: The experimental evaluation shows that fundus images are a
solid base for computer-assisted glaucoma screening, if modern pattern
recognition technology is applied. The chosen approach gives insights on
glaucomatous optic nerve appearance in relation to varying papilla sizes as
it shows a large diagnosed set of data separate for different glaucoma stages
and papilla sizes.
WOC2012 Abstract Book
IS-TEL-SA 213 (3)
Advanced Fusion Based Analysis of Ophthalmological Image Data
Jan Jiri (1) , Kolar R. (1) , Odstrcilik J. (1) , Gazarek J. (1)
1. Brno University of Technology
Recent results on ophthalmic image data multimodal fusion by Brno UT group
are shown, namely in preprocessing of retinal data provided by fundus-camera
(FC), Heidelberg retina tomography (HRT) and optical coherence tomography
(OCT) modalities retinal data multimodal flexible registration advanced vessel
tree, optical disc and autofluorescence area segmentation based on fused FC
and HRT data, retinal layers segmentation in OCT data evaluation of retinal
neural fibre layer based on fused FC and OCT data: combined results of
advanced texture analysis in FC data compared with registered OCT 3D data
high resolution retinal FC image database with medical expert evaluated vessel
tree segmentations and neural fibre layer assessment. Particular attention
is devoted to evaluation of retinal neural fibre layer detection or quantitative
assessment based on the cheapest and most widely available modality -
fundus-camera images. The analytic results obtained in these images by the
above techniques are compared with the objective findings, namely via the
flexibly registered OCT data. Results show a still not fully utilised potential of
digital FC images.
IS-TEL-SA 213 (4)
Improved Medical Diagnosis by EGS Glaucocard
Schargus Marc (1) , Grehn Franz
1. University Eye Hospital Wuerzburg
The purpose of the European Glaucoma Society (EGS) Project Glaucocard is
to develop an integrated and interconnected electronic European glaucoma
data record. New standardized digital datasets for glaucoma patients were
defined based on existing standards; the finalized dataset shows 130 field
variables. The digital data from the Glaucocard can be used for referrals and
to store or forward data for teleconsultation of glaucoma specialists to optimize
glaucoma treatment. This will result in an increase of quality in glaucoma care
and save expenses in health care by unnecessary re-examinations.
IS-TEL-SA 213 (5)
Time-Resolved Autofluorescence in Retinal Diseases
Schweitzer Dietrich (1)
1. University of Jena
To find a method for detection of cellular metabolism, a laser scanning
ophthalmoscope was modified for excitation of endogenous fundus
fluorophores by ps-laserpulses. In early AMD, alterations occur in neuronal
retina. Comparing supplied and under-supplied regions in branch arterial
occlusion, a shift from free to protein-bound NADH was found. In well controlled
diabetic patients, having no signs of diabetic retinopathy, a lack of free NADH
was detected. NADH is an electron transporter in basic processes of energy
production.
IS-TEL-SA 213 (6)
Visualization of Fundus Vessel Pulsation Using Principal Component
Analysis
Moret Fabrice (1)
1. Eye Hospital, University of Freiburg
Retinal vessel dynamics such as e.g. spontaneous venous pulsation attracts
increasing attention via its link to glaucoma etiology, through retrobulbar and
intracranial pressures. We present here a method to record and process
fundus movies while removing factors impeding the observation of retina
dynamics. The method allows visualization of minute lateral and diametrical
pulsation of arteries and veins, yields super-resolution quantification of
pulsatile displacements (10 µm), and reveals how the timing of spontaneous
venous pulsation is related to the ocular systole.
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