Purpose : Although the choroidal thickness (ChT) is a pertinent sign to assess ocular health, its... more Purpose : Although the choroidal thickness (ChT) is a pertinent sign to assess ocular health, its analysis is not common because it takes time to manually segment it. Recent imaging developments in Optical Coherence Tomography (OCT) enable a better observation of deeper structures of the eye, like the choroid. We developed an application that automatically estimates ChT, allowing the ophthalmologist to promptly analyze the data and reducing the subjectivity and time consumption of the manual segmentation. Methods : To estimate the ChT, we used Enhanced Depth Imaging OCT B-scans from a Spectralis system (Heidelberg Enginnering, Germany). The automatic methodology can be split into three main parts: preprocessing, delineation of both choroidal limits-the Bruch's Membrane (BM) and Choroidal-Scleral Interface (CSI)-and finally ChT calculation. The preprocessing includes: contrast adjustment (different for each limit), reduction of the shadows cast by retinal vessels and the reduction of the speckle noise using a Stationary Wavelet Transform. The BM and CSI are delineated resorting to a minimum weight path algorithm (Fig. 1). The ChT is the distance between the two delineated limits in the scanned area. Measurements in a series of B-scans can be interpolated and mapped in the fundus image, as shown in Fig. 2; an application was developed for this purpose. A manual segmentation of BM and CSI was outlined by 2 OCT expert ophthalmologists in 8 macular volume videos with 19 B-scans each. Results : The mean absolute errors (MAE) between the automatic and each manual segmentation (7,5±3,2% and 7,9±4,4%) were comparable to the differences between the two manual segmentations (7,8±3,6%).To assess precision, differences were calculated between interpolations of the ChT of orthogonal series of B-scans. The difference of the automatic ChT (4,4±4,5%) is lower than the differences in the manual segmentations (5,5±4,5% and 6,1±5,0%). Conclusions : The automatic estimation of the ChT was successful, with a higher precision than the manual. The developed application allows the physician to easily access the ChT profile information, as well as, if necessary, perform a manual correction to the automatic segmentation.
Lecture notes in computational vision and biomechanics, Oct 13, 2017
The choroid is the middle layer of the eye globe located between the retina and the sclera. It is... more The choroid is the middle layer of the eye globe located between the retina and the sclera. It is proven that choroidal thickness is a sign of multiple eye diseases. Optical Coherence Tomography (OCT) is an imaging technique that allows the visualization of tomographic images of near surface tissues like those in the eye globe. The automatic calculation of the choroidal thickness reduces the subjectivity of manual image analysis as well as the time of large scale measurements.
The high cost and invasiveness of state‐of‐the‐art ATN diagnostic methods underscore the need for... more The high cost and invasiveness of state‐of‐the‐art ATN diagnostic methods underscore the need for alternative approaches for Alzheimer's Disease (AD) patient screening. Blood‐based biomarkers have opened unrivalled opportunities to make AD diagnostics cost‐ and time‐efficient. However, single biomarkers are failing to provide accurate diagnosis/prognosis information for patients suffering from this heterogenous disease, hence the need to combine multiple biomarkers to generate disease‐specific signatures. Here, we present a blood‐based optical fingerprinting tool as a unique ‘holistic’ cost and time efficient solution for frontline AD diagnostics.
Forecasting COVID-19 disease severity is key to supporting clinical decision making and assisting... more Forecasting COVID-19 disease severity is key to supporting clinical decision making and assisting resource allocation, particularly in intensive care units (ICUs). Here, we investigated the utility of time- and frequency-related features of the backscattered signal of serum patient samples to predict COVID-19 disease severity immediately after diagnosis. ICU admission was the primary outcome used to define disease severity. We developed a stacking ensemble machine learning model including the backscattered signal features (optical fingerprint), patient comorbidities, and age (AUROC = 0.80), which significantly outperformed the predictive value of clinical and laboratory variables available at hospital admission (AUROC = 0.71). The information derived from patient optical fingerprints was not strongly correlated with any clinical/laboratory variable, suggesting that optical fingerprinting brings unique information for COVID-19 severity risk assessment. Optical fingerprinting is a lab...
Purpose : Although the choroidal thickness (ChT) is a pertinent sign to assess ocular health, its... more Purpose : Although the choroidal thickness (ChT) is a pertinent sign to assess ocular health, its analysis is not common because it takes time to manually segment it. Recent imaging developments in Optical Coherence Tomography (OCT) enable a better observation of deeper structures of the eye, like the choroid. We developed an application that automatically estimates ChT, allowing the ophthalmologist to promptly analyze the data and reducing the subjectivity and time consumption of the manual segmentation. Methods : To estimate the ChT, we used Enhanced Depth Imaging OCT B-scans from a Spectralis system (Heidelberg Enginnering, Germany). The automatic methodology can be split into three main parts: preprocessing, delineation of both choroidal limits-the Bruch's Membrane (BM) and Choroidal-Scleral Interface (CSI)-and finally ChT calculation. The preprocessing includes: contrast adjustment (different for each limit), reduction of the shadows cast by retinal vessels and the reduction of the speckle noise using a Stationary Wavelet Transform. The BM and CSI are delineated resorting to a minimum weight path algorithm (Fig. 1). The ChT is the distance between the two delineated limits in the scanned area. Measurements in a series of B-scans can be interpolated and mapped in the fundus image, as shown in Fig. 2; an application was developed for this purpose. A manual segmentation of BM and CSI was outlined by 2 OCT expert ophthalmologists in 8 macular volume videos with 19 B-scans each. Results : The mean absolute errors (MAE) between the automatic and each manual segmentation (7,5±3,2% and 7,9±4,4%) were comparable to the differences between the two manual segmentations (7,8±3,6%).To assess precision, differences were calculated between interpolations of the ChT of orthogonal series of B-scans. The difference of the automatic ChT (4,4±4,5%) is lower than the differences in the manual segmentations (5,5±4,5% and 6,1±5,0%). Conclusions : The automatic estimation of the ChT was successful, with a higher precision than the manual. The developed application allows the physician to easily access the ChT profile information, as well as, if necessary, perform a manual correction to the automatic segmentation.
Lecture notes in computational vision and biomechanics, Oct 13, 2017
The choroid is the middle layer of the eye globe located between the retina and the sclera. It is... more The choroid is the middle layer of the eye globe located between the retina and the sclera. It is proven that choroidal thickness is a sign of multiple eye diseases. Optical Coherence Tomography (OCT) is an imaging technique that allows the visualization of tomographic images of near surface tissues like those in the eye globe. The automatic calculation of the choroidal thickness reduces the subjectivity of manual image analysis as well as the time of large scale measurements.
The high cost and invasiveness of state‐of‐the‐art ATN diagnostic methods underscore the need for... more The high cost and invasiveness of state‐of‐the‐art ATN diagnostic methods underscore the need for alternative approaches for Alzheimer's Disease (AD) patient screening. Blood‐based biomarkers have opened unrivalled opportunities to make AD diagnostics cost‐ and time‐efficient. However, single biomarkers are failing to provide accurate diagnosis/prognosis information for patients suffering from this heterogenous disease, hence the need to combine multiple biomarkers to generate disease‐specific signatures. Here, we present a blood‐based optical fingerprinting tool as a unique ‘holistic’ cost and time efficient solution for frontline AD diagnostics.
Forecasting COVID-19 disease severity is key to supporting clinical decision making and assisting... more Forecasting COVID-19 disease severity is key to supporting clinical decision making and assisting resource allocation, particularly in intensive care units (ICUs). Here, we investigated the utility of time- and frequency-related features of the backscattered signal of serum patient samples to predict COVID-19 disease severity immediately after diagnosis. ICU admission was the primary outcome used to define disease severity. We developed a stacking ensemble machine learning model including the backscattered signal features (optical fingerprint), patient comorbidities, and age (AUROC = 0.80), which significantly outperformed the predictive value of clinical and laboratory variables available at hospital admission (AUROC = 0.71). The information derived from patient optical fingerprints was not strongly correlated with any clinical/laboratory variable, suggesting that optical fingerprinting brings unique information for COVID-19 severity risk assessment. Optical fingerprinting is a lab...
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