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Binarization of enhanced depth imaging optical coherence tomographic images of an eye with Wyburn-Mason syndrome: a case report.

Iwata A, Mitamura Y, Niki M, Semba K, Egawa M, Katome T, Sonoda S, Sakamoto T - BMC Ophthalmol (2015)

Bottom Line: The luminal area of the 1,500-μm-wide subfoveal choroid was computed to be 307,165.6 μm(2) in the right eye and 545,780.7 μm(2) in the left eye.The EDI-OCT images showed a thicker choroid, and binarization of the EDI-OCT images showed that the luminal areas were significantly larger in the affected eye, suggesting a dilatation of the choroidal vessels.The results demonstrated that conversion of EDI-OCT images to binary images was a useful method to quantify the choroidal structure.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15, Kuramoto-cho, Tokushima, 770-8503, Japan. rtpgg803@yahoo.co.jp.

ABSTRACT

Background: To report a thicker choroid and larger choroidal luminal area in an eye with Wyburn-Mason syndrome. To the best of our knowledge, this is the first report demonstrating an increase in the choroidal thickness and the luminal area in a case of Wyburn-Mason syndrome. In addition, we report the changing appearance of retinal arteriovenous malformations over a 16-year period.

Case presentation: A 27-year-old woman, who was diagnosed with Wyburn-Mason syndrome at age 11 years, visited our clinic. Her best-corrected visual acuity was 20/12.5 in the right eye and light perception in the left eye. Severely dilated, tortuous vascular loops were distributed from the optic disc over all four quadrants of the left fundus. The vascular loops in some areas were more dilated and tortuous than 16 years earlier. Optical coherence tomography (OCT) showed retinal edema with cystic changes and enlarged choroidal vessel lumens in the left eye. The subfoveal choroidal thickness was manually measured by the caliper function in the enhanced depth imaging OCT (EDI-OCT) images. Binarization of the EDI-OCT images was performed with publicly accessible ImageJ software. The examined area of the subfoveal choroid was 1,500 μm wide, and the dark areas representing the luminal areas were traced by the Niblack method. After determining the distance of each pixel, the luminal area was automatically calculated. The subfoveal choroidal thickness was 250 μm in the right eye and 462 μm in the left eye. The luminal area of the 1,500-μm-wide subfoveal choroid was computed to be 307,165.6 μm(2) in the right eye and 545,780.7 μm(2) in the left eye.

Conclusions: The EDI-OCT images showed a thicker choroid, and binarization of the EDI-OCT images showed that the luminal areas were significantly larger in the affected eye, suggesting a dilatation of the choroidal vessels. The results demonstrated that conversion of EDI-OCT images to binary images was a useful method to quantify the choroidal structure.

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Enhanced depth imaging optical coherence tomographic(EDI-OCT)images and converted binary images. Left column shows EDI-OCT images of the right eye, and right column shows those of the left eye. EDI-OCT images of a vertical scan through the fovea (A, B) were converted to binary images using ImageJ software. A, B: The luminal area (dark area) and the interstitial area (light area) can be seen. The lumens of the choroidal vessels seem larger in the left eye than in the right eye. The examined area was determined to be 1,500 μm wide in the subfoveal choroid. It extended vertically from the retinal pigment epithelium to the chorioscleral border, and the choroidal area was set with the ROI manager of ImageJ. The rectangle surrounded by a red line was excised, and the dark areas were traced by the Niblack method. C, D: Merged images of the binarized images and the margins of traced areas. In the binarized images, the light pixels were defined as the interstitial choroid or choroidal stroma, and the dark pixels were defined as the luminal area. E, F: Merged images of the original EDI-OCT images and the margins of traced areas show that the traced areas coincide with the dark choroidal areas of the EDI-OCT image.
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Fig2: Enhanced depth imaging optical coherence tomographic(EDI-OCT)images and converted binary images. Left column shows EDI-OCT images of the right eye, and right column shows those of the left eye. EDI-OCT images of a vertical scan through the fovea (A, B) were converted to binary images using ImageJ software. A, B: The luminal area (dark area) and the interstitial area (light area) can be seen. The lumens of the choroidal vessels seem larger in the left eye than in the right eye. The examined area was determined to be 1,500 μm wide in the subfoveal choroid. It extended vertically from the retinal pigment epithelium to the chorioscleral border, and the choroidal area was set with the ROI manager of ImageJ. The rectangle surrounded by a red line was excised, and the dark areas were traced by the Niblack method. C, D: Merged images of the binarized images and the margins of traced areas. In the binarized images, the light pixels were defined as the interstitial choroid or choroidal stroma, and the dark pixels were defined as the luminal area. E, F: Merged images of the original EDI-OCT images and the margins of traced areas show that the traced areas coincide with the dark choroidal areas of the EDI-OCT image.

Mentions: SD-OCT was performed with the Heidelberg Spectralis (Heidelberg Engineering, Heidelberg, Germany). SD-OCT demonstrated retinal edema with cystic changes and oval-shaped structures that represented cross sections of abnormal retinal vessels in the left eye (Figures 1E and 1 F). Binarization of a choroidal area in the EDI-OCT image was performed by a modified Niblack’s method as reported in detail (Figure 2) [2]. Briefly, an EDI-OCT image was analyzed by ImageJ software (ImageJ version 1.47, NIH, Bethesda, MD, USA). The examined area was 1,500 μm wide in the subfoveal choroid, and extended vertically from the retinal pigment epithelium to the chorioscleral border. This choroidal area was selected with the ImageJ ROI Manager. Three choroidal vessels with lumens larger than 100 μm were randomly selected by the Oval Selection Tool on the ImageJ tool bar, and the average reflectivity of these areas was determined. The average brightness was set as the minimum value to minimize noise in the OCT image. Then, the image was converted to 8 bits and adjusted by the Niblack Auto Local Threshold. The binarized image was converted to the RGB image again, and the luminal area was determined using the Threshold Tool. The light pixels were defined as the interstitial areas, and the dark pixels were defined as the luminal areas. After adding the data of the distance of each pixel, the luminal and interstitial areas were automatically calculated.Figure 2


Binarization of enhanced depth imaging optical coherence tomographic images of an eye with Wyburn-Mason syndrome: a case report.

Iwata A, Mitamura Y, Niki M, Semba K, Egawa M, Katome T, Sonoda S, Sakamoto T - BMC Ophthalmol (2015)

Enhanced depth imaging optical coherence tomographic(EDI-OCT)images and converted binary images. Left column shows EDI-OCT images of the right eye, and right column shows those of the left eye. EDI-OCT images of a vertical scan through the fovea (A, B) were converted to binary images using ImageJ software. A, B: The luminal area (dark area) and the interstitial area (light area) can be seen. The lumens of the choroidal vessels seem larger in the left eye than in the right eye. The examined area was determined to be 1,500 μm wide in the subfoveal choroid. It extended vertically from the retinal pigment epithelium to the chorioscleral border, and the choroidal area was set with the ROI manager of ImageJ. The rectangle surrounded by a red line was excised, and the dark areas were traced by the Niblack method. C, D: Merged images of the binarized images and the margins of traced areas. In the binarized images, the light pixels were defined as the interstitial choroid or choroidal stroma, and the dark pixels were defined as the luminal area. E, F: Merged images of the original EDI-OCT images and the margins of traced areas show that the traced areas coincide with the dark choroidal areas of the EDI-OCT image.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4359503&req=5

Fig2: Enhanced depth imaging optical coherence tomographic(EDI-OCT)images and converted binary images. Left column shows EDI-OCT images of the right eye, and right column shows those of the left eye. EDI-OCT images of a vertical scan through the fovea (A, B) were converted to binary images using ImageJ software. A, B: The luminal area (dark area) and the interstitial area (light area) can be seen. The lumens of the choroidal vessels seem larger in the left eye than in the right eye. The examined area was determined to be 1,500 μm wide in the subfoveal choroid. It extended vertically from the retinal pigment epithelium to the chorioscleral border, and the choroidal area was set with the ROI manager of ImageJ. The rectangle surrounded by a red line was excised, and the dark areas were traced by the Niblack method. C, D: Merged images of the binarized images and the margins of traced areas. In the binarized images, the light pixels were defined as the interstitial choroid or choroidal stroma, and the dark pixels were defined as the luminal area. E, F: Merged images of the original EDI-OCT images and the margins of traced areas show that the traced areas coincide with the dark choroidal areas of the EDI-OCT image.
Mentions: SD-OCT was performed with the Heidelberg Spectralis (Heidelberg Engineering, Heidelberg, Germany). SD-OCT demonstrated retinal edema with cystic changes and oval-shaped structures that represented cross sections of abnormal retinal vessels in the left eye (Figures 1E and 1 F). Binarization of a choroidal area in the EDI-OCT image was performed by a modified Niblack’s method as reported in detail (Figure 2) [2]. Briefly, an EDI-OCT image was analyzed by ImageJ software (ImageJ version 1.47, NIH, Bethesda, MD, USA). The examined area was 1,500 μm wide in the subfoveal choroid, and extended vertically from the retinal pigment epithelium to the chorioscleral border. This choroidal area was selected with the ImageJ ROI Manager. Three choroidal vessels with lumens larger than 100 μm were randomly selected by the Oval Selection Tool on the ImageJ tool bar, and the average reflectivity of these areas was determined. The average brightness was set as the minimum value to minimize noise in the OCT image. Then, the image was converted to 8 bits and adjusted by the Niblack Auto Local Threshold. The binarized image was converted to the RGB image again, and the luminal area was determined using the Threshold Tool. The light pixels were defined as the interstitial areas, and the dark pixels were defined as the luminal areas. After adding the data of the distance of each pixel, the luminal and interstitial areas were automatically calculated.Figure 2

Bottom Line: The luminal area of the 1,500-μm-wide subfoveal choroid was computed to be 307,165.6 μm(2) in the right eye and 545,780.7 μm(2) in the left eye.The EDI-OCT images showed a thicker choroid, and binarization of the EDI-OCT images showed that the luminal areas were significantly larger in the affected eye, suggesting a dilatation of the choroidal vessels.The results demonstrated that conversion of EDI-OCT images to binary images was a useful method to quantify the choroidal structure.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15, Kuramoto-cho, Tokushima, 770-8503, Japan. rtpgg803@yahoo.co.jp.

ABSTRACT

Background: To report a thicker choroid and larger choroidal luminal area in an eye with Wyburn-Mason syndrome. To the best of our knowledge, this is the first report demonstrating an increase in the choroidal thickness and the luminal area in a case of Wyburn-Mason syndrome. In addition, we report the changing appearance of retinal arteriovenous malformations over a 16-year period.

Case presentation: A 27-year-old woman, who was diagnosed with Wyburn-Mason syndrome at age 11 years, visited our clinic. Her best-corrected visual acuity was 20/12.5 in the right eye and light perception in the left eye. Severely dilated, tortuous vascular loops were distributed from the optic disc over all four quadrants of the left fundus. The vascular loops in some areas were more dilated and tortuous than 16 years earlier. Optical coherence tomography (OCT) showed retinal edema with cystic changes and enlarged choroidal vessel lumens in the left eye. The subfoveal choroidal thickness was manually measured by the caliper function in the enhanced depth imaging OCT (EDI-OCT) images. Binarization of the EDI-OCT images was performed with publicly accessible ImageJ software. The examined area of the subfoveal choroid was 1,500 μm wide, and the dark areas representing the luminal areas were traced by the Niblack method. After determining the distance of each pixel, the luminal area was automatically calculated. The subfoveal choroidal thickness was 250 μm in the right eye and 462 μm in the left eye. The luminal area of the 1,500-μm-wide subfoveal choroid was computed to be 307,165.6 μm(2) in the right eye and 545,780.7 μm(2) in the left eye.

Conclusions: The EDI-OCT images showed a thicker choroid, and binarization of the EDI-OCT images showed that the luminal areas were significantly larger in the affected eye, suggesting a dilatation of the choroidal vessels. The results demonstrated that conversion of EDI-OCT images to binary images was a useful method to quantify the choroidal structure.

Show MeSH
Related in: MedlinePlus