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Human arachnoid granulations Part I: a technique for quantifying area and distribution on the superior surface of the cerebral cortex.

Grzybowski DM, Herderick EE, Kapoor KG, Holman DW, Katz SE - Cerebrospinal Fluid Res (2007)

Bottom Line: En face images were taken of the superior surface of 35 formalin-fixed human brains.The AG surface area was calculated for each hemisphere and for the total brain superior surface.With an increase in the number of samples, this analysis technique can be used to study the relationship between AG surface area and variables such as age, race and gender.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Ophthalmology, Neuro Ophthalmology Research Division, The Ohio State University, 5th Cramblett Hall, 456 West 10th Avenue, Columbus, OH 43210, USA. grzybowski.3@osu.edu

ABSTRACT

Background: The arachnoid granulations (AGs) are herniations of the arachnoid membrane into the dural venous sinuses on the surface of the brain. Previous morphological studies of AGs have been limited in scope and only one has mentioned surface area measurements. The purpose of this study was to investigate the topographic distribution of AGs on the superior surface of the cerebral cortex.

Methods: En face images were taken of the superior surface of 35 formalin-fixed human brains. AGs were manually identified using Adobe Photoshop, with a pixel location containing an AG defined as 'positive'. A set of 25 standard fiducial points was marked on each hemisphere for a total of 50 points on each image. The points were connected on each hemisphere to create a segmented image. A standard template was created for each hemisphere by calculating the average position of the 25 fiducial points from all brains. Each segmented image was mapped to the standard template using a linear transformation. A topographic distribution map was produced by calculating the proportion of AG positive images at each pixel in the standard template. The AG surface area was calculated for each hemisphere and for the total brain superior surface. To adjust for different brain sizes, the proportional involvement of AGs was calculated by dividing the AG area by the total area.

Results: The total brain average surface area of AGs was 78.53 +/- 13.13 mm2 (n = 35) and average AG proportional involvement was 57.71 x 10(-4) +/- 7.65 x 10(-4). Regression analysis confirmed the reproducibility of AG identification between independent researchers with r2 = 0.97. The surface AGs were localized in the parasagittal planes that coincide with the region of the lateral lacunae.

Conclusion: The data obtained on the spatial distribution and en face surface area of AGs will be used in an in vitro model of CSF outflow. With an increase in the number of samples, this analysis technique can be used to study the relationship between AG surface area and variables such as age, race and gender.

No MeSH data available.


Related in: MedlinePlus

A. Image of human brain with dura removed. The AGs are visible on the brain surface as whitish lobules. B. Image of inside of the dura from a human brain with the superior sagittal sinus splayed open. No AGs are visible in the superior sagittal sinus.
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Figure 1: A. Image of human brain with dura removed. The AGs are visible on the brain surface as whitish lobules. B. Image of inside of the dura from a human brain with the superior sagittal sinus splayed open. No AGs are visible in the superior sagittal sinus.

Mentions: Photographic images were taken with accompanying autopsy reports of inspected, formalin-fixed brains. The brains with accompanying scale and identification were submerged in water to control glare. A 35 mm Nikon FM2 camera with a Micro-NIKKOR 55 mm, 1:2.8 lens was stabilized at a fixed distance. Two images were taken of each brain: the brain with attached scale and identifying tag (Figure 1A, tag and scale not shown); and the superior sagittal sinus splayed open with attached scale and identifying tag (Figure 1B, tag not shown). The film (35 mm 100 ASA Kodak Elite Chrome) was processed and scanned on a Polaroid Sprintscan 4000 35 mm slide scanner. Pixel resolution was approximately 60 μm, suggesting that an individual AG would be approximately 5 pixels in diameter on average [3].


Human arachnoid granulations Part I: a technique for quantifying area and distribution on the superior surface of the cerebral cortex.

Grzybowski DM, Herderick EE, Kapoor KG, Holman DW, Katz SE - Cerebrospinal Fluid Res (2007)

A. Image of human brain with dura removed. The AGs are visible on the brain surface as whitish lobules. B. Image of inside of the dura from a human brain with the superior sagittal sinus splayed open. No AGs are visible in the superior sagittal sinus.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1941743&req=5

Figure 1: A. Image of human brain with dura removed. The AGs are visible on the brain surface as whitish lobules. B. Image of inside of the dura from a human brain with the superior sagittal sinus splayed open. No AGs are visible in the superior sagittal sinus.
Mentions: Photographic images were taken with accompanying autopsy reports of inspected, formalin-fixed brains. The brains with accompanying scale and identification were submerged in water to control glare. A 35 mm Nikon FM2 camera with a Micro-NIKKOR 55 mm, 1:2.8 lens was stabilized at a fixed distance. Two images were taken of each brain: the brain with attached scale and identifying tag (Figure 1A, tag and scale not shown); and the superior sagittal sinus splayed open with attached scale and identifying tag (Figure 1B, tag not shown). The film (35 mm 100 ASA Kodak Elite Chrome) was processed and scanned on a Polaroid Sprintscan 4000 35 mm slide scanner. Pixel resolution was approximately 60 μm, suggesting that an individual AG would be approximately 5 pixels in diameter on average [3].

Bottom Line: En face images were taken of the superior surface of 35 formalin-fixed human brains.The AG surface area was calculated for each hemisphere and for the total brain superior surface.With an increase in the number of samples, this analysis technique can be used to study the relationship between AG surface area and variables such as age, race and gender.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Ophthalmology, Neuro Ophthalmology Research Division, The Ohio State University, 5th Cramblett Hall, 456 West 10th Avenue, Columbus, OH 43210, USA. grzybowski.3@osu.edu

ABSTRACT

Background: The arachnoid granulations (AGs) are herniations of the arachnoid membrane into the dural venous sinuses on the surface of the brain. Previous morphological studies of AGs have been limited in scope and only one has mentioned surface area measurements. The purpose of this study was to investigate the topographic distribution of AGs on the superior surface of the cerebral cortex.

Methods: En face images were taken of the superior surface of 35 formalin-fixed human brains. AGs were manually identified using Adobe Photoshop, with a pixel location containing an AG defined as 'positive'. A set of 25 standard fiducial points was marked on each hemisphere for a total of 50 points on each image. The points were connected on each hemisphere to create a segmented image. A standard template was created for each hemisphere by calculating the average position of the 25 fiducial points from all brains. Each segmented image was mapped to the standard template using a linear transformation. A topographic distribution map was produced by calculating the proportion of AG positive images at each pixel in the standard template. The AG surface area was calculated for each hemisphere and for the total brain superior surface. To adjust for different brain sizes, the proportional involvement of AGs was calculated by dividing the AG area by the total area.

Results: The total brain average surface area of AGs was 78.53 +/- 13.13 mm2 (n = 35) and average AG proportional involvement was 57.71 x 10(-4) +/- 7.65 x 10(-4). Regression analysis confirmed the reproducibility of AG identification between independent researchers with r2 = 0.97. The surface AGs were localized in the parasagittal planes that coincide with the region of the lateral lacunae.

Conclusion: The data obtained on the spatial distribution and en face surface area of AGs will be used in an in vitro model of CSF outflow. With an increase in the number of samples, this analysis technique can be used to study the relationship between AG surface area and variables such as age, race and gender.

No MeSH data available.


Related in: MedlinePlus