Merz

Use this probe to estimate surface density (i.e., surface area per volume)

This method uses the curvilinear test system devised by Merz and known as the Merz Coherent Test System.

Thin isotropic sections and systematic random sampling are required to perform this probe.

The program draws semi-circles in a square grid over the material to be examined.

Tick marks are placed wherever the test lines cross the surface for which you are estimating the density. Tick marks are also placed on points located over the region of interest.

  • The more marks for surface, the more surface per volume there is.
  • The longer the lines used to probe (with the same amount of tick marks for surface), the less surface per volume there is.

Procedure

  1. Click Probes>All probes>Surface>Merz.
  2. Specify the diameter of the semi-circle grid elements. This parameter controls both the distance between the grid of half circles which are drawn on the screen and their length.
    • The smaller the diameter is, the more intersections you get and the more precise the estimate is.
    • Experiment to determine an appropriate grid size so that a statistically significant number of intersections are achieved without "over-counting."
  3. Mark each intersection of the surface in the tissue (the surface will appear as a linear structure since the surface is in cross-section) with a semi-circular probe line.
  4. Mark the vertices of the "+" signs located over the region of interest.

    5. To mark multiple points simultaneously, hold down CTRL and draw a marquee around the points.

  5. Move to as many fields of view as necessary, using Meander Scan or any other technique for moving from one field of view to another.

    6. To keep track of sections, use the Serial Section Manager.

  6. When finished, right-click and select Exit Merz Grid.
  7. Use Probes>Stereology results>Probe run list to view the results.

 

See Formulas: Merz