Quarterly Journal of Microscopical Science, Vol s3-105, 503-517, Copyright © 1964 by Company of Biologists

A Counting Method for Measuring the Volumes of Tissue Components in Microscopical Sections

¹ Department of Anatomy, University of Glasgow, Scotland; Department of Anatomy, University of Newcastle upon Tyne, England

Several methods are available for estimating the relative volume of a tissue component from a study of tissue sections. These methods are all based on the fact that the mean relative area of a component in a series of random sections through a tissue is a consistent estimate of its relative volume in the whole tissue. Thus the problem is basically one of measuring area in a section, which can be done by the following simple counting method.

The method consists of placing a regular pattern of points in the form of a square lattice upon the section image, and counting the number of points over the section N, and over the component n

Relative area of component n/N

The method also measures absolute ares, and where d is the distance between adjacent points,

absolute area of component nd²

This capacity to measure absolute area means that the method is particularly suitable for determining a component which has a low relative volume.

The accuracy of the method is influenced by several factors including the size of the grid mesh, and the relative area, shape, and spatial arrangment of the component. With reasonable care the error will not be larger than that of a truly randon system of points, as expressed by the following:

relative standard error (1-p)/n,

where p is the relative area of the component, and the relative standard error (R.S.E.) is S.E./relative area of component.

The method is equallyapplicable to either light or electron microscopy. A series of measurements on electron micrographs of rat cardiac muscle revealed a close agreement between the counting method and planimetry.

The method is rapid, simple and accurate, and requres no complex apparatus.