Studies on quantitative morphology. XIV. Morphometry of connective tissue in normal and cirrhotic rat livers between accuracy and working expense.
The percentages of connective tissue in sections of normal and cirrhotic rat livers up to values of about 40% are measured by point counting with net point distances between 160 microns and 5,120 microns. For a test area of about 1 cm2 a suitable distance of 640 microns led to a sufficient number of data for an always acceptable accuracy, therefore the measuring time per organ was not more than 10 min for approximately 250-400 hits. In the case presented the coefficient of variation for 10 repeated measurements decreases from 26.9% for normal livers down to 3.5% for livers with about 40% connective tissue. An enlargement of the net point distance for this test area to 1,280 microns and about 100 or less hits results in higher coefficients of variation and inacceptable differences between the x min and the x max data during a series, which becomes more clear for lower percentages. A further enlargement of the net point distance is accompanied by a further inaccuracy, but an enlargement of the test area allows larger net point distances.