Morphometry of human nerve biopsies by means of automated cytometry: assessment with reference to ultrastructural analysis.

The morphometric analysis of myelinated fibres is a tool for diagnosis of neuropathies and for assessing nerve regeneration after reconstructive surgery. In order to obtain reliable information, sampling techniques should be avoided and the measurement of all the fibres within a nerve fascicle requiring the use of automated cytometry is necessary. We have developed a programme on the SAMBA cytological image analyser for the automated measurement of myelinated fibres. Different techniques of segmentation were tested and adaptive grey level thresholding gave the more reliable result. Accuracy and reproducibility were tested using a set of five human superficial peroneal nerve biopsies that were previously analysed by means of semi-automatic ultrastructural morphometry. A maximum difference of 9% in the number of fibres counted was obtained when comparing the automatic and the semi-automatic methods. In all cases the histograms of the morphometrical variables (fibre and axon diameters, myelin sheath thickness) were found to be identical to the reference histograms obtained by the semi-automatic method.