Karnes J, Robb R, O'Brien P C, Lambert E H, Dyck P J
J Neurol Sci. 1977 Oct;34(1):43-51. doi: 10.1016/0022-510x(77)90090-9.
A computerized image recognition method was used to measure various attributes of shape of cross-sections of myelinated nerve fibers. Measurements were made at intervals over 1/2 internode of each fiber on 20 fibers from each of 4 sural nerves from rats. Diameters were computed in 6 different ways from the computer measurements and compared for bias, precision, and accuracy between sections and to the diameter of an idealized cylinder reconstructed for each fiber from multiple actual cross sections. The diameter computed from cross-sectional areas of transversely sectioned myelinated fibers, converted into a circle, showed the highest precision, greatest accuracy and least bias. Fibers were classified by shape and the frequency was determined in defined regions (I1 = paranodal, I3= nuclear and I2=region between I1 and I3) of the 1/2 internode. A crenated shape is highly characteristic of the I1 region. The boomerang shape was found most frequently in I3 whereas the circular shape was found most frequently in I2. Epileptical and boomerang shapes of myelinated fibers within fascicles which have been orientated carefully to obtain transverse sections, are not due to obliquity of section. Therefore, using the minor axis to determine the diameter of such profiles, as we had done previously in our laboratory, is in error. We conclude from these studies, that in carefully orientated transverse sections of nerve trucks, the diameter calculated from measurement of area converted to a circular shape is the best among the various estimates of myelinated fiber diameter and is the most suitable one for use in computerized image recognition systems for nerve morphometry. It seems reasonable to extrapolate this general conclusion to myelinated fibers of man.
采用计算机图像识别方法测量有髓神经纤维横切面的各种形状属性。对来自4只大鼠腓肠神经的每根神经中的20根纤维，在每个纤维的1/2节间长度内间隔测量。根据计算机测量结果，以6种不同方式计算直径，并比较各横切面之间的偏差、精密度和准确性，以及与根据多个实际横切面为每根纤维重建的理想圆柱体直径的比较。从横切的有髓纤维横截面积计算得出并转换为圆形的直径，显示出最高的精密度、最大的准确性和最小的偏差。根据形状对纤维进行分类，并确定在1/2节间的特定区域（I1 = 结旁，I3 = 核周，I2 = I1和I3之间的区域）的频率。锯齿状是I1区域的高度特征。回旋镖形状在I3区域最常见，而圆形在I2区域最常见。在仔细定向以获得横切面的束内有髓纤维的癫痫样和回旋镖形状，并非由于切面倾斜。因此，如我们之前在实验室所做的那样，使用短轴来确定此类轮廓的直径是错误的。我们从这些研究中得出结论，在仔细定向的神经束横切面上，根据面积测量转换为圆形计算出的直径，在有髓纤维直径的各种估计中是最好的，并且是最适合用于神经形态计量学的计算机图像识别系统的。将这个一般结论外推到人类的有髓纤维似乎是合理的。
