Morphometric analysis of neoplastic renal aspirates and benign renal tissue

This study was designed to develop a practical morphometric procedure for the diagnosis of carcinoma in renal aspirates. We studied aspirates from renal cell carcinomas (grades 1-2) and normal kidneys. Video images of nuclei were traced on a high-resolution, touch-sensitive screen connected to an image analysis system. From each tracing the computer calculated nuclear perimeter length, nuclear profile area, maximal chord length, and the means and standard deviation for all measurements. Size distribution of nuclear profile areas and perimeter length in discrete bins ranged, respectively, from 30 to 80 at 10 microns2 intervals for areas and from 1 to 12 microns at 1-micron intervals for the maximum chords. The size distribution plots for the maximal chord of individual nuclei demonstrated an early narrow peak at low values for normal renal aspirates (peak located in the class ranging from 7 to 8 microns), while a broader, flatter peak with a shift to the right and a malignant tail was seen in renal cell carcinoma aspirates (peak located at 9-10 microns). These data were used for multivariate analysis to form two categories to establish a data base against which unknown cases could be tested. Multivariate analysis using a total of 14 variables yielded a value of 169.1 for the euclidean distances between the center of clusters of the neoplastic and normal renal aspirates and confirmed the classification with posterior probabilities of 1.0. From these data, automated classificatory analysis of 10 unknown cases was performed by means of the k-nearest neighbor procedure, with correct classification established in each case.