Development of a quantitative analysis method for measuring the change in vascular structure of malignant tumors in small experimental animals

Abstract

The aim of this study was to develop a detailed and quantitative X-ray imaging evaluation method for analyzing the vascular structure of malignant tumors in small experimental animals. A microfocus tube X-ray imaging system and a computed radiography system were used to capture images directly at 7× magnification. Various parameters of the vascular structures in the digital images were quantitatively analyzed with image analysis software after the vascular structure patterns were extracted by a mathematical morphology filter. The evaluation included the following three stages: assessment of the digital images drawn with graphics software, evaluation of digital X-ray images of vascular structure model phantoms made from copper wire, and assessment of the angiography of the mouse tumor model. In the quantitative analysis of the digital images, each vascular structure parameter increased as the thickness, length, and area of the test chart increased. In contrast, nonvascular structure parameters decreased with increases in the thickness, length, and area of the test chart. The results of the analysis of the digital X-ray images of model phantoms were similar to those of the digital test chart image. Vascular structure parameter values were higher in the tumor model mouse than in the control mouse. In contrast, values of parameters that measured the nonblood vessel parameters were lower in the tumor model mouse than in the control mouse. The results of our preliminary investigation suggest that our quantitative X-ray imaging evaluation method may be useful for analyzing the vascular structure of tumors in small experimental animals.