Enhanced endoscopic ultrasound imaging for pancreatic lesions: The road to artificial intelligence

Figure 3 Three-dimensional surface fractal dimension estimate. A and B: Endoscopic ultrasound-elastography images (A) are used to highlight representative parenchymal regions (B) of solid pancreatic lesions; C: A computer-aided image analysis system generates an irregularly-shaped three-dimensional surface as a “shape matrix” of points with the column and row numbers proportional to the x and y coordinates and with the depth information z (x, y) stored as a matrix element. The three-dimensional fractal dimension, which is an index of the “surface roughness”, is automatically determined using the box-counting algorithm. The fractal dimension of a surface is expressed by a real number greater than 2 (the Euclidean dimension of a two-dimensional surface) and less than 3 (the Euclidean dimension of a solid). A surface with a higher surface fractal dimension is wrinkled than one with a lower dimension.