Back Propagation Neural Network-Based Ultrasound Image for Diagnosis of Cartilage Lesions in Knee Osteoarthritis

Table 2

Staging criteria of knee cartilage degeneration under ultrasound detection.

Stage	Cartilage status under ultrasound
No lesion	The surface shows high echo and the lines are smooth, clear, and continuous. The boundary between cartilage and its inferior bone is normal, and the lower vocal cords are evenly distributed and of normal thickness.
Stage I	The change degree is small or the surface is rough, the thickness is close to normal, the degenerated deep layer shows high echo, the sound line is continuous, the smooth slightly less, and the internal echo distribution is basically uniform
Stage II	The surface shows hyperecho and coarse sound line with localized uplift. The deep sound line of the lesion site shows continuous hyperecho with increased echo and uneven distribution.
Stage III	Thin, with obvious defect, but no invasion of subchondral tissue, uneven distribution of low vocal cords, cartilage interruption defect, degenerative deep high echo, irregular voice line increase, showing extremely coarse, local defect
Stage IV	The subchondral bone is exposed, the deep high echo line is discontinuous, the central low echo cord is thinned, the cartilage defect area is enlarged, and the subchondral bone is invaded, obviously thinned, and the whole layer is thinned.