The use of texture analysis in the vertebral morphometric study of a lordotic chub (Squalius cephalus L.)

Objective: To characterise vertebral aspects of a lordotic chub (Squalius cephalus L.) using texture analysis by radiograph and to verify possible alterations in the vertebral microarchitecture of the lordotic tract. Methods: Four vertebrae belonging to the lordotic tract were analyzed for their texture features by means of a software package (MaZda vers. 4.6) and were compared, for the same features, to other four vertebrae cranial (anterior) to the lordotic vertebrae. Results: Two representative features were selected out of 259 extracted texture features by means of the convex hull selection method. In particular, (5, 5) sum of squares (according to cooccurrence matrix method) and 45° short run emphasis (according to run-length matrix method) were used to classify, without classification errors, two selected spinal tracts (the lordotic one and the immediately cranial one, both corresponding to the anal fin pterigiophores vertebral portion) according to the following methods: linear discriminant analysis and hierarchical clustering. Conclusions: This is the first known application of texture analysis in medical imaging applied to fish species and represents a start point for further studies in aquariology and in aquaculture, where spinal deformities occur relative frequently and are cause of economic losses.