“…Although these structures cannot be considered true geometric fractals, since their property of self-similarity does not extend to infinity, it is possible to define it, to a certain degree, where the concept of repetition is limited to a biologically relevant spatial scale window [ 41 ]. While the use of fractal dimension for x-ray image analysis has focused on the study of bone tissue [ 42 , 43 ] examples of its use can be found in a wide variety of clinical settings, as brain structures analysis [ 44 ] or vascular patterns studies [ 45 ]. However, its use in the pneumonia detection in X-ray has been so far limited [ 46 ].…”