A new stage in the development of techniques based on the principle of the first passage of a contrast agent became possible after the introduction of X-ray perfusion computed tomography (PCT) into clinical practice. In recent years, comorbidity has been considered one of the most important problems in therapeutic practice. Its comprehensive study is carried out using epidemiological, genetic, immunological, clinical-functional and other methods to clarify the general biological patterns of a "non-random" combination of a number of diseases - syntropy.