Provided are a method for evaluation of tissue adhesion level which comprises relating the detection result of gadolinium from MRI image, on which a cross-section of a "boundary surface between a first tissue and a second tissue" of an animal administered with gadolinium has been imaged, to the adhesion level between the first tissue and the second tissue; and a detecting agent of tissue adhesion level. The detecting method of the present invention and detecting agent of the present invention are markedly useful, because they make it possible to detect the adhesion level, which is otherwise difficult to detect from the outside of the body, conveniently, speedily and precisely.