Method for assistance with the establishment of a diagnosis of a patient implemented by a device, starting from at least one identified sign and entered by an operator into said device and based on a computerized knowledge database comprising a medical ontology, the medical ontology comprising: ▪ a list of signs (S i), forming a "sign" class, ▪ a list of pathological states (D j), forming a "pathological state" class, and ▪ a first set of logical relationships between the signs and the pathological states, each logical relationship establishing a correlative link between a sign and a pathological state, the method comprising: ▪ a step of searching for potential pathological states, in which all of the pathological states linked by a correlative link to at least one of the identified signs are sought in the pathological state class by means of the first set of logical relationships, said pathological states forming the potential pathological states, and ▪ a step of identifying potential signs in which, for each potential pathological state, all of the signs linked by a correlative link to said potential pathological state are identified in the sign class by means of the first set of logical relationships, said signs forming the potential signs, characterized in that the medical ontology further comprises: ▪ a list of technical methods for acquisition of medical images (M k), forming an "imaging" class, each technical method for acquisition of a medical image defining a type of technology for acquisition of medical images, and a positioning of the medical image on the patient, and ▪ a third set of logical relationships between the signs and the technical methods for acquisition of medical images, each logical relationship defining a technical method for acquisition of a medical image making it possible to observe a sign, the method further comprising: ▪ a step of identifying technical methods for acquisition of interest, in which for each potential sign, all of the technical methods for acquisition of medical images making it possible to observe said potential sign are identified in the imaging class by means of the third set of logical relationships, said technical methods for acquisition of medical images forming the technical methods for acquisition of interest.. ▪ a list of signs (S i), forming a "sign" class, ▪ a list of pathological states (D j), forming a "pathological state" class, and ▪ a first set of logical relationships between the signs and the pathological states, each logical relationship establishing a correlative link between a sign and a pathological state, ▪ a step of searching for potential pathological states, in which all of the pathological states linked by a correlative link to at least one of the identified signs are sought in the pathological state class by means of the first set of logical relationships, said pathological states forming the potential pathological states, and ▪ a step of identifying potential signs in which, for each potential pathological state, all of the signs linked by a correlative link to said potential pathological state are identified in the sign class by means of the first set of logical relationships, said signs forming the potential signs, ▪ a list of technical methods for acquisition of medical images (M k), forming an "imaging" class, each technical method for acquisition of a medical image defining a type of technology for acquisition of medical images, and a positioning of the medical image on the patient, and ▪ a third set of logical relationships between the signs and the technical methods for acquisition of medical images, each logical relationship defining a technical method for acquisition of a medical image making it possible to observe a sign, ▪ a step of identifying technical methods for acquisition of interest, in which for each potential sign, all of the technical methods for acquisition of medical images making it possible to observe said potential sign are identified in the imaging class by means of the third set of logical relationships, said technical methods for acquisition of medical images forming the technical methods for acquisition of interest..