[Supporting system for CT diagnosis referring to previous cases].
Since radiologists make diagnoses by prior experience, images from previous studies are helpful in making diagnoses. We have developed an assisting system for CT image interpretation. The Case-Based Reasoning (CBR) method was implemented in order to search reports and images of past cases. This system translates the text of findings written in Japanese into descriptive units, and evaluates similarities between the current case and all stored cases (case base). The CT images of the similar cases can be retrieved for reference images, as well as reports which show examples of interpretation. Since this system employs a key word extracting method, translation and comparison can be performed within a second. In order to evaluate the validity of the similarity metrics, the correspondence between CT diagnoses by radiologists and those of the best matched cases by this system was examined. Forty-eight test cases were obtained from the reports of three radiologists. The case base was consisted of 1,060 cases written by other four radiologists of other hospitals. The matching ratio between diagnoses of test cases and most similar cases was 68.1%. The ratio became higher with the increasing number of stored cases. In clinical study of other 45 test cases, the best matched three diagnoses of 43 cases (95.6%) contained the established diagnoses. In 44 cases (97.8%), radiologists could make correct diagnoses by using this system. This system is useful to prevent misdiagnoses due to preconceptions and/or lack of knowledge. The diagnostic accuracy was expected to improve by using this system.
Tsukamoto
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Department of Radiology, Keio University, School of Medicine.
D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D012680:Sensitivity and Specificity; D012984:Software; D014057:Tomography, X-Ray Computed