Automatic structuring of breast cancer radiology reports for quality assurance

Hospitals often set protocols based on well defined standards to maintain quality of patient reports. To ensure that the clinicians conform to the protocols, quality assurance of these reports is needed. Patient reports are currently written in free-text format, which complicates the task of quality assurance. In this paper, we present a machine learning based natural language processing system for automatic quality assurance of radiology reports on breast cancer. This is achieved in three steps: We i) identify the top level structure of the report, ii) check whether the information under each section corresponds to the section heading, iii) convert the free-text detailed findings in the report to a semi-structured format. Top level structure and content of report were predicted with an F1 score of 0.97 and 0.94 respectively using Support Vector Machine (SVM). For automatic structuring, our proposed hierarchical Conditional Random Field (CRF) outperformed the baseline CRF with an F1 score of 0.78 vs 0.71. The third step generates a semi-structured XML format of the free-text report, which helps to easily visualize the conformance of the findings to the protocols. This format also allows easy extraction of specific information for other purposes such as search, evaluation and research.