Title
Automatic de-identification of electronic medical records using token-level and character-level conditional random fields
Abstract
De-identification, identifying and removing all protected health information (PHI) present in clinical data including electronic medical records (EMRs), is a critical step in making clinical data publicly available. The 2014 i2b2 (Center of Informatics for Integrating Biology and Bedside) clinical natural language processing (NLP) challenge sets up a track for de-identification (track 1). In this study, we propose a hybrid system based on both machine learning and rule approaches for the de-identification track. In our system, PHI instances are first identified by two (token-level and character-level) conditional random fields (CRFs) and a rule-based classifier, and then are merged by some rules. Experiments conducted on the i2b2 corpus show that our system submitted for the challenge achieves the highest micro F-scores of 94.64%, 91.24% and 91.63% under the 'token', 'strict' and 'relaxed' criteria respectively, which is among top-ranked systems of the 2014 i2b2 challenge. After integrating some refined localization dictionaries, our system is further improved with F-scores of 94.83%, 91.57% and 91.95% under the 'token', 'strict' and 'relaxed' criteria respectively. © 2015 Elsevier Inc..
Year
DOI
Venue
2015
10.1016/j.jbi.2015.06.009
Journal of Biomedical Informatics
Keywords
Field
DocType
De-identification,Electronic medical records,Hybrid method,Natural language processing,Protected health information,i2b2
Conditional random field,Informatics,Data mining,De-identification,Computer science,Protected health information,Artificial intelligence,Natural language processing,Classifier (linguistics),Hybrid system,Security token,CRFS
Journal
Volume
Issue
ISSN
58
SUPnan
1532-0464
Citations 
PageRank 
References 
10
0.57
18
Authors
9
Name
Order
Citations
PageRank
Zengjian Liu1353.84
Chen Yangxin2161.01
Buzhou Tang336834.04
Xiaolong Wang41208115.39
Qingcai Chen580966.72
Li Haodi6253.89
Wang Jingfeng7161.01
qiwen8202.10
Zhu Suisong9161.34