Automating incidental findings in radiology reports using natural language processing and machine learning to identify and classify pulmonary nodules.

Abstract

e18093 Background: Pulmonary nodule incidental findings challenge providers to balance resource efficiency and high clinical quality. Incidental findings tend to be undertreated with studies reporting appropriate follow-up rates as low as 29%. Ensuring appropriate follow-up on all incidental findings is labor-intensive; requires the clinical reading and classification of radiology reports to identify high-risk lung nodules. We tested the feasibility of automating this process with natural language processing (NLP) and machine learning (ML). Methods: In cooperation with Sarah Cannon Research Institute (SCRI), we conducted a series of data science experiments utilizing NLP and ML computing techniques on 8,879 free-text, narrative CT (computerized tomography) radiology reports. Reports used were dated from Dec 8, 2015 - April 23, 2017, came from SCRI-affiliated Emergency Department, Inpatient, and Outpatient facilities and were a representative, random sample of the patient populations. Reports were divided into a development set for model training and validation, and a test set to evaluate model performance. Two models were developed - a “Nodule Model” was trained to detect the reported presence of a pulmonary nodule and a rules-based “Sizing Model” was developed to extract the size of the nodule in millimeters. Reports were bucketed into three prediction groups: > = 6 mm, < 6 mm, and no size indicated. Nodules were considered positives and placed in a queue for follow-up if the nodule was predicted > = 6 mm, or if the nodule had no size indicated and the radiology report contained the word “mass.” The Fleischner Society Guidelines and clinical review informed these definitions. Results: Precision and recall metrics were calculated for multiple model thresholds. A threshold was selected based on the validation set calculations and a success criterion of 90% queue precision was selected to minimize false positives. On the test dataset, the F1 measure of the entire pipeline (lung nodule classification model and size extraction model) was 72.9%, recall was 60.3%, and queue precision was 90.2%, exceeding success criteria. Conclusions: The experiments demonstrate the feasibility of NLP and ML technology to automate the detection and classification of pulmonary nodule incidental findings in radiology reports. This approach promises to improve healthcare quality by increasing the rate of appropriate lung nodule incidental finding follow-up and treatment without excessive labor or risking overutilization.