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Updated: Jul 4, 2025

Author Spotlight: A 3D Digital Model for the Diagnosis and Treatment of Pulmonary Nodules
Published on: May 19, 2023
Evaluation of an artificial intelligence U-net algorithm for pulmonary nodule tracking on chest computed tomography
Yuhei Takeshita1, Shiro Onozawa1, Shichiro Katase1
1Department of Radiology, Kyorin University School of Medicine, 6-20-2 Shimorenjaku, Mitaka-shi, Tokyo, Japan 181-8611 Japan.
Objectives:
To apply image registration in the follow up of lung nodules and verify the feasibility of automatic tracking of lung nodules using an artificial intelligence (AI) method.
Methods:
For this retrospective, observational study, patients with pulmonary nodules 5-30 mm in diameter on computed tomography (CT) and who had at least six months follow-up were identified. Two radiologists defined a 'correct' cuboid circumscribing each nodule which was used to judge the success/failure of nodule tracking. An AI algorithm was applied in which a U-net type neural network model was trained to predict the deformation vector field between two examinations. When the estimated position was within a defined cuboid, the AI algorithm was judged a success.
Results:
In total, 49 lung nodules in 40 patients, with a total of 368 follow-up CT examinations were examined. The success rate for each time evaluation was 94% (345/368) and for 'nodule-by-nodule evaluation' was 78% (38/49). Reasons for a decrease in success rate were related to small nodules and those that decreased in size.
Conclusion:
Automatic tracking of lung nodules is highly feasible.

