Technical note: Evaluation of a V‐Net autosegmentation algorithm for pediatric CT scans: Performance, generalizability, and application to patient‐specific CT dosimetry. Issue 4 (22nd February 2022)

• Record Type: Journal Article
• Authors: Adamson, Philip M.; Bhattbhatt, Vrunda; Principi, Sara; Beriwal, Surabhi; Strain, Linda S.; Offe, Michael; Wang, Adam S.; Vo, Nghia‐Jack; Gilat Schmidt, Taly; Jordan, Petr
• Is Part Of: Medical physics. Volume 49:Issue 4(2022)
• Page Start: 2342
• Page End: 2354
• Publication Date: 2022-02-22
• Subjects: deep learning -- organ dose -- segmentation; Medical physics -- Periodicals; Medical physics; Geneeskunde; Natuurkunde; Toepassingen; Biophysics; Periodicals; Periodicals; Electronic journals; 610.153
• DOI: 10.1002/mp.15521
• Languages: English
• ISSNs: 0094-2405

Abstract

Abstract: Purpose: This study developed and evaluated a fully convolutional network (FCN) for pediatric CT organ segmentation and investigated the generalizability of the FCN across image heterogeneities such as CT scanner model protocols and patient age. We also evaluated the autosegmentation models as part of a software tool for patient‐specific CT dose estimation. Methods: A collection of 359 pediatric CT datasets with expert organ contours were used for model development and evaluation. Autosegmentation models were trained for each organ using a modified FCN 3D V‐Net. An independent test set of 60 patients was withheld for testing. To evaluate the impact of CT scanner model protocol and patient age heterogeneities, separate models were trained using a subset of scanner model protocols and pediatric age groups. Train and test sets were split to answer questions about the generalizability of pediatric FCN autosegmentation models to unseen age groups and scanner model protocols, as well as the merit of scanner model protocol or age‐group‐specific models. Finally, the organ contours resulting from the autosegmentation models were applied to patient‐specific dose maps to evaluate the impact of segmentation errors on organ dose estimation. Results: Results demonstrate that the autosegmentation models generalize to CT scanner acquisition and reconstruction methods which were not present in the training dataset. While models are not equally generalizable across age groups, age‐group‐specific models do not hold any advantage over combining heterogeneous age groups into a single training set. Dice similarity coefficient (DSC) and mean surface distance results are presented for 19 organ structures, for example, median DSC of 0.52 (duodenum), 0.74 (pancreas), 0.92 (stomach), and 0.96 (heart). The FCN models achieve a mean dose error within 5% of expert segmentations for all 19 organs except for the spinal canal, where the mean error was 6.31%. Conclusions: Overall, these results are promising for the adoption of FCN autosegmentation models for pediatric CT, including applications for patient‐specific CT dose estimation.