European Radiology Experimental (Oct 2019)

Fully automated convolutional neural network-based affine algorithm improves liver registration and lesion co-localization on hepatobiliary phase T1-weighted MR images

  • Kyle A. Hasenstab,
  • Guilherme Moura Cunha,
  • Atsushi Higaki,
  • Shintaro Ichikawa,
  • Kang Wang,
  • Timo Delgado,
  • Ryan L. Brunsing,
  • Alexandra Schlein,
  • Leornado Kayat Bittencourt,
  • Armin Schwartzman,
  • Katie J. Fowler,
  • Albert Hsiao,
  • Claude B. Sirlin

DOI
https://doi.org/10.1186/s41747-019-0120-7
Journal volume & issue
Vol. 3, no. 1
pp. 1 – 14

Abstract

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Abstract Background Liver alignment between series/exams is challenged by dynamic morphology or variability in patient positioning or motion. Image registration can improve image interpretation and lesion co-localization. We assessed the performance of a convolutional neural network algorithm to register cross-sectional liver imaging series and compared its performance to manual image registration. Methods Three hundred fourteen patients, including internal and external datasets, who underwent gadoxetate disodium-enhanced magnetic resonance imaging for clinical care from 2011 to 2018, were retrospectively selected. Automated registration was applied to all 2,663 within-patient series pairs derived from these datasets. Additionally, 100 within-patient series pairs from the internal dataset were independently manually registered by expert readers. Liver overlap, image correlation, and intra-observation distances for manual versus automated registrations were compared using paired t tests. Influence of patient demographics, imaging characteristics, and liver uptake function was evaluated using univariate and multivariate mixed models. Results Compared to the manual, automated registration produced significantly lower intra-observation distance (p < 0.001) and higher liver overlap and image correlation (p < 0.001). Intra-exam automated registration achieved 0.88 mean liver overlap and 0.44 mean image correlation for the internal dataset and 0.91 and 0.41, respectively, for the external dataset. For inter-exam registration, mean overlap was 0.81 and image correlation 0.41. Older age, female sex, greater inter-series time interval, differing uptake, and greater voxel size differences independently reduced automated registration performance (p ≤ 0.020). Conclusion A fully automated algorithm accurately registered the liver within and between examinations, yielding better liver and focal observation co-localization compared to manual registration.

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