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Uncertainty estimation for DL-based motion artifact correction in 3D brain MRI
Karsten Sommer1, Jochen Keupp1, Christophe Schuelke1, Oliver Lips1, and Tim Nielsen1
1Philips Research, Hamburg, Germany
An uncertainty metric based on test-time augmentation is explored for 3D motion artifact correction. Analysis on test data revealed that this metric could accurately predict global error levels but failed in certain cases to detect local “hallucinations”.
Example results from the synthetic test dataset where the uncertainty metric Δy accurately predicted the validity of the corrections: For the input image shown in the top row, the network produces a faithful reconstruction of the ground truth image, which is accurately predicted by the low uncertainty metric. For the center and bottom row, substantial deviations from the ground truth can be observed (marked by arrows), which is accurately predicted by the relatively high uncertainty metric (SD=standard deviation).
Example results on the synthetic test dataset where the uncertainty metric Δy did not accurately predict the validity of the corrections. In particular, multiple local hallucinations can be observed (indicated by red arrows), although the TTA metric values are relatively low (Δy=0.3).