Slide 1

Lesion Segmentation Methodology

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Purpose Currently in a dilemma as Hagen did a substantial amount of work editing the z-score FLAIR masks in MNI space, but realize that it is more standard to do such work in patient space Goal of this presentation is to determine how much of Hagens work can be salvaged and how much editing needs to be redone with the new patient space method Secondary goal is to determine if zscore > 2 is a good method for selecting DAWM

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3 Methods to Choose From Z-score in MNI -> threshold (4, 2) -> patient space -> threshold (.95,.5, 0) The original method, Hagen edited these Z-score in MNI -> patient space -> threshold (4, 2) z-score in MNI Mean and std. dev. in MNI -> patient space -> z-score -> threshold (4, 2) z-score in patient space

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P015 Low CIS FLAIR

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P015 Low CIS Original Method, Lesion Cores, Threshold.95

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P015 Low CIS Original Method, Lesion Cores, Threshold.5

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P015 Low CIS Original Method, Lesion Cores, Threshold 0

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P015 Low CIS z-score in MNI, Lesion Cores

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P015 Low CIS z-score in patient space, Lesion Cores

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P015 Low CIS z-score in MNI, Lesion Penumbra

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P015 Low CIS z-score in patient space, Lesion Penumbra

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P009 Low CIS FLAIR

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P009 Low CIS Original Method, Lesion Cores, Threshold.95

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P009 Low CIS Original Method, Lesion Cores, Threshold.5

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P009 Low CIS Original Method, Lesion Cores, Threshold 0

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P009 Low CIS z-score in MNI, Lesion Cores

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P009 Low CIS z-score in patient space, Lesion Cores

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P009 Low CIS z-score in MNI, Lesion Penumbra

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P009 Low CIS z-score in patient space, Lesion Penumbra

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Observations z-score in MNI and in patient space give very similar results, I would argue for z-score in MNI as the better choice for simplicity The Original Method with threshold 0 is reasonable balance between lesion cores and penumbra, needs a look at by expert eyes Threshold z-score > 2 fills in obvious DAWM around lesion cores nicely Not so great job with areas that did not contain a core

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Proposed Options Lesion cores Keep Hagens masks and threshold at.5 after warping to patient space Alternatively, carry through z-score in MNI method and apply penumbra selection method to them using Hagens masks Lesion penumbra (DAWM) Z-score in MNI method thresholded at 2 then penumbra selection