FLAIR Lesion Pre-Selection: Again

Last Time

• Noticed a questionable aspect of the pipeline: normalizing values in a scan by the max

• SPM homogeneity correction is perhaps an alternate way to normalize the values across patients

• The goal here is to create a lesion core pre-selection that is close to Hagen’s edited versions– We favor selecting too much over too little as this is

easier to edit

P009-Original FLAIR

P009-SPM Normalized FLAIR

P009-SPM Normalized FLAIR Lesions

P009-Hagen’s Lesions

P009-Max Normalized FLAIR Lesions

P015-Original FLAIR

P015-SPM Normalized FLAIR

P015-SPM Normalized FLAIR Lesions

P015-Hagen’s Lesions

P015-Max Normalized FLAIR Lesions

P028-Original FLAIR

P028-SPM Normalized FLAIR

P028-SPM Normalized FLAIR Lesions

P028-Hagen’s Lesions

P028-Max Normalized FLAIR Lesions

Observations

• SPM normalization usually gives a more conservative estimate, but not always as in P028– Hagen did find himself removing a lot of material

from the max normalized lesions so this is probably good

• SPM normalization gives boundaries comparable to those edited by Hagen for the lesions is to does catch

Conclusion

• We would have to consult Hagen to see which he prefers to work from

• My take:– Lesion boundaries are improved at the cost of

missing some of the smaller focal lesions– I would switch to SPM normalization as I find that

fine tuning boundaries is time consuming