RT Journal Article
SR Electronic
T1 Reducing False-Positives in CT Perfusion Infarct Core Segmentation Using Contralateral Local Normalization
JF American Journal of Neuroradiology
JO Am. J. Neuroradiol.
FD American Society of Neuroradiology
SP 277
OP 283
DO 10.3174/ajnr.A8111
VO 45
IS 3
A1 Rau, Alexander
A1 Reisert, Marco
A1 Taschner, Christian A.
A1 Demerath, Theo
A1 Elsheikh, Samer
A1 Frank, Benedikt
A1 Köhrmann, Martin
A1 Urbach, Horst
A1 Kellner, Elias
YR 2024
UL http://www.ajnr.org/content/45/3/277.abstract
AB BACKGROUND AND PURPOSE: The established global threshold of rCBF <30% for infarct core segmentation can lead to false-positives, as it does not account for the differences in blood flow between GM and WM and patient-individual factors, such as microangiopathy. To mitigate this problem, we suggest normalizing each voxel not only with a global reference value (ie, the median value of normally perfused tissue) but also with its local contralateral counterpart.MATERIALS AND METHODS: We retrospectively enrolled 2830 CTP scans with suspected ischemic stroke, of which 335 showed obvious signs of microangiopathy. In addition to the conventional, global normalization, a local normalization was performed by dividing the rCBF maps with their mirrored and smoothed counterpart, which sets each voxel value in relation to the contralateral counterpart, intrinsically accounting for GM and WM differences and symmetric patient individual microangiopathy. Maps were visually assessed and core volumes were calculated for both methods.RESULTS: Cases with obvious microangiopathy showed a strong reduction in false-positives by using local normalization (mean 14.7 mL versus mean 3.7 mL in cases with and without microangiopathy). On average, core volumes were slightly smaller, indicating an improved segmentation that was more robust against naturally low blood flow values in the deep WM.CONCLUSIONS: The proposed method of local normalization can reduce overestimation of the infarct core, especially in the deep WM and in cases with obvious microangiopathy. False-positives in CTP infarct core segmentation might lead to less-than-optimal therapy decisions when not correctly interpreted. The proposed method might help mitigate this problem.MAmicroangiopathic alterationNoMAno microangiopathic alterationrCBFrelative CBFrCBVrelative CBVTmaxmaximum of the residue function