Advanced perfusion settings

Advanced settings related to perfusion analysis, AIF deconvolution options, CA leakage correction method and tissue segmentation.

The Advanced perfusion settings dialog box is displayed by clicking on the Advanced options ... button accessed from the Perfusion Settings dialog box. The settings contain five sub-settings tabs

Analysis tab: Selects whether relative mean transit time (rMTT) is determined from the area under curve (AUC) / peak height ratio of the first-pass curve (default) or from the first moment of the first-pass curve

Segmentation tab:

· Vessel segmentation: selects number of clusters used for the k-means cluster algorithm used to identify vessels in the DSC perfusion series and whether a pre-cluster mask should be applied to remove regions with high MTT or high baseline signal intensity before applying the main segmentation procedure. See Emblem et al doi: 10.1002/mrm.21944 for details. NOTE: these methods should be used with care as no guarantee can be made that high CBV pathologic tissue as incorrectly identified as vessels.

· Brain mask: selects which tissue type should be used when generating a brain mask.

· Normalization: selects which tissue type to use for automated normalization of perfusion metrics to normal appearing brain (either WM, GM or both). The option <remove non-Brain from ref mask> attempts to remove ‘atypical’ regions from the generated brain mask. See Emblem et al: doi: 10.3174/ajnr.A1680 for details.

CA leakage tab:

· Contrast agent leakage correction method:

· Weisskoff method: leakage correction is performed according to the method initially proposed by Weisskoff et al and later by Boxerman et al (http://www.ajnr.org/content/ajnr/27/4/859.full.pdf)

· Leakage correction performed based on analysis of the tissue residue function following automated AIF deconvolution. See Bjornerud et al (doi: 10.1038/jcbfm.2011.52) and Lee et al (doi: 10.3174/ajnr.A5732) for details.

· Option to include both T1-dominant and T2-dominant leakage or only T2-dominant leakage in the analysis and for setting a lower cutoff for K2 (extravasation constant) to include in output map.

AIF and deconvolution tab:

AIF deconvolution analysis: when AIF deconvolution is performed, CBV can be determined either from the area under the first-pass curve (AUC) , normalized to the AUC of the AIF (default) or from the AUC of the resulting residue function.
Iterative Tikhonov regularization: specifies number of iterations to use for the analysis
Auto-AIF detection: number of iterations to use for the K-means cluster analysis to identify the AIF
AIF K-means Cluster Parameters: specifies which features of the dynamic curve to be used to identify AIF voxels
Population based AIF: specifies properties of pre-defined AIFs used as a population based AIF
Parameter estimation: selection of which method to use to estimate relative mean transit time (rMTT) from the dynamic curve.

Advanced perfusion settings

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