Table 4.

Pros and cons of the most common electric field modeling outcome measures.

	Structure ROI	Geometric ROI	Whole brain percentile
Pros	Confined: Defining an ROI facilitates interpretation of E- field magnitudes within a predefined brain area. Highly flexible: The ROI can be tailored to available neuroimaging data and/or specific research questions Individualized: Size of the ROI is personalized to factors such as brain size and anatomical features.	Confined: Defining an ROI facilitates interpretation of E-field magnitudes within a predefined brain area. Flexible: The center of the ROI can position based neuroimaging data and/or research questions. Transferrable: Similar volumes across brain regions, participants or montages are analyzed.	Unconfined: By considering the whole brain, information is always given about the peak E-field magnitude regardless of location Reproducible: Easy to replicate as only a single percentile value is required to obtain the same results
Cons	Confined: By focusing on only one ROI, other important E-fields outside of the ROI may be overlooked. Transferrable: Uniqueness may hinder comparisons with other structural ROIs defined via different atlases or data.	Confined: By focusing on only one ROI, other important E-fields outside of the ROI may be overlooked. Size: Defining ROI size can be arbitrary, yet it can strongly affect the obtained E-field magnitude. Included region: Different cytoarchitectural / functional regions may be included in the same ROI across persons.	Spatially uncertain: Different brain volumes and regions may be analyzed across montages and participants. This can also impede interpretation of the obtained E-field magnitude.

E-Field = electric field, ROI = Region of Interest.