Fig 1.
Automated brain volume measurements at 3T and 1.5T.
Examples of the performed measurements for the robustness analysis for one subject on 3T and 1.5T MRI. Individual measurements are shown using a probabilistic (SPM and FSL) or a binary approach (Freesurfer). GM: gray matter. WM: white matter. CSF: cerebrospinal fluid.
Fig 2.
Reference measurements and automated brain volume measurements at 3T.
Examples of the performed measurements for the accuracy analysis for one subject on 3T MRI. Individual measurements are shown in native space (probabilistic for SPM and FSL, and binary for Freesurfer). Also, binary measurements for each tissue compartment are shown for all methods (using a threshold of 0.5 in case of probabilistic segmentation). GM: gray matter. WM: white matter. CSF: cerebrospinal fluid.
Table 1.
Automated volume measurements at 3T and 1.5T (n = 10).
Table 2.
Robustness analysis across different field strengths (n = 10).
Fig 3.
Bland-Altman plots at 3T and 1.5T.
X-axis: mean brain volume measurement at 3T and 1.5T. Y-axis: difference (in cc) in brain volume measurement between 3T and 1.5T. The mean, lower (- 1.96 SD) and upper (+ 1.96 SD) limits of agreement are shown. A negative difference on the y-axis is seen when brain volume measurements at 1.5T were larger than at 3T. TBV: total brain volume. GM: gray matter volume. WM: white matter volume. CSF: cerebrospinal fluid volume. ICV: intracranial volume.
Fig 4.
Bland-Altman plots automated versus manual volume measurements.
X-axis: mean brain volume measurement of automated and manual volume measurements. Y-axis: difference (in cc) in brain volume measurement between automated and manual volume measurements. The mean, lower (- 1.96 SD) and upper (+ 1.96 SD) limits of agreement are shown. A negative difference on the y-axis is seen when brain volume measurements were larger with manual volume measurements than with automated volume measurements. TBV: total brain volume. GM: gray matter volume. WM: white matter volume. CSF: cerebrospinal fluid volume. ICV: intracranial volume.
Table 3.
Accuracy of automated volume measurements (n = 20).
Table 4.
Summary of robustness across field strength and accuracy results.