Fig 1.
Sagittal (left), axial (middle), and coronal (right) views indicating the structures from which SNR measurements were taken. These T1w images were taken from one subject in the MPI-CBS database. CC, corpus callosum; RCN, right caudate nucleus; LCN, left caudate nucleus.
Fig 2.
PRISMA flow diagram.
Fig 3.
Mid-sagittal T1w images from each neuroimage database.
One participant was selected at random from each of the databases to serve as an example of the image quality expected.
Table 1.
Overview of the acquisition parameters and details of each database.
Fig 4.
SNR estimations for the left and right caudate nucleus.
Data averaged over the individuals of each database. Error bars indicate standard error of the mean.
Fig 5.
The relationship between sample size and SNRCC.
Error bars indicate standard error of the mean. Both the SNR values and the standard errors are presented on the log scale. Circular symbols indicate 3T data, triangular symbols indicate 7T data.
Fig 6.
Overview of ratios for databases containing a T1w image.
SNRCC values are shown in black, CNR values in grey. Each value has been normalized by the voxel dimensions specific to the image it describes. Error bars indicate standard error of the mean. Databases marked with an apostrophe (‘) indicate 7T data. The dotted vertical lines indicate the mean of the SNRCC (black) and CNR (grey).
Table 2.
Summary table describing the SNRCC, SNRCN and CNR of the T1w images of each database.
Fig 7.
Overview of the ratios for databases containing a T2w image.
SNRCC values are shown in black, CNR values in grey. Error bars indicate standard error of the mean. The dotted vertical lines indicate the mean of the SNRCC (black) and CNR (grey).
Table 3.
Summary table describing the SNRCC, SNRCN and CNR of the T2w images of each database.
Fig 8.
The relationship between the SNRCC and voxel dimensions of T1w images with scanning time in 18 databases.
A) Graphical representation of SNRCC and scan time. Error bars indicate standard error of the mean. B) Graphical representation of voxel dimensions and scan time. Both legends contain information relating to the adjusted R-squared value, intercept, slope, F statistic, degrees of freedom and p-value. Circular symbols indicate 3T data, triangular symbols indicate 7T data.
Fig 9.
Graphical representation of difference in normalized SNRCC values for quantitative T1 maps and T1-weighted images.
Databases marked with an apostrophe (‘) indicate 7T data. qT1, quantitative T1 map; T1w, T1-weighted; wb, whole-brain; sb, slab. Error bars indicate standard error of the mean.
Table 4.
Normalized SNRCC, SNRCN and CNR values for the databases that presented slabs as well as whole brain data.
Fig 10.
Comparison of ratios for T1w images across age groups.
A) SNRCC. B) SNRCN. C) CNR. Error bars indicate standard error of the mean. Each bar singular represents five participants. Databases marked with an apostrophe (‘) indicate 7T data.
Fig 11.
Comparison of ratios for T2w images across age groups.
A) SNRCC. B) SNRCN. C) CNR. Error bars indicate standard error of the mean. Each bar singular represents five participants.