Fig. 4From: An automatic pipeline for PET/MRI attenuation correction validation in the brainMR to CT based PET attenuation correction relative (a–c) and absolute (d–e) bias in FreeSurfer ROIs in the prefrontal cortex. ROIs were reconstructed with (a and d) and without (b and e) background activity and from the original PET images (c and f)Back to article page