Large intracranial artery regions in MRI head templates for calcium segmentation

We defined five rectangular ROIs around large intracranial arteries on two T1-weighted MRI templates of the head from Armitage et al., which are available online from the Edinburgh DataShare at https://doi.org/10.7488/ds/7763. The five ROIs are the following: 1. Vertebral arteries from the foramen magnum up to the termination. 2. Basilar artery from the joining of the vertebral arteries to the Circle of Willis. 3. Internal carotid artery, the cavernous segment up to the Circle of Willis. 4. The M1 segment of the left MCA. 5. The M1 segment of the right MCA. The MRI templates are age-specific for ranges 65-70 and 75-80. We use these approximate regions for subsequent precise segmentation and quantification of intracranial arterial calcification in co-registered CT scans.