[[Computed axial tomography]] (CAT) or computed tomography (CT) creates tomographic images of the body. For neuroimaging studies, computer-processed X-rays are used and the amount of X-ray blockage by different structures is used to generate image 'slices' of the brain. CAT scans are particularly useful for determining the size (volume) of specific structures of the brain.<ref>{{cite book|last=Jeeves|first=Malcolm|title=Mind fields : reflections on the science of mind and brain|year=1993|publisher=Anzea Publishers|___location=Homebush West, NSW|isbn=9780858925250|pages=21}}</ref>
=== MRI and fMRI ===
[[Magnetic resonance imaging]] and [[functional magnetic resonance imaging]] have many applications when researching the human brain.<ref name="issr-journals.org">{{cite journal | last1 = Sahito | first1 = F. H. | year = 2013 | title = Interrogational Neuroimaging: The Missing Element in Counter-Terrorism | journal = International Journal of Innovation and Applied Studies | volume = 3 | issue = 3| pages = 592–607 |url=http://www.issr-journals.org/xplore/ijias/IJIAS-13-145-02.pdf }}</ref> A 2005 study examined the correlation between brain volume and intelligence. MRI-based measures of in vivo brain volume had reliabilities in the 0.90s. The study estimated that the correlation between brain volume and intelligence was 0.33.<ref>{{cite journal | last1 = Mcdaniel | first1 = M. | year = 2005 | title = Big-brained people are smarter: A meta-analysis of the relationship between in vivo brain volume and intelligence | url = | journal = Intelligence | volume = 33 | issue = 4| pages = 337–346 | doi = 10.1016/j.intell.2004.11.005 }}</ref>
