Measure: To estimate the cranial capacity of each skull in the Gizmo, measure the area of the part of the cranium that houses the brain. This part of the cranium is roughly behind the red line in the diagram at right.
Chemical dyes are sometimes injected into patients prior to an MRI (magnetic resonance imaging) to enhance internal images. However, certain widely used MRI dyes may cause a number of side effects, including a serious, potentially fatal disease known as nephrogenic systemic fibrosis, or NSF.
The contrast material used for MRIs is less likely to cause an allergic reaction than the contrast material used for CT scans. An MRI can last anywhere from 15 minutes to more than an hour. You must hold very still because movement can blur the resulting images.