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.
MRI stands for magnetic resonance imaging; it basically uses powerful magnets and radio waves to create detailed images of the interior of your body. It can be done with or without contrast. Contrast is a type of dye that is injected intravenously either right before, or during the procedure. Certain abnormalities, such as tumors, will absorb the dye and show up very clearly on the MRI with contrast. Your doctor will determine whether you need an MRI with contrast or without, and may order both tests. An MRI scan is different than a regular x-ray or a CT scan, which both use ionizing radiation to create images. MRI scans generally produce clearer images with much more detail than an x-ray or CT scan.