Statistical bias is reduced as the findings are evaluated without any direct patient contact. 11 The radioactive gamma rays are emitted through the body as the natural decaying process of these isotopes takes place. 20 Creation of three-dimensional images edit Volume rendering techniques have been developed to enable CT, MRI and ultrasound scanning software to produce 3D images for the physician. American Journal of Neuroradiology. Because CT and MRI are sensitive to different tissue properties, the appearances of the images obtained with the two techniques differ markedly. In pregnancy edit Main article: Medical imaging in pregnancy Medical imaging may be indicated in pregnancy because of pregnancy complications, intercurrent diseases or routine prenatal care.