Principles of Neuroimaging

Abstract

Imaging of the brain and spinal cord has been transformed by the development of ultrasonography (US), MR imaging, and CT imaging. US is easy to perform at the patient’s bedside, but it is operator dependent. Fully innocuous and clinically very efficient, it still lacks specificity in comparison with other modalities, CT scanning and, mostly, MR imaging. In addition, the use of neuroimaging is restricted in infants whose fontanelles are still open. Because of growing concerns regarding the use of ionizing radiation in children, MRI has become the major imaging modality. Most sequences play a specific role in the diagnosis, and protocols may, on the whole, be tailored to the expected diagnosis in individual patients. It is extremely versatile as, in addition to anatomical images of the nervous system, its envelopes, and its vessels, it can provide information on the structural organization of a lesion, its perfusion, its energy metabolism, as well as its relationship with the “eloquent” neighboring structure and the functions of the surrounding brain. Its main limitation is the need for a sedation in the non-cooperative children. In spite of the risks inherent to the ionizing radiations, CT scanning remains a useful approach in traumatology and in most of the diseases that affect primarily the bone.