Physiologic Basis of Functional Magnetic Resonance Imaging Functional magnetic resonance imaging (fMRI) is based on the blood oxygen level–dependent (BOLD) contrast effect and neuronal activity–cerebrovascular flow coupling. Oxygenated blood (oxyhemoglobin) is diamagnetic, producing little susceptibility-related dephasing on magnetic resonance (MR)…
Of the advanced magnetic resonance imaging (MRI) modalities, diffusion-weighted (DW) MRI has probably garnered the most excitement in both clinical and research settings during the past decade. Standard now in nearly every neuroimaging MR protocol, DW-MRI has demonstrated substantial clinical…
Magnetic resonance spectroscopy (MRS) capability is available in most clinical magnetic resonance (MR) scanners. The additional information from MRS allows the assessment of cellular metabolism noninvasively. For the brain in particular, it has been proved that MRS of protons or…
The human brain undergoes four phases of development: (1) dorsal induction (primary and secondary neurulation), (2) ventral induction (patterning of the forebrain), (3) neuronal proliferation and migration, and (4) myelination. During the third week of embryogenesis, initiation of the central…
Congenital Depressions Congenital depressions of the calvaria result from mechanical factors that occur before or during birth. During labor, calvarial depressions are caused by excessive localized pressure on the head by the bony prominences in the maternal pelvis, including the…
Anatomy At birth, the mandible consists of two lateral halves united in the midline at the symphysis by a bar of cartilage ( Fig. 22.1 , e-Fig. 22.2 , and Fig. 22.3 ). Bony fusion of the symphysis usually occurs…
Primary Neoplasms Primary neoplasms of the skull are rare. The most common lesions in children with a solitary nontraumatic lump on the head are dermoid tumors (61%), cephalhematomas (9%), Langerhans cell histiocytosis (LCH) (7%), and occult meningoceles and encephaloceles (4%).…
The clinical and radiologic features of craniosynostosis result from lack of sutural formation or premature fusion across membranous sutures. The premature sutural closure prevalence is displayed in e-Table 20.1 . Normal sutures permit skull growth perpendicular to their long axes.…
The fetal abnormalities described in this chapter are those most likely to be assessed by a pediatric radiologist who primarily performs fetal magnetic resonance imaging (MRI), computed tomography (CT), radiography, and ultrasound. These additional modalities are particularly useful for acquiring…
Anatomy of the Skull The skull is divided into three portions: the neurocranium, the face, and the base. The neurocranium is composed of the membranous portions of the occipital, parietal, frontal, and temporal bones, and is bounded inferiorly by the…