Advances in gene sequencing and genotype-phenotype profiling have furthered understanding of many brain malformations. Some malformations previously considered disparate in terms of gestational timing and etiology are now considered phenotypic variants of common pathways while others previously considered variants of…
A significant number of deaths and permanent neurologic disabilities occur during the first month of life, the neonatal period. During the first month of life, term infants and particularly preterm neonates are vulnerable to a wide range of adverse events…
Central nervous system (CNS) anomalies occur in 1.4 to 1.6 per 1,000 live births and 3% to 6% of still births. Whereas some anomalies can be detected as early as the first trimester (such as anencephaly), others may not develop…
Perfusion Imaging In the cerebrovascular literature, perfusion imaging refers to an all-encompassing term of various methods to measure hemodynamically derived functional parameters in the brain. In radiology, the three most common parameters that are assessed and utilized clinically are cerebral…
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…