Neuroradiology

A Case-Based Guide

Swati Goyal

• Éditeur: CRC Press
• Année: 2020
• ISBN:
  9781000198843
• Édition: 1
• Sujet: Medizin
• Sous-sujet: Radiologie, Radiotherapie & Nuklearmedizin

This book covers the complete gamut of neuroradiology cases, including normal anatomy, pitfalls, and artifacts across the brain and spine in a single volume, enriched with high-resolution images that support the interpretation of CT and MRI images of the brain, spine, head, and neck. It includes case studies commonly encountered in clinical practice, in addition to normal anatomy, that prepare the reader for the challenges in the clinical setting. Each case study discusses the clinical history, relevant imaging findings, differential diagnosis, and management, serving as a helpful read for trainee radiologists, neurophysicians, neurosurgeons, and CT/MRI technicians, along with physicians interested in medical imaging.

Key Features

• Provides a succinct overview of normal variants with case studies structured into thematic chapters

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• Serves as a basic accompaniment for radiology residents, fellows, practicing radiologists, neurophysicians, neurosurgeons, emergency medicine practitioners, trainee and practicing radiographers, and those studying for Board exams

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• Highlights the relevance of artificial intelligence in clinical practice

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1

Normal Brain Development and Congenital Malformations

Normal brain development has four phases:

1. 1) Dorsal induction involves the process of neurulation or neural tube formation.
2. The appearance of the neural plate (at around 4.5–5 weeks of gestation), followed by its invagination, leads to the formation of a neural groove. Thickening and proliferation of the lateral portion of the groove form neural folds. The apposition of the neural folds in the midline forms the neural tube.
3. Malformations at dorsal induction include anencephaly, cephalocele, and Chiari 2 malformation.
4. Secondary neurulation involves the formation of the distal spine, including the skull, dura, pia, and vertebrae, at 4–5 weeks. Abnormalities at this phase result in spinal dysraphic disorders like spina bifida occulta, meningocele, lipomeningocele, neurenteric cysts, dermal sinus, caudal regression syndrome, etc., which will be discussed in the next section.
5. 2) Ventral induction involves formation of primary brain vesicles by rostral expansion of the neural tube. The proximal two-thirds of the neural tube develops into the future brain, with the caudal one-third developing into the future spinal cord. The lumen of the tube develops into the ventricular system of the brain and the central canal of the spinal cord.
6. Abnormal development at this time results in anomalies such as holoprosencephaly, hydrocephalus, aqueductal stenosis, corpus callosum agenesis, and posterior fossa malformations such as the Dandy-Walker malformation, cerebellar hypoplasia, and rhombencephalosynapsis.
7. 3) Neuronal proliferation, differentiation, migration, and histogenesis occur at around 8–22 weeks of gestation. At this time, neurons migrate peripherally from the germinal matrix (that lines the ventricular surface) to the pia mater/cortex. Brain insults during this time result in abnormalities like lissencephaly (smooth brain) to schizencephaly (split brain), polymicrogyria, laminar/focal heterotopia, microcephaly, megalencephaly, focal cortical dysplasia, hemimegalencephaly, schizencephaly, vascular anomalies, and phakomatoses.
8. 4) Myelination will be discussed in Chapter 6.

Case Studies

Chiari Malformations

Figure 1.1 (a and b) Chiari 2 malformation, (c) Chiari 3 malformation.

Disorder of primary neurulation.

Clinical

Headache, vertigo, sensory changes, limb weakness, ataxia.

IMAGING

Chiari 0 Malformation

Syrinx without tonsillar ectopia.

Chiari 1 Malformation

Congenital tonsillar ectopia with inferior displacement/herniation (>5 mm) of elongated and pointed tonsils into the upper cervical canal through the foramen magnum. It is associated with:

• Syringohydromyelia (syrinx) – CSF accumulation within the spinal cord
• Hydrocephalus
• Osseous anomalies like basilar invagination, atlanto-occipital assimilation, platybasia, and Klippel-Feil syndrome

Chiari 1.5 Malformation

Inferior displacement of the cerebellar tonsils and brainstem.

Chiari 2 Malformation

• Hydrocephalus
  • Lateral ventricles – colpocephaly
  • 3rd ventricle – large massa intermedia
  • 4th ventricle – tube-like, elongated, and inferiorly displaced
• Brain...