Sartor / Kress / Haehnel Brain Imaging

Direct Diagnosis in Radiology
1. Auflage 2007
ISBN: 978-3-13-257972-9
Verlag: Thieme
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 312 Seiten, ePub

Dx-Direct is a series of eleven Thieme books covering the main subspecialties in radiology. It includes all the cases you are most likely to see in your typical working day as a radiologist. For each condition or disease you will find the information you need -- with just the right level of detail. Dx-Direct gets to the point: - Definitions, Epidemiology, Etiology, and Imaging Signs - Typical Presentation, Treatment Options, Course and Prognosis - Differential Diagnosis, Tips and Pitfalls, and Key References ...all combined with high-quality diagnostic images. Whether you are a resident or a trainee, preparing for board examinations or just looking for a superbly organized reference: Dx-Direct is the high-yield choice for you! The series covers the full spectrum of radiology subspecialties including: Brain Gastrointestinal Cardiac Breast Urogenital Spinal Head and Neck Musculoskeletal Pediatric Thoracic Vascular

K. Sartor, S. Haehnel, B. Kress

Zielgruppe

Ärzte

Autoren/Hrsg.

Sartor, Klaus

Kress, Bodo

Haehnel, Stefan

Fachgebiete

• Medizin | Veterinärmedizin Medizin | Public Health | Pharmazie | Zahnmedizin Medizinische Fachgebiete Bildgebende Verfahren, Nuklearmedizin, Strahlentherapie Radiologie, Bildgebende Verfahren
• Medizin | Veterinärmedizin Medizin | Public Health | Pharmazie | Zahnmedizin Medizinische Fachgebiete Bildgebende Verfahren, Nuklearmedizin, Strahlentherapie Neuroradiologie
• Medizin | Veterinärmedizin Medizin | Public Health | Pharmazie | Zahnmedizin Klinische und Innere Medizin Neurologie, Klinische Neurowissenschaft

Inhaltsverzeichnis

1 Trauma
Cerebral Contusion
Diffuse Axonal Injury
Subdural Hematoma (SDH)
Epidural Hematoma
Traumatic Subarachnoid Hemorrhage
Cerebral Edema
Herniation Syndromes
Skull Fracture
2 Inflammation
Multiple Sclerosis (MS)
Postinfectious Encephalomyelitis (ADEM)
Herpes Simplex Encephalitis
Cerebral Abscess
Meningitis
Cerebral Vasculitis
Toxoplasmosis
Progressive Multifocal Leukoencephalopathy (PML)
Tuberculosis of the CNS
CNS Cysticercosis
3 Aneurysms
Subarachnoid Hemorrhage (SAH)
Saccular Aneurysm
Fusiform Aneurysm
4 Vascular Malformations
Cavernous Hemangioma
Venous Dysplasia
Capillary Telangiectasia
Pial Arteriovenous Malformation (AVM)
Cranial Dural Arteriovenous Fistula
Variants of Vascular Anatomy
Vascular Compression Syndromes
5 Stroke
Ischemic Brain Infarction
Cerebral Microangiopathy
Primary Intracerebral Hemorrhage
Amyloid Angiopathy
Vascular Dissection
Impaired Venous Drainage
Diffuse Hypoxic Brain Damage
6 Tumors
Meningioma
Higher Grade Gliomas
Brain Metastasis
Low-Grade Astrocytoma
Primary CNS Lymphoma
Sellar Masses
Nerve Sheath Tumors
Oligodendroglioma
Pilocytic Astrocytoma
Medulloblastoma
Pineal Tumors
Epidermoid
Embryonal Tumors
Ependymoma
Glioneuronal Tumors
Hemangioblastoma
Gliomatosis Cerebri
Choroid Plexus Papilloma
7 Cysts
Arachnoid Cyst
Virchow-Robin Spaces
Pineal Cyst
Colloid Cyst
Rathke Cleft Cyst
Choroid Plexus Cyst
8 Meninges
Meningeal Carcinomatosis
Reactive Meningeal Enhancement
CNS Sarcoidosis
9 Ventricles and Cisterns
Obstructive Hydrocephalus
Idiopathic Normal-Pressure Hydrocephalus
Pseudotumor Cerebri
10 Leukoencephalopathies
Wallerian Degeneration
Alzheimer Disease
Central Pontine Myelinolysis
Toxic Leukoencephalopathies
Reversible Posterior Leukoencephalopathy
Multiple System Atrophy
Wilson Disease
Hepatic Encephalopathy
Amyotrophic Lateral Sclerosis (ALS)
Wernicke Encephalopathy
Superficial Siderosis of the Brain
11 Congenital Malformations
Chiari Malformations
Defective Migration
Anomalies of the Corpus Callosum
Dandy-Walker Complex
Periventricular Leukomalacia (PVL)
Neurofibromatosis Type I (Von Recklinghausen Disease)
Neurofibromatosis Type II
Tuberous Sclerosis (Bourneville-Pringle Disease)
Sturge-Weber Syndrome
Von Hippel-Lindau Syndrome
Holoprosencephaly
12 Artifacts in MRI
13 Postoperative Changes

Leseproben

1 Trauma

Cerebral Contusion

Definition

• Epidemiology

  The most common type of bleeding in craniocerebral trauma.

• Etiology, pathophysiology, pathogenesis

  Traumatic intra-axial bleeding • Injury to cerebral parenchyma • May occur in combination with other forms of hematoma (subdural, subarachnoid, intracerebral) in up to 20% of all cases • Localization: frontobasal, occipital, parietal.

Imaging Signs

• Modality of choice

  CT.

• CT findings

  Hypodense in the acute stage, later hyperdense with a hypodense halo (perifocal edema) • Size: a few millimeters to several centimeters • Bleeding at point of impact and contrecoup bleeding are present, whereby the size of the contrecoup hemorrhage can be larger than that at the point of impact • There may be a mass effect depending on the size of the hemorrhage and the extent of the edema:

  • – Cerebral swelling with reduced definition of the cortex.
  • – Midline displacement.
  • – Compression of ventricular system with obstructed flow of CSF.
  • – Compression of the cisterna ambiens.
• MRI findings

  Not indicated in diagnosing acute cases • High sensitivity for older hemorrhages (subacute to chronic) • Hypointense susceptibility artifact on T2*-weighted images • Signal intensity on T1- and T2-weighted images corresponds to that of the bleeding in the respective stage of the hemoglobin breakdown process (p. 101).

Clinical Aspects

• Typical presentation

  Often unspecific, depending on the extent of bleeding • Headache • Vomiting • Nausea • Vertigo • Alertness is impaired, occasionally to point of loss of consciousness • Hemiparesis • Oculomotor impairment.

• Treatment options

  Surgical treatment is rarely indicated • Observation and control of edema are usually sufficient • Bleeding into the ventricular system may require drainage of cerebrospinal fluid.

• Course and prognosis

  This depends on the extent of the bleeding.

• What does the clinician want to know?

  Localization • Extent • Mass effect • Impingement • Rupture into the ventricular system • Obstructed flow of CSF.

Fig. 1.1 Hemorrhagic contusion in the superior frontal gyrus, 24 hours old. Axial CT.

Differential Diagnosis

The various forms of bleeding can occur in combination, rendering a differential diagnosis difficult.

Hemorrhagic infarction

– Significant perifocal edema usually present initially – Significantly reduced ADC

Venous infarction

– Atypical location of hemorrhage (e.g. temporooccipital) – No history of trauma – Significant surrounding edema usually present initially

Congophilic hemorrhage

– Usually multifocal hemorrhages (T2*-weighted MR image) – Additional signs suggestive of microangiopathy

Tips and Pitfalls

CT too early: Cerebral contusion may only be detectable after several hours. Therefore, a follow-up examination of intubated patients is indicated within six hours • Conscious patients should undergo a follow-up examination the following day.

Fig. 1.2a,b Bifrontal hemorrhagic contusion 3–4 days old. Axial T2*-weighted MR image (a) and axial T1-weighted MR image (b). Loss of signal due to susceptibility artifact on T2*-weighted images (a). Hyperintense signal (methemoglobin) on the T1-weighted image (b).

Selected References

Parizel P et al. Intracranial hemorrhage: Principles of CT and MRI interpretation. Europ Radiol 2001; 11 (9): 1770–1783

Struffert T et al. Schädel- und Hirntrauma. Radiologe 2003; 43: 861–877

Wiesmann M et al. Bildgebende Diagnostik akuter Schädel-Hirn-Verletzungen. Radiologe 1998; 38: 645–658

Diffuse Axonal Injury

Definition

• Etiology, pathophysiology, pathogenesis

  Stretched or torn nerve fibers • Loss of neurons • Petechial hemorrhage where perineural vessels are involved • Only about 20% of the lesions are hemorrhagic • Only half of the cases are posttraumatic; drug use is the next most common cause (recurrent hypoxia) • Disorder is most commonly supratentorial, in order of decreasing incidence: frontotemporal white matter—corpus callosum— brainstem.

Imaging Signs

• Modality of choice

  MRI.

• CT findings

  Findings are often unimpressive in the acute phase • Follow-up examinations demonstrate hemorrhages measuring a few millimeters at the corticomedullary junction • Edema is absent • Lesions in the corpus callosum and brainstem are difficult to detect • Nonhemorrhagic shear injuries cannot be diagnosed • Atrophy is a late sign of a shear injury.

• MRI findings

  T2*-weighted images will show a hemosiderin effect from hemorrhagic shear injuries • The apparent diffusion coefficient (ADC) is reduced • Usually at the corticomedullary junction • Linear or oval shaped • No surrounding edema • Often demonstrated only by histologic findings as many injuries are not detectable on MR images, especially nonhemorrhagic injuries.

Clinical Aspects

• Typical presentation

  The critical clinical condition is inconsistent with the “harmless” CT findings • Consciousness is severely impaired • Decerebrate rigidity • Convulsions • Intubation indicated.

• Treatment options

  No specific therapy is available • Control of edema • Management of acute complications.

• Course and prognosis

  Poor prognosis • Protracted convalescence • Atrophy indicative of loss of neurons.

• What does the clinician want to know?

  Differentiate from a “normal” cerebral contusion • Course.

Fig. 1.3 Diffuse axonal injury. Axial CT. Streaklike hemorrhages in the white matter (arrows). Hemorrhage in the corpus callosum and cingulate gyrus.

Differential Diagnosis

Contusion hemorrhage

– Perifocal edema – Typically frontobasal and also occipital

Subarachnoid hemorrhage

– Blood in the sulci

Calcifications

– Do not show dynamic development on follow-up studies

Microangiopathy

– Periventricular location – Located deep in white matter – Does not show dynamic development on follow-up studies at short intervals

Tips and Pitfalls

Failing to consider diffuse axonal injury • An MRI study need not be obtained in the early phase, i.e., within the first seven days. Only in this phase is it possible to demonstrate the injury on the basis of the reduced apparent diffusion.

Fig. 1.4a,b Coronal T2*-weighted (a) and axial T1-weighted MR images (b). Susceptibility artifact on the T2*-weighted image (a). After a few days the hemorrhages are also recognizable on the T1-weighted images by their hyperintense signal (b).

Selected References

Chan J et al. Diffuse axonal injury: detection of changes in anisotropy of water diffusion by diffusion-weighted imaging. Neuroradiology 2003; 45: 34–38

Niess C et al. Incidence of axonal injury in human brain tissue. Acta Neuropathol 2002; 104: 79–84

Struffert T et al. Schädel- und Hirntrauma. Radiologe 2003; 43: 861–877

Subdural Hematoma (SDH)

Definition

• Epidemiology

  Incidence: 10–20% of all patients with craniocerebral trauma.

• Etiology, pathophysiology, pathogenesis

  Acute or chronic accumulation of blood between the dura mater and arachnoid • Usually venous bleeding • Acute subdural hematomas are an absolute emergency indication • Combinations with other forms of hematoma (subdural, subarachnoid, intracerebral) may occur in up to 20% of all cases...

Über Autor(innen)

K. Sartor, S. Haehnel, B. Kress