ABSTRACT
Radiological imaging of the vascular system is an essential component in the clinical evaluation of vascular emergencies. Duplex ultrasound is still in use as a basic diagnostic means and enables initial diagnostic information. Digital subtraction angiography (DSA), the longtime gold standard, is now more often used with therapeutic interventions rather than purely diagnostic studies. However, over the past 10 years, there has been a rapid development of new technology that has deeply changed vascular imaging and allows a non-invasive depiction with a robust technique, greater speed and higher resolution. Advanced cross-sectional imaging techniques such as magnetic resonance imaging (MRI) and multidetector computed tomography (MDCT) angiography nowadays enable a dedicated diagnostic evaluation of acute aortic and peripheral arterial pathologies. Due to its enormous innovation and broad and quick availability angiographic multidetector computed tomography (MDCT) could replace catheter-based angiography in the diagnostic assessment. This article summarizes the performance of MDCT angiographic imaging and its diagnostic and therapeutic significance for the diagnostic assessment of non-traumatic aortic and peripheral arterial diseases.
Subject(s)
Angiography/methods , Emergency Medical Services/methods , Tomography, X-Ray Computed/methods , Vascular Diseases/diagnostic imaging , Blood Vessels/injuries , HumansABSTRACT
MR imaging is an excellent tool for use in diagnosing congenital malformations of the brain. Such malformations cannot be reliably recognized or classified without an insight into the basic processes of the fetal development of the brain. Cortical malformations are classically divided into (1) malformations of neuronal proliferation, i.e. of stem cell proliferation in the periventricular germinal matrix zone, (2) disorders of neuronal migration, i.e. of the radial migration of the neurons from the periventricular germinal matrix zone to the cortical surface, and (3) disorders of cortical organization. Other cerebral malformations are agenesis or dysgenesis of the corpus callosum, encephaloceles, and various kinds of holoprosencephaly. Chiari malformation ans disorders on the Dandy-Walker spectrum are relatively common, primarily infratentorial disorders. Rarer infratentorial disorders are Joubert syndrome, rhombencephalosynapsis and Lhermitte Duclos syndrome.
Subject(s)
Brain/abnormalities , Magnetic Resonance Imaging , Nervous System Malformations/diagnosis , Agenesis of Corpus Callosum , Brain/pathology , Brain Diseases/congenital , Brain Diseases/diagnosis , Cerebellum/abnormalities , Cerebellum/pathology , Cerebral Cortex/abnormalities , Cerebral Cortex/pathology , Choristoma/congenital , Choristoma/diagnosis , Corpus Callosum/pathology , Holoprosencephaly/diagnosis , Humans , Neurons/pathologyABSTRACT
MR imaging is an excellent tool for use in diagnosing congenital malformations of the brain. Such malformations cannot be reliably recognized or classified without an insight in to the basic processes of the fetal development of the brain. Cortical malformations are classically divided into (1) malformations of neuronal proliferation, i.e. of stem cell proliferation in the periventricular germinal matrix zone, (2) disorders of neuronal migration, i.e. of the radial migration of the neurons from the periventricular germinal matrix zone to the cortical surface, and (3) disorders of cortical organisation. Other cerebral malformations are agenesis or dysgenesis of the corpus callosum, encephaloceles and various kinds of holoprosencephaly. Chiari malformations and disorders on the Dandy-Walker spectrum are relatively common, primarily infratentorial disorders. Rarer infratentorial disorders are Joubert syndrome, rhombencephalosynapsis and Lhermitte Duclos syndrome.
Subject(s)
Brain Diseases/congenital , Brain/abnormalities , Magnetic Resonance Imaging , Adolescent , Adult , Agenesis of Corpus Callosum , Brain/pathology , Brain Diseases/diagnosis , Cerebellum/abnormalities , Cerebellum/pathology , Cerebral Cortex/abnormalities , Cerebral Cortex/pathology , Child , Child, Preschool , Corpus Callosum/pathology , Diagnosis, Differential , Female , Humans , Infant , Infant, Newborn , Male , Middle Aged , Sensitivity and Specificity , SyndromeABSTRACT
Disorders of supratentorial cortical development are usually divided into disorders of neuronal proliferation, neuronal migration and cortical organization. Based upon molecular biologic discoveries, a modified classification has recently been proposed. The category of malformations of abnormal neuronal and glial proliferation and apoptosis now includes microlissencephalies, megalencephalies, hemimegalencephalies and cortical dysplasias with balloon cells. Malformations due to abnormal neuronal migration now subsume the lissencephaly spectrum including the subcortical band heterotopias, the cobblestone complex and the group of heterotopias. Malformations due to abnormal cortical organization include the spectrum of polymicrogyria and schizencephaly as well as cortical dysplasias without balloon cells. High-resolution magnetic resonance imaging (MRI) has led to an increasing awareness of these malformations. This article aims to illustrate the classification, MRI presentation and relevant clinical features of the most commonly encountered disorders of cortical development.
Subject(s)
Cerebral Cortex/abnormalities , Image Enhancement , Image Processing, Computer-Assisted , Magnetic Resonance Imaging , Nervous System Malformations/diagnosis , Brain/pathology , Cerebral Cortex/embryology , Cerebral Cortex/pathology , Child , Child, Preschool , Female , Humans , Infant , Infant, Newborn , Male , Nervous System Malformations/classification , Nervous System Malformations/embryology , Pregnancy , Prenatal DiagnosisABSTRACT
The corpus callosum is formed between the 7th and the 20th gestational week. If this process is disrupted, partial or complete callosal agenesis may ensue. As large parts of the supra- and infratentorial brain are created during this critical period, associated anomalies need always to be searched for when callosal agenesis is present. Associations with neuro-genetic syndromes also exist. The corpus callosum is generally formed from front to back ("front-to-back rule"). Therefore, a partial callosal agenesis usually involves the posterior portion of the corpus callosum, while a secondary lesion of the corpus callosum does not follow this rule. Holoprosencephalies are a notable exception to this rule, as the frontal part of the corpus callosum is absent in spite of their classification as congenital malformations. They represent a disturbance of the differentiation and cleavage of the prosencephalon with a disruption of the separation of the cerebral hemispheres. Holoprosencephalies can be due to genetic causes, but also to intrauterine infections or other teratogenic causes. The holoprosencephalies are subdivided into alobar, semilobar and lobar holoprosencephalies. This article aims to describe the most important features of callosal agenesis and holoprosencephalies highlighting the respective imaging characteristics.
