新生儿颅脑超声.pptx

新生儿颅脑超声影像新生儿颅脑超声影像 汪元芳 MD,ARDMS,ARVT NeurosonographyNeurosonography 1 1 Routinely for premature infants at 6 days and 4 weeks and as needed to rule out Intraventricular Hemorrhage and Periventricular Leukomalacia,as well as other abnormalities Typically up to 9 months or as long as fontanelle is open Use anterior fontanelle mostly,also transmastoid and posterior for better visualization of the posterior fossa and 4th ventricle Highest frequency transducer to allow sufficient penetration and resolution(curved or vector),linear images to define superficial structures Corpus Collosum CSP Cavum Vergae Velum Interpositum Ventricles Choroid Plexus Cerebellum Caudate Nucleus Thalamus Sylvian Fissures Circle of Willis Cerebral Hemispheres Brain Covering Lobes of Cerebrum Lateral Ventricle -Frontal Horn -Body -Occipital Horn -Temporal Horn -Choroid Plexus-Lateral Ventricles-Foramina of Monro -3rd Ventricle-Aqueduct of Sylvius-4th Ventricle-Foramina of Magendie and Luschka-Foramen Magnum Subarachnoid Space Subdural Space -Enlargement of frontal,temporal extracerebral CSF spaces,enlargement of the frontal horns,and macrocephaly -Will show bridging cortical veins(to distinguish between subdural collections which are never benign)Coronal Images(frontal occipital)Frontal at level of orbits Orbital Bones Frontal horns Anterior to Foramen of Monro MCA Region(Measure Lat.Vents.)Foramen of Monro Posterior aspect of 3rd ventricle through thalami Cerebellum and Lateral Vents.Bodies Tentorium Laertal Vents.Including Choroid Plexus Cortex of occipital lobes and posterior Interhemispheric Fissure(periventricular white matter)MCA Region of Circle of Willis MCA 3rd Vent Sylvian Fissures Thalami Cerebellum Tentorium Cerebellar Vermis Choroid Plexus in Lat.Vents.Periventricular White Matter Interhemispheric Fissure(Falx)Parasagittal Midline including corpus callosum,cavum,3rd and 4th vents,vermis,cisterna magna Caudothalamic groove Frontal horn of lat.Vent Body of lat.Vent including temporal and occipital horns Sylvian fissue Sulci/Gyri lateral 3rd Vent.4th Vent.Cerebellar Vermis Aqueduct of Sylvius Corpus Collosum Cavum Vergae Cisterna Magna Velum Interpositum Cavum Septum Pellucidum Thalamus Caudothalamic Groove Caudate Nucleus Temperal Horn of Lat.Vent Sylvian Fissure Frontal Horn of Lat.Vent Periventricular White Matter Premature Smooth Brain Sulcation Term Transmastoid View of cerebellum,4th ventricle,foramen magnum Cerebellar hemisphere closer to transducer will have best resolution,thus we image the cerebellum from both the right and left mastoid fontanelles Posterior fontanelle Image the occipital horns of the lateral ventricles Occipital Horn of Lat.Vent 4th Vent.Cisterna Magna Cerebellum Complications of prematurity:IVH and PVL Germinal matrix consists of proliferating cells that give rise to neuroblasts which migrate out to form the neurons of the cerebral cortex and the basal ganglia Highly vascular,consisting of network of thin-walled capillaries,veins and arterioles Early in gestation,germinal matrix forms subependymal lining of entire ventricular system.Maximizes in size at 23-24wks,then slowly regresses,involuting 3rd vent and occipital and temporal horns first During end of gestation,only small area remains over caudate nucleus.By 36 weeks,almost completely gone.Germinal matrix hemorrhage in infants is usually venous in origin Risk Factors for IVH-premature infant Instability of Cardiovascular system leading to sudden increases in blood pressure Absence of autoregulatory mechanism which maintains constant blood flow to brain Mechanics of ventilation,tracheal suctioning,pnuemothorax,patent ductus arteriosus,and high inspired oxygen content because they all increase systemic pressure flow to brain Clinical Findings Diminished consciousness,apnea,decreased hematocrit,coma,seizures 50%silent,detected by imaging 80-90%of IVH occurs within first 4 days of life Grade I Hemorrhage Coronally,echogenic mass inferolateral to floor of frontal horns and medial to head of caudate nucleus Parasagitally,increased echogenicity anterior to caudothalamic groove Unilateral or bilateral,subependymal,normal ventricle sizes Resolving clot undergoes central liquefaction and may form tiny subependymal cyst Grade 2 Hemorrhage IVH,hemorrhage ruptures through subependymal lining into lat.Vents Echogenic material fills part or all of NON-dilated ventricular system,may adhere to choroid and be difficult to distinguish Decreases in size and echogenicity over several weeks Subependymal lining of vents may develop echogenic lining due to chemical ventriculitis Grade 3 Hemorrhage IVH with ventricular enlargement of one or both lat.Vents May extend into 3rd,4th vents,and cavum Usually resolves over 5-6 weeks May resolve completely or persist as bands or septations Post-hemorrhagic hydrocephalus in more than 2/3,usually remains mild-mod,few need shunt placement(10%)Grade 4 Hemorrhage IVH with extension into the brain parenchyma adjacent to one or both