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central nervous system radiographic pathology
 

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CNS RADIOGRAPHIC PATHOLOGY

CNS RADIOGRAPHIC PATHOLOGY

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    central nervous system radiographic pathology central nervous system radiographic pathology Presentation Transcript

    • 1By:Yannick Ngerageze
    • 2 2Introduction• The nervous system is a very complex system in the body.• It has many, many parts.• The nervous system is divided into two main systems, the central nervous system (CNS) and the peripheral nervous system.• Generally, CT, MRI and nuclear medecine are imaging modalities of choice for brain diseases Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 3 3Brain anatomyCerebrum • The cerebrum is the largest part of the brain and contains two hemispheres. • Each cerebral hemisphere contains four lobes; the frontal lobe, the parietal lobe, the occipital lobe, and the temporal lobe Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 4 4Cerebellum • The cerebellum is the second largest area of the brain. • The brain stem is at the bottom of the brain and connects the spinal cord to the cerebrum. • The pons, midbrain, and medulla oblongata are part of the brain stem Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 5 5Ventricular System • There are two lateral ventricles, one in each cerebral hemisphere. • The third ventricle is located near the hypothalamus • And the fourth ventricle between the medulla oblongata and the brain stem and the cerebellum. Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 6 6Meninges• The meninges are three membranes that cover the brain and spinal cord and protect the CNS.• The dura mater is the tough outer membrane.• The arachnoid is the middle web-like membrane.• The pia mater is the inner most membrane and is delicate and highly vascular.• The subarachnoid space is between the arachnoid and pia mater and contains cerebrospinal fluid (CSF). Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 7 7Meninges Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 8 8Spinal Cord Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 9 9Diseases of the nervous system• Edema, herniation and • Primary disease of myelin hydrocephalus • Acquired metabolic and• Vasular diseases toxic disturbances• Central Nervous System • Degenerative diseases (CNS) trauma • Diseases of the peripheral• Congenital malformations nervous system and perinatal brain injury • Neoplasms• Infections of CNS Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 10 10Inceased ICP , herniation, Cerebraledema, and hydrocephalus• Skull is rigid and nonexpandable.• Increased fluid or additional tissue in intracranial space leads to increased ICP• Causes of increased ICP ▫ Space-occupying mass : tumor, abscess, hematoma ▫ Diffuse lesions : brain edema, encephalitis, subarachnoid hemorrhage ▫ Increased volume of CSF : hydrocephalus Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 11 11Cerebral edema• Abnormal fluid accumulation in cerebral parenchyma• Types: ▫ Vasogenic edema: increased vascular permeability  Tumor, inflammation ▫ Cytotoxic edema : altered cell regulation of fluid  Toxin Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 12 12CT Image• It cause: ▫ Increased brain weight ▫ Flat gyri ▫ Narrow sulci • MRI and CT can be used Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 13 13Cerebral herniation• Sutures for children accommodates to increased intracranial pressure.• In adults it is poorly tolerated• As expanding brain parenchyma encounter, many different patterns of herniation may develop• 3 most common forms are: • Subfalcine (cingulate); Transtentorial (uncal) Tonsillar (foramen magnum) Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 14 14CT and MRI Images Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 15 15Hydrocephalus Is the dilatation of the ventricular system (accumulation of CSF) Dilated venticles compress white matter Noncommunicating: due to obstruction within the ventricular system, e.g. Tumor, aqueductal stenosis Communicating: due to obstruction of CSF flow in the subarachnoid space with decreased reabsorption Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 16 16Image Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 17 17Cerebrovascular diseases• Brain is highly aerobic organ ▫ 20% of total body oxygen consumption ▫ 15% of resting cardiac output• Autoregulation of cerebral blood flow• Irreversible damage of the brain 6-8 min causes of oxygen deprivation ▫ Functional hypoxia  Low inspire of oxygen  Impaired oxygen carrying capacity ▫ Ischemia  Decreased perfusion pressure – hypotension  Occlusion of vessels Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 18 18Cerebrovascular diseases• Cerebral vascular diseases can be divided into three major category:• Parenchymal injuries: those associated with generalized reduction in blood flow, including global hypoxic ancephalopathy• Infarct : caused by local vascular obstruction• Hemorrhages : within the parenchyma or subarachnoid space Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 19 19 Global cerebral ischemia• Ischemic/hypoxic encephalopathy• Cause – profound systemic hypotension ▫ Transient :complete recovery ▫ Prolong : brain necrosis• Brain death : brain stem damage which cause cardiovascular failure Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 20 20 Cerebral infarction• The major cause of infarct is stroke• Stroke: sudden neurologic deficit caused by abnormal blood supply (including intracerebral hemorrhage)• Etiology  Atherosclerosis of bifurcation of carotid a., basilar a.  Arteritis : infection (TB, syphilis),  Others : aneurysm Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 21 21Hemorrhage• Saccular aneurisms and subarachnoid hemorrhage (caused by a rupture of a saccular aneurism) are mostly located on arterial bifurcations. Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 22MRI image Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 23 23 Traumatic injuries• Epidural hematoma• Subdural hematoma• Subarachnoid hemorrhage• lacerations Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 24 Epidural hematoma• Skull fracture at temporal bone may causes laceration of middle meningeal artery• Draw back of the skull may be the cause Prepared by Yannick Ngerageze a radiographer at gihundwe hospital 24
    • 25 25 Subdural hematoma• Potential space, subdural, contains bridging veins from cortical surface to empty into superior sagittal sinus• Brain moves freely but venous sinus is fixed• Brain displacement during trauma can tear the veins at the point they penetrate the dura Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • Subdural hematoma• Clinically manifest at first 48 hrs.• Most-nonlocalising signs : headache, confusion• May be focal signs : contralateral paralysis, seizures Prepared by Yannick Ngerageze a radiographer at gihundwe hospital 26 26
    • Acute epidural and Acute subduralAcute epidural Acute subdural Prepared by Yannick Ngerageze a radiographer at gihundwe hospital 27
    • 28MRI images of chronic hematomaChronic epidural hematoma Chronic subdural hematoma Prepared by Yannick Ngerageze a radiographer at gihundwe hospital 28
    • 29CT image of lacerations:• Tearing of the frontal and temporal lobes or blood vessels of the brain• The force of the blow causes the brain to rotate across the hard ridges of the skull, causing the tears Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 30 30 Spinal cord injury• Displacement of vertebral column causes by ▫ Stab wound ▫ Bullets ▫ Vertebral fracture with dislocation• Neurologic manifestation: ▫ Thoracic vertebra or below – paraplegia ▫ Cervical vertebra (below C4) – quadriplegia ▫ Cervical vertebra (upper C4) – respiratory arrest Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 31 31MRI image of traumatic spinal cord• MRI is the best modality for spinal cord injuries as it is super in soft tissues differentiation Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 32 32Congenital malformation• Neural tube defect ▫ Commonest ▫ Defective closure of the midline structure over the neural tube ▫ Risk factor : folate deficiency in initial week of gestation Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 33 33Congenital malformation1. Anencephaly: ▫ No brain (linked with folate deficiency, age of mother over 40; more often affects girls) ▫ Fatal, spontaneous abortion2. Encephalocele ▫ Ossification defect in the skull ▫ Herniation of the brain & meninges ▫ Occipital, frontal, orbital & nasal Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 34 EncephaloceleAnencephaly Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 35Ultrasound of an intrauterine foetuwith encephalocele Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 36 36 Neural tube defectSpina bifida ▫ Defective development and closure of vertebral arch ▫ Most common in lumbar region ▫ 2 types  Spina bifida occulta  Spina bifida cystica Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 37 37Neural tube defect• Spina bifida occulta ▫ Asymptomatic ▫ Normal spinal cord and meninges ▫ May have sinus tract of overlying skin• Spina bifida cystica ▫ Meningomyelocele (myelomeningocele)  Extension of CNS tissue through a defect ▫ Common in LS region ▫ Meningocele  Only meningeal extrusion Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 38 38Images• Clinical ▫ Motor & sensory deficit in lower extremity ▫ Disturbances of bowel & bladder control ▫ Superimposed infection from overlying skin Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 39Neural tube defect of a fetus Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 40 40CNS infection• A CNS infection is an infection which involves the central nervous system in some way.• Meningitis is one of the most common and well known types, involving the meninges, the coverings of the brain and spinal cord.• Other types of infections involve the brain or spinal cord directly.• For example, a cerebral abscess is a bacterial brain infection and encephalitis is typically a viral infection of the brain. Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 41 41Meningitis• Meningitis is one of the most common forms of infection affecting the nervous system.• It is characterized by infection of the membranes covering the brain and spinal cord, centered in the cerebrospinal fluid that surrounds the nervous system.• There is types: bacterial, viral and fungal meningitis Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 42 42CT and MRI Images Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 43 43V.3 Brain abscess• It is a bacterial brain infection.• Also called a cerebral abscess, these infections are destructive lesions within the substance of the brain itself. Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 44CT with contrast and MRI image Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 45 45Neoplasm of CNSGlioma• It is a type of tumor that starts in the brain or spine.• It is called a glioma because it arises from glial cells.• The most common site of gliomas is the brain.• The main types of gliomas are: ▫ Ependymomas: ependymal cells. ▫ Astrocytomas: astrocytes ▫ Oligodendrogliomas : oligodendrocytes.• Mixed gliomas, such as oligoastrocytomas, contain cells from different types of glia.• The exact causes of gliomas are not known. Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 46 46CT and MRI Image Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 47 47Diseases of myelin Demyelinating diseases: • Acquired disorders of myelin, such as multiple sclerosis. Dysmyelinating diseases: • Genetic disorders of myelin and its turnover, such as leukodystrophies Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 48 48Multiple sclerosis• It is known as disseminated sclerosis is an inflammatory disease in which the fatty myelin sheaths around the axons of the brain and spinal cord are damaged.• Leading to demyelination and scarring as well as a broad spectrum of signs and symptoms.• Most likely MS occurs as a result of some combination of genetic, environmental and infectious factors Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 49 49MRI Images Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 50 50Acquired metabolic and toxicdisturbancesNutritional diseases:• Thiamine deficiency is common in alcoholics (first cause of brain changes in alcoholics, other than traumatic lesions) hemorrhagic white matter• B12 deficiency causes sub acute degeneration of spinal cord with myelin vacuolization, causing motor and sensory abnormalities, weakness, confusion Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 51 51Toxic disturbanceCocaine encephalopathy• Cocaine can cause vasospasm and vasculitis leading to ischemic and hemorrhagic infarction.• On MRI, lesions with increased signal intensity on T2 weighted images are reported in the globus pallidi, splenium, and cerebral white matter, with affected regions often showing restricted diffusion Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 52Degenerative diseases1. Alzheimer’s Disease• Most common cause of dementia• Defective processing of amyloid precursor protein• Affects hippocampus/parahippocampal cortex, cerebral cortex, tremor• MR used to rule out other causes of dementia Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 53T1 weighted MR Control Alzheimer’s Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 54Alzheimer’s – CT CT- Diffuse cerebral atrophy, enlarged ventricles and widened sulci Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 55Parkinson’s Disease• Hypokinetic disorder• Loss of dopaminergic neurons in substantia nigra Pill-rolling tremor, cog-wheel rigidity, bradykinesia, shuffling gait, mask-like facies• On MRI, there is a decreased pars compacta width (substantia nigra) may be evident on MR Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 56T2 weighted MR Control Parkinson’s Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 57 57Conclusion• The brain is totally made by soft tissue surrounded by bone tissues• As bone are hyperdense tissues,cross sectional images are mostly needed to rule out brain tissues diseases• Both MRI and CT are used in brain diseases diagnosis because both of them can produce sectional images but MRI is the best for soft tissue imaging• Some times nuclear medicine is used mostly in functional studies• Plain radiography is rarely used Prepared by Yannick Ngerageze a radiographer at gihundwe hospital
    • 58 58References• Robbins (2003),Basic Pathology 7th edition, Saunders USA .• Kumar (2006) Clinical Medicine 6th edition Elsevier USA.• http://www.health.com/health/library/mdp/0,, zm6056,00.html accessed on 19/02/12 Prepared by Yannick Ngerageze a radiographer at gihundwe hospital