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--- neuro [2019/04/22 08:20] – nfasano
+++ neuro [2022/07/18 14:17] (current) – [Terminology] nfasano
@@ Line 1: / Line 1: @@
+====== Perfusion CT ======
+===== Core vs Penumbra =====
+^ ^MTT^CBF^CBV^
+|Core|↑|↓↓|↓↓|
+|Penumbra|↑|↓|nl or ↓|
+===== Rapid AI =====
+  * CBF - cooler = worse
+    * CBF < 30% criteria
+  * MTT - hotter = worse
+    * Tmax > 6.0 seconds
+  * Report:
+    * Mismatch volume
+    * Mismatch ratio
+==== Interpretation ====
+  * Start with TTP and delay images to spot abnormality
+  * MTT & CBF
+  * Then CBV to determine core vs penumbra
+==== Reporting ====
+  * Sample
+    * Acute R MCA territory infarct with MCA/PCA penumbra.
+    * CBF < 30% of 17 mL, Tmax > 6 sec of 155 mL, and mismatch volume of 127 mL (ratio 8.5).
+==== Terminology ====
+  * AIF = Arterial In-flow
+  * VOF = Venous Out-flow
+  * CBF = Cerebral Blood Flow (core infarct/overestimates infarct)
+  * CBV = Cerebral Blood Volume (core infarct/good for visual estimate)
+  * Tmax = Arterial in-flow to capillary time (ischemia)
+  * MTT = Mean Transit Time = Capillary transit time (ischemia/least sensitive)
+  * TTP = Time to Peak = Arterial in-flow to capillary time AND capillary transit time (ischemia)
+==== Microbleeds on MRI ====
+  * <5 - tPA safe
+  * >5 - safety unknown
+====== Vascular Supply ======
+  * Recurrent artery of Heubner (aka medial lenticulostriate)
+    * branch of ACA
+    * caudate head, ant limb of internal capsule, septum pellucidum
+  * Lateral lenticulostriate
+    * branch of MCA
+    * lentiform nucleus, caudate capsule, internal capsule
+  * Thalamic and midbrain perforators
+    * branch of PCA
+  * SCA
+    * superior cerebellum
+  * AICA
+    * inferolateral pons
+    * middle cerebellar peduncle
+    * anterior cerebellum
+  * PICA
+    * medulla
+    * posterior and inferior cerebellum
+{{brainvascterritories.jpg|Brain Vascular Territories}}
+{{:aspects-score.png|Aspects Score}}
+  * Areas with hemorrhage count as abnormal in aspects scoring.
+  * Dense MCA does not count.
+==== Vertebral Artery Anatomy ====
+{{:verta.jpg|:verta.jpg}}
+  * Part one is from the origin to the point at which it enters the transverse foramina of either the fifth or sixth cervical vertebra.
+  * The second part courses within the intervertebral foramina
+  * The third part exits behind the atlas and heads towards the foramen magnum.
+  * The fourth part (intracranial) begins as it pierces thedura and arachnoid mater at the base of the skull, and ends as it meets its opposite vertebral artery to form the midline basilar artery at the level of the medullopontine junction.
 ====== White Matter Dz ======
 ===== Multiple Sclerosis Criteria =====
@@ Line 221: / Line 284: @@
   * causes hoarsness and dysphagia
-====== Vascular Supply ======
-  * Recurrent artery of Heubner (aka medial lenticulostriate)
-    * branch of ACA
-    * caudate head, ant limb of internal capsule, septum pellucidum
-  * Lateral lenticulostriate
-    * branch of MCA
-    * lentiform nucleus, caudate capsule, internal capsule
-  * Thalamic and midbrain perforators
-    * branch of PCA
-  * SCA
-    * superior cerebellum
-  * AICA
-    * inferolateral pons
-    * middle cerebellar peduncle
-    * anterior cerebellum
-  * PICA
-    * medulla
-    * posterior and inferior cerebellum
-{{brainvascterritories.jpg}}
-{{:aspects-score.png|}}
 ====== Brainstem and Cranial Nerves ======
-{{brainstem.jpg}}
+{{brainstem.jpg|Brainstem and Cranial Nerves}}
 ===== Facial Nerve Segments =====
@@ Line 302: / Line 347: @@
   * arachnoid cyst - usually thoracic spine, posterior
   * epidermoid cyst
+==== Extradural ====
+  * disk
+  * meningioma
+  * schwannoma
+  * neurofibroma
+  * mets/myeloma/lymphoma
+  * epidural abscess
+  * epidural hematoma
+  * synovial cyst
+  * leptomeningeal enhancement
+  * sarcoid
+==== Transverse Myelitis ====
+  * Parainfectious (occurring at the time of and in association with an acute infection or an episode of infection).
+    * Viral: herpes simplex, herpes zoster, cytomegalovirus, Epstein-Barr virus, enteroviruses (poliomyelitis, Coxsackie virus, echovirus), human T-cell, leukemia virus, human immunodeficiency virus, influenza, rabies
+    * Bacterial: Mycoplasma pneumoniae, Lyme borreliosis, syphilis, tuberculosis
+  * Postvaccinal (rabies, cowpox)
+  * Systemic autoimmune disease
+     * Systemic lupus erythematosis
+     * Sjogren's syndrome
+     * Sarcoidosis
+  * Multiple Sclerosis
+  * Paraneoplastic syndrome
+  * Vascular
+     * Thrombosis of spinal arteries
+     * Vasculitis secondary to heroin abuse
+     * Spinal arterio-venous malformation
+==== Enhancing Nerve Roots (cauda) ====
+  * drop mets
+  * sarcoid
+  * leukemia, lymphoma
+  * CMV
+  * Guillan-Barre
+  * CIDP (also enlarged)
+  * meningitis
+==== Cord Infarct ====
+  * Snake eyes appearance on axial imaging
+  * Anterior spinal artery infarct
+  * Increased T2 in central gray matter
+==== DDx Heterogeneous Marrow Signal ====
+  * normal variant
+  * anemia
+  * chronic disease
+  * neoplastic processes such as lymphoma, metastatic disease, or myelodysplastic syndromes.
+==== Loss of Fatty Marrow ====
+  * Lymphoma
+  * Extramedullary Hematopoesis
+  * Myelofibrosis
+  * (XRT will __//increase//__ fatty marrow)
+==== Dorsal Column Increased Signal ====
+  * B12 deficiency
+  * Syphillis
+==== Epidural Lipomatosis ====
+  * Cushing's Dz
+  * Steroids
+  * Congenitalß
+==== Posterior Element Lesion (GO APE) ====
+  * Giant Cell
+  * Osteoblastoma/Osteoid Osteoma
+  * ABC
+  * Plasmacytoma
+  * EG
+==== Vertebral Body Lesion (CALL HOME) ====
+  * Chordoma
+  * ABC
+  * Leukemia
+  * Lymphoma
+  * Hemangioma
+  * Met/Myeloma
+  * EG
+==== Posterior Scalloping ====
+  * Increased Intraspinal Pressure
+    * Tumor
+    * Syrinx
+    * Communicating HCP
+  * Dural Ectasia
+    * NF-1
+    * Marfan
+    * Ehlers-Danlos
+  * Congenital
+    * Achondroplasia
+    * Mucopolysaccharidoses -> Hunter/Hurler/Morquio's (look for beaking
+    * Osteogenesis Imperfecta Tarda
+  * Bone Resorption
+    * Acromegaly
+==== Hemivertebrae ====
+  * VACTERL
+  * NF-1
+  * Chiari II
+  * Anterior Meningocele
+==== Benign vs Malignant Compression Fractures ====
+  * Malignancy tends to involve the pedicles, whereas benign does not
+  * Look for other levels of involvement - if you see noncompressed vertebral bodies at other levels which also have abnormal signal, then you can assume malignant
+  * Cortical destruction is a feature of malignancy
+  * Malignant frxs tend to show abnormal T1 signal involving >80% of the v.b., benign has less
+====== Orbits ======
+===== Orbital DDx =====
+==== Intraconal ====
+  * cavernous hemangioma (capillary in children)
+  * schwannoma
+  * lymphangioma
+  * varix
+  * optic n tumor (meningioma, glioma)
+  * pseudotumor - pain, opthalmoplegia, proptosis, unilateral, enlarged lacrymal gland
+    * Tolosa-Hunt involves orbital apex and cavernous sinus
+  * thyroid opthalmopathy - spares tendon insertions, often bilateral, does not enhance
+  * lymphoma
+==== Extraconal ====
+  * lacrymal gland
+    * lymphoma, pseudotumor
+  * sinus disease
+    * mucocele, invasive infections, neoplasm
+  * orbital bone disease
+    * fibrous dysplasia, osteomyelitis, subperiosteal abscess, tumors, trauma
+  * nasal disease
+    * infection, neoplasm
+  * dermoid
+  * rhabdomyosarcoma
+    * common in children
+  * mets
+==== Extraocular Muscle ====
+  * mets
+  * inflammation
+  * thyroid eye disease
+    * bilateral
+    * sparing of muscle tendons
+  * pseudotumor
+  * lymphoma
+==== Lacrymal Gland ====
+  * lymphoma
+  * sarcoid
+  * inflammatory
+    * Sjogren's
+    * Miukulicz's
+  * epithelial tumors
+    * pleomorphic adenoma
+    * adenoid cystic
+    * mucoepidermoid
+  * mets
+===== Optic Nerve Pathology =====
+  * use term 'optic nerve sheath complex'
+  * Optic Neuritis -> hyperintense, enlarged
+  * Glioma -> enlarged nerve, do __not__ enhance
+  * Meningioma -> crescentic
+  * Sarcoid -> enhances
+  * Lymphoma/leukemia
+  * Pseudotumor
+  * Graves
+===== Globe =====
+  * Retinoblastoma
+    * intraocular mass
+    * high density (Ca<sup>2+</sup>, hemorrhage)
+    * 30% bilateral
+  * Melanoma
+    * thickening of choroid, usually posterior
+    * usually unilateral
+    * high T1, low T2 with enhancement
+  * Persistent Hyperplastic Primary Vitreous
+    * unilateral small globe
+    * no calcification
+  * Coats' Disease
+    * unilateral dense vitreous w/ focal mass or Ca<sup>2+</sup>
+  * Drusen
+    * focal Ca<sup>2+</sup> in optic nerve head
+    * usually bilateral and asymptomatic
+    * may be mistaken for papilledema
+====== Temporal Bone ======
+===== DDx for mass in mesotympanum =====
+  * aberrant ICA
+  * glomus tumor (tympanicum)
+  * cholesteatoma
+====== Nasal Cavity/Sinuses ======
+Maxillary sinus lesion extending to base of tooth? -> Think dentigerous cyst\\
+Esthesioneuroblastoma has a bimodal age distribution -> children (11-20) and older adults (51-60)
+===== Mucocele Characteristics =====
+  * Expansion of sinus
+  * Complete filling of sinus
+  * Order of prevalence = FEMS (frontal>ethmoid>maxillary>sphenoid)
+===== Inverting Papilloma =====
+  * typically arises from the lateral nasal wall and extends into the ipsilateral ethmoid or maxillary sinus
+  * worry about coexisting SCC (common)
+===== Antrochoanal Polyp =====
+  * benign polyp arising in antrum and extending into the nasal cavity
+  * __no__ sinus expansion
+===== Temporal Bone Fxs =====
+^Transverse^Longitudinal^
+|Sensorineural Hearing Loss|Conductive Hearing Loss|
+|rhinorrhea|otorrhea|
+|50% facial nerve dysfunction|10-20% facial nerve dysfunction|
+|persistent vertigo|incudostapedial joint dislocation|
+====== Head & Neck ======
+Sjogren's can look like fatty replaced salivary glands
+===== Lymph Node Levels =====
+{{:lymphzones.gif|:lymphzones.gif}}
+===== Lymph Node Chains =====
+{{:neck_nodes_1.gif|:neck_nodes_1.gif}}
+{{:neck_nodes_2.gif|:neck_nodes_2.gif}}
+===== Spaces of the Neck =====
+{{:neck_spaces.jpg|:neck_spaces.jpg}}
+====== Neoplasms ======
+===== Most Common Intraaxial Tumors =====
+^ Location ^ Adult ^ Child ^
+| Supratentorial | Astrocytoma\\  * Pilocytic\\  * Anaplastic\\  * GBM\\ Oligodendroglioma\\ Gliomatosis Cerebri\\ Metastasis | PXA\\ PNET\\ Ganglioglioma/Gangliocytoma\\ Desmoplastic Infantile Ganglioglioma (DIG)\\ DNET |
+| Infratentorial | Astrocytoma\\ Hemangioblastoma\\ Metastasis\\ Subependymoma\\ Ganglioglioma | Juvenile Pilocytic Astrocytoma\\ PNET/Medulloblastoma\\ Ependymoma\\ Brainstem Astrocytoma |
+| Intraventricular | Meningioma\\ Metastasis\\ Central Neurocytoma\\ Subependymoma\\ Astrocytoma\\ Oligodendroglioma\\ CP papilloma (4th vent) | CP papilloma/carcinoma (atria)\\ Ependymoma\\ Astrocytoma\\ PNET\\ Teratoma |
+| Spinal |  |  |
+  * Probably should add lymphoma to all of these, especially in HIV pts
+===== Intraventricular Mass =====
+  * Child
+    * PNET/Medulloblastoma
+      * usually 4th ventricle, but can be in lateral vents
+    * Choroid Plexus Papilloma/Carcinoma
+      * lateral ventricles
+      * always have hydrocephalus
+    * Ependymoma
+    * Teratoma
+    * Astrocytoma
+  * Adult
+    * Meningioma
+    * Central Neurocytoma
+    * Gliomas -> Subependymoma, Astrocytoma
+===== Extra-axial Mass =====
+  * Meningioma
+  * Hemangiopericytoma
+  * Schwannoma
+  * Metastases
+  * Lymphoma
+  * Dermoid
+  * Epidermoid
+  * Arachnoid cyst
+  * Bone neoplasm or infection
+  * Leukemia
+  * Sarcoidosis
+===== Lesions which cross the corpus callosum =====
+  * GBM
+  * Lymphoma
+  * Tumefactive MS (horseshoe enhancement)
+===== One-Liners =====
+Subependymal Spread Pattern -> think of pineal germinoma
+====== Paraneoplastic Syndromes ======
+===== Limbic Encephalitis =====
+  * high T2 signal in medial temporal lobes
+  * may have associated atrophy
+  * may enhance
+  * associated with small cell lung CA
+====== Infectious ======
+===== HSV Encephalitis =====
+  * temporal lobe involvement
+  * may or may not enhance
+  * restricted diffusion
+===== Creuzfeld-Jakob Disease =====
+  * T2 hyperintense areas in cortex and basal ganglia which restrict
+  * no enhancement
+====== Trauma ======
+  * Skull fractures that are accompanied by dural tears can result in the formation of a leptomeningeal cyst = "Growing Fracture"
+===== Diffuse Axonal Injury =====
+  * responsible for coma and poor outcome in the majority of patients with significant closed head injury
+  * specific anatomic structures involved
+  * body and splenuim (most common location) of the corpus callosum
+  * septum pellucidum
+  * dorso-lateral quadrant of the rostral part of the brainstem
+  * adjacent to the superior cerebellar peduncle
+  * diffuse damage to other axons including the int. capsule may also be present
+  * punctate subcortical hemorrhage and hemorrhage in WM adjacent to the 3rd vent also occur
+====== Random ======
+Mets are very unlikely in the brainstem
+===== Superficial Siderosis =====
+  * low signal intensity in periphery of midbrain, particularly posterior
+===== Rhomboencephalosynapsis =====
+  * rare malformation with vermian aplasia or hypoplasia with fusion of the cerbellar hemispheres
+  * no 4th ventricle midline defect
+  * associated with fusion of the thalami and/or inferior colliculi
+  * associated with septo-optic dysplasia
+===== Lhermitte-Duclos =====
+  * cerebellar hamartoma
+  * courdoroy appearance w/ calcification
+  * related to Cowden syndrome
+===== Wernicke's encephalopathy =====
+  * increased signal within the periaqueductal region of the midbrain, medial thalamic regions along the lateral walls of the third ventricle, and mammilary bodies
+  * triad of opthalmoplegia, ataxia, and altered mental status
+  * related to alcohol abuse
+====== Dental ======
+{{:tooth_nomenclature.jpg|Tooth Nomenclature}}
+  * The wisdom teeth are the 3rd molars (not pictured).
+====== Differentials ======
+===== PRES vs basilar territory infarct =====
+  * PRES
+    * Mostly FLAIR abnormality
+    * Vasogenic edema
+    * Thalamus usually spared
+  * Basilar territory infarct
+    * Restricted diffusion
+    * Matched DWI/FLAIR abnormality
+    * Vascular territory
+===== Dark spots on GRE =====
+  * Amyloid angiopathy
+  * Hypertensive microbleeds
+  * Cavernomas (familial)
+  * DAI
+  * Calcifications
+  * Hemorrhagic mets
+===== Ring-enhancing lesion =====
+  * Metastasis
+    * Multiple lesions with rim enhancement
+    * No restricted diffusion
+  * Glioblastoma
+    * Shaggy enhancement
+  * Lymphoma
+    * Increased diffusion due to cellularity
+    * NOT lightbulb bright on DWI
+  * Abscess
+    * Restricted diffusion
+    * Lightbulb bright on DWI
+===== Parenchymal Hemorrhage =====
+  * Hypertensive (75%)
+  * AVM
+  * Dural AVF
+  * DVA
+  * Cavernous malformation
+  * Capillary telangiectasia
+  * Aneurysm
+  * Amyloid angiopathy
+  * Vasculitis
+  * Infarct
+  * Dural venous thrombosis
+===== Basal Ganglia Calcification =====
+  * Senescent
+  * Hypoparathyroidism
+  * Pseudo and Pseudo-pseudohypoparathyroidism
+  * Hyperparathyroidism
+  * TORCH
+  * AIDS
+  * TB
+  * Lead
+  * CO
+  * XRT/Chemo
+  * Mitochondrial diseases
+  * Fahr syndrome
+===== Diffuse Subcortical Calcifications =====
+  * Prior Infection
+  * Hypoparathyroidism
+  * Lead Exposure
+  * Leukemia
+  * Prior XRT
+===== Basal Ganglia Hyperintense T1 (HTN) =====
+  * TPN (Manganese)
+  * Hepatic failure
+  * NF-1
+  * Dystrophic calcifications
+===== Basal Ganglia Hyperintense T2 (TINT) =====
+  * Tumor
+    * Lymphoma
+  * Ischemia
+    * Hypoxic encephalopathy/Near drowning
+    * Venous infarction
+  * Neurodegenerative
+    * Huntington's
+    * Wilson's disease - bright T2 peripherally, dark centrally
+    * Hallevorden-Spatz - bright T2 centrally, dark peripherally
+    * Leigh - uniformly bright T2, involves pons, does not involve caudate
+    * Kearns-Sayre
+  * Toxin
+    * CO, CN poisoning
+    * hypoglycemia
+    * methanol
+===== Basal Ganglia Hypointense T2 =====
+  * Old age
+  * Chronic degenerative disease
+    * Parkinson's
+    * MS
+  * Childhood hypoxia
+===== Corpus Callosum Lesion =====
+  * GBM - will see edema
+  * Lyphoma - homogeneously enhancing
+  * XRT
+  * MS
+  * Marchiafava-Bignami
+===== Basimeningeal Enhancement =====
+  * Basically STL -> Sarcoid, TB, Lymphoma
+  * Infection
+    * TB
+    * Fungal
+    * Pyogenic
+    * Cysticercosis
+  * Tumor
+    * Leukemia/Lymphoma
+    * Carcinomatosis
+  * Inflammatory
+    * Sarcoid
+    * Rheumatoid
+    * Whipple's Disease
+===== Low Lying Cerebellar Tonsils =====
+  * Chiari I/II
+  * Intracranial Hypotension
+  * Mass Effect
+===== Involvement of Cerebellar Peduncles =====
+  * MS
+  * Sinus Thrombosis
+  * Olivopontocerebellar Atrophy
+    * It's all in the name -> ataxia/dementia syndrome w/ cerebellar and brainstem atrophy
+===== Leptomeningeal Enhancement =====
+  * Leptomeningeal Carcinomatosis
+  * Meningitis
+  * Sarcoid, TB, Lymphoma
+===== Layering Restricting Material in Vents =====
+  * Blood
+  * Pus (Ventriculitis)
+===== Brainstem Hemorrhage =====
+  * Hemorrhagic Infarct
+  * Trauma (usually anterior -> Duret hemorrhage)
+  * AVM
+  * DAI
+===== Obstruction at Aqueduct of Sylvius =====
+  * Aqueductal Stenosis
+  * "Pencil" Glioma -> surrounding the aqueduct
+===== Suprasellar Cystic Mass =====
+  * Rathke Cleft Cyst
+    * Simple, uniloculated
+  * craniopharyngioma (calcification)
+  * JPA
+===== Jugular Foramen Mass =====
+  * Paraganglioma - aggressive appearance
+  * Schwannoma
+  * Meningioma
+===== Anterior Neck Cyst =====
+  * Thyroglossal Duct Cyst
+  * Delphian Lymph Node
+  * Lymphangioma
+===== Parotid Cysts =====
+  * Lymphoepithelial
+  * Branchial Cleft
+  * Lymphangioma
+  * Abscess
+  * Cystic Tumors
+===== Bilateral Parotid Cysts =====
+  * Warthin's Tumor
+  * Sjogren's
+  * Lymphoepithelial Cysts
+  * Lymph Nodes -> Lymphoma, Skin Cancers
+  * Sarcoid
+===== Horner's Syndrome =====
+  * ICA Dissection
+  * Tumor along course of ICA
+  * Pancoast Tumor
+===== Diffuse Skull Thickening =====
+  * Anemias -> ß-thal
+  * Osteopetrosis
+  * Paget's
+===== Focal Non-destructive Skull Widening =====
+  * Meningioma
+  * Fibrous Dysplasia
+===== Lytic, Non-aggressive Skull Lesion =====
+  * Epidermoid
+  * Fibrous Dysplasia
+===== Pediatric Skull Lesion =====
+  * EG
+  * Metastatic Neuroblastoma
+===== Basilar Invagination =====
+  * Rheumatoid Arthritis
+  * Achondroplasia
+  * Down Syndrome
+===== Etat Crible =====
+  * Small foci of increased signal in the basal ganglia
+  * Causes:
+    * lacunar infarctions
+    * gliosis
+    * dilated perivascular spaces
+    * demyelination
+    * nonspecific protein depositions
+    * cysts
+    * ventricular diverticuli