BRAIN- CT Flashcards
Pt needs an XRAy of skull from head trauma. What are reasons for skull XR?
**RARE to order AP, lateral view Foreign body Child abuse Mets, Multiple Myeloma
In order to view maxillary sinuses which Xray technique is required?
Towne
If you suspect a CVA, what type of CT is needed first?
CT w/o contrast
What are indications for CT?
Head trauma (clinically significant) Headache (atypical, worst ever) Delirium (unexplained) HA + fever (meningitis, abscess, enceph) Seizure (1st ever) Vertigo w/ central sx Coag + trauma (old ppl on Coumadin!) Cancer Hx + new HA, ALOC, focal neuro Vomiting in absence of abdominal sx Child abuse
BLOOD CAN BE VERY B*AD
check, blood, cisterns, brain, ventricles, bone
What is normal regarding these structure on CT w/o contrast?
- Basal ganglia calcifications
- Pineal gland
- choroid plexus
- Pituitary
Normal HYPERattenuation (white)
What is abnormally white and black on CT With contrast?
- Abnormal white things:
- Blood
- Tumor/ mass/ infxn
- Abnormal dark things
- Air, edema, ischemia
In order to determine the following what image is advantagous? Vascular lesions Arteriovenous malformation, aneurysm Tumors (ring-enhanced lesion) Brain abscess (ring-enhanced lesion)
CT Contrast
What is considered abnormal on CT w/ contrast?
White things:
- Abnormal meningeal uptake –peripheral enhancement of edema
- Fresh bleeding
- “ring enhancement” of tumors, infxn
IF the following is suspected what is ideal imaging: CVA -Early Meningioma Neuro deficits- MS Axonal injury Cerebellar lesions
MRI No radiation T1- fluid black, T2 fluid white Gladolium contrast avail NO ACUTE CVA d/t instablity
When looking at the AP for XR, what can you see posteriorly?
Occipital and Lambdoid sutures
AP- cassette at back beam face pt, seeing Posterior
PA- cassette at front beam face back, seeing Anterior
If you see the following on a CT, then what level is this? Eye Sphenoid sinus Temporal bone Mastoid air cells Pons 4th ventricle-post and inf Cerebellum
Inferior
Close to base of skull
Trauma in this area can cause epidural bleed due to what?
Pterion- merge of sutures
Thinnest part of sckull
MCA runs here
How should the systematic approaches be for CT?
Name Symmetry Densisty Lucenty Blood- new or old Ischemia Infarct Edema Tumors, mets Hydrocephlus Bony windows
ON the brain CT, what is normal grey and darker grey?
White matter- dark grey contain myelin
INT
Gray- Grey matter- cell bodies, EXT
What can be seen at the midbrain slice?
Frontal lobe **Sylvian fissure- PAIR lateral Temporal lobe Suprasellar cistern- middle, pituitary Midbrain 4th ventricle- post Cerebellum
This can be seen at within the MOST important view, SMILEY FACE.
Superior sagittal sinus (in falx)- forehead
Lateral ventricles (frontal and occipital horns)-EYES
3rd ventricle- NOSE
4th ventricle- Mouth
cerebellum- chin
Mid superior up
These are seen at what level.
Lateral ventricles- longer, darker
Caudate nucleus -abutting frontal part of lateral ventricle, light grey
Internal capsule – anterior & posterior limbs (the white matter bw insula & basal ganglia)- thickened canal. cheek crease
Putamen (part of lentiform nucleus)- lateral to capsule
3rd ventricle- NOSE
Quadrigeminal cistern - CHIN-, replace 4th ventrical(posterior to colliculi)
Cerebellar vermis
Thalamus- medial to capsule, CHEEKS
Corpus callosum- EYEbrow togther
EVIL face
Basal Ganglia level
What are the darker grooves and the tissue btwne the grooves?
GYRI- tissue wormy like
SULCI- tunnel spaces
Describe the pattern of menigies in CT and MRI?
Superficial to Deep
Dura Mater- on the skull , 2
Arachonoid- weblike btwn dura and pia. Sub
PIA mater- on the brain tissue
What are the phases of blood attenuation on CT?
Acute bleed- hypER- white
Subacute -isodesne- same color
Chronic hypO- Darker grey
Describe each soft tissue structure normal seen on CT.
CSF → hypoattenuated
Bone, calcifications →hypERattenuated
Vascular structures →HYPER- BLACK if no blood or blocked
AA- MCA, ACA, PCA, VBA
What should be examined b4 any DX of skull on CT?
Bony window
Suture(sutures have cortical bone on joint surfaces)
Mrs. Happy has shoulder pain, what image is appropriate?
MRI, but relative risk d/t Gadlonium contrast
Mrs. KFC has CR 1.8, w/ BUN <20:1. What is not allowed?
MRI w/ contrast
Unstable pt
Hepatorrenal dfx
After symmetry, and attenuatin is examined what is next to examine on CT brain?
Brain atrophy- wider sulci, space btwn skull
Midline shift- mm
Cerebral edema
Cerebral mass
Pneumocephalus- air, black dots
Since the skull is box, but a bleed occurs what happens to structures intracranially?
MIDLINE shift- structures like lateral seen clearly but pushed over
Examine- Falx (sicklelike) cerebri
EFFACement- squishes structures, CANNOT be seen clearly
Encephalomalacia looks like what on CT?
Darker area, that isn't normally dark softening of brain tissue 1. infarct 2. infx 3. trauma
What is a type of hydrocephalus, dilated ventricles, when the **ENITRE ventricle and 4th ventricle is enlarged?
Communicating HYDROcephalus
Extravasuclar cause, dec reabsorption of CSF
If your grandparent has acute, gait disturbance, dementia, incontinence. Then what should be ordered?
**Normal Pressure Hydrocephalus- COMMUNICATING HYDRO CT brain gyri/sulci are normal 4th Ventricle enlarged
If the all the ventricles are enlarged except the 4th ,what is suspected?
NON Communicating HYDROcephalus
Obstruction of outflow of CSF, tumor, mass
After, IV and treatment post head trauma, what are key findings to R/o on CT?
Subdural hematoma Epidural hematoma Intracerebral Hemorrhage Cerebral contusion Skull FX
REASONS to order NON Contrast 1st Neuro finding Glasco <8 LOC Wounds Vomiting w/ no Abdominal and post trauma-epidural MC
On the head trauma case, there is a crescent/concave shape hyperattenueted and diminished ventricle?
SUBDURAL Less bad d/t VENOUS orgin, slow bleed BTWN dura and arachnoid Does not cross midline May cross sutures Acute subacute chronic
On the head trauma case, there is a biconvex/oval shape hyperattenueted and and a midline shift?
EPIDURAL- dura and skull ACUTE confined due to not crossing sutures W/ skull FX Loss of gyri culci Midline shift effacement Pneumocephalus
What is the story with epidural?
Pt trauma, LOC, THEN wakes up ok, but risk of herniatio
What is reason to not have contrast on acute head trauma?
SUBARACHONOID HEMORRHAGE
- cisterns and sucli- white
- Effacement
Thunderclap worse HA
Eti- **#1 Trauma, aneurysm, AVM, tumor
hyperattenation on NON con CT
IF contrast all white, CAN miss BLEED
What will reveal axonaly injury?
MRI
If a suspected CVA is indicated, what is FIRST?
NON CONTRAST CT
<6H ischemia does show
IF stable, MRI is ideal
What occurs weeks after CVA on CT?
HYPO attenuated fluid
INFarts seen in region
What should be ordered for worst headache of life, women, obese, young w/ VA changes, n/v?
CT
BIH/pseudotumor
What type of CT abnormalities are common in htn, DM, atherosclerosis?
Lacunar infarcts- darkened spots, often found incidentally in basal ganglia, pons
MRI- T2 infarcts will be white
MRI- T1 infarct will be BLACK
What cause ICP and is seen on NON CONT CT?
Mass, blood edema, hydrocephalus
SX- HA, vomiting, papilledema, LOC
What are indicators of cerebral edema?
Effaced gyri sulci
Undistinguished grey and white matter
Ventricles compressed
Global or local
What are causes of cerebral edema?
Infx
Trauma
Toxic
Psuedotumor
What is HypOattenuated RING around infxn, malignancy, acute hemorrhage and ONLY Affects **white matter location?
Vasogenic Cerebral Edema
+/- Midline shift
What is hypOattenuated REGION where ischemia occurred. May see watershed/trickl effect point of infarct. Which region is often seen?
CYTOTOXIC cerebral Edema
affect ***BOTH white and grey matter.
PT C/C mild weakness in arms? What is on DDX
CVA
Signs on NON con CT
1. Hyperdense vessel sign at MCA
- Loss of “insular ribbon” (the white matter between insular cortex & nuclei)
- Lentiform & caudate nucleus NOT distinguishable -loss of white matter btwn the two
- Effacement of sulci
Tumors such as glioma, astrocytoma are common where?
intra-axial w/in parenchymal
Menigioma, acousti neuroma are seen where?
extra-axial invasion
What is round multiple and enhanced with contrast?
Metastases
What tapeworm common in uncooked pork, what will have vasogenic edema surrounding it? Curable
Neurocysticercosis
multiple cyst ring-like lesions in brain
