Neuroimaging

Question 1

when should you order a CT head in the setting of psychosis

Answer 1

first episode psychosis WITH neuro sx, atypical clinical picture and older age

Question 2

would you pick CT or MRI in the following presentation:

sustained confusion

Answer 2

MRI

Question 3

would you pick CT or MRI in the following presentation:

screening exam

Answer 3

CT

Question 4

would you pick CT or MRI in the following presentation:

acute hemorrhage

Answer 4

CT

Question 5

would you pick CT or MRI in the following presentation:

atypical clinical findings

Answer 5

MRI

Question 6

would you pick CT or MRI in the following presentation:

delirium

Answer 6

CT

Question 7

would you pick CT or MRI in the following presentation:

subtle cognitive deficits

Answer 7

MRI

Question 8

would you pick CT or MRI in the following presentation:

abrupt personality changes w neuro signs and symptoms

Answer 8

MRI

Question 9

would you pick CT or MRI in the following presentation:

calcified lesions

Answer 9

CT

Question 10

would you pick CT or MRI in the following presentation:

skull injury

Answer 10

CT

Question 11

would you pick CT or MRI in the following presentation:

brain injury

Answer 11

MRI

Question 12

would you pick CT or MRI in the following presentation:

patients who cannot tolerate a longer exam

Answer 12

CT (for those who cant tolerate longer MRI)

Question 13

list advantages to CT

Answer 13

SENSITIVE in detecting intracranial HEMORRHAGE, mass effect, hydrocephalus, middle ear/temporal bone pathology, bone lesions and skull #s

FOREIGN BODIES are obvious on CT

good SCREENING exam for evaluating brain for presence of abnormalities

Question 14

what are disadvantages of CT

Answer 14

radiation

cost

availability

Question 15

list 2 advantages to MRI

Answer 15

NO radiation exposure

superior to CT for SOFT TISSUE contrast and multi-planar capabilities

Question 16

list disadvantages to MRI

Answer 16

cost

limited availability

long acquisition time

Question 17

what would be the neuroimaging modality of choice for assessing subacute and chronic brain bleeds

Answer 17

MRI

Question 18

MRI is LESS sensitive than CT for which two conditions

Answer 18

subarachnoid hemorrhage and calcifications

Question 19

how are CT images constructed

Answer 19

based on different densities of stuff in the head

Question 20

what are T1 weighted MRI sequences best for

Answer 20

best for ANATOMICAL DETAIL

Question 21

what are T2 weighted MRI sequences best for

Answer 21

usually best for PATHOLOGICAL LESIONS

Question 22

how do you distinguish between T1 and T2 weighted images on MRI

Answer 22

mnemonic: Water is White on T2 –> World War 2 (WW2)

Question 23

what is currently the most sensitive MRI technique for detecting a cerebrovascular incident

Answer 23

diffusion weighted imaging (DWI)

Question 24

what is another use for DWI MRI

Answer 24

detection of diffuse axonal injury in the brain

Question 25

what MRI technique is used to detect EDEMA in the brain

Answer 25

FLAIR

Question 26

what is the standard CT scan in a trauma case

Answer 26

non con CT

Question 27

what brain abnormality is associated with "thunderclap headache"

Answer 27

subarachnoid hemorrhage

Question 28

what imaging technique would I choose if i suspect acute ischemic stroke within 6 hours

Answer 28

DWI MRI CT can help rule out hemorrhagic stroke, which is important. But CT can be normal in ischemic stroke within 3-6 hours but DWI MRI is able to detect infarcts within minutes of the event

Question 29

what are the most common CNS tumors

Answer 29

Glial tumors

Question 30

what is the modality of choice for detection of pituitary tumor

Answer 30

MRI

Question 31

what is the most sensitive technique to detect meningitis

Answer 31

MRI --but contrast enhanced CT can also be used *NON con CT is NORMAL in more than 50% of cases so not a good test for meningitis

Question 32

what are "Dawsons fingers"

Answer 32

a highly specific sign of MS on MRI represent demyelinating plaques through the corpus callus arranged at right angles along the medullary veins

Question 33

what normal age-related changes may be seen on neuroimaging

Answer 33

atrophy increased ventricular size non-specific white matter changes

Question 34

can neuroimaging be used to rule IN alzheimers disease?

Answer 34

no--> neuroimaging has low specificity in AD is used to rule out other causes

Question 35

what do you see on CT in AD

Answer 35

diffuse cerebral atrophy enlarged ventricles WIDENED SULCI *can also see medial temporal love atrophy on MR*

Question 36

what is Pick disease

Answer 36

a progressive dementia with death occurring 2-3 years after onset typically affects frontal and/or temporal lobes causing apathy, lack of initiative, personality change speech, language change begin early and progress quickly incontinence can occur early (unlike in AD, where continence is usually preserved until late in disease)

Question 37

what brain changes are seen in Pick disease

Answer 37

swollen neurons (pick cells) neuronal inclusions (pick bodies) neuronal loss, gliosis, brain strophy

Question 38

what do you see on CT in Pick disease

Answer 38

prominent atrophy of the frontal and/or temporal lobes *on MRI, there is sulci prominence wiht atrophy of insula, inferior frontal and superior frontal lobes and enlargement of frontal or temporal horns of the lateral ventricles

Question 39

what do you see on neuroimaging in huntingstons disease

Answer 39

significant caudate atrophy

Question 40

is neuroimaging useful in parkinsons

Answer 40

not generally useful

Question 41

what imaging technique is useful in assessing normal pressure hydrocephalus

Answer 41

MRI *T2 weighted

Question 42

what do SPECT look at

Answer 42

uses combo od CT and radioactive tracer to evaluate cerebral blood flow and to look for areas of hypoperfusion in the brain

Question 43

what are DAT-SPECT scans and what are they good for

Answer 43

"DAT" = dopamine transporter scans asses dopamine uptake in the BASAL GANGLIA in vivo good for differentiating LBD from AD as there is a greater reduction of dopamine terminals in the striatum in LBD comapred to their relative preservation in AD *DAT-SPECT can be abnormal in other neurodegenerative disorders where dopamine tarnsmission is affected ie FTD, corticobasilar degeneration, PSP, MSA

Question 44

what finding on SPECT suggests AD

Answer 44

medial temporal parietal lobe hypoperfusion

Question 45

what finding on SPECT suggests parkinsons/LBD

Answer 45

parietal-occipital distribution of hypoperfusion

Question 46

what does EEG measure

Answer 46

measures electricity generated by neural activity --> measures the electricity generated when clusters of neurons fire together

Question 47

alpha wave intrusions into delta sleep on EEG ("alpha-delta sleep") can be seen in what disorders

Answer 47

MDD and fibromyalgia