neuroanatomy chapter 4

Question 1

describe the axial slices in MRI scans

Answer 1

true horizontal slices

Question 2

what should be included on all CT and MRI films so that the exact angle of scanning can be documented

Answer 2

scout images (localizer images)

Question 3

what do CT scans measure

Answer 3

density of tissue

Question 4

what color do bones appear in CT scans

Answer 4

white

Question 5

what color does air appear in CT scans

Answer 5

black

Question 6

what color is CSF in CT scans

Answer 6

dark gray

Question 7

what color is fat in CT scans

Answer 7

nearly black

Question 8

how do fresh in cranial hemorrhages show up on CT scnas

Answer 8

coagulate nearly immediately and therefore show up as hyper dense areas relative to the brain

Question 9

what is the term for anything that distorts the brain’s usual anatomy by displacement

Answer 9

mass effect

Question 10

what does the contrast material contain for CT scans

Answer 10

iodine

Question 11

what is the imaging method of choice for detecting low-contrast or small lesions

Answer 11

MRI

Question 12

are bone and fresh hemorrhage imaged better with CT or MRI

Answer 12

CT

Question 13

what is the preferred technique for patients with head trauma or suspected intracranial hemorrhage

Answer 13

CT

Question 14

what axis does T1 relaxation occur

Answer 14

along the z-axis parallel to the magnetic field

Question 15

what does T1 relaxation depend on

Answer 15

net direction of spins (parallel or anti-parallel

Question 16

what plane does T2 relaxation occur

Answer 16

X-Y plane perpendicular to the magnetic field

Question 17

what does the T2 relaxation depend on

Answer 17

net coherence of precessions

Question 18

what color is white and gray matter in T1

Answer 18

gray is gray and white is white (opposite for T2)

Question 19

describe water and fat in T1

Answer 19

water is dark and fat is bright

Question 20

describe water and fat in T2

Answer 20

water is bright and fat is dark

Question 21

describe FLAIR imaging

Answer 21

produces scans that appear similar to T2-weighted images but with dark CSF

Question 22

what imaging uses rapid image acquisition with strong gradients to measure the diffusion of water protons in brain tissue

Answer 22

DWI

Question 23

what imaging technique can detect cellular changes associated with acute ischemic stroke within 30 minutes of onset

Answer 23

DWI

Question 24

what color is acute ischemic stroke on DWI

Answer 24

bright

Question 25

what color is acute ischemic stroke on ADC

Answer 25

dark

Question 26

what paramagnetic substance is used for intravenous contrast with MRI

Answer 26

gadolinium

Question 27

what occurs as a result of protons moving rapidly into or out of the area being imaged

Answer 27

flow artifact

Question 28

what does subacute hemorrhage contain that causes it to appear white

Answer 28

methemoglobin

Question 29

what does chronic hemorrhage contain to cause it to appear dark

Answer 29

hemosiderin

Question 30

what does magnetic resonance spectroscopy (MRS) measure

Answer 30

brain neurotransmitters and other biochemicals

Question 31

what does diffuse tensor imaging (DTI) allow for

Answer 31

sensitive assessment of white matter pathways based on water diffusion constrained by axon fibers

Question 32

what is neuroangiography mainly used for now that CT and MRI are widely available

Answer 32

visualize lesions of the blood vessels themselves

Question 33

what can doppler ultrasound be used for

Answer 33

to measure flow and lumen diameter of large blood vessels in the head and neck

Question 34

what is doppler ultrasound most useful for assessing

Answer 34

proximal portions of the internal carotid

Question 35

what is transcranial doppler most often used for

Answer 35

ICU to detect vasospasm following subarachnoid hemorrhage

Question 36

what is MRI mainly used for

Answer 36

to detect regions of decreased or absent arterial blood flow caused by atherosclerotic narrowing, thrombosis, or dissection

Question 37

what can venous flow be visualized by using

Answer 37

magnetic resonance venography (MRV)

Question 38

what is the wada test used for

Answer 38

to help localize the side of language and memory function

Question 39

what was the original method for measuring brain activity

Answer 39

EEG

Question 40

what is brain metabolism most often evaluated by

Answer 40

FDG-PET

Question 41

what is used to map local brain consumption of glucose

Answer 41

FDG-PET

Question 42

what are used to generate a map of regional cerebral blood flow at rest

Answer 42

SPECT

Question 43

what is lctal SPECT used for

Answer 43

to help localize the region of seizure onset by measuring cerebral blood flow to indirectly map local electrical brain activity during seizures