NeuroImaging

Question 1

Transmission Imaging

Answer 1

Radiation sent through body + detected on other side (e.g. X-Ray, CT, Fluoroscopy, Mammography)

Question 2

Reflection Imaging

Answer 2

Radiation passes partially into body and reflected back (e,g, Ultrasound, OCT)

Question 3

Emission Imaging

Answer 3

Generate radiation inside body and detect as it leaves the body (e.g. MRI, nuclear)

Question 4

Direction: rostral —> caudal

Answer 4

Coronal

Question 5

Direction: dorsal —> ventral

Answer 5

Sagittal

Question 6

Direction: medial —> lateral

Answer 6

Axial

Question 7

T1 Weighting makes Vitreous and CSF ____ (white/dark)

Answer 7

Dark

Question 8

T2 Weighting makes Vitreous and CSF ____ (white/dark)

Answer 8

White

Question 9

CT scan is best to scan what parts of the body?

Answer 9

Bone, Blood, Muscle

Question 10

CT scans can vary in cut size from __ mm to ___ mm

Answer 10

1 - 10

Question 11

CT scan is a series of ___ scans

Answer 11

A-scans

Question 12

Indications for CT

Answer 12

1. Orbital/sinus pathology or trauma (except ON)
2. Acute cerebral or subarachnoid hemorrhage
3. Metallic foreign body

Question 13

Disadvantages of CT Scans

Answer 13

1. High cost
2. Restricted to axial and coronal (no sagittal)
3. Ionizing radiation
4. CI in pregnancy, children
5. Iodine contrast CI’d in kidney dz, allergy

Question 14

TRUE/FALSE: Diabetic patients cannot get a CT scan

Answer 14

FALSE, but the patient must stop metformin 48 hours prior to scan

Question 15

What gives rise to a MRI signal?

Answer 15

Change of quantum states of proton spin, against strong magnetic field (10,000x stronger than earth’s) — with radio frequency specific to Hydrogen

Note: uses the hydrogen in our water molecules

Question 16

MRA

Answer 16

MRI Angiography — allows non-invasive imaging of BV w/o radiation or contrast

Question 17

In MRI, signal intensity is determine by:

Answer 17

1. Proton density
2. T1 relaxation time
3. T2 relaxation time

Question 18

Proton density

Answer 18

Concentration of protons in tissue

Question 19

In a cerebral tumor, which ‘weight’ is used to view anatomy? Which one is used to view lesion?

Answer 19

Anatomy — T1
Lesion — T2

Question 20

FLAIR

Answer 20

Fluid Attenuated Inversion Recovery
Technique used to suppress certain anatomy tissue

Good for detecting demyelination; order w/ optic neuritis

Question 21

Disadvantages of MRI

Answer 21

1. Cost
2. Poor images of lungs
3. Inability to show calcification
4. Fresh blood not well visualized
5. Difficult to tolerate exam time

Question 22

CI for MRI

Answer 22

1. Pacemakers
2. Cochlear implants
3. Metallic FB
4. Arterial aneurysmal clips
5. Stents

Question 23

What to order: blunt oculofacial trauma

Answer 23

X-ray, CT

Question 24

What to order: orbital cellulitis

Answer 24

CT now
MRI later

Question 25

What to order: orbital tumor

Answer 25

MRI

Question 26

What to order: Aneurysm, AVM

Answer 26

MRI/MRA, cerebral angiography (invasive)

Question 27

What to order: HTN, amaurosis fugax

Answer 27

Echocardiography, Carotid Doppler

Question 28

What to order: histoplasmosis

Answer 28

X-ray, CT

Question 29

What to order: Crohn’s, UC

Answer 29

Barium X-ray, CT

Question 30

What to order: Sarcoidosis, TB

Answer 30

Chest X-ray, CT

Question 31

What to order: Thymoma

Answer 31

Chest X-ray, CT

Question 32

What to order: Thyroid Disease

Answer 32

Thyroid scan, Iodine uptake

Question 33

What to order: Primary tumor or Mets

Answer 33

Mammography, CT, MRI