Procedures- Brain

Question 1

What type of acquisition is used for a CT head scan?

Answer 1

Axial

Question 2

What are the axial plane CT images to be set parallel to during acquisition?

Answer 2

Infra-orbital mental line

Question 3

How many degrees above the IOML is the head acquisition performed?

Answer 3

15

Question 4

If the acquisition for a CT head is set to 15 degrees above the IOML, what is the scan plane parallel to and how is it beneficial?

Answer 4

Parallel to the skull base;

Reduces orbital dose and minimize beam-hardening artifact

Question 5

Which type of image acquisition provides the best z-axis resolution?

Answer 5

Axial/sequential

Question 6

What size slices or sections are acquired from the skull base through the posterior fossa?

Answer 6

2-5mm

Question 7

What size slices or sections are acquired from posterior fossa through the vertex?

Answer 7

5-10mm

Question 8

What artifact is reduced when thinner sections are acquired through the posterior fossa?

Answer 8

Beam-hardening caused by petrous pyramids

Question 9

Z-axis resolution allows for high quality exams of the brain with what type of acquisition?

Answer 9

Helical/volumetric

Question 10

Which type of scan acquisition is preferred whenever MPR or 3-D imaging is anticipated or when examination speed is a critical issue?

Answer 10

Helical/volumetric

Question 11

What size slice thickness/detector configuration is used for data acquisition of a CT head?

Answer 11

Thin (~0.6mm)

Question 12

What size slice thickness is used for reconstructions of a CT head?

Answer 12

Thick

Question 13

What algorithm is used for reconstruction of a CT head?

Answer 13

Standard or soft tissue

Question 14

What type of algorithm can also be used for reconstruction of the head for suspected fractures or other skeletal abnormalities?

Answer 14

Bony or high spatial frequency

Question 15

What’s the WW and WL setting for Gray/white matter?

Answer 15

WL: 35 and WW: 100

Question 16

What’s the WW and WL of bone?

Answer 16

WL:400 and WW: 3,000

Question 17

What’s the WW and WL of a hemorrhage/hematoma?

Answer 17

WL: 75 and WW: 150

Question 18

What’s the WW and WL for acute ischemia?

Answer 18

WL: 35 and WW:25

Question 19

What type of pathology is improved by high-contrast windowing?

Answer 19

Acute stroke

Question 20

What CT exam of the brain is routinely indicated for trauma to diagnose intracranial hemorrhage or hematoma?

Answer 20

Non-contrast

Question 21

Why is administering CM in a trauma patient initially contraindicated?

Answer 21

Contrast can mask subtle signs of hemorrhage

Question 22

What exam is usually ordered first by protocol for evaluation of acute stroke?

Answer 22

Unenhanced CT of the brain

Question 23

What must be ruled out on a scan before thrombotic therapy?

Answer 23

Hemorrhage

Question 24

What are other indications of a head CT?

Answer 24

• Congenital abnormalities
• Hydrocephalus
• Mass or tumor
• Primary neoplasms of brain- meningioma, schwannoma, and gliomas like astrocytoma
• Metastatic lesions usually from lung, breast, renal and GI cancer
• Bony abnormalities
• Endocrine pathology

Question 25

What indications would iodinated contrast be administered for a head scan?

Answer 25

Arteriovenous malformation, suspected neoplasm, or attention to the pituitary gland

Question 26

What type of scan acquisition, what size thickness, and what imaging plane is acquired for a pituitary scan?

Answer 26

Coronal plane, thin section (1-3mm), helical imaging

Question 27

What type of imaging technique is required for a study of the temporal bones and internal auditory canal?

Answer 27

High-resolution imaging technique

Question 28

What factors are involved when using a high-resolution imaging technique for temporal bones and internal auditory canals?

Answer 28

Thin slices Small DFOV high-resolution reconstruction algorithm

Question 29

What two planes are thin sections of a temporal bone reconstructed into?

Answer 29

Axial and coronal

Question 30

What factor of MPR imaging allows for reduced radiation dose from coronal sliced images during axial acquisitions?

Answer 30

Isotropic

Question 31

Should reconstructions of temporal bones be acquired unilaterally or bilaterally?

Answer 31

Bilaterally

Question 32

What is the reason for using a small DFOV or increased zoom factor on a temporal bone reconstruction image?

Answer 32

To maximize resolution of the small bony components of the inner ear

Question 33

What type of algorithm is used to reconstruct the temporal bones?

Answer 33

High spatial frequency/bone

Question 34

What is the biggest cause of image degradation when imaging temporal bones?

Answer 34

Motion

Question 35

What are 2 indications for CM for a CT of the temporal bones?

Answer 35

Tissue neoplasm, vascular anomalies

Question 36

When imaging orbits, the axial is to be parallel to what anatomical landmark?

Answer 36

IOML

Question 37

What size slices should an axial acquisition of the orbits be?

Answer 37

Thin- (1-3mm)

Question 38

How do coronal images align with axial images of the orbits?

Answer 38

Perpendicular

Question 39

Why would the acquisition angle be adjusted for a CT of the orbits?

Answer 39

To avoid dental apparatus

Question 40

What anatomical structure is the area of interest for oblique Sagittal and oblique coronal MPR of the orbits?

Answer 40

Optic nerve

Question 41

What algorithm is used when reconstructing orbits?

Answer 41

Standard or soft tissue

Question 42

What would an additional bone algorithm for orbit reconstructions be useful for?

Answer 42

Trauma indications

Question 43

What is the WW and WL of soft tissue of the orbits?

Answer 43

WL 40 and WW 400

Question 44

What would the WW and WL setting be for orbit bone window?

Answer 44

WL 400 and WW 3,000

Question 45

What indications would require CM to be administered for a CT of the orbits?

Answer 45

Vascular abnormalities, inflammation, suspected neoplasm

Question 46

When imaging sinuses, the axial images should be parallel to what?

Answer 46

Hard palate

Question 47

The acquisition for a sinus exam should extend inferiorly and anteriorly to include which to anatomical structures?

Answer 47

Maxillary and ethmoid sinuses

Question 48

The acquisition for a sinus exam should extend superiorly to include which to anatomical structure?

Answer 48

Frontal sinus

Question 49

The acquisition for a sinus exam should extend posteriorly to include which to anatomical structure?

Answer 49

Sphenoid sinus

Question 50

Which two patient positions can be performed to obtain coronal images of the sinuses?

Answer 50

Prone or supine with head dropped back

Question 51

What is a benefit of having an additional coronal position?

Answer 51

Demonstrates changing air-fluid levels and other sinus-related disease

Question 52

The coronal and sagittal planes of the sinuses help visualize which anatomical structure?

Answer 52

Osteomeatal complex

Question 53

Which structure is a common place to acquire sinus inflammation?

Answer 53

Osteomeatal complex

Question 54

What type of sinus scan provides a limited coronal acquisition through the sinuses?

Answer 54

Low-dose survey

Question 55

What two reconstructions should be created when imaging the facial bones?

Answer 55

Axial and coronal

Question 56

Which two algorithms are used to visualize the facial bones?

Answer 56

Standard and bone algorithms

Question 57

What is the WL and WW of soft tissue for the facial bones?

Answer 57

WL 40 and WW 400

Question 58

What is the WW and WL of bone for the facial bones?

Answer 58

WL 400 and WW 3,000

Question 59

What two plane acquisitions are needed for CT of the TMJ joints?

Answer 59

Axial and coronal

Question 60

What two positions can the patient perform TMJ joints for a CT?

Answer 60

Open- and closed- mouth

Question 61

What is an indication for CM with a TMJ CT scan?

Answer 61

Suspected neoplasm