S1_L2: Computed Tomography Scan

Question 1

TRUE OR FALSE: Denser structures are seen as darker shades of gray.

Answer 1

False

Question 2

TRUE OR FALSE: One disadvantage of doing CT Myelogram is that allergic reactions may occur in patients sensitive to the contrast media.

Answer 2

True

Question 2

TRUE OR FALSE: Modifying the window is a form of data conversion in the post processing stage of CT imaging.

Answer 2

True

Question 2

TRUE OR FALSE: One advantage of CT scan imaging is that it is less time consuming than ultrasound.

Answer 2

True

Question 3

TRUE OR FALSE: The x-ray tube is found inside the collimator assembly.

Answer 3

False

Question 4

TRUE OR FALSE: Thinner CT slices for a tibial shaft fracture is recommended for adequate visualization of the extent of the fracture.

Answer 4

False

Question 5

TRUE OR FALSE: Tumor is difficult to visualize in CT scan because tumors may have the same radiodensity as the surrounding structures even with the use of contrast media.

Answer 5

False

Question 6

TRUE OR FALSE: Coronal images are viewed from back to front.

Answer 6

False

Question 7

TRUE OR FALSE: Remnant radiation is the radiation that bounces off of the patient.

Answer 7

False

Question 8

This individual discovered computed tomography in 1972.

Answer 8

Godfrey Hounsfield

Question 9

Godfrey Hounsfield’s work was based on whose mathematical formulas for reconstruction of images for digital signals?

Answer 9

Alan Cornack

Question 10

The first computed tomography scanners were dedicated for scanning and imaging of the ___.

Answer 10

brain/head

Question 11

In 1976, whole body CT scans became possible. Godfrey Hounsfield was awarded the Nobel Prize in Medicine in 1979.
A. Only the 1st statement is true
B. Only the 2nd statement is true
C. Both statements are true
D. Both statements are false

Answer 11

C. Both statements are true

Question 12

Unlike x-rays, CT creates images based on cross-sectional (axial) slices, created by up to ____ projections from different angles.

Answer 12

1000

Question 13

Enumerate the 3 elements of the CT scan

Answer 13

Gantry, operator’s console, and computers

Question 14

Functional imaging is neuroimaging that demonstrates the microanatomy and macroanatomy of the brain. Structural imaging is neuroimaging that displays the activity of the brain based on metabolic activity.
A. Only the 1st statement is true
B. Only the 2nd statement is true
C. Both statements are true
D. Both statements are false

Answer 14

D. Both statements are false, terminologies were interchanged.

Note: The more metabolic activity (hyperactive area), the more the contrast media lightens up. However, all of it must normally light up in the same intensity.

Question 15

A computed tomography scan creates images based on the radiodensity of tissues. Magnetic resonance imaging creates images based on the energy emitted from hydrogen protons in water or soft tissues.
A. Only the 1st statement is true
B. Only the 2nd statement is true
C. Both statements are true
D. Both statements are false

Answer 15

C. Both statements are true

Question 16

Element of the CT scan that transforms radiant energy to something we are able to see

Answer 16

Computers

Question 17

Element of the CT scan that is CT technology used to control the scanning process, select slice thickness, reconstruction algorithms (post-processing), and other specifications.

Answer 17

Operator’s console

Question 18

Element of the CT scan into which the patient slides during the examination

Answer 18

Gantry

Question 19

1. Imaged part can be rotated “in space” on the computer screen
2. Acquires all the data in a single sweep of the scanner

A. Three-Dimensional CT
B. CT Myelogram
C. Cone Beam CT

Answer 19

1. A
2. C

Question 20

1. Used mostly in dentistry for TMJ
2. Multiplanar reconstruction
3. Invasive in nature, where a contrast media is injected into the subarachnoid space

A. Three-Dimensional CT
B. CT Myelogram
C. Cone Beam CT

Answer 20

1. C
2. A
3. B

Question 21

1. For breast cancer detection as it is used for imaging of the breast
2. Fallen out of favor d/t nature & with the advent of the MRI

A. Three-Dimensional CT
B. CT Myelogram
C. Cone Beam CT

Answer 21

1. C
2. B (MRI is more preferred as it is a non-invasive procedure)

Question 22

Cone Beam CT uses a large, cone-shaped x-ray beam matched with a ____.

Answer 22

Flat-panel detector

Question 23

TRUE OR FALSE: CT myelography is better able to distinguish between osteophytes, ligament infolding, and annular material than the MRI.

Answer 23

True Source: Fundamentals of Musculoskeletal Imaging, 4th ed.

Question 24

TRUE OR FALSE: Images captured using the three-dimensional CT is best viewed in digital format than on printed format.

Answer 24

True, it is easier to see the 3D image on the monitor in order to see the different angles of the particular area you are interested in.

Question 25

TRUE OR FALSE: Cortical bone is more dense than cancellous bone.

Answer 25

True E.g., The cranium is a flat bone with cancellous bone sandwiched between cortical bone.

Question 26

For axial cuts/images, images are viewed in a ___ manner

Answer 26

caudo-cephalad

Question 27

TRUE OR FALSE: For sagittal cuts, images are viewed from left to right for either side of the body.

Answer 27

True

Question 28

CT scan slices are identified in terms of ____ that correspond to scout images.

Answer 28

slice numbers

Question 29

It appears as a small locator image inserted into the left uppermost corner of the image for each slice.

Answer 29

Scout image

Question 30

TRUE OR FALSE: Slice thickness for musculoskeletal CT can vary from 0.5 to 2 mm, for small joints, to 2 to 3 mm, for the pelvis.

Answer 30

True

Question 31

Thinner slices are typically used in areas of rapidly changing anatomy. Smaller bones or joints can be missed in thicker slices. A. Only the 1st statement is true B. Only the 2nd statement is true C. Both statements are true D. Both statements are false

Answer 31

C. Both statements are true

Question 32

The ability to select the range of radiodensities displayed in an image.

Answer 32

Windowing

Question 33

CT image made for the purpose of viewing musculature, soft tissues, or viscera.

Answer 33

Soft tissue window

Question 34

CT image for viewing of the bone

Answer 34

Bone window

Question 35

A brain image of the Circle of Willis looks like a ___.

Answer 35

star

Question 36

To see the circle of willis in a CT scan, the slice is taken just above the ____.

Answer 36

Base of the skull

Question 37

The eyes of the brain images Mr. Happy & Mr. Sad represent what structure?

Answer 37

anterior horns of the lateral ventricles

Question 38

The smile/mouth of the brain image Mr. Happy represents what structure?

Answer 38

Quadrigeminal cistern

Question 39

The frown (down-turned lips) of Mr. Sad represents what structure?

Answer 39

posterior horns of the lateral ventricles

Question 40

The lateral ventricles are represented by what brain image?

Answer 40

(Back-to-Back) Worms

Question 41

Each limb of the Cross brain image is made up what 2 structures?

Answer 41

Lesser wings of the sphenoid & petrosal portion of the temporal bone

Question 42

TRUE OR FALSE: Gray matter is more dense than white matter.

Answer 42

True: it appears whiter due to its higher radiodensity, however, it is not as dense as bone.

Question 43

To see the coffee beans brain image, the slice/cut must be taken almost at the ___ of the skull.

Answer 43

Vertex

Question 44

The coffee beans brain image represents what structure?

Answer 44

Brain parenchyma

Question 45

The temporal lobe is present in which cranial fossa?

Answer 45

Middle cranial fossa

Question 46

Coronal slices offer the best view of the ventricular system. Sagittal slices best show the spinal cord, medulla, pons, and midbrain. A. Only the 1st statement is true B. Only the 2nd statement is true C. Both statements are true D. Both statements are false

Answer 46

C. Both statements are true

Question 47

It is the modality of choice for acute settings due to the short scanning times

Answer 47

Computed tomography

Question 48

It is the most commonly used slice for diagnostic purposes

Answer 48

Axial slice

Question 49

Case: A 56 y/o male pt was brought to the ER with signs of hydrocephalus and Arnold Chiari Type II malformation. Which CT slice is best to use for this patient? A. Axial B. Coronal C. Sagittal

Answer 49

B. Coronal

Question 50

Case: A 28 y/o male pt was brought in after sustaining a MVA head on collision. Which CT slice is best to use for this patient to detect any debris in the skull? A. Axial B. Coronal C. Sagittal

Answer 50

C. Sagittal

Question 51

Aperture that creates a narrow fan-shaped beam of x-rays and through which x-rays pass.

Answer 51

Collimator Assembly

Question 52

Device that controls the radiation center and determines the slice thickness of the CT scan.

Answer 52

Collimator Assembly

Question 53

Device that measures remnant radiation, it is found opposite the x-ray tube.

Answer 53

Detector array Note: Up to 1,000 detectors are arranged in an array, encircling the patient.

Question 54

It amplifies the signal from the detectors in the form of varying electrical current, known as the analog signal. This signal will later on be converted into digital for an image to be seen in the computer. A. X-ray tube B. Detector Array C. Data Acquisition D. Collimator Assembly

Answer 54

C. Data Acquisition

Question 55

It is the best imaging for evaluation of loose bodies in a joint.

Answer 55

Computed tomography scan

Question 56

TRUE OR FALSE: CT is the modality of choice for detailed imaging of cortical and trabecular bone.

Answer 56

True Source: Fundamentals of Musculoskeletal Imaging

Question 57

It is an indirect imaging of the brain that demonstrates blood vessels in and around the brain. A. Computed tomography B. Cerebral angiography C. Magnetic resonance imaging D. Ventriculography

Answer 57

B. Cerebral angiography

Question 58

An invasive, indirect imaging of the brain performed by injecting air in the ventricular system. A. Computed tomography B. Cerebral angiography C. Magnetic resonance imaging D. Ventriculography

Answer 58

D. Ventriculography Note: It can be used in cases of patients with hydrocephalus.

Question 59

TRUE OR FALSE: The scout image is a 3 dimensional digital radiograph, showing the localization of the structures to be scanned.

Answer 59

False, it is a 2 dimensional digital radiograph

Question 60

TRUE OR FALSE: The screening process is where transduction occurs.

Answer 60

True

Question 61

Sagittal or coronal cuts are performed to visualize the image that is created by the CT. A. Matrix B. Image C. Post Processing

Answer 61

B. Image

Question 62

The matrix becomes an image using a mathematical process known as ____.

Answer 62

back projection

Question 63

The result is manipulated in the computer's software to improve contrast and modify the window. A. Matrix B. Image C. Post Processing

Answer 63

C. Post Processing

Question 64

In data conversion, radiodensities are converted by the computer into a ____.

Answer 64

matrix Additional: Each cell of the matrix is a pixel (picture element). Each pixel is assigned a shade of gray, which represents the radiodensity of that cell of the matrix, expressed in terms of Hounsfield units.

Question 65

In viewing CT images, tissues have differing radiodensities represented by different shades of ____.

Answer 65

gray

Question 66

In the CT, ____ structures are represented by white or a light shade of gray.

Answer 66

dense Note: Less dense structures are darker.

Question 67

A limitation of the CT scan is low radiation exposure. It also has a limited capability for determining the histological make up of tissues. A. Only the 1st statement is true B. Only the 2nd statement is true C. Both statements are true D. Both statements are false

Answer 67

B. Only the 2nd statement is true

Question 68

It identifies blood clots or thrombosis, and hemorrhage. The point of occlusion associated with stroke can also be seen. A. Computed tomography B. Cerebral angiography C. Magnetic resonance imaging D. Ventriculography

Answer 68

B. Cerebral angiography Note: When haziness is seen due to the contrast media leaking in the brain, this represents a hemorrhagic stroke.

Question 69

Standard thickness for CT axial slices

Answer 69

2-3 mm Note: 0.5mm is used for smaller images

Question 70

Neuroimaging used for diagnosis of lesions that are too small to be detected.

Answer 70

Functional imaging

Question 71

TRUE OR FALSE: CT scan has the same imaging principles as conventional radiography, where x-rays are attenuated by body tissues.

Answer 71

True

Question 72

CT scans provide accurate measurement of osseous alignment. CT scans are less expensive than MRI and less problematic for claustrophobic patients. A. Only the 1st statement is true B. Only the 2nd statement is true C. Both statements are true D. Both statements are false

Answer 72

C. Both statements are true

Question 73

CT scan is more time consuming than MRI or UTZ. UTZ is fast but operator-dependent; without an US specialist, you won’t be able to do it. A. Only the 1st statement is true B. Only the 2nd statement is true C. Both statements are true D. Both statements are false

Answer 73

B. Only the 2nd statement is true

Question 74

CT scan is not used for subtle fractures, complex fractures, and comminuted fractures. Instead, CT scan is used for IV disc conditions when combined with diskograms. A. Only the 1st statement is true B. Only the 2nd statement is true C. Both statements are true D. Both statements are false

Answer 74

B. Only the 2nd statement is true

Question 75

In the 1970s, CT was used with nuclear medicine. In the 1980s, radioactively labeled chemicals were used for functional imaging of the brain. A. Only the 1st statement is true B. Only the 2nd statement is true C. Both statements are true D. Both statements are false

Answer 75

B. Only the 2nd statement is true 1970s: CT scan was used for neuroimaging. 1980s: CT & nuclear medicine, single-photon emission CT, & positron emission tomography.

Question 76

CT scan is used to detect degenerative changes, spinal arthritic changes, and spinal stenosis especially with CT myelography. It can also be used for serious trauma, as multiple injuries to both osseous and soft tissue structures can be determined. A. Only the 1st statement is true B. Only the 2nd statement is true C. Both statements are true D. Both statements are false

Answer 76

C. Both statements are true

Question 77

During CT scanning, the x-ray tube revolves circumferentially (360º) around the patient in the gantry to get a slice. Then, it stops and the table is moved for a new slice, known as the stop-and-go action. A. Only the 1st statement is true B. Only the 2nd statement is true C. Both statements are true D. Both statements are false

Answer 77

C. Both statements are true Note: Movement of the tabletop is referred to in terms of pitch.

Question 78

The x-ray tube and the high-voltage generator can be found in the ____.

Answer 78

Gantry

Question 79

TRUE OR FALSE: Modern scanners move and scan continuously during the examination process, thus creating helical slices.

Answer 79

True

Question 80

Duration of CT scan

Answer 80

~10 mins, which is why it is used for acute cases