Image Post- Processing

Question 1

If the radiologist needs to know the ratio of fluid to blood in a cerebral lesion, what quantitative tool can help to estimate this ratio

Answer 1

Histogram analysis

Question 2

Which of these axial data sets would be best suited for creating 5 mm coronal reformatted images through the abdomen

Answer 2

1.25 mm axial images

Question 3

If a multiplanar reformation is rendered as a maximum intensity projection, what CT number will be displayed for a voxel containing mostly air, lung, and a small amount of iodinated contrast?

Answer 3

CT number for contrast

Question 4

Which of these quantitative analysis methods in CT can be used to identify the maximum Hounsfield value in an area of concern

Answer 4

Histogram analysis

Question 5

Which of the following multiplanar reformations are impossible to create

Answer 5

standard reformation from bone algorithm reconstruction

Question 6

Histogram analysis is useful for which of these applications

Answer 6

defining the range of CT numbers in a region of ROI

Question 7

What is the effect of using overlapping slices for volume rendered images

Answer 7

increased smoothing in the images

Question 8

the slice thickness of a reformation will affect

Answer 8

1. spatial resolution

2. image noise

Question 9

Which three of these measurements is usually acquired using a simple region of interest tool

Answer 9

1. average HU value
2. standard deviation
3. Area (cm square)

Question 10

Using edge-enhanced images for volume rendering is expected to result in

Answer 10

image noise

Question 11

The process of converting axial images into coronal images requires a technique called

Answer 11

multiplanar

Question 12

Which three of the following is considered a “post-processing” application of the CT image data

Answer 12

1. multiplanar reformation
2. 3D rendering
3. ROI measurement

Question 13

What multiplanar rendering technique is used to display images maximizing visibility of airways within the lungs

Answer 13

minimum intensity projection

Question 14

Which of these methods is used to estimating a patient’s risk of coronary artery disease (CAD)

Answer 14

calcium scoring

Question 15

Patients with an Agatston grade greater than 400 have a severe risk of major adverse cardiac events. The Agatston grade for coronary calcification is acquired using

Answer 15

Calcium scoring

Question 16

Which of these 3D rendering techniques display only one tissue type

Answer 16

shaded surface display

Question 17

Ejection fraction analysis in CT is used for

Answer 17

Evaluating the efficiency of heart contractions

Question 18

A physician is requesting a 3D imaging showing several tissues with various levels of transparency. the appropriate rendering technique is:

Answer 18

Volume redering

Question 19

Consider a voxel in a multiplanar reformation that includes equal portions of water, fat, and bone. what HU will be displayed on the pixel

Answer 19

average of all HU in the voxel

Question 20

What of the statements correctly describes the creation of multiplanar reformations (MPRs)

Answer 20

MPRs must be created with the same algorithm as the image data