Imaging Process

Question 1

CT Imaging Process

Answer 1

1. Data Acquisition
2. Image Reconsruction
3. Image Display, Storage, and Communication

Question 2

Collects raw attenuation date from multiple angles

Answer 2

Data acquisition

Question 3

Converts raw data into cross-sectional images via algorithms

Answer 3

Image reconstruction

Question 4

Converts reconstruction data into a visual image on monitor

Answer 4

Image Display, Storage, and Communication

Question 5

Process of collecting raw x-ray attenuation data from the patient
and converting it into a digital form
that can later be reconstructed into
images

Answer 5

Data acquisition

Question 6

Data Acquisition methods

Answer 6

1. Slice-by-Slice
2. Volumetric

Question 7

Slice-by-Slice aka

Answer 7

Axial scanning or
Step-and-shoot,

Question 8

Traditional CT acquisition method

Answer 8

Slice-by-Slice

Question 9

The x-ray tube rotates once
around the patient while the
table remains stationary.
Data is collected for that slice,
then the table indexes (moves)
to the next position, and the
process repeats.

Answer 9

Slice-by-Slice

Question 10

1. X-ray tube completes one
   full rotation.
2. Detectors capture
   attenuation data for one
   slice.
3. Patient table advances by
   the preset slice thickness
   (or overlap).
4. The next slice is acquired.

Answer 10

Slice-by-Slice

Question 11

True slice thickness and excellent z-axis resolution.

Answer 11

Slice-by-Slice, Advantage

Question 12

Minimal interpolation artifacts.

Answer 12

Slice-by-Slice, Advantage

Question 13

High image quality for small regions.

Answer 13

Slice-by-Slice, Advantage

Question 14

Best for fine-detail studies, e.g., temporal bone, orbits,
inner ear.

Answer 14

Slice-by-Slice, Advantage

Question 15

Inefficient for trauma or vascular studies.

Answer 15

Slice-by-Slice, Limitation

Question 16

Not ideal for large-area coverage or dynamic studies.

Answer 16

Slice-by-Slice, Limitation

Question 17

Patient movement between slices can cause
misregistration artifacts.

Answer 17

Slice-by-Slice, Limitation

Question 18

Slow because of stop-and-go table motion.

Answer 18

Slice-by-Slice, Limitation

Question 19

XRT rotates
continuously while the patient
table moves through the gantry,
creating a helical or spiral path

Answer 19

Volumetric

Question 20

This was made possible by slip-ring technology, which allows
continuous rotation without
cables winding.

Answer 20

Volumetric

Question 21

This captures data for an entire
volume in one pass, which can
later be reconstructed into slices
of any thickness or orientation.

Answer 21

Volumetric

Question 22

1. Continuous XRT rotation
   with simultaneous table
   translation.
2. Helical path of data collection
   across the z-axis.
3. Computer algorithms interpolate
   data into slices.
4. Images can be reconstructed
   retrospectively with chosen
   thickness and intervals.

Answer 22

Volumetric

Question 23

Fast: covers large regions quickly.

Answer 23

Volumetric, Advantages

Question 24

Flexible reconstructions: thin, thick, overlapping slices possible
after the scan.

Answer 24

Volumetric, Advantages

Question 25

Isotropic voxels: nearly equal dimensions in x, y, and z planes → excellent multiplanar reconstruction and 3D imaging.

Answer 25

Volumetric, Advantages

Question 26

Ideal for angiography, perfusion, cardiac CT, trauma scans.

Answer 26

Volumetric, Advantages

Question 27

Eliminates misregistration between slices.

Answer 27

Volumetric, Advantages

Question 28

Relies on interpolation, which may cause helical artifacts (windmill, z-axis blurring).

Answer 28

Volumetric, Limitations

Question 29

Higher radiation dose possible if pitch and tube current not optimized.

Answer 29

Volumetric, Limitations

Question 30

Motion during scan affects the entire volume, not just one slice.

Answer 30

Volumetric, Limitations