Question 1

When viewing an axial CT image of the spine:&#10;A) The spinous process points down and the patient's left side is to the left on the image&#10;B) The spinous process points down and the patient's right side is to the left on the image&#10;C) The spinous process points up and the patient's left side is to the left on the image&#10;D) There are no fixed conventions for viewing these images

Accepted Answer

In axial CT images of the spine, the convention is that the patient's right side appears on the left side of the image, and the spinous process points downwards. This orientation is consistent with the radiological convention of viewing images as if facing the patient, with the patient lying on their back (supine).

Question 2

&#10;&#10;-Refer to the figure. What imaging method is displayed in this axial scan of the lower thoracic spine?&#10;A) CT, soft tissue window&#10;B) CT myelogram&#10;C) CT, bone window&#10;D) 3D CT

Accepted Answer

The image is a CT scan set to a bone window, which is evident from the high contrast between bone and soft tissues, allowing for detailed visualization of the bony structures.

Question 3

&#10;&#10;-In CT scans, which improves spatial resolution (visible details in the image)?&#10;A) Small matrix size&#10;B) Thick slices&#10;C) Small field of view&#10;D) Low bone density

Accepted Answer

A smaller field of view (FOV) concentrates the scan data into a smaller area, effectively increasing the detail visible in the image, thus improving spatial resolution.

Question 4

&#10;&#10;-In CT images:&#10;A) Cortical bone appears dark&#10;B) Fat appears light gray&#10;C) Dense structures appear white&#10;D) Muscles have a lighter shade than do tendons

Accepted Answer

Dense structures, such as bone, appear white on CT images because they absorb more X-rays compared to softer tissues.

Question 5

&#10;&#10;-Windowing (typically expressed in terms of Hounsfield units) refers to the:&#10;A) Size of the field of view in the images&#10;B) Pixel density displayed in the images&#10;C) Range of radiodensities displayed in an image&#10;D) Collimation used when producing the images

Accepted Answer

Windowing in the context of medical imaging, particularly in computed tomography (CT), refers to the process of adjusting the range of radiodensities (measured in Hounsfield units) that are displayed in an image. This allows for the visualization of different tissues and structures by enhancing the contrast between areas with similar densities.

Question 6

&#10;&#10;-Cone beam CT has which characteristic?&#10;A) It constructs images from a large number of slices&#10;B) It has longer scanning times but greater image detail&#10;C) It is associated with less radiation exposure&#10;D) It has less spatial resolution than conventional scanners

Accepted Answer

Cone beam CT is known for its lower radiation exposure compared to conventional CT scanners, making it a preferred choice in certain applications such as dental imaging and orthopedics.

Question 7

&#10;&#10;-What is true of resolution in CT images?&#10;A) Contrast resolution distinguishes between tissues that have very different radiodensities&#10;B) Spatial resolution improves with larger matrix size&#10;C) Higher contrast resolution always improves the image quality&#10;D) Spatial resolution improves the larger the field of view

Accepted Answer

Spatial resolution in CT images improves with a larger matrix size because it increases the number of pixels in the image, allowing for finer detail to be resolved.

Question 8

&#10;&#10;-Musculoskeletal CT scanning is typically done with:&#10;A) A slice thickness of 0.5 mm or less&#10;B) Contrast-enhanced CT&#10;C) Slices of less than 3 mm&#10;D) Comparison with MRI

Accepted Answer

Musculoskeletal CT scans are typically done with slice thicknesses of less than 3 mm to provide detailed images of bone and soft tissue structures.

Question 9

&#10;&#10;-The main advantages of CT lie in:&#10;A) Displaying fine detail of cortical bone&#10;B) Its ability to differentiate between malignant and benign tumors&#10;C) Showing the histological makeup of tissues&#10;D) Low radiation

Accepted Answer

CT scans are particularly good at imaging and displaying fine details of cortical bone, which is one of their main advantages. They use X-rays to create detailed images, allowing for the visualization of bone structures with high clarity. Choices B and C are not specific advantages of CT; while CT can help in assessing tumors and tissues, it does not directly show histological makeup or definitively differentiate between malignant and benign tumors without further analysis or additional imaging modalities. Choice D is incorrect because CT scans typically involve a higher dose of radiation compared to conventional X-ray imaging.

Question 10

&#10;&#10;-Refer to the figure. In this image, the arrow points to:&#10;A) Muscle&#10;B) Tendon&#10;C) Entrapped air&#10;D) Intermuscular fat plane

Accepted Answer

The arrow is pointing to an intermuscular fat plane, which is a layer of fat between muscles, often visible in imaging as a distinct line or plane.

Deck 4: Computed Tomography