Help
Options
Question
Modern CT scanners rely on _______ to process acquired data.
click to flip
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't know
Question
To assure fast scan times and immediate data processing, CT computers depend on:
Remaining cards (92)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
CT Registry
| Question | Answer |
|---|---|
| Modern CT scanners rely on _______ to process acquired data. | minicomputers |
| To assure fast scan times and immediate data processing, CT computers depend on: | parallel processing |
| Large array parallel processors are responsible for: | performing numerous tasks simultaneously |
| Backprojection is associated with: | artifacts |
| Which of the following processes is associated with reconstructing volumetric acquired data to make the data look like individual slices? (back projection, pitch, filtering, linear interpolation) | linear interpolation |
| The term "misregistration" refers to: | incorrect image reconstruction |
| Refers to the automatic removal of artifacts that occur in anatomy of various densities? | filtered backprojection |
| What does longitudinal interpolation with z-axis filtering calculate? | interslice distance |
| Filtered backprojection is most closely associated with: | artifact-free images |
| Interpolation is directly affected by: | pitch |
| The ability of the CT scanner to calculate image data from multiple, overlapping acquisition data sets is called _____ sampling. (a. interpretive b. interleaved c. interlaced) | interleaved or interlaced |
| True or False: Image reconstruction occurs only after a scan is completed. | True |
| Which of the following terms is most closely associated with image reconstruction immediately following a scan? (filtered backprojection, interleaved sampling, longitudinal interpolation, multiplanar postprocessing) | multiplanar postprocessing |
| True or False: One advantage of reformatting is that image detail is increased. | False |
| Which of the following is not a postprocessing technique? (image smoothing, maximum intensity projection (MIP), volume rendering, longitudinal interpolation) | longitudinal interpolation |
| Which of the following techniques requires 100% of the data set for postprocessing?(MIP, MinIP, volume rendering, shaded surface rendering) | volume rendering |
| Which type of postprocessing techniqe would most likely be used for CT virtual colonography exams? | minIP |
| What is the window level if the CT/HU range is 200 to 1000? | 600 |
| Which postprocessing techniques is referred to as 4D reconstruction? | volume rendering |
| True or False: Virtual reality (VR) and volume rendering imaging techniques are identical | False |
| When manipulating an image using the zoom tool, the resolution: (increases, decreases, stays the same) | decreases |
| Which of the following image manipulation tools is most useful for viewing 3D images? (swivel, pan, zoom, scroll) | swivel |
| Which of the following workstation applications would most likely be used by cardiologists?(a. ejection fraction, b. calcium scoring, c. stereotaxis) | ejection fraction & calcium scoring |
| Xenon studies are most closely associated with: | neurology studies |
| CT fluoroscopy is especially useful for: | biopsies |
| A precise set of steps to be performed in a specific order to solve a problem describes a/an: | algorithm |
| The process of converting the data from the attenuation profile to a matrix is known as: | back projection |
| What is interpolation? | A mathematical method of estimating an unknown value using the known values on either side of the unknown. |
| Which of the following acquisition FOV is typically used for head CT's? (250mm, 350mm, 450mm, 500mm) | 250 |
| Increasing the scan field of view: | increases the # of detector cells collecting data |
| The range of the CT numbers in the image that determines the maximum number of shades of gray is called the: | window width |
| When the detector reads each arriving ray and measures how much of the beam is attenuated defines which of the following? (WW, WL, Ray Sum, Hounsfield) | Ray Sum |
| Convolution | The process of applying a filter function or filtered back-projection to an attenuation profile |
| Kernal | a post-processing filter applied to image data |
| Usually images are post processed to: a. speed imaging time b. improve contrast resolution c. provide additional image analysis d. reduce the x-ray tube load | c. provide additional image analysis |
| Which of the following is the result of preprocessed scan data and are subjected to the image reconstruction algorithm used by a scanner? a. measurement data b. raw data c. convolved data d. image data | b. raw data |
| Which of the following mathematical reconstruction methods is used by most modern CT scanners? a. back-projection b. iterative methods c. fourier transform d. filtered back-projection | d. filtered back-projection |
| Which of the following mathematical techniques is used exclusively for image reconstruction with helical CT scanners? a. back-projection b. convolution c. interpolation d. iterative techniques | c. interpolation |
| In a_____ CT scanner, the x-ray tube rotates continuously around the patient as the patient travels through the gantry | helical/spiral |
| Compared with volume acquisition, axial acquisition results in: a. increased noise b. lower partial volume averaging c. better high-contrast resolution d. thinner slices | b. lower partial volume averaging |
| Compared with traditional single-slice axial scanners, helical/spiral scanners acquire images at ___ rate. a. a faster b. a slower c. the same | a. a faster |
| The Lambert-Beer Law is most closely associated with a ____ beam. a. polychromatic b. fanned c. homogeous d. heterogeneous | c. homogeneous |
| The data acquisition system (DAS) is located: a. between the detectors and the analog-to-digital converter b. between the detectors and the computer c. between the detectors and the digital-to-analog converter d. in the gantry | b. between the detectors and the computer |
| Which of the following includes a sampler, quantizer, and a coder? a. DAC b. ADC c. DAS d. detector array | b. ADC |
| A digital-to-analog converter is needed to: a. change the remnant beam to an electric signal b. transform the electric signal to light c. display data on a LCD monitor d. encode transmitted radiation into binary data | c. display data on a LCD monitor |
| True or False: A log amplifier calculates the amount of attenuation that occurs during data acquisition. | True |
| The detectors measure the transmitted x-ray beam. The beam that has been attenuated or changed after interacting with the tissues of the patient is called the ____ beam. a. primary b. incoming c. secondary d. dominant | c. secondary |
| Which operation forms the basis for CT reconstruction? a. Lambert-Beer Law b. Fourier transform c. convolution d. filtered back-projection | b. Fourier transform |
| What does the Fourier transform calculate? | attenuation-to-detector time |
| Linear attenuation coefficients are directly related to: a. helical scanners only b. axial scanners only c. attenuation d. patient dose | c. attenuation |
| Which of the following artifacts is a result of faulty detector elements: a. partial volume averaging b. ring artifacts c. aliasing artifacts d. streaking | b. ring artifacts |
| Which of the following is a filtering technique in which the reformatted raw data are copied to create what looks like the original raw data set? a. convolution b. kernal c. MPR d. sectional reformatting | a. convolution |
| Which of the following terms is also referred to as a convolution algorithm? a. kernal b. interpolation c. ring artifact d. iterative algorithm | a. kernal |
| Which of the following is not an example of a kernal? a. edge enhancement filter b. smoothing filter c. standard convolution algorithm d. interative algorithm | d. interative algorithm |
| A smoothing filter is applied to scans that display very: a. high contrast b. high brightness c. low brightness d. low contrast | d. low contrast |
| Overlap occurs when the pitch is less than: | 1.0 |
| Dose modulation is most closely related to which of the following terms? (choose all that apply) 1. automatic mA 2. convolution 3. automatic exposure control | 1 & 3 |
| Increased pitch results in: a. increased spatial resolution b. increased partial volume averaging c. increased image contrast d. ring artifacts | b. increased partial volume averaging |
| Auto milliamperage is generally used during the acquisition of: a. a topogram b. a region of interest c. a standard convolution algorithm d. interative data | a. topogram |
| Which of the following is another name for Hounsfield units? a. pixel values b. CT numbers c. beam attenuation numbers d. all of these | d. all of these |
| What hounsfield values are in the naturally occurring range? | -1000 to 1000 |
| Which of the following is the term that refers to the systematic collection of information from the patient to produce the CT image? a. back projection b. data acquisition c. radiation attenuation d. HU | b. data acquisition |
| Attenuation depends on which of the following: a. electrons per gram b. atomic number c. tissue density d. all of these | d. all of these |
| What is the HU for water? | 0 |
| The data acquisition system of a CT scanner: (choose all that apply) 1. measures transmitted intensity 2. converts transmission data into a digital signal 3. sends the digital information to the CPU | 1, 2 &3 |
| The component of the CT scanner responsible for the mathematical calculations of the image reconstruction process is the: a. DAS b. ADC c. DAC d. Array processor | d. array processor |
| Which of the following parts of the scapula is located most superiorly? a. glenoid process b. coracoid process c. acromion process d. coronoid process | c. acromion process |
| True/False: The coracoid process projects anteriorly from the scapula and does not articulate with any other bones. | True |
| The bronchus intermedius is found on the right or left side and divides to give rise to both the middle and lower lobe bronchi? | Right |
| Which of the following chambers of the heart are located most posteriorly? (right atrium, right ventricle, left atrium, left ventricle) | left atrium |
| Which of the following receive air through the bronchus intermedius? (right upper & middle lobes, right middle & lower lobes, left upper & middle lobes, left middle & lower lobes) | right middle and lower lobes |
| True/False: The transverse colon is always found within the upper abdominal cavity | False |
| Which lobe of the liver is largest? | Right |
| The gallbladder is found on the visceral surface of the liver near the anterior or posterior abdominal wall? | anterior |
| True or False: The common bile duct lies anterior to the duodenum | False |
| Which of the following is not true of the pancreas? a. surrounded by mesentery b. has exocrine functions c. has endocrine functions d. all of the above are true | a. surrounded by mesentery |
| The symphysis pubis is classified as what type of joint? | amphiarthrodial |
| The most inferior part of the pelvis is formed by the | ischium |
| The obturator foramen is formed by which bones? | pubis and ischium |
| The sigmoid colon begins at what level | pelvic brim |
| The sigmoid colon ends at what level? | S3 |
| Which of the following is true of the prostate? a. is a fatty gland b. produces sperm c. has high concentrations of smooth muscle and connective tissue d. lies below the pelvic diaphragm | c. |
| Which of the following extends through the pelvic diaphragm? (rectum, urethra, vagina, or all of them) | all |
| Which of the following is not within the broad ligament? (ovaries, oviducts, round ligatment, all are within) | all are within the broad ligament |
| Which of the following best describes the position of the oviduct within the broad ligament? a. within the upper margin b. within the mid-region c. within the lower margin d. not within the broad ligament | within the upper margin |
| The internal iliac veins originate from which of the following? (femoral veins, lower abdominal veins, anterior part of the pelvis, gluteal veins) | gluteal veins |
| Which of the following is located nearest the third ventricle? a. thalamus, b. caudate, c. globus pallidus, d. putamen | thalamus |
| What is the function of the thalamus? | Directs sensory impulses to the cerebral cortex |
| Which of the following is not considered part of the midbrain? a. substantia nigra, b. quadrigeminal plate, c. cerebral peduncles, d. mammillary bodies | d. mammillary bodies |
| The substantia nigra has fibers connecting with all of the following except: a. hypothalamus, b. cerebral cortex, c. basal nuclei, d. all | d. all of these have connection with substantia nigra |
| The nucleus that follows the curve of the lateral ventricle and is involved in muscle control is the: | caudate |
| The internal capsule of the brain separates what? | basal ganglia and thalamus |
| The external capsule of the brain separates what? | putamen and claustrum |
Created by:
AngieJ313