During CT exams of the chest and abdomen, the highly radiosensitive breast tissue can be protected with minimal image artifact with the use of specialized shielding composed of:
The use of water as an oral contrast material for CT of the abdomen and/or pelvis has several potential advantages, including:
1. increased palatability and improved patient comfort
2. better demonstration of enhancing bowel wall
3. no interference with 3D application
A. 1, 2, and 3
If all other technical factors remain constant, which of the following would serve to decrease patient radiation dose during a helical exam?
D. increased pitch
A patients blood pressure is measured as 140/70 mm Hg. The number 140 represents:
A. the pressure within the arterial vessels during contraction of the heart
A(n) ______ contrast material may be described as one that does not dissociate into charged particles in solution.
Which of the following radiation dose indices is a measure of the total radiation exposure for an entire series of CT images?
B. dose length product (DLP)
Proper immobilization during a CT procedure a CT procedure may involve the use of:
1. soft, hook-and-loop (velco) immobilization straps
2. adhesive medical tape
3. good patient communication
A. 1 and 3 only
The normal range of glomerular filtration rate (GFR) for men is:
B. 70 _+ 14mL/min/m2
Effective dose is a relative radiation dose measurement term that accounts for the:
C. tissue radiosensitivity
Risk factors for contrast-induced nephrotoxicity (CIN) include:
2. advanced age
B. 1 and 2 only
The reduction in number of infectious organisms without a complex elimination is termed.
A. medical asepsis
Which of the following is the preferred range for [atient heart rate for optimal cardiac CT studies?
D. 65-75 bpm
Late effects of radiation, such as genetic mutations, may occur with even small doses of radiation and are termed:
Uriticaria is which of the following:
Which of the following type(s) of oral contrast material could cause peritonitis if leakage from the digestive tract occurs from perforation?
B. barium sulfate
Which of the following is not an advantage of an automatic power injector over the manuel bolus method of IV contrast agent administration?
B. decreased risk of contrast induced nephrotoxicity
Which of the following is/are severe adverse reaction(s) to iodinated IV contrast media?
C. 1 only
Which of the following laboratory values is the most dependable measure of renal failure?
Which of the following angiocatheter sizes may be safely used for the automated power injection of iodinated contrast agents at flow rates higher than 3 mL/sec?
1. 18 gauge
2. 20 gauge
3. 22 gauge
A. 1 and 2 only
Which of the following portions of the electrocardiogram (ECG) corresponds to the period of atrial systole?
D. P wave
Which of the following statements is true regarding the relationship between multiple scan average dose (MSAD) and image spacing during axial (step-and-shoot) scanning?
D. MSAD increases with overlapping scans
Which of the following terms is used to describe the IV injection of medication or contrast agent in one compete dose over a short time?
Used in determining the biologic effect of iodinated contrast media, the term ____ refers to the number of ions formed when a substance dissociated in solution.
The dosimetry index used to approximate the radiation dose for CT sections acquired during a helical scan is called the:
D. CTDI vol
The injection rate of an automatic injector is set at 1.5mL/sec. What is the injection time for a contrast agent volume of 150mL?
D. 100 seconds
150ml of contrast divided by 1.5mL/sec = 100 seconds
Which of the following must be included when one is obtaining informed consent for an invasive procedure?
1. explanation of the exam technique
2. the possible risks and benefits of the exam
3. alternatives to the procedure involved
A. 1, 2, and 3
Which of the following techniques may be employed to reduce patient radiation dose during a cardiac CT exam?
C. prospective ECG gating
Which of the following may be considered a low osmolar contrast medium?
1. iothalamte meglumine
2. diatrizoate sodium
D. 3 only
Following the intrathecal injection of an iodinated contast agent for a post-myelography CT study of the lumbar spine, the patient should be instructed to:
B. rest for 8-24 hours with the head slightly elevated
Compared with single slice CT (SSCT), patient radiation dose during a multidetector CT study may be higher because of:
1. use of a cone beam of radiation
2. acquisition at thinner sections widths
3. higher powered x-ray tubes
B. 1 and 2 only
Which of the following pharmaceuticals ma be administered prior to a cardiac CT procedure in an effort to improve visualization of the coronary vessels?
A. 1 and 2 only
A _____ is a benign, highly vascular mass commonly found in the liver.
Which of the following is the preferred contrast enhancement phase for CT acquision of the spleen?
B. portal venous phase
Which of the following terms describes the appearance of an acute subdural hematoma on a CT image of the brain?
The angiographic assessment known as a "CT run-off" evaluates the peripheral arterial tree from the renal arteries through the:
A. distal lower extremity
During a PET-CT exam, the amount of FDG uptake in an anatomic region is directly proportional to the areas:
A. metabolic acitivity
Accurate demonstration of _____ would most likely require the IV injection of an iodinated contrast agent during a CT study of the chest.
B. a dissection aortic aneurysm
Vascular components of the brains blood supply known as the Circle of Willis include the:
1. internal carotid arteries
2. basilar artery
3. anterior communication artery
B. 1 and 3 only
The benign mass of the eighth cranial nerce known as a vestibule schwannoma may be also termed a(n):
D. acoustic neuroma
The thick, layered portion of the peritoneum responsible for attaching portions of the intestines to the bowel wall is called the:
After initiation of rapid bolus administration of an iodinated contrast agent, the nephrographic phase of renal contrast enhancement occurs at approximately:
D. 70-90 seconds
Retrospective ECG gating utilizes which of the following portions of the cardiac cycle for image reconstruction?
1. atrial systole
2. ventricular systole
3. cardiac diastole
D. 3 only
Which of the following is a common complication of CT-guided biopsy of the lung?
An enema is indicated prior to a CT exam of the pelvis to administer positive contrast material into the large bowel. Which of the following dosages would be sufficient to opacify the rectosigmoid region?
B. 150-250 mL
A CT exam of the lumbar spine reveals a herniated disc at the level of L2-L3. Which of the following reformation planes would best demonstrate posterior compression of the disc material onto the spinal cord?
A common formula used to calculate the maximum dosage of IV iodinated contrast material used in any CT exam is:
B. 2mL per kg of body weight
Which of the following MDCT exams may include endobrachial views?
D. virtual bronchoscopy
The stanford type A dissection aneurysm affects which portion of the aorta?
a. ascending thoracic
d. descending thoracic
a. ascending thoracic
During the HRCT of the lungs, edematous changes in the posterior lungs may be differentiated by positioning of the patient in the ____ position.
The firm, outer portion of each intervertebral disc is called the:
B. anulus fibrosis
Which of the following refers to the surgical resection of the pancreas and duodenum for treatment of pancreatic carcinoma?
B. Whipple procedure
During which of the following IV contrast phases does the bladder wall enhance?
Coronary artery calcium (CAC) quantitation by MDCT exam is used primarily to assess:
D. atherosclerotic disease
A specialized CT exam involving the administration of an enteral contrast agent directly into the small bowel via nasogastric tube is called:
D. CT enteroclysis
The epithelial lining of the urinary tract is called the:
A common area for inflammation, the primary drainage opening within the sinus cavities is referred to as the:
A. ostiomeatal complex
During a CT exam of the chest, the administration of a saline flush following the bolus injection of iodinated IV contrast media helps alleviate artifact from dense contrast in the:
C. superor vena cava
Delayed post-contrast acquisition of the lower extremities following a CTA of the pulmonary arteries is termed:
D. CT venography
The overall quality of MPR and volume-rendered 3D images for a carotid artery CTA may be improved by:
1. reducing the kVp for an increase in displayed vessel opacification and contrast
2. retrospective reconstruction with a 50% overlap in section increment
3. bolus-tracking software to maximize contrast enhancement
A. 1, 2, and 3
Which of the following is the most common sign of GI pathology on CT images?
A. wall thickening
Often evaluated during body CTA exam, the branches of the celiac axis are the:
1. left gastric artery
2. common hepatic artery
3. splenic artery
B. 1, 2, and 3
Vital components of a CT urogram (CT-IVP) protocol include:
1. administration of 1200 to 1500mL of a positive oral contast agent 90 minutes prior to exam
2. thin-section excretory phase of imaging of the entire urinary tract
3. volume-rendered 3D and maximum intensity projection (MIP) imaging of the urinary tract
B. 2 and 3 only
Arterial phase CT imaging of the liver is used to optimally demonstrate which of the following?
A. hepatocellular carcinoma (HCC)
Non-contrast CT of the urinary tract is a valuable tool in the investigation of:
D. urinary tract lithiasis
Which of the following techniques may be used to improve visualization of the vocal cords during a CT exam of the neck?
1. oral administration of thick barium paste
2. CT acquisition with the mouth open as widely as tolerable
3. scanning while the patient phonates the letter "e"
D. 3 only
Percutaneous drainage under CT guidance may be used for the aspiration of which of the following pathologic process?
C. abdominal abscess
The device contructed to house the x-ray tube and date acquisition system (DAS) for a CT scanner is called the:
Third generation CT scanners use which of the following scan geometries?
A quality control procedure determines that the low contrast resolution of a CT scanner is extremely poor. Likely causes are:
1. tube arcing
2. increased electronic noise
3. decreased tube current
C. 2 and 3 only
When one is viewing a maximum intensity projection (MIP) image, each pixel represents:
A. the maximum attenuation occuring within the voxel
A CT image is reconstructed using a 512 squared matix and a display field of view of 40cm. What is the linear dimension of each pixel?
Which of the following statements about collimation of the CT x-ray beam is FALSE?
C. increases in collimation increase the intensity of the primary beam
Which of the following terms may be used to describe the quantity of radiation emitted from the CT x-ray tube toward the patient?
B. photon fluence
Which of the following mathematical techniques is used exclusively for image reconstruction with helical CT scanners?
Which of the following is the most common type of noise found in the CT image?
A. quantum noise
PACS is connected with imaging modalities and other peripheral devices on a computerized communication system called a:
The major disadvantage of the back-projection method of image reconstruction is the appearance of the:
C. star artifact
The most evident method of reducing involuntary motion of a ct image is:
A. reduced scan times
Soft copies of CT images are stored on which of the following media:
1. hard drives
2. magnetic optical disk
3. laser film
A. 1 and 2 only
The process of displaying CT images in a different orientation from the one used in the original reconstruction process is called:
C. multiplanar reformation
The process of gray-scale mapping of the CT image may be referred to as:
In the formula used to calculate the linear attenuation coefficient, I=Ioe (with a little -ux, used like a squared number), the symbol Io identifies:
D. incident intensity
First generation CT scanners possess which of the following characteristics?
B. pencil thin x-ray beam
The intensity of the x-ray beam after it passed through an object to a detector is called the:
D. transmitted intensity
An accurate, modern CT scanner possesses a spatial resolution up to:
A. 25 lp/cm
A high-resolution comb is utilized by an MSCT detector array in an effort to reduce:
D. scatter radiation
The distance between the centers of two adjacent reconstructed images is termed the:
D. section interval
The maximum number of simultaneous sections an MSCT system can acquire per gantry rotation is controlled by the number of:
D. data channels
Matrix size describes which of the following?
A. number of pixels used to display the image
An ROI measurement with an average CT number of zero is:
The implementation of corrective actions to improve any identified performance inadequacies of the CT system is referred to as:
C. quality control
The major disadvantage of the fan- or cone-shaped x-ray beams used in modern CT units in comparison with the "pencil-thin" beams of older units is:
C. greater patient radiation dose
When choosing a scan field of view, the CT Tech is controlling the:
1. diameter of data acquisition
2. number of activated detectors within the array
3. correction of factors for the specfic area of anatomic interest
B. 1, 2, and 3
As the attenuation of a volume of tissue decreases, the transmitted intensity of a CT x-ray beam:
Which of the following parameters or factors is improved by the selection of a smaller x-ray tube filament?
A. spatial resolution
The geometric efficiency of a CT detector is influenced primarily by the:
B. amount of interspace material between detectors
Which of the following factors may affect the attenuation of an object during CT data acquisition?
An image that is reconstructed a second time with some change in technical factor is said to be:
The Feldkamp-Davis-Kress (FDK) algorithm may be applied to MSCT acquisition data to overcome image artifacts from:
B. beam divergence
MSCT systems are typically capable of differeniating adjacent objects with attenuation differences as small as:
C. 3 HU
The ability of an MSCT system to freeze motion and provide an image free of blurring is called:
C. temporal resolution
Ring artifacts on the CT image are associated with which of the following tube-detector geometries?
What is the maximum beam collimation for an MSCT system with 16 rows of 1.25mm detectors?
C. 20.0 mm
16 rows x 1.25mm= 20.0mm
The polyenergetic x-ray beam emitted from a CT x-ray tube is susceptible to artifacts due to the phenomenom known as:
A. beam hardening
In an MSCT System, which of the following technical parameters determines the reconstructed section width?
D. detector collimation
Daily air or water calibration of the CT system is performed to evaluate which of the following components of image quality?
The reduction in intensity of an x-ray beam as it interacts with matter is called:
Pixels whose average attenuation coefficients are less than the coefficient of water have which of the following types of CT number values?
Which of the following actions would serve to magnify the CT image on the display monitor?
D. decrease display field of view
The bit depth of a digital imaging system defines the number of information bits contained within each:
The technical factor(s) necessary for the acquistion of an isotropic data set is/are:
1. thin detector collimation
2. high mA setting
3. small DFOV
D. 1 and 3 only
In multislice CT (MSCT), the combined thicknesses of all of the sections simultaneously acquired with each gantry rotation are called the:
B. total collimation
MSCT systems typically employ which of the following types of detectors?
C. solid state scintillation
Which of the following technical adjustments may be employed to reduce step artifact in a multiplanar reformation of an image?
1. acquisition of an isotropic data set
2. overlapping section increment
3. increase in effective mA
A. 1 and 2 only
Which of the following is a manifestation of the partial volume artifact?
During volumetric CT acquisition, the slice sensitivity profile graphically represents the:
D. effective section width
An increase in the sampling rate during the CT data acquisition corresponds to an increase in: