CT Registry Review Test: Hardest Trivia Quiz!
A CT scan(computed tomography) is a scanning process through which you get computer-processed X-ray. Medical imaging is the standard application of X-ray CT used for diagnostic and therapeutic purposes. Take this quiz to test your knowledge of different methods and system used in the CT Scan. Attempt all the questions, and try your best. Let's take the exam. All the best!
- 1.
An average range for activated PTT is:
- A.
10-12 seconds
- B.
17-21 seconds
- C.
25-35 seconds
- D.
43-55 seconds
Correct Answer
C. 25-35 secondsExplanation
The average range for activated PTT is 25-35 seconds. This means that when the PTT (Partial Thromboplastin Time) test is performed, the normal range for the time it takes for blood to clot is between 25 and 35 seconds. If the result falls within this range, it indicates that the clotting process is functioning properly.Rate this question:
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- 2.
The drug SOLU-CORTEF may be classified by which of the following?
- A.
Anticholinergic
- B.
Bronchodilator
- C.
Antihistamine
- D.
Corticosteroid
Correct Answer
D. CorticosteroidExplanation
SOLU-CORTEF is classified as a corticosteroid. Corticosteroids are a class of drugs that mimic the effects of hormones produced by the adrenal glands. They have anti-inflammatory and immunosuppressive properties, making them useful in treating a variety of conditions such as allergies, asthma, and autoimmune disorders. SOLU-CORTEF, specifically, is a brand name for hydrocortisone sodium succinate, which is commonly used as an injectable corticosteroid for emergency situations such as anaphylaxis or adrenal crisis.Rate this question:
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- 3.
Which of the following is considered on of the isomolar contrast media (IOCM)?
- A.
Iodixanol
- B.
Iopamidol
- C.
Iohexol
- D.
Ioversol
Correct Answer
A. IodixanolExplanation
Iodixanol (Visipaque) is an example of a non-ionic isomolar contrast agent. Iohexol (omnipaque), iopamidol
(Isovue), and ioversol (Optiray) are all non-ionic low-osmolar contrast media (LOCM)Rate this question:
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- 4.
Advantages of a saline flush immediately following IV administration of iodinated contrast material include: 1.reduction in required contrast agent dose. 2.reduction in the incidence of contrast-induced nephrotoxicity (CIN). 3.recuction of streaking artifact from dense contrast agent in the vasculature.
- A.
1 only
- B.
3 only
- C.
2 and 3 only
- D.
1,2 and 3
Correct Answer
D. 1,2 and 3Explanation
A saline flush immediately following IV administration of iodinated contrast material has several advantages. Firstly, it can help reduce the required contrast agent dose, which can be beneficial in patients who may be at risk for adverse reactions or have limited renal function. Secondly, it can reduce the incidence of contrast-induced nephrotoxicity (CIN), a potential complication of contrast administration that can cause kidney damage. Lastly, it can help reduce streaking artifact from dense contrast agent in the vasculature, which can improve the quality of imaging studies. Therefore, all three options (1, 2, and 3) are correct.Rate this question:
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- 5.
Which of the following medications may be administered to dilate the coronary vasculature prior to a cardiac CT examination?
- A.
Sublingual nitroglycerine
- B.
A B-adrenergic receptor blocking agent (B-Blocker)
- C.
Atropine
- D.
Albuterol
Correct Answer
A. Sublingual nitroglycerineExplanation
Sublingual nitroglycerine may be administered to dilate the coronary vasculature prior to a cardiac CT examination. Nitroglycerine is a vasodilator that works by relaxing and widening the blood vessels, including the coronary arteries. This helps to improve blood flow to the heart and can be beneficial before a cardiac CT examination to enhance the visualization of the coronary arteries.Rate this question:
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- 6.
Which of the following is a parenteral route of medication administration?
- A.
Sublingual
- B.
Intramuscular
- C.
Transdermal
- D.
Oral
Correct Answer
B. IntramuscularExplanation
Parenteral administration involves the injection of medication into the body. Common routes of parental medication administration include intramuscular, intravenous, intradermal, and subcutaneous.Rate this question:
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- 7.
Which of the following methods may be employed to reduce the radiation dose to the pediatric patient undergoing CT? 1. reduce mA. 2.limit phases of acquisition. 3.increase pitch.
- A.
1 only
- B.
1 and 2 only
- C.
1 and 3 only
- D.
1,2 and 3
Correct Answer
D. 1,2 and 3Explanation
To reduce the radiation dose to a pediatric patient undergoing CT, three methods can be employed. First, reducing mA (milliamperage) helps to lower the radiation dose. Second, limiting phases of acquisition means reducing the number of scans or images taken, which also decreases the overall radiation exposure. Third, increasing pitch refers to the speed at which the patient table moves through the CT scanner. A higher pitch means the patient spends less time in the scanner, resulting in a lower radiation dose. Therefore, options 1, 2, and 3 are all valid methods to reduce the radiation dose in pediatric CT scans.Rate this question:
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- 8.
Which of the following types of isolation techniques protects against infection transmitted through fecal material?
- A.
Acid-fast bacillus isolation
- B.
Contact isolation
- C.
Enteric precautions
- D.
Drainage-secretion precautions
Correct Answer
C. Enteric precautionsExplanation
usually gown and gloves which is enteric precautions.Rate this question:
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- 9.
Which of the following is considered one of the ionic radiopaque contrast media (RCM)?
- A.
Iohexol
- B.
Iothalamate meglumine
- C.
Iopamidol
- D.
Ioversol
Correct Answer
B. Iothalamate meglumineExplanation
Ionic contrast media are salts consisting of sodium and/or meglumine.Rate this question:
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- 10.
The radiation dose index calculation that takes into account the variations in absorption across the field of view due to beam hardening is termed:
- A.
CTDIw
- B.
CTDI100
- C.
CTDIvol
- D.
MSAD
Correct Answer
C. CTDIvolExplanation
CTDIvol is the correct answer because it stands for Computed Tomography Dose Index Volume. It is a radiation dose index calculation that takes into account the variations in absorption across the field of view due to beam hardening. This index is used to estimate the radiation dose delivered to the patient during a CT scan, considering the volume of tissue being exposed. CTDIvol provides a more accurate representation of the radiation dose compared to other dose index calculations like CTDIw or CTDI100, which do not consider the variations in absorption. MSAD is not related to beam hardening or dose index calculations.Rate this question:
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- 11.
Which of the following units is used to express the total patient dose from a helically acquired CT examination?
- A.
Roentgens (R)
- B.
Curies (Ci)
- C.
R-cm (roentgens per centimeter)
- D.
MGy-cm (milligrays per centimeter)
Correct Answer
D. MGy-cm (milligrays per centimeter)Explanation
The Dose Length Product (DLP) is expressed in units of milligrays per centimeter (mGy-cm).Rate this question:
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- 12.
Components of a comprehensive CT stroke management protocol typically include: 1.pre-contrast sequence of the brain. 2.CTA of the brain and carotids. 3.CT perfusion (CTP) of the brain.
- A.
2 only
- B.
1 and 2 only
- C.
2 and 3 only
- D.
1,2 and 3
Correct Answer
D. 1,2 and 3Explanation
A comprehensive CT stroke management protocol typically includes a pre-contrast sequence of the brain, CTA of the brain and carotids, and CT perfusion (CTP) of the brain. These components are important for a thorough evaluation of the stroke, as they provide information about the location and extent of the stroke, as well as the blood flow in the brain. By combining these different imaging techniques, healthcare professionals can make more accurate diagnoses and determine the most appropriate treatment options for the patient.Rate this question:
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- 13.
Use Fig 5-1 Number 1 on the figure corresponds to which of the following?
- A.
Left pulmonary artery
- B.
Ascending aorta
- C.
Inferior vena cava
- D.
Descending aorta
Correct Answer
A. Left pulmonary arteryExplanation
Figure 5-1 is being referenced to answer this question. Number 1 on the figure corresponds to the left pulmonary artery.Rate this question:
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- 14.
Use Fig 5-1 Which number on the figure corresponds to the superior vena cava?
- A.
2
- B.
3
- C.
4
- D.
5
Correct Answer
C. 4Explanation
Based on the given information, the superior vena cava can be identified as number 4 on the figure.Rate this question:
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- 15.
Use Fig 5-2 Number 2 on the figure corresponds to which of the following?
- A.
Left internal jugular vein
- B.
Left external carotid artery
- C.
Left internal carotid
- D.
Left external jugular vein
Correct Answer
C. Left internal carotidExplanation
Based on Fig 5-2, number 2 corresponds to the left internal carotid.Rate this question:
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- 16.
Use Fig 5-2 Number 5 on the figure corresponds to which of the following?
- A.
Right internal jugular vein
- B.
Right external carotid artery
- C.
Right internal carotid artery
- D.
Right external jugular vein
Correct Answer
A. Right internal jugular veinExplanation
Based on the given information, number 5 on Fig 5-2 corresponds to the right internal jugular vein.Rate this question:
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- 17.
Use Fig 5-2 Number 1 on the figure corresponds to which of the following?
- A.
Vocal cords
- B.
Uvula
- C.
Aryepiglottic fold
- D.
Epiglottis
Correct Answer
D. EpiglottisExplanation
Number 1 on the figure corresponds to the epiglottis. The epiglottis is a flap of cartilage located at the base of the tongue, and its main function is to prevent food and liquid from entering the trachea during swallowing. It covers the opening of the larynx, ensuring that food and liquid go down the esophagus and into the stomach instead of the airway.Rate this question:
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- 18.
The abdominal aorta bifurcates at the level of:
- A.
T10
- B.
T12
- C.
L2
- D.
L4
Correct Answer
D. L4Explanation
The correct answer is L4. The abdominal aorta is the largest artery in the abdominal cavity and it bifurcates, or splits into two branches, at the level of the fourth lumbar vertebra (L4). This split forms the two common iliac arteries, which further divide into the internal and external iliac arteries. The bifurcation at L4 is an important landmark in the abdominal anatomy and is commonly used as a reference point for various medical procedures and assessments.Rate this question:
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- 19.
On an ECG of the complete cardiac cycle, at which portion of the R-R interval is the heart muscle in diastole?
- A.
10-20%
- B.
35-50%
- C.
55-75%
- D.
85-95%
Correct Answer
C. 55-75%Explanation
During the cardiac cycle, the heart goes through systole (contraction) and diastole (relaxation) phases. The R-R interval represents the time between two consecutive ventricular contractions. In this case, the heart muscle is in diastole (relaxation) during the 55-75% portion of the R-R interval. This means that the heart is not actively contracting during this time and is instead filling with blood in preparation for the next contraction.Rate this question:
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- 20.
The still viable ischemic cerebral tissue that surrounds the infarct core in a patient with an acute stroke is termed the:
- A.
Thrombolytic zone
- B.
Hemorrhage focus
- C.
Ischemic penumbra
- D.
Stroke volume
Correct Answer
C. Ischemic penumbraExplanation
The still viable ischemic cerebral tissue that surrounds the infarct core in a patient with an acute stroke is termed the ischemic penumbra. This refers to the area of the brain that is at risk of further damage due to inadequate blood supply but is still potentially salvageable if blood flow is restored in a timely manner. The term "ischemic penumbra" is used to describe this region of reversible ischemic injury in stroke patients.Rate this question:
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- 21.
Which of the following technical maneuvers may be used to remove unwanted pulsation artifacts from cardiac motion during a CTA of the chest for pulmonary embolism?
- A.
Automated bolus tracking
- B.
Automatic tube current modulation
- C.
Retrospective ECG gating
- D.
Saline flush
Correct Answer
C. Retrospective ECG gatingExplanation
Retrospective ECG gating is a technical maneuver that can be used to remove unwanted pulsation artifacts from cardiac motion during a CTA of the chest for pulmonary embolism. This technique involves acquiring images of the heart at different phases of the cardiac cycle and then reconstructing a motion-free image by selecting the best data from each phase. By synchronizing the image acquisition with the ECG signal, retrospective ECG gating ensures that the images are acquired at the same point in the cardiac cycle, minimizing motion artifacts caused by pulsation. This technique improves the diagnostic accuracy of the CTA by providing clearer images of the pulmonary arteries.Rate this question:
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- 22.
Diffuse fatty infiltration of the hepatic parenchyma may be referred to as:
- A.
Chromatosis
- B.
Steatosis
- C.
Cirrhosis
- D.
Lipomatosis
Correct Answer
B. SteatosisExplanation
Steatosis refers to the diffuse fatty infiltration of the liver parenchyma. This condition is characterized by the accumulation of fat within the liver cells, which can lead to liver dysfunction and inflammation. Steatosis is commonly associated with obesity, diabetes, alcohol abuse, and certain medications. It can be reversible if the underlying cause is addressed, but if left untreated, it can progress to more severe liver diseases such as cirrhosis. Lipomatosis refers to the presence of multiple lipomas, while chromatosis is not a recognized medical term for liver conditions.Rate this question:
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- 23.
Use Fig 5-4 Which of the following corresponds to the low-attenuation area indicated by Number 3 on the figure?
- A.
Renal cortex
- B.
Renal pelvis
- C.
Renal calyx
- D.
Renal pyramid
Correct Answer
D. Renal pyramidExplanation
The low-attenuation area indicated by Number 3 on the figure corresponds to the renal pyramid.Rate this question:
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- 24.
Use Fig 5-4 Number 2 on the figure corresponds to which of the following?
- A.
Hepatic vein
- B.
Suprarenal lymph node
- C.
Adrenal gland
- D.
Common bile duct
Correct Answer
C. Adrenal glandExplanation
Figure 5-4 shows a diagram or image that is not provided in the given context. Without the figure, it is not possible to determine the specific location or number 2 on the figure. Therefore, an explanation cannot be provided.Rate this question:
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- 25.
Use Fig 5-5 Number 4 corresponds to which of the following?
- A.
External auditory meatus
- B.
Internal auditory canal
- C.
Vestibule
- D.
Carotid canal
Correct Answer
D. Carotid canalExplanation
The correct answer is carotid canal because in Figure 5-5, number 4 is labeled as the carotid canal.Rate this question:
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- 26.
Use Fig 5-5 Number 3 on the figure corresponds to which of the following?
- A.
Vestibule
- B.
Semicircular canal
- C.
Cochlea
- D.
Incus
Correct Answer
A. VestibuleExplanation
Number 3 on Fig 5-5 corresponds to the vestibule.Rate this question:
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- 27.
Use Fig 5-6 The pathologic process indicated by number 3 on the figure most likely corresponds to:
- A.
Atelectasis
- B.
Lymphadenopathy
- C.
Pleural effusion
- D.
Ground-glass opacity
Correct Answer
D. Ground-glass opacityExplanation
The pathologic process indicated by number 3 on the figure most likely corresponds to ground-glass opacity.Rate this question:
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- 28.
Use Fig 5-6 Number 2 on the figure corresponds to which of the following?
- A.
Right atrium
- B.
Pulmonary trunk
- C.
Ascending aorta
- D.
Right ventricle
Correct Answer
C. Ascending aortaExplanation
Number 2 on the figure corresponds to the ascending aorta.Rate this question:
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- 29.
This HRCT image of the chest was most likely acquired with a section width of:
- A.
1mm
- B.
5mm
- C.
7mm
- D.
10mm
Correct Answer
A. 1mmExplanation
The HRCT image of the chest was most likely acquired with a section width of 1mm because a thinner section width allows for higher resolution and better visualization of small structures in the chest. This is particularly important in HRCT imaging, which is used to evaluate lung diseases such as interstitial lung disease, lung nodules, and pulmonary embolism. A section width of 1mm provides more detailed and accurate images, helping in the detection and characterization of these conditions.Rate this question:
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- 30.
Use Fig 5-6 Number 2 on the figure corresponds to which of the following?
- A.
Left mainstem bronchus
- B.
Anterior segment of left upper lobe bronchus
- C.
Posterior segment of left upper lobe bronchus
- D.
Anterior segment of left lower lobe bronchus
Correct Answer
B. Anterior segment of left upper lobe bronchus -
- 31.
The pituitary gland is best demonstrated during CT in which of the following imaging planes?
- A.
Axial
- B.
Coronal
- C.
Sagittal
- D.
Transaxial
Correct Answer
B. CoronalExplanation
The pituitary gland is best demonstrated during CT in the coronal imaging plane. This is because the coronal plane allows for a clear visualization of the pituitary gland, which is located at the base of the brain. The coronal plane provides a view from the front to the back of the body, making it ideal for assessing the pituitary gland's position and any abnormalities. The axial plane would provide a view from top to bottom, the sagittal plane would provide a view from side to side, and transaxial is not a recognized imaging plane.Rate this question:
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- 32.
Use Fig 5-7 Number 8 on the figure corresponds to which of the following?
- A.
Duodenum
- B.
Descending colon
- C.
Jejunum
- D.
Ascending colon
Correct Answer
D. Ascending colonExplanation
Based on the given information, it can be inferred that number 8 on Fig 5-7 corresponds to the ascending colon.Rate this question:
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- 33.
The adult spinal cord ends at what vertebral level?
- A.
T11-T12
- B.
L1-L2
- C.
L3-L4
- D.
Superior portion of the coccyx
Correct Answer
B. L1-L2Explanation
The adult spinal cord ends at the vertebral level of L1-L2. This is because the spinal cord extends from the base of the skull to the upper part of the lumbar spine. The spinal cord itself terminates around the level of the first lumbar vertebra (L1) or the second lumbar vertebra (L2). Below this level, the spinal canal continues as the cauda equina, a bundle of nerves that extends down to the lower back.Rate this question:
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- 34.
Which of the following terms is used to describe a fibroid tumor of the uterus?
- A.
Leiomyoma
- B.
Cystic teratoma
- C.
Endometriosis
- D.
Corpus luteum
Correct Answer
A. LeiomyomaExplanation
A fibroid tumor of the uterus is commonly referred to as a leiomyoma. Leiomyoma is a benign tumor that arises from the smooth muscle cells of the uterus. It is the most common type of tumor found in the female reproductive system. Fibroids can vary in size and may cause symptoms such as heavy menstrual bleeding, pelvic pain, and pressure on nearby organs. Treatment options for leiomyoma include medication, minimally invasive procedures, and surgery, depending on the severity of symptoms and desire for fertility preservation.Rate this question:
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- 35.
Use Fig 5-8 Number 1 on the figure corresponds to which of the following?
- A.
Sphenoid sinus
- B.
Ethmoid sinus
- C.
Frontal sinus
- D.
Maxillary sinus
Correct Answer
B. Ethmoid sinusExplanation
Based on the given information, number 1 on Fig 5-8 corresponds to the ethmoid sinus.Rate this question:
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- 36.
Which of the following anatomic organs is located within the peritoneal cavity?
- A.
Pancreas
- B.
Kidneys
- C.
Uterus
- D.
Liver
Correct Answer
D. LiverExplanation
The liver is located within the peritoneal cavity. The peritoneal cavity is a space in the abdomen that is lined by the peritoneum, a thin membrane. The liver is the largest solid organ in the body and is situated in the upper right quadrant of the abdomen. It is surrounded by the peritoneum, which helps to protect and support the liver. The liver plays a vital role in various metabolic processes, including detoxification, protein synthesis, and bile production.Rate this question:
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- 37.
During a complete CT scan of the pelvis, sections should be obtained from the:
- A.
Iliac crests to the pubic symphysis
- B.
Kidneys through the bladder
- C.
Bottom of the kidneys to the pubic symphysis
- D.
Iliac crests to the lesser trochanter
Correct Answer
A. Iliac crests to the pubic sympHysisExplanation
During a complete CT scan of the pelvis, sections should be obtained from the iliac crests to the pubic symphysis. This is because the iliac crests are the highest point of the hip bones and the pubic symphysis is the joint between the two pubic bones. By including these landmarks in the scan, it ensures that the entire pelvis is captured in the imaging, providing a comprehensive view of the pelvic region.Rate this question:
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- 38.
Because of its inherent iodine concentration, the thyroid gland appears________on CT images.
- A.
Hypodense
- B.
Isodense
- C.
Hyperdense
- D.
Mottled
Correct Answer
C. HyperdenseExplanation
The correct answer is hyperdense. The thyroid gland appears hyperdense on CT images due to its inherent iodine concentration. This means that it appears brighter or denser compared to the surrounding tissues.Rate this question:
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- 39.
Air trapping within the trachea and bronchial tree may be optimally demonstrated with multiplanar volume reconstructions (MPVR's) of the thorax known as:
- A.
Maximum intensity projections (MIPs)
- B.
3D volume renderings
- C.
Shaded-surface displays (SSDs)
- D.
Minimum intensity projections (min-IPs)
Correct Answer
D. Minimum intensity projections (min-IPs)Explanation
Minimum intensity projections (min-IPs) are a type of multiplanar volume reconstruction (MPVR) technique used to demonstrate air trapping within the trachea and bronchial tree. In min-IPs, the minimum intensity value along each ray path is projected onto the image, resulting in a visualization of the areas with the lowest intensity, which in this case represents the trapped air. This technique allows for optimal visualization and identification of air trapping in the thorax.Rate this question:
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- 40.
The specialized CT examinations of the bladder in which an iodinated contrast agent is directly administrated under gravity into the bladder via Foley catheter is termed:
- A.
CT IVP
- B.
CT urogram
- C.
CT enteroclysis
- D.
CT cystography
Correct Answer
D. CT cystograpHyExplanation
CT cystography is the correct answer because it involves the administration of an iodinated contrast agent directly into the bladder via a Foley catheter. This procedure is used to visualize the bladder and detect any abnormalities or injuries. CT IVP (Intravenous Pyelogram) involves the injection of contrast dye into a vein to visualize the urinary system, CT urogram is a CT scan of the urinary tract, and CT enteroclysis is a CT scan of the small intestine.Rate this question:
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- 41.
Collimation of the CT x-ray beam occurs: 1.at the x-ray tube, regulating slice thickness. 2.just beyond the patient, focusing off-axis transmitted radiation. 3.before the detectors, limiting the amount of scatter radiation absorbed.
- A.
1 only
- B.
1 and 2 only
- C.
1 and 3 only
- D.
1,2 and 3
Correct Answer
C. 1 and 3 onlyExplanation
Collimation of the CT x-ray beam occurs at the x-ray tube, regulating slice thickness. This means that the x-ray beam is narrowed down to a specific size, controlling the thickness of each slice that is captured during the CT scan. Additionally, collimation occurs before the detectors, limiting the amount of scatter radiation absorbed. This helps to improve the image quality by reducing the amount of unwanted scattered radiation that can interfere with the clarity of the image. Therefore, the correct answer is 1 and 3 only.Rate this question:
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- 42.
The mathematical technique allowing the reconstruction of motion-free images from helically acquired CT data is called:
- A.
Convolution
- B.
Radon transformation
- C.
Interpolation
- D.
Fourier reconstruction
Correct Answer
C. InterpolationExplanation
Interpolation is the mathematical technique used to reconstruct motion-free images from helically acquired CT data. It involves estimating the values of data points within a given range based on the values of known data points. In the context of CT imaging, interpolation helps in filling in the missing data points caused by the helical acquisition process, resulting in a complete and accurate image reconstruction. Convolution, radon transformation, and Fourier reconstruction are not specifically related to the reconstruction of motion-free images from helically acquired CT data.Rate this question:
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- 43.
The full width at half maximum (FWHM) of a CT scanner is used to describe:
- A.
Spatial resolution
- B.
Contrast resolution
- C.
Noise
- D.
Calibration accuracy
Correct Answer
A. Spatial resolutionExplanation
The full width at half maximum (FWHM) of a CT scanner refers to the width of the peak of a spatial resolution curve where the intensity is at half of its maximum value. It is a measure of how well the scanner can distinguish between two closely spaced objects or details in an image. Therefore, the FWHM is used to describe the spatial resolution of a CT scanner, which is its ability to accurately represent the spatial details of an object or structure in the image.Rate this question:
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- 44.
Voxels with equal dimensions along the x,y, and z axes are referred to as:
- A.
Prospective
- B.
Isotropic
- C.
Retrospective
- D.
Anisotropic
Correct Answer
B. IsotropicExplanation
Voxels with equal dimensions along the x, y, and z axes are referred to as isotropic. Isotropic means that the voxel has uniform dimensions in all directions, resulting in equal resolution along each axis. This is important in medical imaging, as it allows for accurate and consistent measurements and comparisons of structures in three-dimensional space. Anisotropic voxels, on the other hand, have unequal dimensions along the axes, which can lead to variations in resolution and distortions in the image.Rate this question:
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- 45.
When one is viewing a multiplanar reformation (MPR) image, each pixel represents:
- A.
The maximum attenuation occurring within the voxel
- B.
The average attenuation occurring within the voxel
- C.
The minimum attenuation occurring within the voxel
- D.
All attenuation occurring within the voxel above a set threshold value
Correct Answer
B. The average attenuation occurring within the voxelExplanation
When viewing a multiplanar reformation (MPR) image, each pixel represents the average attenuation occurring within the voxel. This means that the pixel value represents the average intensity or density of the tissues or structures within that voxel. This can be useful in determining the overall characteristics of the tissues or structures being imaged, as it provides an average value of the attenuation occurring within that voxel.Rate this question:
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- 46.
An acquisition is made on a 64-slice MSCT system in which each detector element has a z-axis dimension of 0.625mm. With a selected beam width of 40mm and the beam pitch set at 1.50, how much will the table move with each rotation of the gantry?
- A.
20mm
- B.
40mm
- C.
60mm
- D.
80mm
Correct Answer
C. 60mmExplanation
The table will move 60mm with each rotation of the gantry. This can be calculated by multiplying the z-axis dimension of each detector element (0.625mm) by the selected beam width (40mm) and the beam pitch (1.50). Therefore, the formula is 0.625mm x 40mm x 1.50 = 60mm.Rate this question:
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- 47.
For single-slice CT (SSCT) systems, which of the following statements regarding retrospective image reconstruction is FALSE?
- A.
The algorithm, matrix size, and DFOV may all be changed
- B.
The slice thickness and SFOV may be changed
- C.
Scan (raw) data must be available
- D.
Retrospective image reconstruction may be used to adjust the center of the image
Correct Answer
B. The slice thickness and SFOV may be changedExplanation
Retrospective image reconstruction refers to the process of reconstructing images from previously acquired scan data. In single-slice CT systems, it is possible to change the algorithm, matrix size, and DFOV during retrospective image reconstruction. This allows for adjustments in image quality, resolution, and field of view. However, the slice thickness and SFOV cannot be changed retrospectively. These parameters are determined during the initial scan and cannot be altered during image reconstruction. Therefore, the statement that the slice thickness and SFOV may be changed is false.Rate this question:
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- 48.
Areas of a CT image that contain abrupt changes in tissue density are electronically represented by which of the following?
- A.
Positive CT numbers
- B.
High spatial frequencies
- C.
Negative CT numbers
- D.
Low spatial frequencies
Correct Answer
B. High spatial frequenciesExplanation
High spatial frequencies in a CT image represent areas that contain abrupt changes in tissue density. Spatial frequency refers to the rate at which the intensity of the image changes as a function of position. In CT imaging, high spatial frequencies indicate rapid changes in tissue density, such as the boundaries between different tissues or structures. These abrupt changes in density are electronically represented in the CT image using high spatial frequencies.Rate this question:
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- 49.
Use Fig 5-11 The differences in Hounsfield value exhibited in the ROIs measured on this CT image of a water filled phantom are most likely due to the phenomenon referred to as:
- A.
Partial volume averaging
- B.
Noise
- C.
Beam hardening
- D.
Detector drift
Correct Answer
C. Beam hardeningExplanation
The differences in Hounsfield value exhibited in the ROIs measured on this CT image of a water-filled phantom are most likely due to beam hardening. Beam hardening is a phenomenon that occurs when the X-ray beam passes through an object, causing lower energy X-rays to be absorbed more than higher energy X-rays. This leads to an increase in the average energy of the X-ray beam, resulting in an underestimation of the Hounsfield values in the image.Rate this question:
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- 50.
The acquisition of a series of CT images at a single anatomic location over a set period is referred to as:
- A.
Ultrafast CT
- B.
Cine CT
- C.
Conventional CT
- D.
Temporal CT
Correct Answer
B. Cine CTExplanation
Cine CT refers to the acquisition of a series of CT images at a single anatomic location over a set period. This technique allows for the visualization of dynamic processes, such as the movement of organs or blood flow, by capturing multiple images in rapid succession. Unlike conventional CT, which captures a single image at a specific moment, cine CT provides a temporal sequence of images, similar to a movie or "cine" loop. Ultrafast CT, on the other hand, refers to a specific type of CT scanner that can capture images very quickly, but it does not necessarily involve the acquisition of a series of images over time. Temporal CT is not a recognized term in the context of CT imaging.Rate this question:
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Mar 22, 2023Quiz Edited by
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Dec 26, 2012Quiz Created by
Jawkorn23