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CT Basic
modules
| Question | Answer |
|---|---|
| The process of using motion to blur certain portions of the patient's anatomy in order to demonstrate a particular area of interest is called the __________________ principle. | Tomographic |
| Which plane divides the body into an anterior and posterior portion? | Coronal |
| Who created the first primitive computed tomography scanner? | Godfrey Hounsfield |
| The first clinical CT scanners were only capable of imaging the: | Head |
| Which of the following are typical matrix sizes of modern CT scanners? | 512 x 512 and 1024 x 1024 |
| Whish of the following is a characteristic of third generation CT scanners? | The x-ray tube and detectors rotate continuously in a 360 degree arc. |
| Which generation of CT scanners was designed specifically for cardiac imaging? | Fifth |
| What is another term to describe sixth generation CT scanners? | Helical |
| The way in which the x-ray beam passes through the patient and is acquired by the CT detectors is known as beam_____________. | Geometry |
| In second generation CT scanners, the beam was shaped like a: | Fan |
| Single-slice CT scanners frequently had to stop and reverse direction to unwind the generator and data cables. Which technology helped to salve this problem? | Slip rings |
| Which of the following are methods of data acquisition in computed tomography? | Sequential and spiral |
| In helical CT scanning, a pitch of 1 results in _______ bands of data. | adjacent |
| Most modern CT scanner tables are make of : | carbon fiber |
| Which of the following factors determines the weight limit of a CT table? | The maximum load at which the table can be moved accurately. |
| CT tube voltages range from ____ to _____ kilovolts. | 80, 140 |
| Which of the following are types of filtration used in CT? | mathematical and beam- shaped |
| Modern detectors are scintillation devices that use a crystal to produce______ when struck by x-ray photons. | Light |
| One advantage of a multi-slice detector system is that_______. | The data can be reconstructed into different slice thicknesses without rescanning the patient. |
| Which component of the CT scanner is responsible for amplifying and digitizing the signals from the detectors? | Data acquisition system |
| In a busy CT department, and x-ray tube is expected to last approximately | 1 year |
| The detector's ability to gather the x-ray photons that pass through the patient is called _________ efficiency. | capture |
| Which type of detectors are the industry standard because of their increased sensitivity and reliability? | Scintillation |
| Collimators used in CT include: | pre- patient and post-patient |
| Which type of CT scanning is characterized by a stop-and -start rotation motion? | Axial |
| If a patient takes several breath holds with different levels of inspiration throughout the exam, the reconstruction images may demonstrate what specific type of artifact? | Misregistration |
| The development of ________ allowed the x-ray tube and detectors to rotate around a patient continuously. | slip ring |
| If gaps exist between slices of a CT scan, the pitch setting would be: | greater than 1 |
| Which of the following factors determines pitch? | table movement |
| The actual area of interest scanned by the CT scanner is the: | Scan field of View (SFOV) |
| A_________ image looks similar to a plain-film radiograph and is used to set the scan box. | Scout |
| The CT number for water is approximately: | 0 |
| The window width adjustment influences: | Contrast |
| Which CT computer component is responsible for applying algorithms to the attenuation data to produce the final CT image? | Array processor |
| Which of the following is an information collection device in the data acquisition system used in digital imaging? | Detector |
| Pixel size can be determined by dividing the field of view by the ? | matrix size |
| Which type of voxel is equal on all sides? | Isotropic |
| In which of the following situations would helical/spiral scanning be used? | A large area of anatomy must be covered in a short period of time. |
| The analog-to-digital converter contains several elements. Which ADC part assigns the binary units that become the digital signal? | Coder |
| The Digital-to-analog converter ensures that the data are free from artifacts and contain enough useable data. These steps are known as: | Preprocessing |
| After the attenuated x-ray beam strikes the detector array, the CT scanner performs an important mathematical operation known as a Fourier transform. What does the Fourier transform calculate? | The length of time for the x-rays to pass trough the patient and strike the detectors. |
| Which artifact indicates that data from a detector element are missing? | Ring |
| Which technology allows continuous x-ray production in today's CT scanner | Rotating anode |
| Most modern CT scanners use row of detector elements covered with: | scintillation crystals |
| What is the purpose of filters within an x-ray tube of a CT scanner? | To remove low-energy x-ray photons from the beam. |
| Beam hardening occurs when: | The filter removes many of the weaker x-rays from the beam. |
| On a CT scanner, the purpose of collimators is to: | ensure uniform slice thickness |
| Which type of collimator is responsible for reducing patient dose? | Pre-patient |
| The scan field of view is primarily responsible for | Spatial resolution |
| The pixel size in an image using a 512 x 512 matrix and a display field of view of 30.2 cm is ____________ mm. | 0.59 |
| What does the slice thickness affect? | How the details of an exam will appear. |
| Using a pitch of less than 1.0 results in? | An overlap between each slice. |
| In CT scanning, kilovolt peak(kvp) can affect several scan parameters, including: | beam hardening |
| Which type of filter adds definition to the slight changes in densities within soft tissues? | Standard convolution algorithm |
| The region of interest, or ROI, is a tool used for quality control purposes, What does ROI measure? | CT/Hounsfield number for water |
| What determines the focal spot size? | Cathode filament and anode target angle |
| Which unit of radiation is a measurement of absorbed dose and has been replaced by the gray (Gy)? | Rad |
| Which dose index takes into account the amount of radiation exposure per section as well as how many sections are imaged? | Dose length product (DLP) |
| Who is the person responsible for accurately calculating a true patient dose? | medical physicist |
| Generally, the kilovolt peak range for CT is ___________ kVp. | 100-140 |
| Which of the following techniques reduces patient dose by synchronizing the timing of the scan with anatomic function? | Gating |
| The National Council on Radiation Protection and Measurements recommends an occupational dose limit for radiation workers of no more than ______ millisievert (mSv) per year. | 50 |
| Water, milk and specially weighted barium sulfate are examples of ______ contrast agents. | Negative oral |
| When choosing a site to start an IV line, which of the following sites are usually the best choice regardless of the test performed? | A site that can accommodate the largest gauge catheter possible and the location closest to the antecubital vein. |
| When beginning an IV line, which of the following is a sign that you've gained access to the vein? | A flash of blood within the catheter |
| Extravasation is when contrast leaks into the surrounding tissue instead of flowing into the vein. What action should the CT technologist take if extravasation occurs? | Call for help if necessary Properly document the extravasation |
| What is one way that a CT technologist can identify a power port-a-cath? | The port is marked with the letters CT that are clearly visible on a chest radiograph. |
| Patients should stop taking_____ for 48 hours after contrast injection because IV contrast can cause acute renal failure, which then can lead to a potentially toxic build-up of the drug in the patient's kidneys. | Metformin |
| What group recommends the clinical practice standards for CT technologists? | American Society of Radiologic Technologists |
| When should adhesive tape be used for patient restraint? | As the absolute last resort |
| The Alliance for Radiation Safety in Pediatric Imaging has launched the_______ campaign, which provides resources to help CT technologists adjust scan parameters for children. | Image Gently |
| Why is a chest scan the CT examination most often performed on pregnant patients? | To detect pulmonary embolism |
| According to the U.S. Food and Drug Administration, radiopaque noniodinated contrast media are classified as pregnancy_____ drugs. | Category B |
| Which of the following are potential reactions to contrast media? | Vomiting, metallic taste, dyspnea |
| Radiology departments are equipped with crash carts in the event of a patient emergency. Which of the following crash cart medications is used to open airways and increase heart rate? | Epinephrine |
| The ability of the computed tomography (CT) scanner to distinguish between adjacent tissues having similar mass density and effective atomic density is called: | Contrast resolution |
| What is the ability of the CT scanner to discriminate objects of varying density, a small distance apart, against a uniform background? | Spatial resolution |
| In third generation CT scanners, a smaller______ produces better spatial resolution. | focal spot |
| Which of the following factors determines subject contrast? | the anatomy of interest |
| Which selectable factor determines the detectors that are activated during the scan and the size of the resulting pixels? | scan field of view |
| In CT, anatomical coverage is determined by the : | slice thickness |
| Which CT artifact occurs when similar tissue types share the same voxel and the tissues are averaged as one Hounsfield unit? | partial volume averaging |
| Motion artifacts often appear as _________ on the image. | ghosting |
| Which of the following techniques can be used to reduce patient movement and therefore the possibility of motion artifacts during CT scanning? | positioning devices for comfort cardiac triggering |
| Tube arcing causes artifacts that appear as: | an obvious band of increased noise across the entire image |
| What causes cone beam artifacts? | insufficient projection samples |
| Edge gradient artifacts can be reduced by using: | increased data sampling rates |
| For a quality control (QC) program to be effective, it should: | Record quantitative results. Define the desired result. |
| How often should the CT number calibration test be performed? | daily |
| The acceptable range of CT numbers is typically ______ Hounsfield units from 0. | 2 to 7 |
| The low-contrast resolution test uses a phantom with multiple holes that decrease in diameter. The test should display approximately_______ % of the holes. | 50 |
| Which test determines the uniformity of CT numbers throughout the image? | CT number flatness |
| It is important for CT technologists to understand the medical physicist's measurements in order to: | observe daily image quality |
| Beam hardening produces broad streak artifacts on a CT image. Which of the following affects beam hardness? | The increase in energy results from lower energy x-rays being absorbed by the body, leaving higher than average energy photons that reach the detectors. |
| The thickness of each slice for a routine head computed tomography (CT) scan is measured in: | millimeters (mm) |
| For the routine head CT exam, axial slices are acquired: | Parallel to the orbital meatal line. |
| Which reconstruction algorithm is used for trauma head CT scans to best demonstrate bony detail? | Sharp |
| The common contrast injection parameter for a routine head CT scan is _____ml at __________ml per second. | 100; 1 |
| The scan range protocol for a routine neck CT scan should include anatomy from: | External auditory meatus (EAM) to the carina. |
| The slice thickness and spacing for a routine neck CT scan should be set close to __________ mm every _________ mm. | 3; 3 |
| Which of the following is an indication for a CT examination of the cervical spine? | Degenerative disease |
| For CT imaging of the cervical spine, technical factors are consistent for almost all patients except: | children |
| What is the matrix size for a CT cervical spine scan? | 512 x 512 |
| For CT examinations of the chest, it's important that the patient raises and extends his or her arms overhead to prevent___ artifacts. | Beam hardening |
| Which of the following are advantages of positioning the patient feet first into the gantry for a routine chest CT scan? | The CT technologist can easily see the patient throughout the exam the injector and contrast line can be positioned in a convenient location. |
| For a routine chest CT scan of an average adult patient, the kVp should be set to: | 120 |
| To display the lung parenchyma, the window width (WW) should be set to ____ and the window level (WL) to ____. | 1500: -600 |
| For a CTA chest exam, center the patient within the scanner using the laser light by raising the table height to a level that: | bisects the midcoronal plane |
| Common post processing protocols for the CTA examination of the thoracic aorta include: | AP, lateral and oblique sagittal MIPS |
| When using the bolus tracking mechanism for a pulmonary embolism study, the region of interest (ROI) or monitoring location should be the : | main pulmonary artery |
| For a pulmonary embolism study, a threshold of _______ Hounsfield units (HU) must be met to trigger the start of the scan. | 90 to 100 |
| When using the bolus tracking mechanism for a CTA scan of the thoracic aorta, the ROI or monitoring location should be placed at the : | ascending aorta |
| What is the scan range, or starting and stopping locations, for a routine abdomen and pelvis CT scan? | above the dome of the liver through the symphysis pubis |
| For a routine abdomen and pelvis CT scan, most protocols are set to an interval of ____ mm. | 5 |
| To demonstrate the structures within the abdomen and pelvis, the WW is set to_____ and the WL is set to ____. | 350; 40 |
| For a routine CT scan of the abdomen and pelvis the total dosage of contrast given to pediatric patients is based on their: | weight |
| To measure the threshold that triggers the start of a CTA scan of the abdomen and pelvis, the ROI is placed within the: | descending aorta |
| CTA of the abdomen requires scanning with peak contrast enhancement with injection parameters of a total of ____mL injected at a rate of _____mL per second. | 125; 4 |
| When scanning the thoracic or lumbar spine, which display field of view would most likely be used? | 12 cm |
| Which of the following is an appropriate scan range for the routine thoracic spine CT scan? | C7 to L1 |
| The technical factor selection for a routine lumbar pine CT scan of an average patient is____ kVp and _____ mAs | 120; 300 |
| For the greatest detail and smooth reformatting of routine extremity CT scans, the slices should overlap by ____%. | 50 |
| To best demonstrate bony anatomy in a routine CT exam of the ankle, scan parameters would include a WW of ____, a WL of ___ and a ____ algorithm. | 2000; 200; bone |
| Which of the following are advantages of CT compared with MRI for the management of trauma patients? | Patients can be monitored easily and Fresh bleeding and bony injury are better demonstrated. |
| A "Triple Rule Out" CT angiography scan is frequently performed on an emergency basis to evaluate: | pulmonary embolism |
| In musculoskeletal CT imaging, subtle fractures, particularly those oriented in the axial plane, are better seen on ____ images. | 2-D |
| CT arthrography is used routinely to evaluate ______ joints. | shoulder |
| Before a CT biopsy, images are taken to: | Document the needle insertion site in relation to the lesion. |
| CT-guided radiofrequency ablation uses _______ to destroy tumors. | heat |
| Which of the following roles does CT play in cryoablation treatment? | Guiding the placement of ablation probes Ensuring that the ice ball encompasses the tumor |
| For CT urography, why do some departments place a compression belt around the patient's abdomen? | To help retain contrast in the renal pelves and proximal ureters |
| Most standard CT angiography (CTA) exams, regardless of body part, include all to the following components. | axial reformat, MIP, volume-rendered |
| Surgeons use CT angiography before and after endovascular artery repair to: | Evaluate the distance of an aneurysm from the renal arteries Select the correct-sized stent for the artery Detect possible leaks of contrast |
| IV placement in the ______ vein is preferred when imaging the thorocoabdominal aorta so as not to obscure the great vessels. | Right antecubital |
| The CTA acquisition for renal arteries is similar to other CTA exams with the exception of | A smaller display field of view |
| CT is used to assess liver donor candidates before donation and post surgery. Typically, the only post processing performed for the postoperative CT exam involves: | liver volumes |
| Perfusion studies of the _____ are the most common CT perfusion application. | Brain |
| Virtual bronchoscopy (VB) uses a high-resolution CT data set to evaluate pulmonary disease. An advantage of VB over fiberoptic bronchoscopy is that it can: | Be correlated with cross-sectional images to localize lesions. |
| CT colonography involves the acquisition of an overlapping isotropic data set in the supine and prone position. Why is glucagon administered before the scan? | To reduce peristalsis in the colon. |
| Tri-phase CT enterography uses three acquisitions to evaluate patients with? | Obscure gastrointestinal bleeding. |
| Manufacturers have developed dual-source/ dual-energy acquisition methods to improve CT image quality. Which of the following areas have benefited from dual-energy scanning? | Differentiating cysts and tumors Characterizing the composition of stones Demonstrating uric acid crystals in tissues |
| Cardiac CT includes studies that calculate the amount of calcium in the arteries or valves. The _____ score is used to assess the patient's risk of a cardiac event compared with other people of the same sex. | Agatston |
| With _____ gating, CT data are acquired during a predetermined portion of the heart cycle based on an electrocardiogram (ECG) signal. | Prospective |
| Which of the following radiopharmaceuticals is most commonly used for PET-CT imaging of cancer? | Fluorine 18 fluorodeoxyglucose |
| CT scanners used for cancer treatment planning and simulation differ from most typical CT scanners in that they have: | An extra set of wall-mounted lasers |
| A typical portable CT scan takes about ____ minutes to perform. | 45 |
| Most incisional hernias occur within 2____ following surgery. | yeart |
| The pressure from hydrocephalus is caused by: | Enlarged ventricles caused by inadequate cerebrospinal fluid drainage. |
| Which of the following conditions can cause hydrocephalus in adults? | Ruptured aneurysms Brain tumors Closed head injuries |
| ________ can assist in determining location and size of lymphoma masses and in staging lymphoma. | CT |
| The Centers for Disease Control and Prevention (CDC) defines ___________ as an Aids- defining condition. | Lymphoma in the central nervous system of a patient with a compromised immune system due to HIV |
| Involvement of 2 lymph node regions located on the same side of the diaphragm is considered Stage _____ lymphoma. | II |
| __________ is usually the examination of choice for pinpointing the extent of lymphoma and its response to treatment. | Positron emission tomography- CT (PET-CT) |
| Meningiomas occur most often in______. | Middle-aged women |
| Which of the following is true regarding use of CT for evaluating ovarian cysts? | When ovarian cysts are found on CT, they usually are incidental findings. |
| In 2010, about ______ new cases of pancreatic cancer were diagnosed in the United States. | 43,000 |
| Most pancreatic cancers originate in the: | Ducts that transport pancreatic juices. |
| Which of the following is true about pleural effusion? | A patient can have symptoms or no symptoms Cough is a common symptom Pleural effusion is cause by more fluid being produced than the body can absorb |
| Simple renal cysts normally: | Have smooth, thin walls Are round or oval |
| Polycystic disease is the : | Presence of more then 1 cyst |
| About 30% of sarcomas originate in the _______. | abdomen or trunk |
| Which of the following statements about sarcoma symptoms is true? | Pain is a symptom of sarcoma. |
| Symptoms of sinus masses often mimic symptoms of _______. | sinusitis |
| The blockage of an artery in the lung is called a____________. | Pulmonary embolus |
| Fatty plaques that narrow a vessel and restrict blood flow are called? | atherosclerotic calcifications |
| Toxoplasmosis is caused by a______________. | Parasite |
| Most people who have toxoplasmosis are: | asymptomatic |
| Which of the following statements is true regarding traumatic injury? | Traumatic injury can affect internal organs and the skeletal system Trauma to the head can injure the brain Traumatic brain injury can cause death. CT plays a major role in evaluating traumatic injury. |
| On CT images, an acute or subacute hemorrhage in the brain can be indicated by ________ attenuation. | varing |
| The cavities containing the lungs are lined with continuous serous membranes called: | Pleura |
| Which of the following arteries branch from the aortic arch? | Brachiocephalic Right subclavian Right common carotid |
| Which chamber of the heart has the thickest walls? | Left ventricle |
| The trachea divides into the left and right mainstem bronchi at the level of ? | carina, sternal angle |
| Which structure is quite prominent in infancy and early childhood and can be misinterpreted as a mass on chest radiographs of small children? | thymus |
| Which of the following is on of the muscles of the rotator cuff? | Teres minor |
| The diaphragm has 3 large openings. Which of the following are a hiatus in the diaphragm? | Caval, oesophageal, aoritc |
| Which is a powerful muscle used to flex the thigh? | Iliacus |
| Which is a retroperitoneal structure? | kidney ( not the stomach liver, or overies) |
| What is a hilum? | An area where blood vessels and nerves enter and exit an organ. |
| Which part of the small intestine encircles the head of the pancreas? | duodenum |
| All human tissue and organs develop from primary germ layers. Which germ layer forms the human central nervous system? | ectoderm |
| The immovable joints of the skull are called? | sutures |
| The hearing organs are housed in the _____ bone. | temporal |
| What is the only movable joint in the skull? | temporomandibular |
| What is the white, fatty substance that covers the nerve fibers of the brain's white matter? | myelin |
| What is an important function of the choroid plexus? | To produce cerebrospinal fluid |
| In CT, when the falx cerebri and other midline structures of the brain deviate from their normal location. It is called: | mass effect |
| Which gland is considered the master gland of the body because it regulates the functions of many other glands? | pituitary |
| What region of the brain is responsible for controlling muscle tone and coordinating muscular activity? | Cerebellum |
| Which cranial nerve controls the sense of hearing and equilibrium? | vestibulocochlear |
| Which cranial verve has the widest distribution, helping regulate heart rate, blood pressure, digestive secretions and respiration? | vagus |
| Which gland can be palpated by placing the index and middle fingers just anterior and inferior to the ear lobe? | parotid |
| The inner portion of each adrenal gland is called the _____. | medulla |
| An adrenal gland growth could result in: | High blood pressure Increased heart rate |
| Which of the following statements is true regarding aneurysms? | Aneurysms can be caused by congenital factors. |
| Arterial walls are composed of ________ layer(s). | 3 |
| A carotid artery aneurysm at the level of C4 is important because normally, it can cause: | Blood supply to a portion of the brain to cease. |
| Diverticula occur most often in the ____. | large intestine |
| Complicated diverticulitis symptoms include: | Bloating Rectal bleeding |
| Aneurysm dissection occurs when a _______ causes a split along the length of the inner layer of the vessel wall's intima. | clot |
| Patients with acute appendicitis generally have pain in the ____________ abdominal quadrant. | right lower |
| The speckled appearance of a bezoar on a transverse abdominal CT image is cause by: | Contrast adhering to some fibers. |
| Of all Americans who have arteriovenous malformations (AVMs), about ____ have symptoms. | 36,000 |
| A stroke that is caused by the rupture of a blood vessel is called a ______ stroke. | hemorrhagic |
| Symptoms of stroke include: | Sudden confusion Dizziness Trouble walking |
| In the vast majority of cases, cholecystitis occurs as a complication of _______________. | Gallbladder stones |
| Cancers that originate in the cells that manufacture and secrete mucus and other fluid are known as ________. | adenocarcinomas |
| Congenital abnormalities may be present in ______ % to ________% of live births. | 3; 5 |
| Polysplenia is one of the _____________ abnormalities. | situs |
| When the inferior vena cava is interrupted because of a condition such as polysplenia, venous blood flow is returned via the ______ system. | Azygos |
| Narrowing of vascular lumen caused by atherosclerosis can lead to a heart attack because: | Blood flow can be completely blocked to a portion of the heart. |
| In CT, a patient's calcium can be measured using the ______ scoring system. | Agafston |
| Which of the following is true regarding hemangiomas? | A hemangioma is a collection of blood vessels. Hepatic hemangiomas often have very subtle appearances Internal hemangiomas appear similar to masses. |
| Conditions that could cause mild biapical scarring on CT scans include: | Emphysema Tuberculosis Pneumonia |
| On CT scans, biapical scarring of the lungs has a _____ appearance. | blurry, web-like |
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