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CT Registry Prep 1
| Question | Answer |
|---|---|
| _______ blood pressure indicates the pressure within the arteries during cardiac contraction, should be less than ____ | systolic 120 |
| _______ blood pressure is measured during relaxation of the heart and should be less than _____ | diastolic 80 |
| _____ is a device used to measure pulse and respiratory status. can be placed ____, ____, or ____. Should be within ________ | pulse oximeter, finger, toe, or earlobe, 95% to 100% |
| Normal respiration for child | 20-30 resp |
| __________ refers to the series of blood flow related events that occur from the beginning of one heartbeat to that of the next. | cardiac cycle |
| It is the frequency of the _________ that determines the patients heart rate. | cardiac cycle |
| __________ is a graphic representation of the electrical activity of the heart. Used during cardiac CT to evaluate heart rhythm and cycle | electrocardiogram (ECG or EKG) |
| Atrial systole is contractions of left and right atria, corresponds with the ______ | p wave |
| Ventricular systole is contractions of the left and right ventricle, corresponds with the beginning of the ______ | QRS complex |
| Complete cardiac diastole is a period of ______ after heart contracts, corresponds with the T wave | Relaxation, |
| Cardiac CT images are typically reconstructed from the data acquired during ________ | diastolic phase |
| Patients with _____ heart rates exhibit longer diastolic phases, which yield higher quality cardiac CT exams | slower |
| ________ may be used to reduce the patients heart rate for cardiac CT. 65 beats is prefered for optimal imaging. | Beta-adrenergic (b-blockers) |
| If not contraindicated, sublingual ________ may be used before cardiac CT to cause dilation of coronary vessels improving the vision | nitoglycerine |
| Normal adult patient temperature | 97.7 F- 99.5 F (36.5 C- 37.5 C) |
| Normal respiration for adult | 12-20 resp |
| Normal adult patient pulse | 60-100 |
| Normal patient blood urea nitrogen (BUN) | 7-25 mg/dL |
| Normal patient creatinine (Cr) | .5-1.5 mg/dL |
| Normal patient GFR (Glomerular Filtration Rate) | Adults 90-120ml/min can decrease with age 70+/- 14 mL/min/m men & 60+/- 10mL/min/m women |
| Normal patient PT (prothrombin time) | 12-15 sec |
| Normal patient PTT (partial thromboplastin time) | 25-35 sec |
| Normal patient INR (international normalized ratio) | .8-1.2 |
| Normal patient platelet count | 140,000-440,000 uL of blood |
| Is the approximation of creatinine clearnace or the rate by which creatinine is filtered from the blood | GFR (glomerular filtration rate) |
| Is a measure of blood coagulation | PT (prothrombin time) |
| Is utilized for diagnosing deep vein thrombosis and pulmonary embolism | d-dimer |
| The presence of elevated _____ in the blood may indicate recently degraded blood clots | d-dimer |
| If d-dimer is elevated, testing such as CT _____ of the pulmonary arteries may be indicated | angiography |
| Injection of medication or contrast into blood stream is a type of _____ administration | parenteral |
| The volume of contrast is administered at a slow rate over a long period Is called | drip infusion |
| The volume of contrast is pushed into the blood at a rapid rate Is called | bolus injection |
| power injectors are capable of consistently injecting large volumes of contrast agent at a flow rate of up to ________ | 5-6 mL/sec |
| For flow rates up to 3mL/sec, a _______angiocath is used | 22 gauge |
| For flow rated exceeding 3mL/sec, a ________or larger is used | 20 gauge (Possible 18 for trauma) |
| Flushing the tubing with _____ saline immediately after contrast bolus allows for reduction of contrast agent and a streaking artifact | 30-50ml |
| In the event of extravasation, remove catheter, apply __________ compress | warm and moist |
| ______ contrast agents belong to a class of substances known as radiopaque contrast media (RCM) | positive |
| Examples of 2 radiopaque contrast media (RCM ) | barium and iodine |
| _________ describes the contrast agents propensity (natural tendency) to cause fluid from outside the vessel to move into blood stream | osmolarity |
| _______ contrast media have greater osmolarity (double of non ionic) due to more iodine (salt) atoms per molecule. Water soluble and mostly harmless to body but have more side affects. | ionic |
| ______ contrast media have low osmolality and less toxicity fewer side affects are non salt chemical compounds. | non ionic |
| ______ contrast media have the same osmolality as blood and can be offered to improve pt comfort and reduced potential of side effects | iso-osmolar (IOCM) |
| an example of non-ionic iso-osmolar contrast | Iodixanol-Visipaque |
| Enteral Rectal Contrast Media (RCM) are administered | orally or rectally |
| Barium sulfate is used to opacify the GI tract, and typical transit time is______ | 30-90 min |
| 3 Reasons barium is contraindicated (not used) | suspected perferation, future surgery, aspiration |
| 3 negative contrastS used for CT are | water, air, and gas |
| The range of serum iodine concentration for adequate opacification during CT is ______ | 2-8mg/ml |
| Flow rate for central venous catheter | 2mL/sec |
| 3 examples of central venous catheters | subclavian lines, implanted access ports, and peripherially inserted central cath (PICC) |
| For studies of distal large bowel, contrast agent may need to be administered ______prior | 4-6hrs |
| A ____ enema is used to opacify the rectum, the sigmoid, and the distal large bowel | 150-300ml |
| Myelograms uses what method to inject contrast | intrathecally |
| Injecting contrast into joint space is what type of administration | intra-articular |
| 2 pretreatments for patients that maybe allergic to contrast that are taken 24 hrs prior to exam are______ | diphenhydramine HCL (benadryl) and a corticosteroid |
| People that are at increased risk for adverse reaction | asthma, allergies, renal disease, mult myeloma, diabetes mellitus, pheochromocytoma, sickle cell disease, hyperthyroidism, cardiac disease |
| contraindications for IV dye | allergy to iodine, allergy to iodinated contrast, renal insufficiency/failure |
| nausea and vomiting Is a | mild reaction |
| vasovagal response (Drop in heart rate and B/P making patient faint) is a | moderate reaction |
| tachycardia from hypotension (Low B/P) is a | moderate reaction |
| profound (severe) hypotension is a | severe reaction |
| laryngeal edema (throat swelling) is a | severe reaction |
| for a bronchospasm reaction to iv contrast what is used to treat | bronchodialator-inhaler |
| for a urticaria (skin rash) reaction to iv contrast what is used to treat | diphenhydramine-benadryl |
| for a hypotension reaction to iv contrast what is used to treat | elevate legs and iv fluids |
| cutaneous (skin) reaction to iv contrast are most common within ________ after administration | 3hrs to 7 days |
| ________ is a potentially serious delayed effect of contrast agent administration | contrast-induced nephrotoxicity (CIN) |
| 4 Groups of patients at risk for contrast induced nephrotoxicity (CIN) include __________ | diabetes, myeloma, advanced age, cardiovascular disease |
| patients taking metformin are at increased chance of _______ when given IV dye | lactic acidosis |
| what dilates the vessels for cardiac studies | sublingual nitroglycerine |
| What phase of kidneys best show transitional cell carcinoma | excretory |
| A rim of viable ischemic (severely damaged) cerebral tissue that surrounds the infarct core in a patient with an acute stroke is termed _________ | ischemic penumbra |
| arterial phase of liver time range of bolus tracking is ______ | 25-35 sec |
| portal hepatic phase of liver time the range of bolus tracking is _______ | 60-80 sec |
| equilibrium, wash out, or delivery phase of liver the range of bolus tracking is _______ | 3-4 min |
| arterial phase of pancreas the range of bolus tracking Is _______ | 20-30 sec |
| Delayed/Late arterial phase of pancreas the range of bolus tracking is _______ | 35-45 sec |
| venous phase of pancreas the range of bolus tracking is _______ | 60-80 sec |
| corticomedullary phase of kidney the range of bolus tracking is ______ | 30-40 sec |
| nephrographic phase of kidney the range of bolus tracking is _______ | 70-90 sec |
| excretory phase of kidney the range of bolus tracking is _______ | 2-3 min |
| A math/statistical method that allows for motion free images from helically acquired images | interpolation |
| ________ is multiple detectors that are the same length | uniform matrix array |
| ________ thinnest at center, surrounded by detectors of incrementally increasin widths of z axis | adaptive matrix array |
| ________ narrow detectors are positioned midline flanked by wider detectors | hybrid matrix array |
| _________reduces image unsharpness & removes blurring | convolution |
| __________optimal level that is necessary for 3d recon on a ct scan to define region of interest (ROI) | threshold setting |
| 2 forms of analytic image recon | fourier recon & filtered back recon |
| ________ is the product of the X-ray tube current (in milliamperes) and exposure time per rotation (in seconds). | Tube current time product |
| the full width at half max (FWHM) of scanner is used to describe | spatial resolution |
| ________noise- result of an insufficient xray photon flux per voxel | quantum |
| What causes a star like streak, | Metal artifacts |
| What can be done about streaking or what software can take the streaking out | reconstruction algorithms can be applied to smooth the streaks caused by the metal, interpolation |
| What cause streaks and blurring | motion artifact |
| Artifact that results from beam hardening and appears on image as a vague area of increased density in a somewhat concentric shape around the periphery of an image similar to the shape of a cup | Cupping or Beam Artifacts |
| Bands or streaks, reduced by thinner slices and computer algorithms | Partial volume artifact |
| Equipment miscalibration, poor gantry rigidity, tube wobble or a defective detector element causing a bright or dark ring | Ring artifact |
| What noise- signal maybe lost and noise introduced to the recon process by the various electronic components of ct | electronic |
| What noise- artifacts is viewed as noise | artifactual |
| What artifact occurs between contiguos sections due to inconsistant breathing | misregistration |
| areas of ct image that contain abrupt changes in tissue density are electricaly represented by ______ | high spatial freq |
| the dimensions of a voxel are determined by multiplying the ________ | pixel dimensions x slice thickness |
| the rate at which a quantity of xrays emitted from the tube pass through a unit area over a unit of time is called | photon flux |
| Iothalamate Meglumine (Conrad) and Diatrizoate Sodium (Gastroview and Hypaque) which have high osmolarity are what kind of contrast | ionic and developed first |
| Iopamidol (Isovue), Iohexol (Omni), Lopromide (Ultravist) are what kind of contrast | nonionic |
| iodixanol or visi is what kind of contrast | nonionic iso osmolar |
| the radiation dose index calculation that takes into accound the variations in absorption across the vield of view due to beam hardening is called ________ | CTDIw (CT dose index weighted) |
| A math process that allows MDCT images to be recon at any point along the acquired volume is called___________ | z-filtering |
| _________ is the measure of total radiation exposure for entire series of ct images | CTDI vol (CT dose index volume) |
| dose length product is calculated by multiple what | CTDI vol and total scan length |
| _________used to approximate the radiation dose for the ct section acquired during a helical scan | CTDI vol |
| quantity of xrays passing through a unit area. emitted from tube toward pt | photon fluence |
| Limited resolution on modern ct scanner | 25 lp/cm |
| A high resolution comb is utilized by an MSCT detector array is used in an effort to reduce ______ | Scatter |
| What is the distance between centers of 2 reconstructed ct images called | section interval |
| clinical indication of coronary artery calcium (CAC) | artherosclerosis |
| which are tissues other than the structure excluded by setting the threshold value and eliminating pixels above and below | 3d shaded surface |
| when a sharp or high pass recon is used, it does so at the expense of losing | Contrast resolution |
| convolution enhances important characteristics of attenuation profiles thus reduces what | streak and star artifact |
| all mdct scanners that have 4 or more rows of detectors use ____________ not filtered back projection | cone beam reconstruction |
| spatial resolution is dependent on what two things | reconstruction field of view (fov) and image matrix |
| increasing matrix size will ______ voxel size | decrease |
| decreasing reconstruction fov will _____ voxel size | decrease |
| increase slice thickness by _______ voxel size | increasing |
| decreasing reconstruction fov will ________ pixel size | reduce |
| decreasing reconstruction fov will __________ spatial resolution | increase |
| decreasing reconstruction fov will ______ noise | increase |
| decreasing reconstruction fov will _______ size anatomy | increase |
| on mdct penumbra appears | on first and last slice |
| on sdct, penumbra appears | around every slice |
| 5mGy= ___ | .05 rad |
| 1mGy=___ | .01 rad |
| hypotension, gray tone to skin, tachycardia, cold clammy blue color, confusion Are symptoms of | Shock |
| osmolarity of plasma | 285 |
| a bone window utilizes a _____ ww (window width) and _____ wl (window level) | Wide High |
| soft tissues use a ww of ___________ and window level of ___________ | 300-400 0-50 |
| cone beam artifact looks like _____ coming from structures around the _____ of the image | stars edge |
| Measure of total pt radiation dose over a given scan acquisition length and is proportional to scan length | dose length product (DLP) |
| units to express total pt dose | milligray (mGy) per cm |
| the 3d ct technique that includes all the voxel info in the recon model with adjustments to opacity | volume rendering |
| reformatted ct that lie perpendicular to the original plane | orthogonal |
| controlling factors for temporal resolution | gantry rotation speed and recon method |
| daily air and water calibrations are used to evaluate | linearity |
| 3 Phases of tissue enhancement classifications are________ | Bolus and Non-equilibrium and Equilibrium |
| linear attenuation coefficient for dense bone | .528 |
| linear attenuation coefficient fo muscle | .237 |
| linear attenuation coefficient for white matter | .213 |
| linear attenuation coefficient for gray matter | .212 |
| linear attenuation coefficient for blood | .208 |
| linear attenuation coefficient CSF (cerebral-spinal fluid) | .207 |
| linear attenuation coefficient for water | .206 |
| linear attenuation coefficient for fat | .185 |
| linear attenuation coefficient for lungs | .093 |
| linear attenuation coefficient for air | .0004 |
| ct # dense bone | +1500-2000 |
| ct # muscle | +50 +65 |
| ct # white matter | +40 +46 |
| ct # gray matter | +35 +40 |
| ct # blood | +30 +35 |
| ct # csf | +15 |
| ct # fat | -50 -100 |
| ct # lungs | -550 -950 |
| window level and window width of abdomen | +50 L +400 W |
| window level and window width of brain | +40 L +80 W |
| window level and window width of subdural | +50 -100 L +130-300 W |
| window level and window width of stroke | +35 L +10-30 W |
| window level and window width of lung | -600 L +1500 W |
| Window level and window width of liver | +40 L +150 W |
| Window level and window width of spinal bone | +400 L +1800 W |
| A patient that has severe vagal reaction to IV contrast that includes bradycardia. what do you give them? | Atropine |
| Test bolus and bolus triggering are used for _______ | Ensuring imaging during peak enhancement regardless of patient age,disease, or cardiac output |
| in msct, the beam pitch is equal to _____ | table feed per rotation divided by total collimation |
| calculation of the avg cumulative dose to each section within acquisition of multiple sections | msad (multi scan average dose) |
| if a person is left dominate, the posterior descending artery branches off of_______ | left circumflex artery |
| if a person is right dominate, the posterior descending artery branches off of_______ | right coronary artery |
| what quantifies effective dose | sieverts |
| test phantom of water is scanned at 5 ROI (region of interest) this is done to evaluate | cross field uniformity |
| Mild agatston score for calcium seen in heart | 11-100 |
| Moderate agatston score for calcium seen in heart | 101-400 |
| Extensive agatston score for calcium seen in heart | >400 |
| normal range of cerebral blood volume contained within 100g brain tissue | 4-5 |
| Due to it inherent retrospective reconstruction capability the helical CT allows substantially better what? | longitudinal spatial resolution |
| smaller filament size _______ | improves spatial resolution |
| What controls the volume of transmission data acquired for each gantry rotation | sampling freq or views per rotation |
| An increase in sampling frequency increases | spatial resolution |
| A technique that allows the user to select the pixels for a ct 3d reformat is called ________ | thresholding |
| a decrease in apperature size will _____ noise | increase |
| International system SI unit of radiation dose expressed as absorbed dose and can be used for any type of radiation (alph,beta,neutron,gamma) and does not describe biological effects of radiation | gray (rad) |
| Biological effects of radiation are measured in units of | Sieverts (older version rem) |
| ability of a ct system to maintain constant Hounsfield units across homogenous (same) image | uniformity |
| isotrophic resolution is approached by using _____ _____ and ____ _____ | thin slices, small dfov (display field of view) |
| dimensions of a voxel is found by using | pixel size and section width |
| high osmolar contrast has avg osmolarity of | 1000-2400 |
| a decrease in tube total rotation = ______ and _________ | decrease in time decrease pt dose |
| decrease in total tube rotation from 360 to 180 is known as | half scan or segmenting |
| Gantry Control to amplifier to software & hardware (s/h) to Analog to Digital Converter (adc) to array processor to host computer to storage or console | CT system components left side |
| console to host computer to scan controller to digital to analog converter (dac) & high volt generator to gantry control then Gantry | CT system components right side |
| this is where instructional commands are entered, info about patient, image parameters, post process technique | console |
| Primary link between tech and other components of imaging system. It translates techs commands entered at the console into the computer language and passes it onto the scan controller or storage device is__________ | host computer |
| host computer passes commands to this which is responsible for timing and operation correct performance of each CT system component once the scanner has been started controls high-voltage generator, gantry and patient tablet | scan control |
| The components that convert the digital commands coming out of the scan controller into analog commands that can be executed by the power producing and mechanical components | dac (digital to analog converter) |
| To save the digital data in case it is needed at any time in the future images of kept the long term storage by | Archiving |
| A pre-defined set of parameters that is used to run a CT scan for specific clinical application | Protocol |
| The negative terminal of the CT x-ray tube in the part of the tube with the negatively charged electrons flow into the tube from the high bolted generator | cathode |
| The positive terminal of the CT x-ray tube in the part of the tube where the target material is located | anode |
| A structure on the cathode terminal of the CT x-ray tube from which the electron beam is released | filament |
| The area on the anode target bombarded by the electron beam and a factor in determining the image resolution | focal spot |
| As the mA increases the number of photons | Increase |
| The perimeter that determines the energy level of x-ray photons produced by the x-ray tube | tube voltage kV |
| As the kV increases the penetrability of the photons | Increase |
| This restricts x-rays to only the selected cross-sectional region | Collimation |
| Has the collimation increases scatter production which results in patient does | decreases |
| What are the two types of detectors used in CT | Gas and solid state detectors |
| When a photon strikes an xenon atom the atom splits into an ion and an electron and can be measured as an | electrical impulse |
| Xenon gas detectors can only be used in what generation scanner which is giving a chamber aligned with the CT x-ray tube at all times because of the narrow chambers | Third |
| What is the most prevalent type of detectors used in today’s CT scanners | Solid state |
| Specialized computer component used to reconstruct a CT images | Array processor |
| A component that aids in the distribution viewing and storage facility for digital images across an imaging facilities computer network | picture archiving & communication system (PACS) |
| The standard used for communicating digital medical information which was established to improve workflow efficiency between imaging systems in healthcare environments worldwide | digital imaging & communications in medicine (DICOM) |
| low window level is | brighter |
| high window level is | darker |
| intrathecal injection goes into | subarachnoid space |
| patients vessels dilate to compensate for the increased volume of fluid. causes the flushed nausea feeling and is directly contributed to the total voume, rate of injection viscosity (Thickness) is what type of reaction | chemotoxic |
| What reaction- result of histamine being release | idiosycratic |
| The methods and tools used to protect patients in personnel from ionizing radiation exposure | Radiation safety |
| Radiologist or medical physicists who are approved by the NRC and state organizations to ensure that institutions comply with guidelines for radiation safety | Radiation safety officer |
| What stage in which the radiation can cause the most harm to the fetus due to the embryo being more sensitive to harmful effects of radiation than an adult | First trimester |
| medical wrong doing or failure to do something a professional negligence most common charge against healthcare workers | malpractice |
| breach or failure to fulfill expected standard of care and an unintentional arming of a person by acting in an improper way | negligence |
| the negligent act speaks for itself | res ipsa loquitor |
| Because in which a person is harmed because of another persons actions or failure to act. Examples are assault and battery and false imprisonment and malpractice | tort |
| Intentionally threatening or attempting to harm a person. And example is telling a person that he is going to do something that he does not want to | assault |
| Intentionally touching another person without a persons permission even if contact is not causing harm. Example is doing something to the patient that the patient has said they don’t want done | battery |
| Intentionally violating a persons freedom. Example is using restraints | false imprisonment |
Created by:
Reeni1995
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