277 Quiz 1

6 basic components of patient interactions in relation to CT procedures
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Terms in this set (128)
Explain how kV and mAs are set in CTkV is fixed mAs ranges for different body parts - the machine sense and plans off of the topogram______ data is always automatically created from the scan data with little intervention from the technologist, this is often referred to as _________ dataAxial Raw4 things the technologist has control over when creating images from scan dataDFOV Multiplanner reconstruction WW/WL KernalWhy do we created images in multiple window width and level?To demonstrate different anatomy within the sam scan rangeCT is able to show a wide range of structural differences by assigning a _____________ unit, or CT ___________, based on _______________Hounsfield Number Attenuation2 factors that affect attenuationDensity Atomic numberWhat does window width determineNumber of HU's represented on a specific image Range of CT numbersRegarding window width values higher than the selected range will be __________ and values lower than the selected range will be ___________White BlackWhat is window levelCenter CT value of the window levelWhat does window level determineWhich HU's are displayed as shades of grayIf 0 is selected as the window level and 300 is selected as the window width, what is the range-150 to 150The window level should be set at a point that is roughly the same value as the average __________ number of the __________ of interest.Attenuation TissueWhen viewing tissue types that vary greatly would you want a narrow or wide window widthWideWhy do wider window width settings suppress the display of noise on an imageDecreased image contrastWhat is the HU of air-1000What is the HU of water0Average HU of the brain70Would you use a wide or narrow window width for imaging the brain and whyNarrow Because the tissues are similar densityBecause bone is very dense a ________ window level will be necessaryHigherWould imaging of bone need a wide or narrow window widge and whyWide Because the tissues have such varying densities2 categories of processing kernalsSmoothing Edge enhancing3 most commonly used convolution kernals, are they smoothing or edge enhancing?Smooth - smoothing Soft tissue - smoothing Sharp - edge enhancingWhat convolution kernal is used in angios and 3D reconstructionsSmoothWhat convolution kernal is used in all abdominal and chest imagingSoft tissueWhat convolution kernal is used in bone and lung tissueSharp3 post processing applications that the technologist buildsMPR - multi planar reconstruction MIP - maximum intensity projections VR - volume renderingWhat is multi planar reconstructionCreating images in coronal, sagittal, or oblique from a stack of continuous axial imagesWhat are maximum intensity projectionsTaking the highest value of a projection, and only displaying thoseWhat os volume renderingCreating a true 3D environment by removing structures to demonstrate below surface anatomyWhat is MPR helpful in determiningLocation and complexity of pathologyWhen is MIP often usedIn angiographyMost of the time contrast is injected through a peripherally, inserted IV in the ____________________ vein, this would mean the contrast begins in the ___________Antecubital SVC5 phases of contrast enhancement, what 2 are the most commonPre-arterial Arterial - most common Venous - most common Equilibrium DelayWhat phase of contrast enhancement is used in a PE study?Pre-arterialWhat phase of contrast enhancement shows equal distribution in the arterial and venous systems?EquilibriumWhat phase of contrast enhancement is used for pathologies with a delayed uptake?Delay3 contrast enhancement phases in the kidneyArterial + phase Nephrogenic phase Excretory phase2 methods to ensure optimal IV contrast enhancementBolus tracking Test bolusWhat is it called when the scanner automatically initiates a prescribed, scan wanna threshold, level of contrast enhancement is reached at a specific ROIBolus trackingWhat is it called when a small injection of contrast is used to measure the contrast transit time prior to a scanTest bolusDuring acquisition delay the term for when the CT number is hit and the bolus tracking tool will trigger the system to begin the scanThresholdWhat is the time from injection to the star of monitoring scans calledMonitor delayWhat is the time between consecutive monitoring scans calledMonitoring intervalWhat is the time from when the threshold is reached and the prescribed scan beginsScan delayWhat type of contrast appears dark or black on imagesNegative contrastWhat type of contrast appears light or white on imagesPositive contrastName of the negative contrast study pre-CT to examine the brainPneumoencephalogramWhy is contrast used in CTTo delineate structures that are similar in both anatomical area and absorption3 types of positive contrast used in CT, which is the most commonOral Rectal IV - most commonTrue or False An iodine based solution is used for oral contrast in CTTrueWhat type of oral contrast has become more popular in CTWaterWhy is barium not used as an oral contrast in CTIt is think and causes artifactsGeneral wait time after giving a patient oral contrast in CT1 hourWould a patient with IBS require more or less wait time after being administered oral contrastLessWould a patient with chronic constipation require more or less wait time after being administered oral contrastMoreOsmolalityThe number of particles in solution, per unit liquid, as compared with bloodViscosityThickness or friction of a fluid as it flowsIonicityAgents containing molecules that will form ions in solution5 properties of an ideal IV contrast agentIsomolar to blood Low viscosity Non-ionic High clearance High concentrationWhat is the range of a typical IV contrast amount50-150mLRange of injection rate of IV contrast0.1mL/s to 6mL/sHow many mL of saline flush is required to flush out any contrast still in the tubing or peripheral venous system10-50mL3 contraindications to oral contrastInability to consume foods Inability to hold down food Patient is criticalTrue of False Oral contrast cannot be administered through an NG/OG tubeFalse3 things to look for on lab work to assess patients ability to receive contrastBlood Urea Nitrogen (BUN) Serum Creatinine (SeCr) Estimating Glomerular Filtration Rate (eGFR)4 normal contrast reactionsWarm/hot flash Wetting sensation near bladder Salty/metallic taste in mouth Mild discomfort at injection site2 risks involved in CT during pregnancyIonizing radiation Iodine based contrast media crossing the placenta membraneTrue or False The risks involved in CT during lactation are very minimalTrue4 contraindications of IV contrastLow eGFR Renal failure or insufficiency Metformin Thyroid diseasesWhy is metformin a contraindication of IV contrastCombined with decreased renal function can cause lactoidosisTrue or False Patients on metformin may receive IV contrast if they withhold taking it for 24-48 hours post injectionTrueCINContrast induced nephropathy5 priority questions for pre contrast interviewPrevious allergies/reaction Kidney disease/function Diabetes Pregnant Asthma3 risks of contrast media administrationExtravasation Allergic reaction Contrast induced Nephropathy (CIN)ExtravasationLeakage of fluid out of its intended locationWhat is extravasation often called in CTBlowing an IVWhat to do if an IV blowsStop scan Elevate Cold pack DocumentThe best way to deter extravasationProper IV insertionIs cyanosis a sign of mild, moderate, or severe range of allergic reactionSevere3 risk factors that may increase the chance of anaphylaxis in CTAsthma Eczema/hayfever Previous reaction5 steps/roles of tech if a patient has an allergic reactionStop injection Report Do not leave patient Do not remove IV DocumentTrue or False A CT tech can inject epinephrineFalseTrue or False Epinephrine can be injected intramuscularly if IV access is compromisedTrue7 contents of contrast reaction kitEpinephrine Diphenhydramine (Benadryl) Antagonist inhaler Atrophine Hydrocortisone Prednisolone Nitroglycerine sprayWhat drug is key in an acute allergic reaction scenarioEpinephrineProphylaxis TreatmentPre treating an allergic reaction before it happensHow is prophylaxis treatment done prior to a contrast injectionCombination of a steroid and antihistamines are given to a patient in staggered intervals before the scanContrast induced nephropathyAcute impairment of renal function caused by IV contrastWhat causes contrast induced nephropathyProgressive rise in SeCr (decrease in eGFR) within 24 hours post contrast injectionIf a patient has had a mastectomy on their left side, which side should an IV be inserted on?RightWhat IV size is best for most contrast CT scans20gTrue of False 24g IV's are optimal for arterial scans due to their sizeFalseWhat size IV is optimal for a patient who needs both a CT head with contrast and a CT PE chest scan18gIf a patient comes to the department with a 24g IV in their hand for a abdopelvis can you use it to inject contrast? Why or why not?No, wrong placement, too small of an IVWhat angle do you insert an IV at10-20°What does the appearance of flashback indicateThat the IV is inside the vesselWhat is a vesicant and why is it a concernFluid that can cause tissue damage Contrast is a vesicantWhat colour corresponds to a 22g IVBlueWhat colour corresponds to a 20g IVPinkWhat colour corresponds to a 24g IVYellowWhat colour corresponds to an 18g IVGreenTrue or False It is okay to inject contrast on the paralysis affected side of a CVA patientFalseThe most important post injection instruction for the average patientHydrateWhen is contrast hand injected in CTPediatric casesDownfall to hand injectingLose the ability to time contrastTrue or False 22g IV is appropriate for arterial scansFalseWhat size IV is used for PE chest and cardiac scans18gInfiltrationInadvertent administration of a non-vesicant med/solution into the surrounding tissue instead of the intended vascular pathwayWhat is the difference between infiltration and extravasationThe fluid that is in the IVTrue or False For contrast injections IV's can be started in the handFalse5 differences between veins and arteriesColour of blood Pulsation Valves Location Blood floowWhat colour is blood in an artery versus a vein and whyArtery = bright red due to high O2 concentration Vein = dark redTrue or False Arteries have a pulse, but veins do notTrueTrue or False Valves are present in both arteries and veinsFalseTrue or False Veins are superficial whereas arteries are deep within the bodyTrueWhat vessels carry blood towards the heartVeins3 contents of an IV start kitTourniquet Alcohol disinfecting pad TagadermWhat step in catheter insertion is essential to not piercing through the vein and ensuring the catheter is placed in the lumen of the vesel"drop" phase