CTA.docx

CTA - correct answer 3D examination of blood flow through arteries and veins after bolus injection of contrast data acquisition by helical scanning useful in imging arteries and veins of entire body CTA - correct answer for vascular abnormalities: aneurysms, stenosis, pulmonary emboli, renal artery assessment, dissection in aorta, atherosclerotic disease CTV - correct answer for evaluation of venous system R/O thrombosis conventional angio - correct answer nurses, techs, physicians sedation given NPO faster, less invasive, cheaper, comfort - correct answer why is CTA better than conventional angio? angioplasty and stenting - correct answer when is conventional angio used true lumen - correct answer true vs false lumen which one is brighter (where O2 and nutrients is going)? kidney function - correct answer when GFR 60, 3x more likely to develop contrast induced nephropahty - prehydration, iso-osmolar contrast, sodium bicarbonate infusion patient Hx - correct answer to consider: contrast, type II diabetes, asthma, certain meds, breastfeeding, liver disease, malignant hyperthermia indications for oral contrast - correct answer liver, ischemic gut, renal stenosis, AAA larger - correct answer larger pts require ____ volume of contrast contrast media timing - correct answer smartprep by GE CARE bolus by siemens surestart by toshiba smartprep - correct answer software offers real time contrast tracking to optimize usage and results identifies peak contrast enhancement for better img quality, higher reliability and added confidence smartprep process - correct answer axial: target vessel selected ROI defined and threshold CT value (usually 1000) is set smart prep: monitors ROI ROI CT # matches or exceeds threshold value, scanning is initiated to capture optimum contrast in vessel smartprep benefits - correct answer lowers contrast usage, injection rates and expense minimize repeat exam and contrast induced nausea better lesion detection and characterization reduces scan to scan and pt to pt variability test bolus - correct answer alternative to smart prep usage is increasing essentially a monitoring scan 10-20 cc's diluted contrast injected and monitored at the appropriate level, middle of area of interest optimal opacification is determined test bolus - correct answer used for peak enhancement scout, small amount of contrast with small phase to find out how long it takes to get to the peak and use that timing for real injection test bolus - correct answer can give a tailored amount of contrast, more precise test bolus - correct answer each scan = 2 sec scan + prep group delay (5 sec added) will determine prep group delay for actual scan for actual arterial scan you have determined optimal prep group delay (scan delay) smartprep - correct answer Want vessel of interest opacified, opacification of other vessels (or lack of) will not hinder scan quality test bolus - correct answer Want ONLY vessel of interest opacified, opacification of other vessels will hurt scan quality factors affecting enhancement - correct answer cardiovascular function, renal function selected delay time will depend on location of scan start and location of interest as well as pitch used bc of table speed parameters - correct answer common to do C- exam first want thinner slices to get better detailed but it would be slower scan 1mm - correct answer collimation of COW bc it doesn't have as many rows and detectors so x-ray tube is on for long time generating heat - correct answer why is thin slice acquisition difficult with old scanners (for COW) parameters - correct answer Abdominal CTA = 3mm collimation Pitch = 2 → acceptable coverage of the area of interest 120kVp is commonly used mA = based on the size of the patient's body section to be examine image recon interval - correct answer spacing between the center of the slice overlap - correct answer 3D image quality ↑ when reconstruction intervals ______ MPR - correct answer 1st visualization tool in CTA simple and fast reconstructed in any plane compromised: COW and intracranial AVMs SSD - correct answer faster than VR useful for vascular relationships, vessel origins and surface contours of vessels editing: to remove overlapping structures artifact: low quality of imgs MIP - correct answer most frequently used popular and more accurate than SSD 2D angiographic display of vessels rotating on all spatial axes parallel display of arteries and veins MIP - correct answer editing: unwanted structures beading or stairstep artifact can be decreased overlapping recon intervals volume rendering - correct answer becoming more popular provides accurate vessel diameter and 3D vascular relationships real time (5-10 frames per second) opacity of CTA - correct answer obscurity of structures 0-100% of values increased OP values to help in display of complex 3D relationships decrease OP values to allow see through structures interactive cine - correct answer shows anatomic relationship of blood vessels motion imgs are separated only slightly by time e.g. beating heart stereoscopic veiwing - correct answer experimental technique to enhance the diff 3D relationships among various structures eyewear, perspective and depth cues CT pulmonary angio - correct answer considerations: extremely susceptible to respiratory motion breath hold must be relaxed contrast should be visualized in pulmonary artery, not aorta no beam hardening coming off of SVC or contrast administration CTPA - correct answer test bolus provides more control