CARDIAC COMPUTED TOMOGRAPHY Flashcards
What are the contraindications for cardiac computed tomography?
An inability to remain still, hold one’s breath, or follow instructions; anaphylactic reaction to intravenous iodinated contrast; hemodynamic instability; very high heart rate; atrial fibrillation with variable R-R interval; severe renal dysfunction (except when on dialysis).
What is the difference between prospective triggering and retrospective gating?
Prospective triggering acquires images of the heart in a predetermined phase of the cardiac cycle, while retrospective gating acquires images throughout the cardiac cycle.
When might retrospective gating be used rather than prospective triggering?
When cardiac or valvular function measurements are needed; in patients with irregular heart rhythms or high heart rate; for preinterventional evaluation for structural heart diseases.
Is it possible to scan the entire heart in a single heartbeat?
Yes, using modern CT scanners like wide-array/volume scanners or high-pitch spiral scanning.
What is the radiation dose of a standard cardiac computed tomography examination?
Ranges from less than 1 mSv to as high as 30 mSv, with a median dose in the US between 1 and 10 mSv.
What is blooming and how can it be reduced?
Blooming is an artifact from high attenuation materials bleeding into adjacent structures; it can be reduced by increasing tube voltage, using sharp/stent kernels, thinner slices, adjusting windowing, or using iterative reconstruction.
Is premedication with beta-blockers and nitroglycerin necessary for coronary CTA?
Yes, it is necessary to obtain CT images of diagnostic quality.
What is a coronary calcium score?
A specialized cardiac CT examination that quantifies the amount of coronary calcium, also known as the Agatston score.
Is calcium scoring appropriate in a patient of low coronary heart disease risk but with a family history of premature coronary heart disease?
Yes, it is appropriate to evaluate for subclinical coronary atherosclerosis in this population.
In which patients is coronary computed tomography angiography appropriate?
In patients with nonacute symptoms potentially representing ischemic equivalents and low or intermediate pretest probability of CAD.
What is CAD-RADS classification?
A standardized reporting system classifying CAD based on the highest grade coronary artery lesion detected on coronary CTA, ranging from CAD-RADS 0 to CAD-RADS 5.
Is coronary computed tomography angiography an appropriate first test for a patient with nonacute chest pain and intermediate pretest probability of coronary artery disease?
Yes, it is appropriate for patients unable to exercise with low or intermediate probability of CAD.
Is coronary computed tomography angiography an appropriate test for a patient with low to intermediate pretest probability of coronary artery disease presenting with acute chest pain?
Yes, it is appropriate for evaluation in this scenario.
Is coronary computed tomography angiography useful for detecting in-stent restenosis in patients with stents less than 3 mm in diameter?
No, stents less than 3 mm in diameter are not appropriate for evaluation by coronary CTA.
Fill in the blank: The ability of a scanner to ‘freeze’ cardiac motion depends on the gantry’s _______ and the patient’s heart rate.
rotation speed
True or False: The use of higher pitch in CT scanning increases radiation and contrast doses.
False
What is the purpose of coronary computed tomography angiography (CTA) in patients with prior coronary artery bypass grafts (CABGs)?
Coronary CTA is indicated for symptomatic patients with prior CABGs to evaluate for graft patency and complications such as thrombosis, malposition, aneurysms, and pseudoaneurysms.
What is the Coronary Artery Disease Reporting and Data System (CAD-RADS) classification for 0% to 25% stenosis?
CAD-RADS 0 indicates absence of CAD.
What is the CAD-RADS classification for 50% to 69% stenosis?
CAD-RADS 3 indicates potentially obstructive CAD.
What is the appropriate use of cardiac computed tomography in evaluating coronary anomalies?
Cardiac CT is excellent for evaluating coronary anomalies and assessing adult congenital heart disease.
True or False: Cardiac computed tomography can differentiate between acute and chronic myocardial infarction.
True
What findings are typically observed in cardiac CT for patients with chronic myocardial infarction?
Wall thinning, fatty metaplasia, or calcification may develop.
What is the role of cardiac computed tomography in patients presenting for noncoronary cardiac surgery?
Coronary CTA is useful for assessing coronary arteries for obstructive disease in young and middle-aged patients.
Fill in the blank: Cardiac CT is appropriate for patients with _______ pretest probability of CAD and new-onset heart failure.
low or intermediate
What is the significance of high-risk features found on cardiac CT angiography?
High-risk features correlate with future events.
What is the most common anatomic variant of the pulmonary veins?
A separate ostium for the right middle pulmonary vein.
What is the role of cardiac CT in the evaluation of patients for transcatheter aortic valve replacement (TAVR)?
CT provides important measurements for planning the procedure, including dimensions of the aortic annulus and root.
What is the diagnostic accuracy of plaque characterization by cardiac computed tomography?
CT is excellent for detecting calcified plaques but modestly accurate for noncalcified plaques.
What is the purpose of pulmonary vein mapping before pulmonary vein ablation?
To detect variant anatomy and assist in catheter selection.
What is the role of cardiac CT in assessing patients with suspected Turner syndrome?
Cardiac CT is a reasonable first modality for assessing congenital anomalies associated with Turner syndrome.
What does a CAD-RADS 4B classification indicate?
Left main disease (>50%) or three-vessel severe stenosis (≥70%).
What is evaluated using cardiac CT in patients being considered for transcatheter mitral valve replacement?
The complex mitral valve anatomy is essential for planning.
What noncoronary structures should be included in a cardiac CT examination report?
All significant findings noted in the acquired dataset.
How can fractional flow reserve (FFR) be obtained noninvasively?
By using data from cardiac CTA to generate advanced 3D models and perform computational fluid dynamic analysis.
True or False: Cardiac CT is not useful for evaluating cardiac masses.
False
What is the purpose of CTA of the access vessels before transcatheter procedures?
To measure the minimal luminal diameters and evaluate their suitability for accommodating large sheaths used in prosthesis delivery systems
Also measures vascular calcification and tortuosity.
What aspects of the aorta are evaluated during CTA?
Kinking, dissection, and thrombi
These evaluations are crucial for ensuring safe access during procedures.
What is the role of cardiac CT before transcatheter mitral valve replacement?
Understanding complex mitral valve anatomy for planning percutaneous procedures
Provides measurements like mitral annulus size and neo-left ventricular outflow tract area.
What specific measurements does cardiac CT provide for planning mitral valve procedures?
Mitral annulus size, neo-left ventricular outflow tract area, basal septal thickness, anterior mitral leaflet length
These measurements are essential for different procedural approaches.
How does cardiac CT assist in predicting fluoroscopic projections?
By providing projections oriented orthogonal to the mitral annulus plane
This aids in the accurate placement of devices during procedures.
What is the role of cardiac CT in patients with suspected or confirmed coronavirus disease?
To replace TEE or invasive angiography to exclude thrombus and evaluate prosthetic valves
Also helps diagnose endocarditis and its complications.
In what scenarios can cardiac CT be used to evaluate patients with acute chest pain?
To rule out CAD and workup other possible causes of myocardial injury
Relevant when troponin levels are elevated or in patients with stable chest pain but high suspicion.
True or False: Cardiac CT can replace invasive procedures to prevent the spread of COVID-19.
True
It helps in minimizing patient exposure to invasive techniques.
