B P3 C20 Cardiac Computed Tomography Flashcards
Non–contrast-enhanced ECG gated study during a single cardiac phase used to identify the presence and amount of calcified coronary plaque.
Coronary artery calcium (CAC) scan
Contrast-enhanced ECG gated study performed to identify the presence and amount of both calcified and noncalcified plaque, and to estimate the severity of luminal stenosis.
CCTA
Contrast ECG gated images to evaluate various pathologies ranging from valvular heart disease and cardiac function to cardiac masses and pulmonary venous anatomy.
Cardiac CT to evaluate noncoronary structures
Amount of CAC classified as moderate
Moderate - 100 - 299
The overall amount of coronary plaque can then be categorized as:
Absent (CAC = 0)
Minimal (1 to 9)
Mild (10 to 99)
Moderate (100 to 299)
Severe (300 to 999)
Extreme (≥1000)
Calcifications in the coronary arteries indicate the presence of coronary atherosclerosis, and there is a direct association between the ______________ in both men and women,and across different races.
Amount of coronary calcifications and long-term risk of future cardiovascular events
The absence of coronary calcifications (i.e., CAC score of zero) has been shown to be associated with a ____________ event rate, especially among individuals with a 10-year ASCVD risk that is <20%.
Very low 10 year event rate
In addition to being a strong predictor of CHD events, increased CAC can also be used to predict other forms of cardiovascular disease (CVD), including _______
Atrial fibrillation, stroke, and congestive heart failure
The current 2018 AHA/ACC multisociety cholesterol guideline states that in _________ or __________, if the decision about statin use remains uncertain, it is reasonable to use CAC testing in the decision to withhold, postpone, or initiate statin therapy
Intermediate-risk or selected borderline-risk adults (i.e., 10-year ASCVD risk of 5%–20%)
When CAC testing is used in this context, if the CAC score is zero, it is reasonable to ___________ and __________, as long as higher risk conditions are absent (diabetes mellitus, family history of premature CHD, cigarette smoking).
Withhold statin therapy
Reassess in 5 to 10 years
The AHA/ACC guidelines indicate that if the CAC score is 1 to 99, it is reasonable to initiate statin therapy, especially in those __________
≥55 years of age
If the CAC score is 100 or higher or in the 75th percentile or higher, it is recommended to initiate statin therapy
In patients with severe CAC and when there is uncertainty regarding patient symptoms or exercise capacity, ________ may be reasonable.
Exercise testing
When further testing is considered, ________ may be particularly beneficial
Positron emission tomography myocardial perfusion imaging (PET MPI)
Because?
Normal myocardial blood flow reserve can be used to exclude high-risk anatomy and inform prognosis
_______ should not be performed in asymptomatic individuals with severe CAC.
Invasive angiography
Is repeat CAC testing useful to assess response to statin therapy?
No
The amount of CAC cannot be reduced with therapy, in fact, some studies have shown that statin therapy may be associated with a mild increase in CAC progression. Nevertheless, the strong association of CAC with future cardiovascular events is robust in patients who are on lipid-lowering therapies.
Repeat CAC testing is not useful to assess response to therapy
________ has the highest sensitivity of any noninvasive imaging technique to detect the presence of anatomic stenosis.
CCTA
Sensitivity of 97% (93 to 99) with a specificity of 78% (67 to 86) for detecting >50% stenosis.
When evaluating the diagnostic accuracy of CCTA to detect functionally significant coronary artery disease (CAD), as defined by an invasive fractional flow reserve (FFR) ≤0.80, the sensitivity of CCTA was 93% (89 to 96) with a specificity of 53% (37 to 68).
In this trial, CCTA had the highest diagnostic accuracy to detect significant CAD, defined by invasive angiography as >50% stenosis of the left main stem, >70% stenosis in a major coronary vessel, or 30% to 70% stenosis with FFR ≤0.8. The sensitivity of CCTA was 91% (86 to 95), whereas the specificity was 92% (89% to 95%).
EVINCI (Evaluation of Integrated Cardiac Imaging for the D tion and Characterization of Ischemic Heart Disease) study
In this study, CCTA (90%) and PET (87%) had the highest s sitivity, whereas PET and SPECT had the highest specificity. The overall diagnostic accuracy to detect lesion-specific ischemia was highest for PET.
PACIFIC trial (Prospective Comparison of Cardiac PET/CT, SPECT/ CT Perfusion Imaging and CT Coronary Angiography With Invasive Coronary Angiography)
The overall risk of major CVD events increased in a stepwise manner with both atherosclerotic disease burden (determined by the total CAC score) and number of vessels with ≥50% stenosis.
When stratified by groups of increasing CAC, patients with nonobstructive CAD had a risk of CVD events similar to those with obstructive CAD, suggesting that _________, not stenosis, was the main predictor of future CVD events.
Plaque burden
CCTA as an alternative to invasive angiography to exclude ACS when there is ___________ and when cardiac troponin and/or ECG are normal or inconclusive.
Low-to-intermediate likelihood of CAD
Patients who are ideal candidates for CCTA have
No known CAD
Can achieve a low heart rate (e.g., <70 beats/min with medications)
Can hold their breath during image acquisition
Can tolerate the administration of IV contrast
In this trial, patients randomized to standard care plus CCTA or to standard care alone
Over a median follow-up of 4.8 years, the addition of CCTA to standard of care resulted in a 41% reduction in the combined endpoint of CHD death or nonfatal MI
SCOT-HEART trial
The _________ trial compared a strategy of CCTA versus functional testing
Although there was no difference in this primary outcome, the use of CCTA was associated with a lower rate of death or MI at 12 months (HR 0.66; P = 0.049).
PROMISE trial
The use of CCTA was associated with a lower incidence of invasive angiography showing no obstructive CAD during the 90 days after randomization
However, more patients in the CCTA group underwent invasive angiography within 90 days of randomization (12.2% vs. 8.1%) and more patients in the CCTA group underwent coronary revascularization (6.2% vs. 3.2%).
Patients with diabetes who underwent CCTA had a lower risk of cardiovascular death or MI compared with those who were randomized to functional stress testing
The mechanisms underlying improved patient outcomes in the use of CCTA include
The use of CCTA was associated with greater use of preventive therapies such as statins and aspirin.
The observed reduction in events observed in this trial was explained by modeling, which accounted for the benefits of medical therapy
_______ on CCTA (Hounsfield units [HU] <30) corresponds to lipid-rich plaque; more often seen in patients with ACS, and has been found to be associated with ruptured fibrous caps,75 lesion-specific ischemia, 76and a future risk of MI
Low-attenuation plaque
Noncalcified plaque with higher CT attenuation correlates with fibrous tissues.
___________ compensatory enlargement of the vessel wall as plaque size increases outward to preserve the luminal area.
This feature is associated with a larger burden of plaque, a larger necrotic core, and also higher likelihood of thin-cap fibroatheroma (TCFA) by intravascular ultrasound (IVUS).
Positive remodeling
A remodeling index threshold of ≥1.1 is typically used to define positive remodeling
Remodeling index is calculated as the vessel cross-sec area at the site of maximal stenosis divided by the average of the proximal and distal reference segments’ crosssectional areas
_____defined as small, dense (>130 HU) plaque components surrounded by noncalcified plaque tissue.
Spotty clacifications
Compared with intermediate (1 to 3 mm) calcifications, small (<1 mm) spotty calcification have the strongest association with HRP features defined by virtual histology IVUS, and may represent plaques that are more likely to accelerate.
Weaker marker of future risk compared with other APCs, such as low-attenuation plaque and positive remodeling.
Number of coronary segments with plaque, which can provide an estimate of the overall extent of plaque which can provide incremental prognostic value
Segment involvement score
Risk level of atherosclerosis can be determined based on the
Amount or extent of plaque (e.g., number of segments or vessels that have coronary plaque and CAC score, if available)
Presence of HRP features plaque progression
Lesion location
Extent of obstructive CAD
Risk level of atherosclerosis can be determined based on the
Amount or extent of plaque (e.g., number of segments or vessels that have coronary plaque and CAC score, if available)
Presence of HRP features plaque progression
Lesion location
Extent of obstructive CAD
Cardiac CT has emerged as a useful test to evaluate various forms of valvular heart disease.
Although all four cardiac valves can be assessed when a multiphase acquisition is performed, imaging of the ________ is more challenging,
Tricuspid valve
When there is suspicion for valve d function, cardiac CT can evaluate for valvular ________ and _______
In native valves, cardiac CT can detect ________ with a high diagnostic accuracy, although very small vegetations can be challenging to detect.
In prosthetic valves, cardiac CT can identify paravalvular lesions, such as ____________.
Thrombosis and pannus
Vegetations
Pseudoaneurysm, abscess, or fistula
There are various forms of myocardial and infiltrative heart disease that can be identified on routine cardiac CT.
Images at end diastole can be used to measure left and right ventricular wall thickness, and left and right ventricular size.
_________ on CT refers to the acquisition of images ∼8 minutes after contrast administration
Late enhancement imaging
Identify
Sinus venosus defect
Identify
Anomalous pulmonary venous return
Identify
Atrial septal defect
Identify
Patent foramen ovale
Identify
Ventricular septal defect
