Computed Tomography Coronary Angiography in the.5

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Computed tomography-coronary angiography in thedetection of coronary artery diseaseAnoeshka S. Dharampal, Alexia Rossi and Pim J. de Feyter

Computed tomography-coronary angiography (CT-CA) is a

well-tolerated and reliable non-invasive imaging technique

and cannow be achieved at lowlevels of radiation exposure.

CT-CA is highly valuable to exclude coronary artery disease,

but due to over- and underestimation of the severity of

coronary lesions, CT-CA cannot replace invasive coronary

angiography. Coronary calcium scoring has an incremental

independent prognostic value beyond traditional risk factor

scores (Framingham, European Score) and may be useful to

reclassify risk in asymptomatic individuals at intermediate

risk. Appropriate indications for CT-CA are evolving, but

studies are lacking to demonstrate that CT coronaryimaging improves patient outcome.

J Cardiovasc Med 2011, 12:554–561

Keywords: asymptomatic, calcium score, computed tomography,coronary angiography, coronary artery disease, coronaryimaging, prognostic value, scan mode, spiral, step and shoot,symptomatic

Department of Radiology and Department of Cardiology, Erasmus MC,Rotterdam, The Netherlands

Correspondence to Anoeshka S. Dharampal, Erasmus MC, Department ofRadiology, Room Ca207a, ‘s-Gravendijkwal 230, PO Box 2040, 3015 CERotterdam, The NetherlandsTel: +31 10 7033558; fax: +31 10 7034033;e-mail: [email protected]

Received 18 April 2011 Accepted 20 May 2011

IntroductionThe prevalence of coronary artery disease (CAD) in

Europe is estimated to range between 20000 and

40 000 persons per million suffering from angina. Cardio-

vascular disease (CVD) is the number one cause of death

in the Western world. Each year 4.3 million people die as

a result of CVD. Cardiovascular mortality in women or

men is accountable for 22 or 21% of all deaths.1

Computed tomography-coronary imagingCurrent state-of-the-art-scanners are now considered to

have at least 64 slices or preferably more to achieve

coverage of the heart in less than 10 s which corresponds

to a breath hold of less than 10 s. Technical aspects of

various state-of-the-art-scanners (>64-slice) are shown in

Table 1.2,3 The increased number of detector rows has

improved the coverage of the heart and as result the 320-

slice scanner is able to acquire the data within two heart

beats.4 The spatial resolution of the 64-slice computed

tomography (CT) scanners is approximately 0.5– 0.6 mm

in clinical use and the newer scanners, although having a

better coverage, still have similar spatial resolution. Thetemporal resolution ranges from 75 to 175 ms, but during

fast heart rates (>70 beats/min) motion artifacts are still

not eliminated, although scanning at higher heart rates

is feasible.

The coronary arteries can be scanned in a variety of ways

using ECG synchronization with data acquisition to

obtain ECG-phase correlated images.

The scan can be performed by continuously acquiring

images throughout the cardiac cycle during several heart

beats using the helical scan mode with low-speed table

movement. This is also known as the spiral scan at low

pitch (table movement/rotation time) (Fig. 1a). This

scan mode has the highest effective radiation dose of all

scan modes, but allows image reconstruction throughout

the cardiac cycle with the flexibility to choose a motion-

free phase of the cardiac cycle to evaluate the coron-

aries. This was the scan mode used with the earlier scan

generations. With the use of ECG-triggered tube cur-

rent modulation, the tube current can be set to lower

levels (20 or 4% of the maximum output) in phases that

are not used for coronary evaluation (Fig. 1b and c).This scan mode is associated with a reduction of radia-

tion dose.5,6

Nowadays the most preferred scan mode is the scan

which is performed in steps, because of its significant

effective radiation dose reduction compared to the spiral

scan with low pitch. This so-called ‘step and shoot’ scan

acquires data in one specific phase of the heart cycle

when less coronary motion is expected. The scan acquires

data in this specific phase and subsequently moves to the

next position and ‘waits’ until the same phase in the next

heart beat has arrived to acquire data again. During themovement of the table and ‘waiting’ for the next phase

the tube current is switched off (Fig. 2a). Thus, this scan

mode can be performed at low effective radiation dose.

This scan can also be performed with a wider scan range

per heart beat, also called ‘padding’, with the flexibility to

reconstruct also other phases of the cardiac cycle, allow-

ing reconstruction of coronary images without, or having

the least, motion artifact. To reduce radiation exposure

the ECG-triggered tube current modulation can also be

applied within this broad scan range when, for example,

cardiac function (wall motion and wall thickening) has to

be assessed (Fig. 2b).

Clinical review

1558-2027 ß 2011 Italian Federation of Cardiology DOI:10.2459/JCM.0b013e32834905dc

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Another scan mode is the spiral scan with high pitch. Thisscan mode can only be used in patients with a low and

regular heart rate (<60 beats/min). The prolonged cardiac

cycle in low heart rates enables one quick spiral scan to be

performed in the diastolic phase of the heart to obtain

motion-free images of the coronaries with a very low

effective radiation dose (Fig. 3).

Each scan mode has its advantages and disadvantages, as

summarized in Table 2. In every scan mode the effective

radiation dose (Table 2)7,8 can be lowered by choosing

the right scan settings and also by changing the scan

mode.9 The highest image quality of CT-scan is achieved

in patients with lowest heart rates and this also allows useof scan mode and settings associated with lower radiation

exposure. Heart rate lowering medication is recom-

mended in patients with heart rate greater than

60 beats/min. At very low regular heart rates

(<60 beats/min) the high-pitch spiral scan mode can be

performed with lowest radiation dose.10 The ‘step and

shoot’ scan mode is preferred above the low-pitch spiral

scan in all regular and variable heart rates as this is

associated with a significantly lower effective radiation

dose.11 Other means to reduce radiation dose are the use

of lower tube voltage and tube current according to the

patient’s length and weight.12 ECG-triggered tube cur-

rent modulation should be preferred in either spiral scanwith low pitch or in ‘step and shoot’ scan for the assess-

ment of cardiac function (Figs 1c and 2b).9 In these scans,

using ‘pulsing’, the tube current is kept to 100% in the

phases that are used for coronary evaluation, and in the

other phases the tube current is lowered to levels of 20 or

4% to reduce the effective dose significantly.5,6

Recently, an iterative reconstruction algorithm has been

introduced in cardiac CT which has improved the con-

trast to noise ratio. Preliminary data suggest that iterative

reconstruction may further reduce the radiation dose

(44%) with preservation of the image quality.13

CT-CA in the detection of coronary artery disease Dharampal et al. 555

Table 1 Technical aspects of the new-generation CT scanners

Slices acquiredp er rot ation Scanner description

Detectorwidth (mm)

Longitudinal (z-axis)coverage (cm)

Rotationtime

Temporalresolution

Longitudinal (Z-axis)spatial resolution

64 (a) 32 detector rows 0.6 1.92 330 83 0.4Dual sourceSingle focal spot

128 (b) 64 detector rows 0.6 3.84 300 150 0.33Single source CT

Dual focal spot256 (c) 64 detector rows 0.6 3.84 285 75 0.33Dual source CTDual focal spot

256 (d) 128 detector rows 0.625 8 270 135 0.42Single source CTDual focal spot

320 (e) 320 detector rows 0.5 16 350 175 0.45Single source scannerSingle focal spot

Technical aspects of the (a) 64 (Siemens healthcare, Somatom Definition), (b) 128 (Siemens Healthcare, Somatom Definition ASþ), (c) 256 (Philips Heathcare, BrilianceiCT), (d) 256 (Siemens Healthcare,Somatom Definition Flash)and (e) 320-slice (Toshiba Medical systems, Aquilion One) scanners.2,3 Singlesource CT:one unit roentgentube and the detector rows; dual source CT: two units of roentgen tube and detector rows; single focal spot: the focal spot of the roentgen tube only has one position fromthe detector rows; dual focal spot: roentgen tube alternates from two different positions. Rotation time: the rotation time of the tube and detector unit. Longitudinal (z-axis)coverage:scan coverage at onerotationwithout table movement.Temporalresolution:time windowin which data forimagereconstruction is acquired (shorter time windoweliminates motion artifacts); spatial resolution: the degree of blurring in an image and the ability to discriminate objects and structures of small size.

Fig. 1

Low-pitch spiral scan mode. (a) Spiral scan without ECG-triggeredtube current modulation. Reconstructions are possible throughout thecardiac cycle. In this scan one specific phase of the cardiac cycle (dark

grey columns) is reconstructed for the evaluation of the coronaries.(b) Spiral scan with ECG-triggered tube current modulation. Tubecurrent is reduced to 4% in the phases that are not used for coronaryevaluation. Reconstruction of the heart is possible throughout thecardiac cycle and they can be used for functional assessment.Reconstructions in the full dose, 100% tube current pulsing range areused for coronary evaluation. In this scan one specific phase of thecardiac cycle (dark grey columns) is reconstructed for the evaluation ofthe coronaries. (c) Spiral scan with ECG-triggered tube currentmodulation. Tube current is reduced to 20% in the phases that are notused for coronary evaluation. Reconstructions of the heart are possiblethroughout the cardiac cycle and they can be used for functionalassessment. Reconstructions in the full dose, 100% tube currentpulsing ranges are used for coronary evaluation. In this scan onespecific phase of the cardiac cycle (dark grey columns) isreconstructed for the evaluation of the coronaries.



Computed tomography-coronary angiographylimitationsThe spatial resolution of computed tomography-coronary

angiography (CT-CA) compared to invasive coronary

angiography is still limited and may result in over- and

underestimation of the severity of coronary lesions.Severely calcified obstructions are scored less accurately

due to the blooming artif acts.14 Small vessels are often

more difficult to evaluate15 due to the partial volume

effects. The temporal resolution is limited and coronary

motion artifacts at high heart rates may hinder precise

evaluation of the coronaries. The best-quality images are

obtained when the heart rate is less than 60 beats/min.

Heart rate lowering medication is always recommended,

even when using the newer-generation CT-scanner that

can handle higher heart rates. Variable heart rates and

irregular heart rhythm are sometimes problematic and may

cause motion and stack artifacts.16,17 Although breath holdduration during scanning is minimal (approximately 10s)

respiratory movement, which also causes cardiac motion

(Fig. 4), may occur and result in misalignment of the

reconstructions. In large-sized patients a large amount of

the radiation beam is absorbed by tissue, resulting in noisy

images, which may hamper accurate evaluation of the

coronaries. However, with postprocessing techniques such

as acquiring one-half rotation data instead of one-quarter

rotation data, the image noise will decrease, but the

associated decrease of temporal resolution renders these

images more vulnerable for coronary motion.18

CT-CA requires the use of iodinated contrast agents toenhance the lumen.19 Patients with previous allergic

reactions to contrast agents, insufficient renal function

and hyperthyroidism are considered not eligible for CT

angiography.

Coronary calciumThe presence of coronary calcium is a marker for coronary

atherosclerosis. A higher amount of calcium is associated

with a higher likelihood of obstructive CAD, but this is

not calcium-site specific. Pooled analysis (n¼ 10 355

symptomatic patients) showed a sensitivity of 98%,

556 Journal of Cardiovascular Medicine 2011, Vol 12 No 8

Fig. 2

‘Step and shoot’ scan mode. (a) ‘Step and shoot’ scan performed in the diastolic phase of the cardiac cycle with small scan range. Between each scanthe table moves to the subsequent position to acquire data in the next heart beat in the same phase and scan range. No radiation is given in between thescans. One specific phase of the cardiac cycle (dark grey columns) is reconstructed with the flexibility to reconstruct the nearby located phases in thescan range (padding). (b) ‘Step and shoot’ scan performed in systolic and diastolic phases of the cardiac cycle with ECG-triggered tube currentmodulation. In the systolic phases the tube current is kept at 100% for this high heart rate. The otherphases, expected with more coronary motion aresetto 20% of the tube current. Reconstructions can be made throughout this broad scan range to assess cardiac function. One specific phase of thecardiac cycle (dark grey columns) is reconstructed with the flexibility to reconstruct in the nearby located phases in the scan range.

Fig. 3

High-pitch spiral scan mode. Spiral scan with high pitch (fast tablemovement with fast rotation time) performed in only low heart rates. Thescan only needs one heart beat to cover the whole heart. The scan startsin the middle of the cardiac cycle (60% of the RR interval) and ends inend-diastolic phase. This enables only one reconstruction of the heart.



specificity of 40%, positive predictive value of 68% and

negative predictive value of 93% for the detection of

obstructive disease.20 Absence of coronary calcium is

associated with a very low likelihood of obstructive

CAD, but is not excluded particularly in younger patients

with acute coronary syndrome.

The traditional method to quantify coronary calcification

is the Agatston score. This score is derived from the

number, area (mm2) and the maximum attenuation

within the calcified lesion.21 Large studies in asympto-

matic individuals have shown that the calcium score(Agatston score) is independent and incremental to the

traditional factors for the prediction of cardiovascular

events, in men as well as in women.22–25 Area under

the curve analysis demonstrated a significant improve-

ment of the prediction of the cardiovascular events using

calcium score additional to the traditional risk factor

model (Table 3). The presence of coronary calcifications

in women is associated with a 5.2-fold greater risk of

adverse coronary events compared to women without

calcifications.26 The absence of calcium was associated

with an excellent 10-year survival of 99.4%.22 Higher

calcium score was associated with more adverse event

rates (Table 4). The risk for a cardiovascular event hasbeen shown to increase by 9.9-fold in the presence of a

calcium score of at least 400 compared to the absence of

calcium.27

The Multi-Ethnic Study of Atherosclerosis (MESA)28

and Heinz Nixdorf Recall (NHR)29 study have shown

that calcium score allows further reclassification of

individuals at intermediate risk into lower or higher-

risk categories. The net reclassification improvement,

which quantifies the correctness of upward and down-

ward reclassification, was 55% ( P < 0.001) and 21.7%

( P <0.001), respectively.24,29


Table 2 Advantages and disadvantages of the low-pitch spiral, ‘step and shoot’ and high pitch spiral scan

Advantages Disadvantages Radiation dose (mSv)

Spiral scan low pitch Possible in all heart rates (low, intermediate,high, regular and variable heart rates)

Highest radiation dose from all scan modes $13.37,9

Functional information available with 20%and also 4% tube current outside thepulsing window

In irregular heart rates the pulsing can be suboptimal

Possibility to search for motion-free images

in nearby phase reconstructions

Several heart beats (3–5) are necessary for wholeheart reconstruction

Stack and breathing artifacts can occur

‘Step and shoot’ scan No heart rate lowering medication necessary In case of variable heart rates more contrast mediumis needed

$1.48,11

Possible at every regular and slightly variableheart rate Suboptimal in irregular heart rates

Low radiation dose Several heart beats (3 – 5) are necessary for wholeheart reconstructionPossibility to search for motion-free images in

nearby phase reconstruction Breath hold has to be held for several heart beats (6–10)for the whole scanFunctional information available in broad scan

ranges without and with pulsing Stack and breathing artifacts can occurHigh pitch spiral Single heart beat scan Heart rate dependency and vulnerability $0.8710

No stack artifacts Higher and variable heart rates show more movementartifactsNo breathing artifacts

Heart rate lowering medication is needed in heart rates>60 beats/min.

No breath hold necessary in un-cooperativepatients

Reconstruction in other phase is not possibleLowest amount of contrast materialOnly diastolic imagesVery low radiation doseNo functional informationMaximum field of view is 33 cm

Fig. 4

Breathing artifacts. Breathing during CT-CA with displacement ofthe whole heart with severe stack artifacts (arrowheads in a andb) and movement artifacts of especially the right coronary artery (RCA)(Ã in c).



However, the beneficial effects on outcome following

reclassification into lower or higher-risk category with

subsequent less or more intense control of risk factors

have not been demonstrated in appropriate clinical trials.

Computed tomography-coronary angiographySixty-four-slice CT-CA is currently the most widely used

non-invasive technique for the anatomic assessment of

CAD (Fig. 5). The diagnostic accuracy has been assessed

in a large number of single-centre trials but most impor-

tantly in three large-sized multicentre clinical trials per-

formed in symptomatic patients with low to intermediate

likelihood of pretest of CAD (Table 5).14,30,31

Overall, these studies demonstrated that CT-CA without

obstructive CAD reliably excluded the presence of sig-

nificant (>50% diameter stenosis) CAD (Fig. 6). How-

ever, overestimation of the severity of coronary lesionsresulted in a rather low positive predictive value, and a

high number of false-positive outcomes, which was most

evident on a per vessel assessment. This is caused by the

still limited spatial resolution of the current scanners and

therefore CT-CA today is not ready to replace invasive

coronary angiography. The role of CT-CA in the diag-

nosis of patients with stable angina pectoris is not firmly

established. Discussion remains as to whether a diagnos-

tic functional test, such as bicycle stress test, single-

photon emission computed tomography (SPECT) myo-

cardial perfusion imaging, or stress echo, or a diagnostic

anatomic test, CT-CA, should be used. It has recently

been shown that CT-CA may be useful as a first-line


Table 3 Prediction of cardiovascular events in asymptomatic individuals using traditional risk factors model and by expanding the modelwith calcium score

N Women (%) Follow-up years AUC (RF model) AUC (RFþ calcium score model)

Budoff et al.22 (referral patients) 25 253 46 6.8 0.611 0.813Erbel et al.29 (NHR, population based cohort) 4129 53 5.0 0.681 0.749Polonsky et al.24 (MESA, population based cohort) 5878 54 5.8 0.76 0.81Jain et al.23 (MESA, population-based cohort) 4965 52 5.8 Women: 0.805; men: 0.714 Women: 0.835; men: 0.785

AUC, area under the receiver operating curve; RF, traditional risk factor model (Framingham).

Table 4 Prognostic value of calcium score determined by Agatstonmethod

Calcium score

MESA28 (n¼6809,53% female) (FU 3.75 years)(Hazard rate)

HNR29 (n¼4129,53% female) (FU 5 years)(Hazard rate)

0 1 11–100 6.09 (2.52–14.7) 1.71 (0.84–3.47)101–400 9.58 (4.96–22.6) 3.98 (1.95–8.12)>400 9.94 (4.06–24.3) 9.94 (5.10–19.41)Ln (casc þ1) 1.41 (1.31 –1.51)Ã 1.31 (1.22–1.41)

Prognostic value of calcium score determined by Agatston method in Multi-EthnicStudy of Atherosclerosis (MESA) (

Ã

Polonsky et al.24) and Heinz Nixdorf Recallstudy.

Fig. 5

Detection of obstructive coronary artery disease (CAD) with computed tomography-coronary angiography (CT-CA). A 46-year-old man, with typicalcomplaints, hypercholesterolaemia, stopped smoking 10 years previously. Calcium score: 192. Heart rate during CT-CA: 60 beats/min. High-pitchspiral mode scan was used with effective radiation dose CT-CA: 0.95 mSv. CT-CA (I) shows a pinpoint stenosis in the proximal right coronary artery(RCA). Axial projection (a–c) through the RCA shows the area stenosis of the obstructive lesion in the proximal RCA. Invasive coronary angiography(II) confirms the obstructive stenosis.



diagnostic test in symptomatic patients with a low to

intermediate pretest likelihood of CAD.32

Prognostic value of computed tomography-coronary angiographyCT-CA in symptomatic patients is associated with an

independent and incremental prognostic value beyond

traditional clinical risk factors33–38 as is shown in the

improvement of the C-statistic after including CT-CA in

the model with the traditional risk factors (Table 6).

The presence, extent, severity of coronary plaques and

total coronary plaque burden as determined with CT-CA

confer prognostic value, and in general the presence of

extensive CAD is associated with a worse outcome. As

may be expected, the absence of CAD or the presence of

minimal CAD is associated with an excellent outcome,

with a 10-year survival rate of 98.3%.37

CT-CA based on density values (attenuation values

expressed in Houndsfield units) allows crude character-ization of coronary plaques into calcified, non-calcified or

mixed (noncalcified and calcified) plaques.39 High expec-

tations were generated by the potential that CT-CA

might be able to identify lipid plaques which are con-

sidered to be vulnerable plaques. Although the density

values of fibrous plaques on average are higher than the

density values of lipid plaques, due to the overlap of these

density values, unfortunately, lipid plaques cannot be

distinguished from fibrous plaques.40 CT-CA also allows

assessment of remodelling of the coronary artery associ-

ated with coronary atherosclerosis.41 Motoyama et al.42

demonstrated that the combination of the presence of

low-density plaque and expansive remodelling, repre-senting a vulnerable plaque, indeed was predictive of

adverse events. More studies are needed to confirm

this observation.

Computed tomography-coronary angiographyin asymptomatic patientsOnly very limited information is available concerning the

prognostic value of CT-CA in asymptomatic individuals.

CT-CA was performed in asymptomatic patients who

were at high risk or had diabetes type II. Obstructive

CAD (>50% diameter stenosis) was present in 5–30% of

these patients.43–48 Hadamitzky et al.45 reported that in

451 individuals with a follow-up duration of 27.5 months,

CT-CA had independent predictive value beyond

traditional risk factors.

New developmentsCT-CA provides anatomic assessment of the extent and

severity of CAD and has diagnostic accuracy to detect

obstructive disease. However, the presence of obstruc-

tive disease, in particular in the presence of minimal

luminal stenosis (40–70% diameter stenosis), does not

reliably predict myocardial ischaemia, and often requires

additional functional testing with SPECT, stress echo or

magnetic resonance myocardial perfusion.

A recent promising new CT-development is the intro-

duction of adenosine stress-induced CT myocardial


Table5 Multicenter clinical trials of multislice computed tomography forthe detectionof obstructive coronary arterydisease on a perpatientand vessel level

Sensitivity Specificity PPV NPV N Prevalence (%)

Patient levelMeijboom et al .30 99 (98–100) 64 (55–73) 86 (82–90) 97 (94–100) 360 68Budoff et al.14 95 (85–99) 83 (76–88) 64 (53–75) 99 (96–100) 230 25Miller et al.31 85 (79–90) 90 (83–94) 91 (86–95) 83 (75–89) 291 56

Vessel levelMeijboom et al .30 95(92–97) 77 (74–80) 59 (55–63) 98 (96–99) 1440 26Budoff et al.14 84 (74–91) 90 (88–92) 51 (43–59) 99 (98–99) 910 10Miller et al.31 75 (69–81) 93 (90–94) 82 (77–86) 89 (86–92) 866 31

NPV, negative predictive value; PPV, positive predictive value. N , number of patients and number of total vessels; prevalence of obstructive disease on a per patient andvessel level detected by invasive coronary angiography.

Fig. 6

Exclusion of obstructive disease with CT-CA. A 56-year-old woman,with typical complaints, positive family history, hyperglycaemia nottreated, hypertension. Calcium score: 1.8. Heart rate during CT-CA:73 beats/min. ‘Step and shoot’ scan mode used with broad pulsing(30–76% of the heart cycle) because of variable heart rhythm, resultedin an effective radiation dose of 8 mSV. CT-CA shows no significantlesions in (a) right coronary artery, (b) left main, left anterior descendingand (c) left main, circumflex coronary arteries.



perfusion to identify myocardial ischaemia.49,50 This

would allow assessment of anatomy and function using

CT-cardiac imaging, which may be of clinical and

prognostic value. In addition, delayed enhancement

CT imaging is able to identify the viability of dysfunc-

tional left ventricular myocardium after myocardial

infarction.

In the future, with new-generation scanners and aggres-

sive radiation dose reduction, integration of coronary

anatomy, ischaemia and viability may be achieved with

cardiac CT during a single investigation.

ConclusionComputed tomography-coronary imaging has great

potential to provide anatomic information about obstruc-

tive and non-obstructive coronary plaques, in asympto-

matic individuals as well as in symptomatic patients.

The prognostic value of calcium scoring has been estab-

lished and reclassification of individuals at intermediate

risk to a lower or higher-risk category may further refine

risk stratification and lead to a more cost-effective risk

control strategy. Studies are under way to confirm this

concept. Currently, the prognostic value of CT-CA is not

firmly established, but the improved CT-image qualitywith newer-generation CT scanners will increase insights

into the progression of coronary atherosclerosis, from

earlier subclinical plaque to the more advanced sympto-

matic phase of CAD.

The high negative predictive value of CT-CA, to exclude

the presence of CAD renders CT as a suitable first-line

diagnostic test in symptomatic patients with low to inter-

mediate pretest likelihood of CAD, and may be con-

sidered an alternative to bicycle stress testing, SPECT

myocardial perfusion imaging or stress echo. Clinical

randomized trials should explore whether diagnostic

and treatment strategy using CT-CA as an alternativeto current standard care will improve clinical outcome in

symptomatic patients with stable angina, and whether

such a strategy is cost-effective.

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Table6 Prediction of cardiovascular eventsin symptomatic patients by traditional risk factors model andby expandingthe model with CT-CA

Study N Female (%) Follow-up (years) AUC with RF model AUC with RF and CT-CA model

Ostrom et al.37 2538 30.0 6.5 0.69 0.83Chow et al.34 2609 47.4 2.1 0.72 0.81 (severity CAD)Carrigan et al.33 227 39.0 2.3 0.6 0.75 (total plaque score)

AUC, area under the receiver operating curve; CAD, coronary artery disease; RF, traditional risk factors.



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