coronary ct angiography intern

8/14/2019 Coronary CT Angiography INTERN

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Coronary CT Angiography

Intern


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Udo Hoffmann, Maros Ferencik, Ricardo C. Cury, and Antonio J. PenaCoronary CT Angiography

J Nucl Med May 1 2006 47: 797-806.
http://jnm.snmjournals.org/content/vol47/issue5/cover.shtml


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INTRODUCTION

patient preparation

image acquisition

evaluation techniques


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patient preparation

Image quality improved at low heart rates(


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image acquisition

A low-energy topogramdetermination of the adequate initiation of the coronary CTA image

acquisition to ensure homogeneous contrast enhancement of the

entire coronary artery tree

Two techniques:

1. the timing bolus technique

2. the bolus tracking techniqueCT volume dataset


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The minimal equipment requirement for state-of-the-art

coronary CTA is a 16-slice scanner. However, 40- or 64-slice MDCT scanners are recommended, as theyincreasethe volume coverage and permit reduction ofthe scan time and the amount of contrast agent.


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Radiation exposure

64-slice MDCT:11~22mSv

(ECG-controlled dose modulation is 7

11mSv)

invasive selective coronary angiography:

2.55mSv,

nuclear perfusion imaging with SPECT:15~20mSv


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Image evaluation

multiplanar reformatted (MPR) images

For the confirmation of pathologic findings in the

long and short axes of the vessel.

sliding thin-slab MIP (STS-MIP) images

enhance the visualization of coronary arterystenosis in a long-axis view of the vessel if

narrowing is caused by noncalcifiedatherosclerotic plaque


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Artifact

Motion Artifacts occur at high rates and mostoften in the midsegment of the right coronary artery

Misalignment and Slab Artifacts high

heart rates, heart rate variability, and the presence ofirregular or ectopic heart beats (e.g. PVC)

Blooming Artifacts High-attenuationstructures, such as calcified plaques or stents, appearenlarged (or bloomed) because of partial volume

averaging effects and obscure the adjacent coronarylumen, the main cause of false-positive results incoronary CTA because of overestimation of thedegree of stenosis


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FINDINGS AND POTENTIAL CLINICAL

APPLICATIONS

Detection of Significant Coronary ArteryStenosis

moderate sensitivity (about 80%) and excellent specificity (about 90%)

Detection and Characterization of CoronaryAtherosclerotic Plaque

1. detects calcified or mixed plaque with sensitivities and specificitiesabove 90%.

2. the detection of noncalcified plaques, with sensitivities andspecificities ranging from 60% to 85%, but has the potential tofurther stratify noncalcified plaque into fibrous plaque and lipid-richplaque

3. smaller plaques ( 0.5 mm) are not detected


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Potential Clinical Applications

limitation Data based on single-center, multicenter trials and studies with

intermediate-risk populations are warranted

a very specific subset of symptomatic middle-aged white men who

had a high prevalence of CAD

Other potential applications coronary CTA is to improve the triage and management of

patients with acute chest pain.

preoperative risk

patency of stents placed in the left main coronary artery

bypass patency


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CONCLUSION

Severe coronary calcification remains the majorlimiting factor in coronary CTA.

The high negative predictive value of 64-slice MDCT,relative to invasive selective coronary angiography, can

rule out the presence of hemodynamically significantCAD.

Although data on clinical utility, cost, and cost-effectiveness are not yet available, coronary CTA mayimprove the management of patients with an

intermediate probability of CAD and patients withacute chest pain.


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Thanks for your attention!

coronary ct angiography intern

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