1. AIM OF THE STUDY
To analyse the percentage of coronary artery stenosis with the help of C.T
Coronary Angiogram.

2. INTRODUCTION
Computed Tomography (CT combines X-radiation and radiation detectors
coupled with a computer to create cross- sectional image of any part of the body.
The basic principle behind CT is that the internal structure of an object can be
reconstructed from multiple projections of the body.
The CT was first established as being relatively high dose X-ray imaging
technique. At first the CT practice involved single slice scanners largely operating
in a slice-by-slice axial scanning mode. CT practice continues to evolve with the
introduction of multidetector rows to allow rapid imaging of large volume of the
patient by simultaneous acquisition of multiple slices. CT plays a central,
increasingly influential role in medical imaging, the combination of faster scanning
and improved image quality available with MDCT.
AXIAL Vs HELICAL CT
Axial is slice – by- slice scanning mode. In this, the exposure is made after
each table incremenation according to the region scanned. Conversely, the helical
CT scanners acquire data while the table is moving as a result the X-ray source
moves in a helical pattern around the patient being scanned.

3. In helical CT, the total scan time required to image the patient can be made
much shorter by simultaneous rotation of the X-ray tube and translation of the
patient table. Consequently, helical scanning allows the use of less contrast agent
and increases patient throughput. In some instnces, the entire scan can be
performed within a single breadth hold of the patient, avoidind inconsistent levels
of inspiration.
The speed of the table motion relative to the rotation of CT gantry is a very
important consideration in helical CT and pitch is the parameter that describes this
relationship
PITCH = TABLE MOVEMENT (mm)/360° GANTRY ROTATION
NOMIAL SLICE WIDTH (mm)

4. CARDIAC CT
Multislice CT (MSCT) is the latest technology in this decade, functioning by
acquiring multiple simultaneous slices using multi-detector system. Most advanced
and contemporary models are the 64-slices machine, dual source CT machine and
the 256-slices machine.
One of the latest advances in CT is CT coronary angiogram all these
machines are competing for better performance by improving the spatial and
temporal resolution. To date, a good CT machine can complete the scan in less
than 0.3 seconds in optimal settings.
Cardiac CT provides information about the heart morphology. In cardiac
imaging, faster the data acquisition, better the image quality. Coronary CTA is a
highly accurate non-invasive diagnostic modality for the assessment of coronary
artery disease and its severity. CTA is a useful imaging modality for the
Electrophysiological Cardiologist and Cardiac Surgeon. Coronary CTA allows for
the assessment of vessel wall morphology.
Coronary CTA bridges a very large gap in diagnostic testing between
traditional stress testing and selective coronary angiography. The extremely high

5. negative predictive valve of coronary CTA should reduce the number of normal
catherterization.
PROSPECTIVE TRIGGERING
It is an axial (step and shoot) mode of scanning where the acquisition is done only
during the diastolic phase of the cardiac cycle. (Snap Shot Pulse)
X-RAY ON
PROSPECTIVE TRIGGERING

6. PADDING
In case if you suspect any variation in the heart rate, Padding can be applied
which exposes the patient for additional time before and after the center phase of
the acquisition and utilizes the data for reliable reconstruction.
Heart Rate Dependent Padding
HR Range milli second
30 – 39 175
40 – 49 150
50 – 59 125
60> 100

7. RETROSPECTIVE GATING
It is helical mode scanning where the acquisition is done throughout the
entire cardiac cycle. (Snap Shot Segment)
X-ray
on
Retrospectively gated reconstruction using data from 2/3 of a gantry rotation
to create an image form one cardiac cycle.
SNAP SHOT SEGMENT Heart rate 30 – 74 BPM
Cycle 1
A retrospectively gated reconstruction, using data from 2 cardiac cycles
within the same cardiac phase, to create an image at a given anatomic location.

8. SNAP SHOT BURST Heart rate 75 – 113 BPM Cycle 1
Cycle 2
A retrospectively gated reconstruction, using data from 4 cardiac cycles
within the same cardiac phase, to create an image at a given anatomic location.
Snap Shot Burst Plus Heart rate 114+ BPM Cycle 1
Cycle 2
Cycle 4 Cycle 3

9. Scan Resolution
The 64 slices CT machine with narrow scan collimation provide significantly
enhances the reconstruction work of CT Coronary Angiogram.
Radiation dose and Risk
As the number of slices increase, radiation efficiency also increases.
Radiation dose is affected by mAs (electric current of the machine) and kVp and
both have to be kept as low as possible. The radiation dose of coronary Angiogram
64-slice CT machines is approximately 13-18 mSv respectively. The risk of
developing severe allergic reaction with non-ionic contrast is about 0.2%-0.7% of
patient. Single CT coronary angiogram is about 3 to 6 times the yearly radiation
dose.

10. Spatial Resolution
A good spatial resolution is important as we are scanning coronary arteries,
which have diameter between 1mm to 4mm. The spatial resolution of about
0.33-0.35mm is obtained by a 64-slice machine, with the isotropic voxel geometry
of 0.5mm, and seems to be working well.
Temporal resolution
For complete motionless imaging of heart, we need the temporal resolution to be
20msec. Better temporal resolution can be achieved by faster gantry (CT machine)
rotation.

11. ANATOMY OF THE HEART AND ITS BLOOD VESSELS
CORONARY ARTERIES

12. The two main coronary arteries are the left and right coronary arteries. The left
coronary artery (LCA), which divides into the left anterior descending artery and
the circumflex branch, supplies blood to the left ventricle and left atrium.
The right coronary artery (RCA), which divides into the right posterior
descending and acute marginal arteries, supplies blood to the right ventricle, right
atrium, sinoatrial node (cluster of cells in the right atrial wall that regulates the
heart's rhythmic rate), and atrioventricular node.
Additional arteries branch off the two main coronary arteries to supply the heart
muscle with blood. These include the following:
• Circumflex artery (Cx)
The circumflex artery branches off the left coronary artery and encircles the
heart muscle. This artery supplies blood to the lateral side and back of the
heart.
• Left anterior descending artery (LAD)
The left anterior descending artery branches off the left coronary artery and
supplies blood to the front of the left side of the heart.

13. Smaller branches of the coronary arteries include: acute marginal, posterior
descending (PDA), obtuse marginal (OM), septal perforator, and diagonals. On the
left an overview of the coronary arteries in the anterior projection.
• Left Main or left coronary artery (LCA)
Left anterior descending (LAD)
 Diagonal branches (D1, D2)
 Septal branches
Circumflex (Cx)
 Marginal branches (M1, M2)
Right coronary artery
o Acute marginal branch (AM)
o AV node branch
o Posterior descending artery (PDA).
• Left Main or left coronary artery (LCA)
o Left anterior descending (LAD)

14.  Diagonal branches (D1, D2)
 Septal branches
o Circumflex (Cx)
o Marginal branches (M1, M2)
• Right coronary artery
o Acute marginal branch (AM)
o AV node branch
o Posterior descending artery (PDA)

15. • Left Main or left coronary artery (LCA)
o Left anterior descending (LAD)
 Diagonal branches (D1, D2)
 Septal branches
o Circumflex (Cx)
 Marginal branches (M1, M2)
• Right coronary artery
o Acute marginal branch (AM)
o AV node branch
o Posterior descending artery (PDA)

16. Left Coronary Artery (LCA)
Left coronary (LC), right coronary (RC) and posterior non-coronary (NC) cusp
The left coronary artery (LCA) is also known as the left main.
The LCA arises from the left coronary cusp.
The aortic valve has three leaflets, each having a cusp or cup-like configuration.
These are known as the left coronary cusp (L), the right coronary cusp (R) and the
posterior non-coronary cusp (N).
Just above the aortic valves there are anatomic dilations of the ascending aorta,
also known as the sinus of Valsalva. The left aortic sinus gives rise to the left

17. coronary artery.
The right aortic sinus, which lies anteriorly, gives rise to the right coronary artery.
The non-coronary sinus is positioned on the right side.
LCA divides into LAD and Cx
The LCA divides almost immediately into the circumflex artery (Cx) and left
anterior descending artery (LAD).
The LCA travels between the right ventricle outflow tract anteriorly and the left
atrium posteriorly and divides into LAD and Cx.
• Cx with obtuse marginal branch (OM)
• LAD with diagonal branches (DB)
In 15% of cases a third branch arises in between the LAD and the Cx, known as
the ramus intermedius or intermediate branch. This intermediate branches behaves
as a diagonal branch of the Cx.

18. Left Anterior Descending (LAD)
CT image of the LAD in RAO projection
The LAD travels in the anterior interventricular groove and continues up to the
apex of the heart.
The LAD supplies the anterior part of the septum with septal branches and the
anterior wall of the left ventricle with diagonal branches.
The LAD supplies most of the left ventricle and also the AV-bundle.
Mnemonic: Diagonal branches arise from the LAD.
The diagonal branches come off the LAD and run laterally to supply the antero-
lateral wall of the left ventricle.
The first diagonal branch serves as the boundary between the proximal and mid
portion of the LAD (2). There can be one or more diagonal branches: D1, D2, etc.

19. Circumflex (Cx)
The Cx lies in the left AV groove between the left atrium and left ventricle and
supplies the vessels of the lateral wall of the left ventricle. These vessels are known
as obtuse marginals (M1, M2...), because they supply the lateral margin of the left
ventricle and branch off with an obtuse angle. In most cases the Cx ends as an
obtuse marginal branch, but 10% of patients have a left dominant circulation in
which the Cx also supplies the posterior descending artery (PDA).
Mnemonic: Marginal branches arise from the Cx and supply the lateral Margin of
the left ventricle.
Right Coronary Artery (RCA)

20. RCA, LAD and LCx in Anterior projection
The right coronary artery arises from the anterior sinus of Valsalva and courses
through the right atrioventricular (AV) groove between the right atrium and right
ventricle to the inferior part of the septum. In 50-60% the first branch of the RCA
is the small conus branch that supplies the right ventricle outflow tract. In 20-30%
the conus branch arises directly from the aorta. In 60% a sinus node artery arises as
second branch of the RCA, that runs posteriorly to the SA-node (in 40% it
originates from the Cx).
The next branches are some diagonals that run anteriorly to supply the anterior
wall of the right ventricle. The large acute marginal branch (AM) comes off with
an acute angle and runs along the margin of the right ventricle above the
diaphragm. The RCA continues in the AV groove posteriorly and gives off a
branch to the AV node. In 65% of cases the posterior descending artery (PDA) is a
branch of the RCA (right dominant circulation). The PDA supplies the inferior
wall of the left ventricle and inferior part of the septum.
LEFT: RCA comes off the right sinus of Valsalva
RIGHT: Conus artery comes off directly from the aorta

21. On the image on the far left we see the most common situation, in which the
RCA comes off the right cusp and will provide the conus branch at a lower level
(not shown).
On the image next to it, we see a conus branch, which comes off directly from the
aorta.
The large acute marginal branch (AM) supplies the lateral wall of the right
ventricle.
In this case there is a right dominant circulation, because the posterior descending
artery (PDA) comes off the RCA.
Coronary Anomalies
Coronary anomalies are uncommon with a prevalence of 1%. Early detection
and evaluation of coronary artery anomalies is essential because of their potential
association with myocardial ischemia and sudden death (3). With the increased use
of cardiac-CT, we will see these anomalies more frequently.

22. Coronary anomalies can be differentiated into anomalies of the origin, the course
and termination
The illustration in the left upper corner is the most common and clinically
significant anomaly. There is an anomalous origin of the LCA from the right sinus
of Valsalva and the LCA courses between the aorta and pulmonary artery. This
intra-arterial course can lead to compression of the LCA (yellow arrows) resulting
in myocardial ischemia.
The other anomalies in the figure on the left are not hemodynamically
significant.

23. Why are the coronary arteries important?
Since coronary arteries deliver blood to the heart muscle, any coronary artery
disorder or disease can have serious implications by reducing the flow of oxygen
and nutrients to the heart, which may lead to a heart attack and possibly death.
Atherosclerosis (a build-up of plaque in the inner lining of an artery causing it to
narrow or become blocked) is the most common cause of heart disease.
SUPERIOR VENA CAVA
The superior vena cava is one of the two main veins bringing de-oxygenated blood
from the body to the heart. Veins from the head and upper body feed into the
superior vena cava, which empties into the right atrium of the heart.
INFERIOR VENA CAVA
The inferior vena cava is one of the two main veins bringing de-oxygenated blood
from the body to the heart. Veins from the legs and lower torso feed into the
inferior vena cava, which empties into the right atrium of the heart.

24. AORTA
The aorta is the largest single blood vessel in the body. It is approximately the
diameter of your thumb. This vessel carries oxygen-rich blood from the left
ventricle to the various parts of the body.
PULMONARY ARTERY
The pulmonary artery is the vessel transporting de-oxygenated blood from the right
ventricle to the lungs. A common misconception is that all arteries carry oxygen-
rich blood. It is more appropriate to classify arteries as vessels carrying blood away
from the heart.
PULMONARY VEIN
The pulmonary vein is the vessel transporting oxygen-rich blood from the lungs to
the left atrium. A common misconception is that all veins carry de-oxygenated
blood. It is more appropriate to classify veins as vessels carrying blood to the heart.
RIGHT ATRIUM

25. The right atrium receives de-oxygenated blood from the body through the superior
vena cava (head and upper body) and inferior vena cava (legs and lower torso).
The sinoatrial node sends an impulse that causes the cardiac muscle tissue of the
atrium to contract in a coordinated, wave-like manner. The tricuspid valve, which
separates the right atrium from the right ventricle, opens to allow the de-
oxygenated blood collected in the right atrium to flow into the right ventricle.
RIGHT VENTRICLE
The right ventricle receives de-oxygenated blood as the right atrium contracts. The
pulmonary valve leading into the pulmonary artery is closed, allowing the ventricle
to fill with blood. Once the ventricles are full, they contract. As the right ventricle
contracts, the tricuspid valve closes and the pulmonary valve opens. The closure of
the tricuspid valve prevents blood from backing into the right atrium and the
opening of the pulmonary valve allows the blood to flow into the pulmonary artery
toward the lungs.
LEFT ATRIUM
The left atrium receives oxygenated blood from the lungs through the pulmonary
vein. As the contraction triggered by the sinoatrial node progresses through the
atria, the blood passes through the mitral valve into the left ventricle.

26. LEFT VENTRICLE
The left ventricle receives oxygenated blood as the left atrium contracts. The blood
passes through the mitral valve into the left ventricle. The aortic valve leading into
the aorta is closed, allowing the ventricle to fill with blood. Once the ventricles are
full, they contract. As the left ventricle contracts, the mitral valve closes and the
aortic valve opens. The closure of the mitral valve prevents blood from backing
into the left atrium and the opening of the aortic valve allows the blood to flow into
the aorta and flow throughout the body.
PAPILLARY MUSCLES
The papillary muscles attach to the lower portion of the interior wall of the
ventricles. They connect to the chordae tendineae, which attach to the tricuspid
valve in the right ventricle and the mitral valve in the left ventricle. The contraction
of the papillary muscles opens these valves. When the papillary muscles relax, the
valves close.
CHORDAE TENDINEAE
The chordae tendineae are tendons linking the papillary muscles to the tricuspid
valve in the right ventricle and the mitral valve in the left ventricle. As the

27. papillary muscles contract and relax, the chordae tendineae transmit the resulting
increase and decrease in tension to the respective valves, causing them to open and
close. The chordae tendineae are string-like in appearance and are sometimes
referred to as "heart strings."
TRICUSPID VALVE
The tricuspid valve separates the right atrium from the right ventricle. It opens to
allow the de-oxygenated blood collected in the right atrium to flow into the right
ventricle. It closes as the right ventricle contracts, preventing blood from returning
to the right atrium; thereby, forcing it to exit through the pulmonary valve into the
pulmonary artery.
MITRAL VALUE
The mitral valve separates the left atrium from the left ventricle. It opens to allow
the oxygenated blood collected in the left atrium to flow into the left ventricle. It

28. closes as the left ventricle contracts, preventing blood from returning to the left
atrium; thereby, forcing it to exit through the aortic valve into the aorta.
PULMONARY VALVE
The pulmonary valve separates the right ventricle from the pulmonary artery. As
the ventricles contract, it opens to allow the de-oxygenated blood collected in the
right ventricle to flow to the lungs. It closes as the ventricles relax, preventing
blood from returning to the heart.
AORTIC VALVE
The aortic valve separates the left ventricle from the aorta. As the ventricles
contract, it opens to allow the oxygenated blood collected in the left ventricle to
flow throughout the body. It closes as the ventricles relax, preventing blood from
returning to the heart.

29. PATIENT PREPARATION
 Nil Per Oral – 4 hours prior
 No coffee/ caffeine stimulants 24 hours prior
 Check
 Renal parameters (Blood Urea, Creatinine
 Blood Pressure
 Heart Rate

30.  Get clinical history about the patient which should include present
complaints, family history patient’s weight, height, blood
investigation reports, ECG, Echo, TMT reports, conventional
angiogram reports if done.
PREMEDICIATION
If heart rate < 65, proceed with the examination
If heart rate > 65, to reduce the heart rate. Beta-blockers are prescribed
– Metaprolol
– Esmolol
Contraindications for beta-blockers
Pre-existing bradycardia
Bronchial asthma
Cardiac failure
Allergy to beta blockers
 18G Venflon in anticubital vein preferably in right hand.

31.  Ensure proper placement of ECG leads
PRE PROCEDURAL INSTRUCTIONS
• Explain the procedure to the patient
• Demonstrate Breath-hold instructions.
Two important factors that contribute to successful coronary angiogram
 Stable low Heart rate
 Good breath hold
INDICATIONS
 Non specific chest pain
 TMT – Positive
 Altered ECG signal
 Post PTCA, Stenting, CABG – follow up
 Dyspnoea
 Detection of coronary anomalies

32.  Systemic Hypertension, Diabetic Mellitus, Elevated Cholesterol with chest
pain
CONTRAINDICATIONS
 Renal failure patients
 Calcium score greater than 800
 Pregnancy
MATERIALS AND METHODS
Multislice (64slices) CT scanner
Manufacturer: GE
Model name: Light speed VCT xt
Model No: 5124069-5 (gantry); 5121647 (table)
Sr.No: 399672CN5 (gantry); 165233HM8(table)

33. METHODS
GATING
Imaging must be synchronized to the heartbeat, so that we can acquire data
during a consistent cardiac phase. We achieve this with ECG gating
ECG GATING
The ECG waveforms allow us to predict heart motion. We use a percent R-to-R
valve to control at what cardiac phase image are generated. The goal is to generate
images with the least amount of motion.
RETROSPECTIVE GATING
Retrospective gating acquires image data and times it to the cardiac cycle during
reconstruction
Acquires data from the entire cardiac cycle. It is faster and contiguous
acquisition. ECG trace is recorded simultaneously with the scan.
Algorithms sort data from different phases by shifting temporal window of
acquired helical projection data. Every position of heart covered at every point in
cardiac cycle.

34. Partial scanning and segmented adapted algorithms. Projections of the mid-
diastolic phase are selected to reconstruct images from the slow motion diastole
phase of the heart.
PROSPECTIVE GATING
Prospective means that the scan is timed to and triggered from the beats of the
heart during the acquisition. Prospective gating is the technique that occurs during
image acquisition, as opposed to retrospective gating.
Redundant radiation occurring during exposure can be substantially reduced with
prospective ECG tube current modulation. The technique reduces half the radiation
dose to a patient with a heart rate of 60 beats per minute.
Image reconstruction with sufficient quality is still possible at anytime within the
cardiac cycle.
In coronary CT angiography firstly calcium scoring is done followed by the
contrast study
Contrast: 1.2-ml/Kg body weight (visipaque)
Saline: 30ml.

35. CONTRAST ADMINISTRATION
• Nonionic contrast media
• Volume of contrast based on patient weight (Pt. wt x 1.25 ml)
• Flow rate – 5 - 5.5ml/sec

36. CALCIUM SCORING
Cardiac calcium scoring uses a special X-ray called a computed Tomography
(CT) scan to find the buildup of calcium on the walls of the arteries of the heart
(coronary arteries). This test is used to check for heart disease in an early stage and
to determine how severe it is. Cardiac calcium scoring is also called coronary
artery calcium scoring.
The coronary arteries supply blood to the heart. Normally, the coronary arteries
do not contain calcium. Calcium in the coronary arteries is another risk factor like
high cholesterol or blood pressure.

37. SCAN PROTOCOL
PARAMETERS PROSPECTIVE RETROSPECTIVE
Scan type Axial Helical
Gantry rotation time 0.35sec 0.35sec
Detector coverage 40mm 40mm
Slice thickness 0.625mm 0.625mm
Based on HR
Pitch -
(0.16 – 0.24)
kV 120 120
• Based on BMI
mA Based on BMI
• ECG modulated mA

38. ECG LEAD PLACEMENT
Lead of the right arm (RA) should be placed in the sterna notch. Lead of the left
arm (LA) should be placed in the xyphysternum. Lead of the left lower (LL)
should be placed in the left costal margin.
MECHANICS OF THE STUDY
Performed as routine Chest CT
I/V established for contrast injection
ECG leads for cardiac gating
10-15 seconds breathe hold.

39. PROCEDURE
SCANNING PROCEDURE
The patient lies supine on the CT scan table and the ECG leads are placed. The
aim is to get a good, regular signal. The patient lies still for almost 5 minutes to
establish and regularize the heart rate. The breath – hold instructions are gone
through once again with a practice session.
POSITIONING:

40. All the radio opaque materials are removed from the patient’s body. Patient is
positioned supine on the table same as for thorax study. The ECG leads are placed
on the patient’s chest. Breathing instructions are given to the patient. Contrast
filled pressure injector is connected to the patient. Contrast filled pressure injector
is connected to the patient’s I/V line.
SCANOGRAM:
The scanogram is combined as for a chest CT calcium scoring (axial images),
from the lower neck to up to just before the diaphragms. For planning the contrast
phase from carina to base of the heart.
CALCIUM SCORING:
CT and in particular, electron-beam CT (EBCT) is the most sensitive
radiographic method to detect coronary artery calcification. The value of EBCT
can be summarized as follows:
Absence of Detectable Coronary Artery Calcification EBCT*

41. • Does not absolutely rule out the presence of atherosclerotic plaque,
including unstable plaque
• Highly unlikely in the presence of significant luminal obstructive disease
• Observation made in the majority of patients who have had both
angiographically normal coronary arteries and EBCT scanning
• Testing is gender independent
• May be consistent with a low risk of a cardiovascular event in the next 2-5
years
Presence of Detectable Coronary Artery Calcification EBCT*
• Confirms the presence of coronary atherosclerotic plaque
• The greater the amount of calcification (i.e., calcium area or calcium score),
the greater the likelihood of obstructive disease, but there is no one-to-one
relation, and findings may not be site specific
• Total amount of calcification correlates best with total amount of
atherosclerotic plaque, although the true "plaque burden" is underestimated
• A high calcium score may be consistent with moderate to high risk of a
cardiovascular event within the next 2-5 year

42. Coronary calcification score
• Threshold CT density > 130 HU for pixel areas > 1mm2
• Lesion Score 1 = 130 - 199, 2 = 200 - 299, 3 = 300 - 399, 4 > 400
• Score each region of interest by multiplying the density score and the area
• Total coronary calcium score determined by adding up each lesion score for
all sequential slices
SMART PREP TECHINQUE

43. Smart prep is software used in angiogram
CT coronary angiography is triggered by the arrival of the main contrast bolus.
A pre-scan is taken at the level of aortic root and a region of interest is identified in
the ascending aorta. Repeated scanning is performed at the same level every
second once contrast injection begins.
CTA acquisition is triggered to start as soon as density values in the ascending
aorta reach 2000 HU, at which point patients are instructed to their breath.

44. ANGIOGRAM PLANNING RANGE:
Based on the calcium scoring study, the range is selected. The inferior margin
is at the inferior margin of the heart. The superior margin is above LM. Usually we
add at least a three-four heart beat margin superiorly to allow stabilization of the
heart rate, after and inspiration is achieved. Then injecting the contrast agent
performs the coronary CT angiogram.

45. POST PROCESSING TECHINQUES
Snap shot burst pulse
• Multi Planar Reformation (MPR)/ Curved MPR
• Maximum Intensity Projection (MIP)
• Volume Rendering (VR)
POST-PROCEDURAL CARE
• Extravasation

46. • Allergic Reaction
• Hydrate the patient
• Reassure patient comfort

47. REFERENCES:
Schoenhagen P, Halliburton SS, Stillman AE, et al. Noninvasive Imaging of
Coronary Arteries: Current and Future Role of Multi-Detector Row CT. Radiology
2004; 232:7-17.
[Related Records][Full text]
Schoepf UJ, Becker CR, Ohnesorge BM, Yucel EK. CT of Coronary Artery
Disease. Radiology 2004; 232:18-37.
[Related Records][Full text]
Greenland P, LaBree L, Azen SP, Doherty TM, Detrano RC. Coronary artery
calcium score combined with Framingham score for risk prediction in
asymptomatic individuals. Jama 2004; 291:210-215.
[Related Records]
Wexler L, Brundage B, Crouse J, et al. Coronary artery calcification:
pathophysiology, epidemiology, imaging methods, and clinical implications. A
statement for health professionals from the American Heart Association. Writing
Group. Circulation 1996; 94:1175-1192.
[Related Records]

48. Diamond GA, Forrester JS. Analysis of probability as an aid in the clinical
diagnosis of coronary-artery disease. N Engl J Med 1979; 300:1350-1358.
[Related Records]
Black WC, Armstrong P. Communicating the significance of radiologic test
results: the likelihood ratio. AJR 1986; 147:1313-1318.
[Related Records]
Stanford W, Thompson BH, Weiss RM. Coronary artery calcification: clinical
significance and current methods of detection. AJR 1993; 161:1139-1146.
[Related Records]
Agatston AS, Janowitz WR, Hildner FJ, et al. Quantification of coronary artery
calcium using ultrafast computed tomography. J Am Coll Cardiol 1990;
15:827-832.
[Related Records]
Budoff MJ, Georgiou D, Brody A, et al. Ultrafast computed tomography as a
diagnostic modality in the detection of coronary artery disease: a multicenter study.
Circulation 1996; 93:898-904.
[Related Records]

49. Rifkin RD, Parisi AF, Folland E. Coronary calcification in the diagnosis of
coronary artery disease. Am J Cardiol 1979; 44:141-147.
[Related Records]
Detrano R, Hsiai T, Wang S, et al. Prognostic value of coronary calcification and
angiographic stenoses in patients undergoing coronary angiography. J Am Coll
Cardiol 1996; 27:285-290.
[Related Records]
Rumberger JA, Brundage BH, Rader DJ, Kondos G. Electron beam computed
tomographic coronary calcium scanning: a review and guidelines for use in
asymptomatic persons. Mayo Clin Proc 1999; 74:243-252.
[Related Records]