Coronary CT angiography allows for noninvasive imaging of the heart and coronary arteries. It can be used to evaluate patients with chest pain, assess coronary arteries after revascularization, and detect congenital coronary anomalies. The scan involves a non-contrast scan for calcium scoring followed by a contrast-enhanced scan. Proper patient preparation including beta-blockers and nitroglycerin is important. Images are analyzed using techniques like multiplanar reformation, maximum intensity projection, volume rendering and curved reformation to evaluate coronary artery anatomy and detect any stenosis.

1. BASICS OF
CORONARY CT ANGIOGRAPHY
Dr. Mohamed Abdelfattah Youssef
Assistant lecturer of radio diagnosis

2. INTRODUCTION
Heart disease is the leading cause of death
world wide.
Coronary heart disease is the most common
type of heart disease.
Imaging of the heart is technically
challenging due to continuous cardiac
motion.

3. Indications
Equipments
AND TECHNICAL ASPECTS
Patient preparation
Data acquisition
Post processing

4. Atypical chest pain

5. TYPICAL CHEST PAIN WITH LOW OR INTERMEDIATE RISK
According to Framingham Risk Score

6. https://www.cvdriskchecksecure.com/framinghamriskscore.aspx
http://tools.acc.org/ASCVD-Risk-Estimator/

7. DETECTION OF CAD POST REVASCULARIZATION

8. ASSESSMENT OF CORONARY ARTERY
ANOMALIES

9. Indications
Equipments
and technical aspects
Patient preparation
Data acquisition
Post processing

10. Equipments
64 MSCT or higher with
ECG gating
Injector (Dual head)
Workstation with cardiac
dedicated software

11. TEMPORAL RESOLUTION
Its the duration of time for acquisition of a
single frame of a dynamic process.
It depends on speed of gantry rotation

12. Gantry rotation

13. Spatial resolution
The ability of the imaging modality to
differentiate two objects.
Determined by minimum slice thickness of the machine

15. ECG gating
The least cardiac motion occurs during diastole
Gating techniques are used to improve
temporal resolution and minimize imaging
artifacts caused by cardiac motion

17. 10% 20% 0%90%80%70%60%50%40%30%

18. ECG gating techniques
Prospective ECG triggering :
ECG signal is used to control scanning, so that X rays are generated and
projection data are acquired only during cardiac diastole.
Retrospective ECG triggering :
Every position of the heart must be covered by a detector row at every
point during the cardiac cycle continuously and the ECG signal is
simultaneously recorded

19. 10% 20% 0%90%80%70%60%50%40%30%
Prospective ECG gating

20. 10% 20% 0%90%80%70%60%50%40%30%
Retrospective ECG gating

21. As image
reconstruction
depends on ECG
any kind of
arrhythmia will
interrupt image
reconstruction
causing artifacts

22. Why dual head injectors?
Push contrast from connectors and venous
circulation  20 -40 % contrast saving
Improves peak enhancement and bolus
arrival

23. Wash of contrast from
right side of the heart
Decrease streak artifact
due to contrast pooling
Better visualization of RCA
Why dual head injectors?

24. Indications
Equipments
Patient preparation
Data acquisition
Post processing

25. PATIENT PREPARATION
BEFORE SCAN
24 – 48 Hrs before scan
Stop
Don’t stop other medications.
Kidney function test
Serum creatinine
Fasting 8hours prior to exam

26. History
Consent
Gown
Cannula
Reassurance Sedation
Breathing exercise
Vital data
Patient Positioning and ECG Leads Attachment
Heart rate control
PATIENT PREPARATION
AT DAY OF
SCAN

27. MEDICATIONS
•Oral :50- 100 mg Evening before and morning
of the scan→ 50- 100 one hour before the scan.
•CI: bronchial asthma ,sever aortic stenosis
,heart block and hypotension.
B-Blockers
Metoprolol
•Dinitra Sublingual tab or SL spry 0.4mg
•?? Diagnostic valueNitroglycerin
•Calmepam 1.5 mg
Promazepam

28. ?
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29. Indications
Equipments
Patient preparation
Data acquisition
Post processing

30. Performing scan
I-NONENHANCED STUDY
Non enhanced
prospective ECG gated
scan from the tracheal
carina to the upper third
of the liver.
Send data to work
station for Ca scoring
Ca score > 1000 Terminate scan
Ca score < 1000 Proceed
Scanogram

31. • ROI over ascending /
descending aorta
• Automated bolus trigger
• A threshold of 100-120 HU
• Pro/retrospective ECG gating
• Maximum Gantry Rotation
speed and collimation
• Rate of injection : 5 – 6 mL/sec
Performing scan
II-ENHANCED STUDY
80 -100 cc of high concentration of
nonionic contrast media 350–370 mg of
iodine per milliliter is used followed by
40 cc of saline.

32. Ca scoring value
It was initially invented to Predict the risk of
CAD in the future
Predicts the diagnostic value of coronary CTA

33. Ca scoring
Interpretation

34. PROTOCOL MODULATION FOR
POST CABG Patients
Ca score is not
needed.
Scan extends from
the upper chest to
the upper 13 of the
liver.

35. All outpatients who receive study-
related medication are monitored (ie,
kept in the waiting area) for 30 minutes
after scanning.

36. Indications
Equipments
Patient preparation
Data acquisition
Post processing

37. CORONARY ARTERIES ANATOMY

38. AORTIC ROOT

39. CORONARY ANATOMY
It usually bifurcates
into left anterior
descending
and
left circumflex
arteries
Left coronary artery
LEFT MAIN artery
(LM)
It arises from the
left posterior aortic
sinus
The LM and its bifurcation are covered by PA

40. It runs
downwards in
the anterior
inter-ventricular
groove
Left coronary artery
Left anterior descending
artery (LAD)
CORONARY ANATOMY

41. The LAD artery
gives rise to a
variable
number of
diagonal
branches which
lie on the
lateral aspect
of the left
ventricle.
CORONARY ANATOMY Left coronary artery
DIAGONAL branches
(D1,D2,…..)

42. The circumflex
artery turns
backwards to run
in the left
atrioventricular
groove
Left coronary artery
LEFT CIRCUMFLEX artery
(LCx)
CORONARY ANATOMY
In the atrioventricular
groove the circumflex
artery is often
covered by the
auricle of the left
atrium

43. The LCx gives
rise to a variable
number of
marginal
branches, which
run on the lateral
aspect of the left
ventricle
Left coronary artery
OBTUSE MARGINAL BRANCHES
(OM1,OM2,…..)
CORONARY ANATOMY

44. Left coronary artery
RAMUS INTERMEDIUS artery
CORONARY ANATOMY
In one-third of
population the
left
main coronary
artery trifurcates
into the LAD, left
circumflex,
and an
intermediate
artery,

45. CORONARY ANATOMY
Normally arises from
the right coronary
sinus (CS) and
courses in the right
AV groove toward
the crux
posterior lateral
branch and posterior
descending artery.
RIGHT CORONARY artery
(RCA)
of the heart
where it
usually
divides into
LA RA
POSTERIOR
VIEW

46. Dominance
The coronary artery that gives rise to the
PDA and PLB is referred to as the
“dominant” artery.
Artery Dominance
percentage
RCA 70%
LCx 10%
RCA and LCx
(Co dominant)
20%

47. AXIAL ANATOMY

48. Multiplanar Reformation
Multiplanar Reconstruction (MPR) allows images
to be created from the original axial plane in
either the coronal, sagittal, or oblique planes

49. Maximum Intensity Projection (MIP)
Consists of projecting
the voxel with the
highest attenuation
value throughout the
volume onto a 2D
image

50. Volume Rendering
• VR is a 3D technique
• Useful for evaluating
complex anatomy,
including coronary
artery anomalies,
bypass grafts, fistulas
and bridging.

51. Volume Rendering

52. Curved Reformation
Curved reformatted images
provides evaluation of the
entire vessel length
regardless its tortousity.