1. Role of cardiac CT in coronary artery diseases
Dr. Ahmed Refaey
MBBCh, MS, FRCR

2. Format of the lecture Normal anatomy of coronary arteries
MSCT coronary angio
Clinical application of CTA
Illustrated cases

3. Coronary arteries anatomy

4. LCA “ left coronary artery “
Normally arises from the left sinus of Valsalva
Courses posterior to the right ventricular outflow tract (RVOT), and bifurcates into the left anterior descending (LAD), and the left circumflex (LCX) branches.

5. Right Coronary Artery (RCA)
Normally arises from the right coronary sinus (CS) and courses in the right AV groove toward the crux of the heart

6. Of CAD Diagnosis Clinical Presentation ECG Echocardiography
Stress Test
Thallium Study
Coronary cathetrization
Multislice Coronary CT Scan

7. Methods of imaging of coronary arteries

8. Coronary catheterization
Multislice cardiac CT

9. Coronary catheterization

11. CORONARY CATHETERIZATION
Advantages
High resolution
Option for intervention
Disadvantages
X-ray exposure
Hospitalization
Invasive complications

12. Figure 21.8d
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

13. Multislice CT coronary angiography

14. What is Coronary CTA?
Coronary CTA is a non-invasive minimal risk procedure to directly visualize the coronary arteries through administration of IV contrast
It allows visualization of the coronary arteries similar to a cardiac catheterization with additional information about the WALL of the artery and composition of plaque (calcified or non-calcified)

15. Clinical application of CTA
Diagnosis of CAD
* intermediate liklihood of disease
* after equivocal/discordant stress imaging
* coronary anomalies
* before vascular surgury
* nonischemic vs ischemic cardiomyopathy
* acute chest pain
* bypass graft patency / location

16. Patient Preparation No Caffeine for 12 hours prior to exam
Everyone gets Beta-Blockers (Verapamil can be substituted)

17. Goal Heart Rate
< 60 bpm makes us happy

18. Contraindications Atrial Fibrillation Tachycardia
Beta Blockade Contraindication
Heart Block
Renal Failure (Creat>1.5)
Contrast Allergy

19. The Examination

20. Computed Tomography (CT)
X-ray tube and detector rotate around the patient, transversal slices are constructed following each rotation by computer

21. continuous scanning instead separated slices
Spiral multislice CT
continuous scanning instead separated slices

22. Entire heart imaged in 5-15 seconds
CT images that are used come from mid to end diastole due to relative motion free period

23. CT Angiography

24. Timing

25. CT-Angio Advantage
Excellent for Coronary vessel, bypass vessels, LV wall thickness and function, cardiac anatomy and pericardium assessment

26. Coronary Vessel Analysis

27. Maximum Intensity Projection Soft Plaque in Proximal LAD

28. Curved Planar Image

31. 3-D Volume Rendered Image

33. Effective Radiation Doses for Various Tests
Bone Density mSv
CXR: mSv
Mammogram: mSv
CT of the head: mSv
CT colonoscopy mSv
CT of the abdomen: mSv
Stress Gated Myocardial Perfusion Scan SPECT: mSv
CT chest: mSv
MSCT angiogram: mSv
Coronary angiography: 30mSv
CT chest/abd/pelvis: mSv
Dose allowed for radiological personnel: 20 mSv/year

34. CLINICAL APPLICATION OF CARDIAC CT ANGIO
Examine plaque components
Evaluate coronary vessels
Evaluate stent patency
Assess cardiac function

35. Examine plaque components

36. Plaque Characterization
Calcified vs. Soft
Plaque composition rather than the degree of lumen stenosis determines the risk of plaque rupture.
Vulnerable or “high-risk” plaques have thin fibrous cap with extracellular lipid core.
Not visible by catheterization, but is being explored with CT angio.
Plaques initially grow extrinsic and bulge adventitia, then grow into the lumen resulting in stenosis

38. Coronary Artery Plaque:
approximate amounts of lipid rich, fibrotic and calcified plaque
Fibrotic &
Calcified
20%
66%
The “Tip of the
Atherosclerotic
Iceberg”
Fibrotic
80%
33%
Lipid Rich

40. What does coronary calcification mean?
Calcium score correlates extremely well with coronary event risk
If multi-vessel CAC, then risk increases
Zero calcification suggests a very low probability of obstructive disease
Curved MPR reformatted
image of Right Coronary 17

41. Calcium Scoring “ Agatston score”

42. The Calcium Scale 1–99 mild 100–400 moderate >400 severe
The calcium scale is a linear scale with 4 calcium score categories:
0 none
1– mild
100– moderate
> severe
*Calcium score correlates directly with risk of events and likelihood of obstructive CAD*

45. Agatston-90

47. Examples of Coronary Artery ScansNO
CALCIFICATION
MODERATE
CALCIFICATION
SIGNIFICANT
CALCIFICATION
Images courtesy of HeartScan San Frasco 15

48. Coronary Artery Calcium Scans
Task: Detect Calcium in Coronary Artery
130 kVp
625 mA
.1 sec
3 mm

49. Coronary Artery Calcium Scans

50. Coronary Artery Calcium Scans

51. Coronary Artery Calcium Scans

52. Coronary Artery Calcium Scans

53. Coronary Artery Calcium Scans

54. Coronary Artery Calcium Scans

55. Coronary Artery Calcium Scans

56. Coronary Artery Calcium Scans

57. Coronary Artery Calcium Scans

58. Calcification in LAD 13

59. Calcification in RCA 15

60. EVALUATING CORONARY VESSELS

61. It can look even better than a conventional angiogram

62. Left Main Coronary Artery

63. Left Main, LAD, & Circumflex
Obtuse Marginal

64. Diagonal Branch off LAD

65. Right Coronary Artery
Acute Marginal
Right Coronary Artery
Sinoatrial

66. Right Coronary Artery

67. Evaluate stent patency

69. LAD Stent from Top to Bottom (1 mm)

70. LAD Stent from Front to Back (1 mm)

71. Cardiac function
Recent studies show good correlation between function parameters derived from MDCT and levocardiography.
DETERMINING EJECTION FRACTION

72. FUTURE OF CARDIAC CT One-stop shopping—
( cardiac function, coronary artery evaluation, plaque analysis, calcium quantification.)
Non-invasive

73. Illustrated cases

74. High-resolution Imaging1 LM
LAD 1 2 2 3 4 3
RCA
LCx LM 4
DSCT 74

75. Significant stenosis of the left anterior descending artery

82. Soft Plaque Visualization

85. stent in LAD,LCx & RCA I

86. Aortic Coarctation Visualized
Fröhlich, G et al. Circulation. 2005;112:e81.

87. Pericardial Calcification Multi-Slice CT Scanning Superior to MRI
Hoffmann et al. Circulation 108 (7): 48e Figure IG1

88. Mild CAD, and…

89. Pulmonary Emboli

90. Teaching Points

91. Cardiac Cath: Lumen only-no wall information. Evaluate stenosis
Cardiac Cath: Lumen only-no wall information. Evaluate stenosis. Cannot characterize plaque. Better delineates small vessels
What is needed is a non-invasive, minimal-risk, outpatient procedure to detect early signs of CAD

92. Coronary CTA- Strengths
Noninvasive.
Can measure HU of plaques and characterize them as fatty, atheroma, fibrosis, calcium.
Can evaluate status of bypass grafts.
Can determine stent patency.
Evaluates portions of mediastinum and lungs.

93. Coronary CTA- Weaknesses
Cannot accurately measure stenosis with heavy, calcified plaque burden.
Occlusions can be missed by brisk collateral flow.

94. What do I do with this information?
Reports will be classified in one of four categories of severity:
Normal
Mild Plaque with No stenosis
Moderate Plaque with mild/Mod stenosis
Severe Plaque and stenosis: Cardiac Cath

95. Thank you