The document discusses coronary artery anatomy and various imaging techniques used to assess myocardial viability. It provides details on: 1. The origins, branches and distributions of the right and left coronary arteries. 2. Imaging modalities for evaluating viable myocardium including dobutamine stress echocardiography, nuclear techniques like SPECT and PET, and cardiac MRI. 3. Cardiac MRI's use of late gadolinium enhancement to identify infarcted versus viable myocardium based on the degree and transmurality of enhancement.

1. CORONARY CT

2. Coronary artery
Coronary artery is a vasa
vasorum that supplies the heart.
”.
2

3. Coronary artery
 The coronary artery arises just
superior to the aortic valve and
supply the heart
 The aortic valve has three cusps –
 left coronary (LC),
 right coronary (RC)
 posterior non-coronary (NC) cusps.
3

4. Right coronary artery
 Originates from right
coronary sinus of Valsalva
 Courses through the right
AV groove between the
right atrium and right
ventricle to the inferior part
of the septum
4

5. Branches of RCA
Conus artery
Sinu nodal artery
Right coronary artery
Conus branch
SINU NODAL BRANCH
5
AV NODAL ARTERY

6.  Conus branch – 1st branch supplies the RVOT
 Sinus node artery – 2nd branch - SA node.(in 40%
they originate from LCA)
 Acute marginal arteries-Arise at acute angle and
runs along the margin of the right ventricle above
the diaphragm.
 Branch to AV node
 Posterior descending artery : Supply lower part of
the ventricular septum & adjacent ventricular walls.
Arises from RCA in 85% of case.
6

7. The right coronary artery. Course of
the right coronary artery (RCA)
on a series of axial images
acquired from top to bottom (A-
F). (A-C) The aorta gives rise to
the proximal segment (1), which
courses in an anterolateral
direction. (D) The middle
segment of the RCA takes a
nearly vertical downward
course (2). (E) The RCA then
turns to the left and continues to
the posterior aspect of the heart
(segment 3) along a nearly
horizontal course on the
diaphragmatic surface of the
heart. (F) At the crux of the
heart—the junction of the septa
and walls of the four heart
chambers—the RCA branches
into the posterior descending
artery and right posterolateral
branch (4). Ao, aorta; RV, right
ventricle; LV, left ventricle; LA,
left atrium.

8. Area of distribution
8
RT CORONARY ARTERY----
1)Right atrium
2)Ventricles
i) greater part of Rt. Ventricle
ii) a small part of the Lt ventricle
adjoining posterior IV groove.
3)Posterior part of the IV septum
4)Whole of the conducting system of the heart, except part
of the left br of AV bundle

9. Left coronary artery
 Arises from left coronary
cusps
 Travels between RVOT
anteriorly and left atrium
posteriorly.
 Almost immediately
bifurcate into left anterior
descending and left
circumflex artery.
9

10. Left coronary
artery
LAD
Diagonal artery
Lt Conus artery
Anterior Septal
br
Circumflex
artery
Obtuse marginal
branches
Ventricular
branches
Atrial rami
15

11. The left anterior descending coronary artery. Course of the left anterior descending
coronary artery (LAD) on a series of axial images acquired from top to bottom (A-
H). (A) The aorta gives rise to the left main coronary artery (5), which gives off the
proximal segment (6) of the LAD anteriorly. (B-C) Along its further course, the
artery divides into the middle LAD segment (7) and a diagonal branch (9). (D) In
most individuals, there is a second branching of the LAD. A second diagonal branch
(10) arises from the distal segment (8). (E-H) The distal parts of the LAD can be
followed as they course in the interventricular groove toward the apex. Note that
the diagonal branches may occasionally be larger than the main LAD. Ao, aorta; RV,
right ventricle; LV, left ventricle; LA, left atrium.

12. The left circumflex coronary artery. Course of the left circumflex coronary artery (LCX) on a series of
axial images acquired from top to bottom (A-H). (A) The aorta gives rise to the left main coronary
artery (5), which gives of the proximal segment (11) of the LCX posteriorly. (B-D) Along its further
course, the artery divides into the middle segment of the LCX (13) and a marginal branch (12). (E-
H) The middle segment (13) then gives off a second marginal branch (14). The circumflex branch
turns around the left border and continues on the diaphragmatic surface (distal segment, 15).
Ao, aorta; LA, left atrium; arrow, segment 12

13. LEFT CORONARY ARTERY 16

14. Area of Distribution
14
1) Left atrium.
2) Ventricles
i) Greater part of the left ventricle, except the area
adjoining the posterior IV groove.
ii) A small part of the right ventricle adjoining the
anterior IV groove.
3) Anterior part of the IV septum.
4) A part of the left bundle branch of the AV
bundle.

15. DOMINANCE
15
 Dominance is described by which coronary
artery branch gives off the posterior
descending artery and supplies the inferior
wall, and is characterized as left, right, or
codominant

17. CORONARY CT
ANGIOGRAPHY
17

18. CT CORONARY ANGIOGRAPHY
18
 Coronary computed tomography angiography
(CCTA) is an effective noninvasive method to image
the coronary arteries
 MDCT has multiple detector rows which are placed
opposite the x-ray tube which shortens the
examination time and improves the temporal
resolution

19. INDICATION
 Screening high risk patients
 Evaluation of chest pain
Post CABG
Post stent
32

20. CONTRAINDICATIONS
 Absolute contraindication :
1. Hypersensitivity to iodinated contrast agent
2. Pregnancy
 Relative contraindication
 Irregular rhythm
 Renal insufficiency (sr. creatinine > 1.5 mg/ml)
 Hyperthyroidism
 Inability to hold breath for 10 sec
 History of allergy to other medication
 Metallic interference (e,g: pacemaker, defibrillator wires) 33

21. PATIENT PREPARATION
21
 Avoid caffeine and smoking 12 hours prior to the
procedure to avoid cardiac stimulation.
 B- blocker : Oral or I.V B-blocker is used in patient with
heart rate greater than 65 bpm
 oral 50- 100 mg metaprolol administered 45 min to 1
hr before procedure.
 or I.V Metaprolol 5 to 20 mg at the time of procedure
 Sublingual Nitrates or Nitroglycerine: can be given
immediately before the procedure to dilated the
coronary arteries.

22. Volume and rate of contrast
administration
22
Using 64 detector MDCT technology:
 80ml of contrast agent is injected at 6 ml/sec
f/b 40ml saline solution at 4ml/sec
.

23.  After contrast administration, CT is obtained in
single breath-hold
 Scan volume covers the entire heart from the
proximal ascending aorta (approximately 1–2 cm
below the carina) to the diaphragmatic surface of
the heart
23

24. CAD-RADS

25. CAD-RADS is the Coronary Artery Disease-Reporting and Data
System.
CAD-RADS is developed to standardize reporting of coronary
CTA, to improve communication and to guide therapy.
In 2022 CAD RADS was updated to version 2.0

27. In CAD RADS 2.0 there are modifiers that can be added to
the Cad-Rads category:
N: indicates that a study is non-diagnostic
HRP: high-risk plaque (replaces V-vulnerable plaque)
I: ischemia
S: presence of stents
G: coronary artery bypass grafts
E: exceptions

28. Example of a non-diagnostic scan. Both the RCA and LCX are blurred due to
motion artifacts, resulting in CAD RADS N.

30. Low Attenuation Plaque

31. Positive Remodelling

32. Spotty Calcification

33. Napkin ring:

34. Modifier S Stent in the mid LAD

35. Modifier G: coronary artery bypass grafts

36. ⦿ Refers to cardiac muscle that is alive
• presence of cellular, metabolic, and microscopic contractile
function
⦿Two basic mechanisms of reversible ischemic
dysfunction
• myocardial stunning
• myocardial hibernation

37. ⦿Prolonged post-ischemic ventricular dysfunction that
occurs after brief episodes of non-lethal ischemia
⦿Transient LV dysfunction commonly observed following
an acute myocardial infarction treated with prompt
reperfusion.

38. ⦿Myocardium downregulates its contractile function in
the presence of sustained reduced blood flow.
⦿Cardiac myocytes are depleted of their contractile
material and filled with glycogen (PAS-positive
staining)

39. IMAGING VIABLE MYOCARDIUM
o Dobutamine stress echocardiography
o SPECT(Thallium/ technetium)
o 18 FDG PET
o CMR

40. Echocardiography
To asess Resting LV size and function
⦿LV wall thinning and increased echo backscatter are
markers for scarring
⦿LV end-diastolic wall thickness (EDWT) of <6 mm
indicates non viable myocardium

41. Dobutamine stress Echocardiography
o To assess Contractile Reserve
o dobutamine infusion started at 2.5
μg/kg/min, with gradual increase to 5, 7.5, 10
μg/kg/min.

43. NUCLEAR TECHNIQUES
X It utilizes radionuclide-labeled tracers to assess
myocyte integrity and function by measuring regional
tracer concentration in the myocardium.
o Thallium Membrane function
o Tc-99 membrane & mitochondia function
o FDG Glucose Metabolism
o Fatty acid Fatty acid Metabolism

44. Tc 99
Tc 99 labeled radiotracers are taken up by myocytes
across mitochondrial membranes.
The initial uptake and retention of these tracers reflect
cell membrane integrity and mitochondrial function
and thus indicate viability.

45. ⦿
Quantitative
polar plot
Viability in all
coronary
territories except
in segments of the
apex.
A cutoff of >50% tracer activity indicates viability

46. 18 FDG PET
PET Imaging for viability involves a combination of
Myocardial Perfusion + Metabolic Imaging
N13 Ammonia 18 F-FDG
• Uptake indicates presence Uptake indicates
of blood supply Metabollicaly active cell

47. PERFUSION +
METABOLISM +
PERFUSION -
METABOLISM +
PERFUSION -
METABOLISM -

49. CARDIAC MRI
Gadolinium based contrast agents are administered at
0.1mmol/kg patient weight and images are taken 10
mins after the injection to demonstrate LATE
GADOLINIUM ENHANCEMENT(LGE).

50. RAPID WASHOUT
NO LATE ENHANCEMENT Retention of Gadolinium in Extra
cellular space causing
LATE GADOLINIUM ENHANCEMENT

52. o LGE =100 % of Ventricle wall thickness s/o Transmural infarct
o LGE > 50% of Ventricle wall thickness s/o Non viable
myocardium
o LGE <50% of Ventricle wall thickness suggests viability

54. Thank You