Ct imaging of cvs

1. Cardiac CT

2. Indications
 cardiac or coronary anatomy
 Diagnose coronary artery disease
 Patency of coronary artery bypass grafts or
implanted coronary stents
 cardiac function

5. Technique
Calcium scoring
 When evaluating the heart for potential coronary artery
disease, usually a nonenhanced calcium scoring sequence
is first performed.
 This low-dose technique allows for a detection of
calcifications of the coronary arteries.
 Though this technique does not give any information
about potential hemodynamically relevant stenoses,
an Agatston score can be calculated based on that data.
 The calculated Agatston score allows for an early risk
stratification of patients with a high Agatston score
(>160) have an increased risk for a major adverse cardiac
event

6. Coronary CT angiography
 Contrast media injection, usually between 4-5
mL/sec through an antecubital vein.
 To allow for an improved image quality and dose
reduction, cCTA is usually ECG-triggered to adapt
the scan sequence to the patient's heartbeat.

7. Retrospectively ECG-gated cCTA protocols
 After detection of the heart rhythm, the scan covers
the whole heart during multiple cardiac cycles.
 Heart is scanned in all phases
 Retrospective selection of best phases for
reconstruction of images.
 Optimal phase of reconstruction is in diastole.

8. Prospective triggering
 ECG signals are used to trigger scanning(During the
R wave)
 Dose reduction upto 87% compare to retrospective
technique.

10. Post-processing
 Due to the usually tortuous anatomy of the
coronary arteries, curved multiplanar
reconstructions (MPR) or maximum intensity
projections (MIP) are usually generated to allow for
assessment of coronary lumina on a dedicated
workstation.
 In these images, coronary stenoses can be evaluated
and lumen reduction can be measured.

11. Contraindications
 It is not indicated in some situations:
 if the patient is having an acute myocardial
infarction (heart attack)
 screening of asymptomatic patients with low-to-
intermediate risk of CAD
 evaluation of coronary artery stents <3 mm
 evaluation of asymptomatic patients post CABG (<5
years old) and post stent (<2 years old)

12. C A R D I A C M R I

13. Advantages
 The main advantages of cardiac MRI in comparison
with other techniques are:
 better definition of soft tissues
 use of different types of sequences improves
diagnostic accuracy
 no ionising radiation

14. Limitation
 The main limitation of MRI, compared to cardiac
CT, is the poorer evaluation of the coronary arteries.
 MRI incompatable implants.

15. Dark blood Imaging
 Dark blood imaging involves spin echo sequences. Its
main advantage is a fast acquisition that minimises
respiratory and cardiac movement artefacts.
 Its main issue is a low signal/noise ratio and, therefore, a
deficient spatial resolution.
 These can be T1, T2, or proton density weighted
sequences:
 T1 weighted sequences achieve better anatomic
definition
 T2 and PD weighted sequences reach better tissue
characterization

16. White blood Imaging
 White blood imaging involves gradient echo
sequences and steady-state free precession MRI
(SSFP).
 The main advantage of white blood imaging is its fast
acquisition. It can obtain movement sequences and
allows studying cardiac function and movement.