Cardiovascular CT is a valuable tool for evaluating congenital heart disease in children. It provides high spatial and temporal resolution to depict complex anatomy. Key applications include assessing pulmonary blood flow in pulmonary atresia, vascular rings prior to surgery, coronary artery anomalies, and postoperative complications. Careful patient preparation and protocols are needed given pediatric concerns. CT enables simultaneous evaluation of vascular structures, airways, and cardiac function to comprehensively evaluate complex congenital heart disease.

1. Cardiovascular CT in
congenital heart
disease

2. OVERVIEW
• Introduction
• CT Technique and protocols
• Patient preparation
• Iv contrast agents and injection protocol
• Artifacts in cardiac CT
• How to read cariac CT
• Clinical appications of pediatric cardiac CT

3. introduction
• Designed by Godfrey N.
Hounsfield to overcome
the visual representation
challenges in radiography
and conventional
tomography by
collimating the X-ray
beam and transmitting it
only through small cross-
sections of the body

4. G.N.HOUNSFIELD ALLAN M. CORMACK
In 1979, G.N. Hounsfield shared the Nobel Prize in Physiology &
Medicine with Allan MacLeod Cormack, Physics Professor who
developed solutions to mathematical problems involved in CT.

5. • Echocardiography (echo) comes closest to
meeting the criteria for an ideal diagnostic test,
but there are a number of instances where it is
unable to provide all the requisite information
for therapeutic decision making due to the lack
of acoustic windows, complexity of the
anatomy, limited spatial resolution, or the lack
of tissue characterization

6. • BASIC PRINCIPLE :
• The internal structure of an object can be
reconstructed from multiple projections of
the object.
• CT scanning is a systematic collection
and representation of projection data.

7. Prerequisites for cardiac CT
• Demands
– -complex anatomy
– Small dimensions
– Rapid movement
1. HIGH SPATIAL RESOLUTION
-depiction of vessel wall and small
coronary branches
2.HIGH TEMPORAL RESOLUTION
- Reduce motion artifacts
3. FAST COVERAGE
- Short breath hold time
4.SYNCHRONISATION WITH CARDIAC
CYCLE
- -ecg gating for end diastole and end
systole
5.CONTRAST RESOLUTION

8. CT Technique
• There are four parts to an optimal CT for pediatric
cardiovascular indications:
• planning
• acquisition
• processing,
• and interpretation

9. Planning
• It is the most important step,
ensuring that the
appropriate technology and
technique are chosen for the
given indication, and
adjusted to the patient's
unique anatomical and
hemodynamic situation.
Acquisition
• It involves the actual
performance of the study,
and involves choice of the
scanning and contrast
injection protocol, and real
time adjustment of the
technical parameters

10. Processing
• It involves sophisticated
algorithms that allow the
manipulation of the 3D
image dataset for advanced
visualization such as volume
rendering (VR) or virtual
angioscopy
• The final part is
interpretation of the
images, and creation of the
imaging report

11. Spatial resolution
• Primary strength of CT
• Narrowest distance
between which 2 objects
may be discribed
• In plane :(x ,y)
-0.5 mm
• through plane : plane
- 0.5 to 0.625 mm`
TEMPORAL RESOLUTION
• Vital for coronary imaging
• Ability to resolve fast moving
objects( shutter speed) or time
required to acquire one image
• Temporal resolution must be
less than length of diastolic
phase
• Primary achieved via:
– Fast gantry rotation time
– Multi-segment reconstruction
– Dual source CT

12. ECG Synchronization
• Non-ECG–gated scanning can provide diagnostic images of the
extracardiac vasculature in most patients with CHD.
• For evaluation of the aorta, pulmonary artery and pulmonary veins,
ECG synchronization is usually not necessary.
• ECG gating is the preferred technique for evaluation of
– the morphology of the heart chambers,
– including assessment of ventricle aneurysms, cardiac thrombi, cardiac tumors,
evaluation of small aortopulmonary collaterals in pulmonary atresia, and for
coronary artery assessment

14. Patient Preparation
• Breath Holding
• Premedication: With the advent of 64-slice scanners, with temporal
resolutions of about 50 msec, patients with heart rates of up to 120
bpm can be scanned without premedication
• Sedation: sedation is required for evaluation of infants and children
who are 5 years of age or younger to prevent gross motion artifacts
during scanning

15. Intravenous Contrast Agents and
Injection Protocol
• Contrast Agents:
– ionic media -sodium and/or meglumine
diatrizoate and iothalamate
– nonionic contrast media - iohexol, iopamidol,
ioversol, and iodixanol
Contrast Reaction
Idiosyncratic
Nonidiosyncratic
Premedication- prednisone 50 mg, diphenhydramine

16. Intravenous Contrast Injection
• The usual dose of intravenous iodinated contrast media
is 2 mL/kg with an iodine concentration of 240 to 370
mg/mL
• The greater the iodine concentration, the better the
vascular enhancement, but this also increases the
contrast viscosity
• in general, the more rapid the rate of contrast
injection, the greater will be the level of vascular
enhancement.
• The degree of enhancement is inversely related to
body weight, which is an advantage when imaging
small infants.

17. Artifacts in Cardiac CT
• Awareness of the various artifacts in cardiac CT is essential
to avoid errors from false-positive and falsenegative
interpretation.
• Image Noise
• Pulsation Artifacts
• Respiratory Artifacts
• High Contrast Artifacts
• Inhomogeneous Contrast
• Partial Volume Effects

18. Contrast-Induced Nephropathy
• CIN is defined as an increase in serum creatinine levels by >25%
or 0.5 mg/dL occurring within 3 days after intravascular contrast
administration in the absence of an alternative etiology
• seen within 1 to 2 days, peaks in approximately 4 to 7 days, and
returns to normal by 10 to 14 days
• Risk factors for CIN include
– pre-existing renal insufficiency,
– diabetes mellitus associated with renal impairment,
– large volume of injected contrast media or repeated doses within 72 hours,
– concurrent use of nephrotoxic drugs like aminoglycosides and nonsteroidal
anti-inflammatory agents,
– dehydration, and severe congestive heart failure

19. BIOLOGICAL EFFECTS OF IONIZING RADIATION
• TYPES:
1.DETERMINISTIC EFFECT
2. STOCHASTIC EFFECT
• deterministic (i.e., dose dependent):
– which can present weeks after exposure,
– may result in skin injury, hair loss, and lens injury

20. • Stochastic: which is genetically determined
and not dose dependent.
• Stochastic injury can result in cancer,
pregnancy complications, and inheritable
diseases

21. How to read cardiac ct

22.  Situs solitus Inversus Ambiguus

23. At pulmonary artery level

25. Aortic root level

27. Left ventricular outflow tract

28. Four chamber view

29. Four chambers low level

30. Inferior- coronary sinus level

31. Ten Common Indications for Pediatric
Cardiac CT
Neonate 1 .
Pulmonary
atresia
Source of pulmonary blood flow:
Major aortopulmonary collaterals
(MAPCA) versus ductal dependent
pulmonary flow
2.
Heterotaxy
-Diffuse hypoplasia of the aortic arch,
-anomalous pulmonary venous
Return,
-branch pulmonary artery stenosis
prior to modified Blalock–Taussig
shunt placement
Moss and Adams 9th Edition

32. Indications
3.Tetralogy of Fallot Branch pulmonary artery
stenosis
4. Anomalous
pulmonary venous
return
Mixed TAPVR,
obstructed TAPVR,
repaired TAPVR,
Scimitar syndrome
Infants 5.Coarctation Diffuse hypoplasia of the arch,
atypical coarctation
6.Vascular ring/sling Type of ring/sling,
intrinsic versus extrinsic stenosis
of airway
Moss and Adams 9th Edition

33. Indications
7.Coarctation- post
repair
Status of aortic arch,
collaterals
8.Vascular mediated
airway
compromise
Fixed versus dynamic airway
stenosis, effect on lung.
Older child 9.Anomalous origin
of coronary artery
Type of AAOCA,
presence and length of
intramurality,
Ostial stenosis,
relationship to commissure
10.Aortopathy related
to connective
tissue disease
Screen for aortic dissection
Moss and Adams 9th Edition

34. Systemic Veins
• MRI is preferred
• CT may be used when MRI is contraindicated.
• Acquired thrombosis or stenosis of systemic
veins after
– venous cannulation,
– surgery, or
– prior cardiaccatheterization

35. Systemic Veins
• A delayed phase of contrast enhancement is needed to
demonstrate the left SVC or an interrupted IVC with azygos
connection- for planning cavopulmonary shunt placement
• Screening for thrombosis of the Fontan pathway

36. LEFT ISOMERISM

37. RIGHT ISOMERISM

39. Pulmonary Veins
• In pts TAPVR, CT is indicated when surgically relevant data
cannot be obtained by echo.
• CT helps in presurgical planning by delineating stenosis or
obstruction, site of abnormal connections, and the course of the
anomalous vein in relation to the left atrium.
• Recurrent PV obstruction is the most frequent reason for repeat
surgery following repair of TAPVR.
• CTA can demonstrate the type of stenosis and the entire course of
the individual veins to better effect than echo
• In pulmonary venolobar syndrome (scimitar syndrome), CT can
simultaneously evaluate pulmonary artery anatomy, anomalous
systemic arterial supply to the lung, anomalous pulmonary
venous drainage as well as lung anatomy

41. Subclavian to portal vein

42. PAPVC RUPV TO SVC

44. • Congenital pulmonary vein stenosis and atresia are rare.
• CT angiography is the diagnostic modality of choice to
confirm the diagnosis of diffuse or multifocal pulmonary vein
stenosis

45. PULMONARY ARTERIES
• In pulmonary atresia, nongated CT is helpful in identifying the
– source of pulmonary blood flow by determining the
confluence, size, and location of the mediastinal pulmonary
arteries
– the presence and size of a PDA,
– the presence and location of major aortopulmonary
collaterals(MAPCAs) and
– presence of pulmonary artery stenosis prior to surgery

46. PULMONARY ARTERIES
• tetralogy of Fallot with pulmonary atresia or severe RVOT obstruction
- Juxtaductal stenosis may be seen near the origin of the left pulmonary
artery .
• Patients with syndromes like Williams–Beuren, Alagille, Ehlers–Danlos,
and Takayasu arteritis: Peripheral pulmonary artery stenosis is often
multifocal.
• CT is also effective for clarifying pulmonary artery morphology in the
setting of truncus arteriosus and ductal origin of the pulmonary artery

47. Role of CT in aortic abnormalities
• CT plays an important role in the delineation of aortic abnormalities
in children
– preoperative and postoperative evaluation of coarctation ,
– interrupted aortic arch ,
– aortopulmonary window,
– supravalvular or subvalvular aortic stenosis , and aortopathy
related to connective tissue disease
• In neonates, it may be difficult by echocardiography,
especially in the setting of a large PDA, to diagnose the
presence of coarctation, or differentiate diffuse hypoplasia
from interrupted aortic arch

48. Nine-month-old male with coarctation of aorta

49. FOR ASSESMENT OF CORONARY ARTERIES
• Potential coronary anomalies of significance in children and
young adults include
– anomalous origin from the contralateral aortic sinus with
intramural or intramyocardial course ,
– single coronary artery,
– Anomalous pulmonary artery origin ,
– high takeoff, and multiple ostia of the coronary arteries
coronary CT in children Kawasaki disease to
determine the presence of coronary involvement,
• distal coronary aneurysms,
• mural thrombus, and
• coronary stenosis,

50. Anamolous coronaries

52. FOR ASSESMENT OF CORONARY ARTERIES
• There is an increased incidence of coronary artery
anomalies in CHD.
• With new generation CT, breath holding may not be
necessary to determine coronary artery origins even
in neonates
• Presurgical identification of coronary artery
anomalies is particularly important in patients with
– transposition of the great vessels,
– tetralogy of Fallot,
– truncus arteriosus, and
– Pulmonary atresia with intact ventricular septum

53. Vascular Mediated Airway
Compromise
• This is one of the most important indications for CT due to its
ability to simultaneously assess the vascular anatomy, as well
as the presence and severity of airway compromise
• Common entities include
– vascular rings and sling,
– innominate artery compression syndrome, and
– bronchial compression related to dilated pulmonary
arteries or ascending aorta

54. Pulmonary sling: Posterior view from a
volume-rendered CTA in a 13-month-old male-
anomalous origin of the LPA from the RPA with
a retrotracheal course of the LPA

55. Intracardiac Pathology and Ventricular Function
• intra-atrial thrombus and thrombus associated with ventricular
aneurysm.
• It can demonstrate dystrophic calcification associated with myxoma.
• An important application of CT in the setting of cardiac tumors is to
assess the coronary artery anatomy prior to planning of surgical
resection.
• CT should not be a primary choice for evaluation of ventricular
function in children.
• To assess ventricular function in those with pacemakers or
othercontraindications to MRI

56. Postoperative and Postprocedural Indications for CT
• For assessing complications of Transcatheter placement of
endovascular metallic stents in pulmonary and systemic arteries and
veins in children with CHD
• Conventional digital angiography is the gold standard for identifying
in-stent restenosis, but it is not practical for long-term follow-up
• to determine stenosis or obstruction of modified Blalock–Thomas–
Taussig shunt.
• To determination of patency of Glenn and Fontan circuits and
screening for venovenous collaterals
• CT can play a role in evaluating pulmonary artery stenosis following
arterial switch procedure using a “LeCompte maneuver”

57. Emergent Indications
• CT angiography is the modality of choice in emergent situations
like suspected aortic dissection in patients with Marfan syndrome,
Loeys–Dietz syndrome and other connective tissue disorders.
• Evaluation of pulmonary embolism in the setting of CHD
• for urgent evaluation of source of emboli to the brain in the
setting of an acute cerebrovascular accident

58. Conclusion
• CT is now a major diagnostic tool in children with
heart disease
• multidetector CT has evolved over the last few years,
• Ct provides a number of important advantages for
pediatric cardiovascular disease, including
– isotropic high-resolution imaging without the need for
sedation or breath holding,
– volumetric coverage of the whole chest,
– high temporal resolution,
– novel radiation reduction tools with 60% to 80% reduction
in radiation exposure when compared to 64-detector .