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					                     ANZPIC 2010
                     Perth, Western Australia
                                       1st & 2nd May 2010
“Cardiac CT and the Paediatric Patient”
Sasko Kediev
Medical Imaging Technologist
Children’s Hospital Westmead, Sydney Australia


    This slideshow was presented at the Australian & New Zealand Paediatric
                 Imaging Conference in Perth, Western Australia in May 2010.
   The slideshow is not complete without the presenter’s spoken component,
  and therefore should not be used for educational or instructional purposes.
            Reproduction of any part of this presentation without the author’s
                                               permission is strictly forbidden.
Cardiac CT and the Paediatric Patient

                SASKO KADIEV
        CHILDREN’S HOSPITAL WESTMEAD
     Imaging Options for Paediatric Patient with
                Cardiac Anomalies

1.   Chest X Ray
2.   Echo
3.   MRI
4.   CT
5.   Cardiac Catheterization
                  Chest X-ray

Cardiac Outline          Paediatric Chest X-Ray
Shape
Size
Position
Lungs
Minimal Radiation dose
                     Cardiac Echo

Most favoured modality of
                              Cardiac echo image
imaging.
Can image structures,
measure function, assist in
interventional procedures.
Multi plane and Doppler
imaging (flow)
Performed bedside
No Radiation Dose.
Image quality decreases as
patients get bigger
Poor resolution
                           MRI

Increased imaging                MRI image
resolution able to
demonstrate both anatomy
and function in children of
all ages
Multi plane, 3D and flow
imaging
Nil radiation
Availability issues
Lengthy procedure for sick
patients
Breath holding / Gating
Need for sedation or general
anaesthetic
                              CT
Very high imaging                  CT image
resolution
Short imaging times
Multi plane, 3D and flow
imaging
High availability
Cardiologists and surgeons
adore the entire anatomical
representation.
Functional information
comes at a radiation cost
High radiation exposure
Sedation or anaesthetic
may be required
           Cardiac Catheterization

Excellent 2D imaging      Cardiac cath image
resolution of anatomy
and function. (cine)
Interventional
procedures possible
Highly Invasive
High radiation exposure
Sedation or anaesthetic
are required
Adult cardiac CT V Paediatric cardiac CT
Adult                           Paediatric
First line screening tool for   Image great vessels and four
coronary artery disease         chambers of the heart
High dose technique             Dose similar to CT of
requiring cardiac gating        paediatric chest which for
Heart rate needs to be          CT is a lower dose
slowed via medication for       examination (non gated)
optimal result                  Cardiac gating shows us
Latest CT scanners reject       function and smaller vessels
the need to slow heart.         with more resolution (Dose
                                can double or more )
                                Heart rate is not slowed
                                (Cardiologists reluctance)
                                making gating difficult
Adult Coronary CT images   Paediatric heart images
           Requesting a Cardiac CT

CT request form
Cardiac consult report
We then determine if CT
is the most appropriate
Cardiac report is not
always possible, in which
case call the referrer
Decide if CT is the most
appropriate
Formulate a plan for CT
examination
                 Non Gated / Gated

Non Gated                    Gated
• Visualize great vessels    • All of the non gated
  and chambers                 imaging
• Produce multiplanar        • Imaging of small vessel
  MIPS.                        stenosis
• Great 3D images            • Image function (not our
• Significantly lower dose     preferred method)
                             • Significantly higher dose
                  When do we Gate?

  Investigate aberrant coronary arteries
  Cardiologist request
  Radiologist request
  Why do we gate so few and not all?
1.DOSE
2.We see the functional stuff on echo or MRI
3.The paediatric heart usually beats to fast for quality
  gated images
  3 Easy techniques that will image a host of paediatric
                   cardiac anomalies


1. Hand injection
2. Triggering off aortic arch
3. Triggering off Jugular vein


  Tip
  Find a book or website that demonstrates
  the many congenital cardiac conditions.
  Revise the circulation and formulate a plan
           Hand injection Technique

Neonates and small babies with delicate veins
Dynamic injection by radiologist in lead
Boulas tracking can be used (Beware of delays)
Without tracking start scan with ½ contrast injected
Use 3mls/kilo in patients of this size
Scan in spiral mode at thinnest available collimation
Sequential mode is a possibility in these patients and offers
a huge dose saving
80kv, 20-40mA (non gated), fastest rotation time
Scan coverage to include heart and great vessels
Hand injection Technique
           Triggering off aortic arch

Use in anomalies that complete cycle at Aorta
Co-arction, Vascular rings, Truncus Art., and many others
IV Contrast at 2-3mmls per kilo, saline push optional
Aim to have injection time = scan time+ delay to ROI +
machine delay after activation
Time to aorta varies with size of patient e.g.. 4sec in a
toddler to 10 sec in a teenager
80-100kV according to patient size, 120kV in + 110kg
50-90mA (non gated)
Spiral mode fastest rotation time and thinnest acquisition
Scan entire heart and great vessels
Triggering off aortic arch
                 Triggering off Jugular vein

    Most complex cardiac anomalies, with uncertain circulation.
    e.g. Hypo plastic Left Ventricle, Pt’s undergoing complex redirection
    Patient usually very sick baby
    ROI is positioned outside the neck on a slice through the lower neck
    where the jugular veins can be seen and is triggered by operator
    Duel injection is required with
    2mls/kilo IV contrast in first syringe
    1ml/kilo IV contrast plus 2mls/kilo saline in second syringe (mix well)
•   Injection rate 1ml/sec as patients are usually small (even lower)
•   Once again aim to have injection time = scan time, plus delay to ROI,
    plus machine delay after activation
•   Allow about 2-4sec on these babies for time to ROI
•   Scan 80kV, 20-40mA with mod. At fastest rotation time
•   Scan to include whole heart and great vessels at thinnest acquisition
Triggering off Jugular vein
Triggering off Jugular vein
                     Imaging

  Axial, Coronal, and Sagital MIPS to the arch
  Curved MIP’s through vessels of interest
  Long axis, short axis, 2 and 4 chamber views
  (usually performed on MRI and Echo)
• 3D Surface shaded displays in spin and tumble
  orientations
• 3D Virtual MIP with cross sectional measurements
               Dose considerations

• Lower kV, lower dose, equals increase in contrast
  (win win situation)
• Select mA according to patient size and keep it
  similar to your normal chest CT
• Consider sequential mode for neonates.
  (the 40mm of over beaming on either side of most
  scanners more than doubles the dose to a tiny chest)
• Bismuth shielding of the chest is appropriate and
  dose not degrade the image enough to be of concern.
  ( use appropriate bismuth and place on Pt after
  Topo)
                Conclusions

• CT scan is used in imaging Cardiac
  anomalies in paediatric patient when cardiac
  echo fails to provide accurate enough
  anatomical information.
• When paediatric patients with cardiac
  anomalies are to sick to have an MRI
• When the risks of having a Cardiac Catheter
  out way the possible benefits.
                    Thank You

The Team
Nurse
Radiographer
Recovery Nurse
Anaesthatist
Anaesthetic Nurse
               Acknowledgements

Prof Frandics Chan
Lucile Packard Children’s Hospital

Dr Ella Onikul
Children's Hospital Westmead

Cincinnati Children’s Hospital website
(Congenital abnormalities and treatments)

				
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