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CARDIOVASCULAR JOURNAL OF AFRICA • Vol 24, No 2, March 2013
48
AFRICA
breakthrough in image acquisition and
processing called ClarityIQ Technology,
enables 75% reduction in radiation
dose in neuro-interventions without
compromising image quality. For the first
time, reduction in dose on such a large
scale is substantiated by clinical studies
aiming to prove non-inferiority in image
quality, as assessed by blind reviewers.
Philips also gave a presentation of the
top 10 best practices to reduce dose in the
cardiac catheterisation laboratory. These
10 commandments of dose management
are listed below:
•
Take an integrated approach to dose
management, from patient manage-
ment to system configuration, e.g. by
using the AlluraClarity system.
•
Maintain acute awareness of dose-
related behaviour and exposure
track records, e.g. by using Philips
DoseAware, a solution which provides
individual live feedback of scatter radi-
ation dose, enabling monitoring and
adjustment of behaviour.
•
Reduce the source–image distance and
increase the table height.
•
Use shutters and wedges.
•
Reduce radiation exposure per run.
•
Optimise projection angles.
•
Remove the anti-scatter grid.
•
Use low magnification.
•
Increase the distance from the radia-
tion beam and use protective equip-
ment.
•
Use advanced imaging solutions,
such as the solutions presented by
Dr Fagan: 3DRA, HeartNavigator and
EchoNavigator, all potentially contrib-
uting to reduced exposures.
Multi-dimensional imaging in
children with congenital heart
disease: an end to neonatal
catheterisation?
Another breakfast symposium hosted by
Prof Gerald Greil, consultant paediatric
cardiologist and director of the Congenital
Cardiac Magnetic Imaging Service at
Evelina Children’s Hospital in London.
Prof Greil considered the application of
multidimensional imaging in children
with congenital heart disease. The thrust
of his discussion centred on how magnet-
ic resonance imaging (MRI) is replacing
invasive X-ray-dependent cardiac cath-
eterisation as a diagnostic tool, providing
valuable clinical information regarding
cardiovascular anatomy and physiology.
Retrospective analysis of paediatric
data from elective diagnostic cardiac
catheterisation or MRI in the Cardiology
Department of the Evelina Children’s
Hospital indicates that replacing
catheterisation with cardiovascular MRI
results in reduced rates of complication
and shorter hospital stays, without a
significant impact on surgical outcome.
These conclusions were based on the
outcome measures of indication, length
of stay and incidence of complication. In
cases where the procedures were used to
plan surgery, 30-day survival following
the procedure was recorded. Surgical
outcomes were compared between the
two groups, and those using MRI were
compared with national outcomes from
the Congenital Cardiac Audit Database.
MRI imaging for delineating extra-
cardiac vasculature in newborns with
congenital heart disease is not widely
used. Current MR angiographic
techniques lack the temporal resolution to
assess complex cardiac anatomy within a
single breath-hold, due to fast circulation
times. Prof Griel shared his experiences
of four-dimensional time-resolved
keyhole angiography (4D TRAK) to
confirm diagnoses not fully resolved by
echocardiography in newborns.
MR keyhole angiography permits
rapid acquisition of three-dimensional
datasets with high temporal resolution.
Within a single breath-hold, the sequential
filling of arterial and venous vessels can
be visualised, overcoming the limitations
of temporal resolution that existing MR
angiography presents.
A retrospective review of nine neonates
(
<
28 days old) undergoing cardiac MR
imaging with 4D TRAK performed on
a commercial Philips Achieva 1.5-T
scannerT assessed indication for referral,
diagnosis made from the MRI scans and
correlation with surgical findings. Seven
patients proceeded to surgery based on
the MRI, where findings were confirmed.
One required no further interventions and
one required diagnostic catheterisation
to assess multiple aorto-pulmonary
collateral arteries.
The use of 4D TRAK confers high
diagnostic accuracy vital for surgical
planning. 4D TRAK is appropriate where
diagnostic uncertainty remains following
echocardiographic assessment and
should be considered in place of invasive
diagnostic cardiac catheterisation or
X-ray-dependent computed tomography.
Prof Greil summarised, ‘We combine
X-ray, MRI and echocardiography
within one procedure for each patient,
depending on the complexity of the
cardiovascular condition. This provides
tremendous benefit due to availability
of more comprehensive clinical data.
Therefore, replacing catheterisation
with cardiovascular MRI has resulted in
reduced rates of complication and shorter
hospital stays, without a significant impact
on surgical outcome. It also reduces costs
for healthcare systems.’
R Delport, G Hardy
Prof Greil, with Lee Roering from
Philips.
Philips team with Dr Fagan, 3rd from
left.