CARDIAC CT IMAGING

what is a Cardiac CT Scan?

Heart disease is the world’s biggest cause of death
and a heart attack is often the first symptom of heart
disease. This form of heart disease is due to a blockage
of the coronary arteries. Invasive coronary angiogram
is the standard test to assess the coronary artery
blockages. It requires a catheter to be inserted into the
heart. A cardiac CT scan is a non invasive alternative
test to look at the coronary arteries. The process
which is similar to an x-ray procedure examines the
coronary arteries for blockages and abnormalities
that cause reduced blood flow and can result in chest
pains (angina) or heart attacks. It can also be used
to evaluate the presence and extent of calcium in the
coronary arteries and the ‘calcium score’ obtained
can be used to predict the likelihood of coronary
artery disease.

CT scanning is like looking into your heart by cutting
it into thin slices; hence the frequent reference to the
cardiac scanner as a “multi-slice CT”. A Cardiac CT
scan uses special x-ray equipment to produce detailed
cross-sectional pictures of the heart and is used to
visualise the blood vessels to the heart. The
information is then used to optimise patient care,
helping to determine what treatments or further
evaluations are needed and to tailor long-term health
goals as appropriate.

IJN’s Dual Source CT Scan

Images of coronary arteries used to be difficult to obtain because of their small
size and rapid movement. Refinements in detector technology now allow new
CT scanners to capture a series of images of thinner slices of a heart’s interior.
IJN is the first in Malaysia and among the first in Asia to invest in the Dual
Source CT Scanner, the latest technology that incorporates two x-ray sources
and two detectors in a single scanner. This enables data to be captured twice as
fast and allows unprecedented image quality and detail when compared to
existing scanners, which when reassembled by computers provides a very
detailed multi-dimensional image of the heart’s interior.

How is the procedure performed?

Once your physician has scheduled the examination, you will be given
appropriate instructions on how to prepare for the Cardiac CT Scan. A nurse
will assist you on the day of the examination and will insert an intravenous
line in your arm to facilitate the injection of the contrast dye that enhances
the visibility of the coronary arteries.
The CT technologist begins by positioning you on the CT examination table.
Then you will feel the table move through the scanner as the actual Cardiac
CT Scan is carried out. When the scan is complete, you may be asked to wait as
the CT technologist establishes that the images are clear enough to read. The
scan can be done within a single breath-hold but preparation for the scan may
take up to thirty minutes, so please allow about an hour for the procedure.

Who interprets the results?

A sophisticated computer programme processes and reassembles this series
of pictures to create multi-dimensional cross-sectional images of the heart’s
arteries. They will be analysed by our specialised team that include radiologists
and cardiologists. The results will then be sent to your referring physician who
will discuss the findings with you.

What are the risks?

A Cardiac CT scan is a low-risk non-invasive procedure where the radiation
exposure is kept to a minimum. However, the contrast dye may cause stomach
upset or minor allergic reaction such as a rash, itching, or a feeling of warmth
throughout the body. Usually, these side effects are brief and resolve without
treatment.
Your doctor will discuss with you the possible role of this test. However, some
patients with excessive calcification and irregular heart rates might not be
suitable because these conditions affect the image quality of the CT Scan.