CT
colonography (Virtual colonoscopy)
Breast cancer screening – role of radiology
Radiological
management of uterine fibroids
Radiological
management of varicose veins
Role
of radiology in Hepatitis B screening
Stroke
imaging
CT COLONOGRAPHY (VIRTUAL
COLONOSCOPY)
By Dr Gan Yu Unn
CT colonography is new technique used
to detect cancer and small growths called polyps in the large bowel. This
technique utilises a CT scan and special computer software to detect growths
without the need to insert a long tube (as in fibreoptic colonoscopy or
“scope”) or the instillation of a large amount of barium liquid (as in barium
enema) through the anus. During the scan, room air is gently pumped into the
large bowel through a small rubber tube and most patients find this procedure much
more comfortable compared with other methods.
Colorectal cancer is known to develop
from polyps and can be prevented if these polyps are discovered and removed
early. Research has shown that CT colonography is more accurate than barium
enema and nearly as accurate as fibreoptic colonoscopy in detecting these polyps.
CT colonography is useful for patients
who desire a relatively comfortable method to assess the large bowel. It is
best suited for patients who cannot tolerate or who have a bowel anatomy that
is unfavourable for fibreoptic colonoscopy.
BREAST
CANCER SCREENING – ROLE OF RADIOLOGY
By Dr Ching Boon Chye
1. What is the role of imaging in
detection of breast cancer?
Early breast cancers can be detected by
mammography (x-ray of the breast) or ultrasound. In certain circumstances i.e.
high risk patients, an MRI of the breast may be recommended to detect early
breast cancer.
2. Who should have a mammogram?
It is recommended that patients who
are:
a. 40years and below;
should have monthly breast self examination, clinical examination by a
qualified medical personnel every 3 years and a baseline mammogram.
b. 40 years and above;
should have monthly self examination and yearly clinical examination by a
qualified medical personnel
c. 40 to 49 years;
yearly mammogram should be performed
d. 50 years and above;
2 yearly mammogram
3. Why should I go for a mammogram?
Breast cancer is the most common
cancer in Singapore women affecting all races, accounting for about 200 deaths
per year. Studies in the U.S.A. and Europe have shown that regular screening in
persons above 40 years of age can reduce the death rate by 50%. Mammography is
the most effective tool to detect breast cancer in its early stage when
treatment is most effective. It helps to save your breast and your life!
4. Where can I get more information
about screening for breast cancer?
More information is available at the
Health Promotion Board website on Breast Cancer Screening in Singapore at the
following URL:
http://www.hpb.gov.sg/hpb/default.asp?pg_id=1274
RADIOLOGICAL MANAGEMENT OF
UTERINE FIBROIDS
By Dr Chong Le Roy
1. What are uterine fibroids?
Fibroids of the uterus (womb) are
benign (non-cancerous) growths made up of fibrous and muscle tissue. These may
result in a variety of symptoms, such as excessive menstrual bleeding, pelvic
pain and frequent passing of urine.
2. What is uterine fibroid
embolisation?
Uterine fibroid embolisation is a
non-surgical method of treating symptomatic fibroids of the uterus by injection
of small particles to block the arteries supplying blood to the fibroids. This
destroys the fibroid tissue resulting in decreased size of the fibroids and
relief of symptoms, while leaving the uterus intact. This procedure was first
performed in France in 1995.
3. Which doctors can perform uterine
fibroid embolisation in Singapore?
In Singapore, uterine fibroid
embolisation is performed by doctors specially trained and accredited in
imaging-guided procedures known as interventional radiologists*.
*Interventional radiologists are
specialists with further sub-specialty training and expertise in performing
procedures under imaging guidance using tiny instruments introduced through the
skin, without requiring open surgery. Interventional radiologists are also trained
in performing and interpreting diagnostic imaging studies such as ultrasound,
CT and MRI.
4. What occurs during uterine fibroid
embolisation?
This involves a small 1 cm long skin
incision in the groin following administration of local anaesthestic to make
the skin numb, after which a tiny tube (catheter) is inserted by the
interventional radiologist into an artery of the groin. Using x-ray guidance
and injection of contrast material (“dye”), the blood vessels of the uterus are
mapped. The catheter is then guided into these arteries, and tiny particles
injected until blockage of blood flow to the fibroids is achieved. The catheter
is then removed and the skin incision site bandaged.
5. What are the advantages of uterine
fibroid embolisation compared to open surgery?
Uterine fibroid embolisation is a
minimally invasive procedure, as opposed to open surgery. It is also a less
painful procedure, and requires a shorter hospitalisation and recovery period.
General anaesthesia is also not required.
6. How successful is uterine fibroid
embolisation?
It has been found that the average
volume reduction of fibroids following uterine fibroid embolisation is
approximately 40-50% over 3 months, with the fibroids continuing to shrink over
time. Symptomatic improvement is found in up to 85-90% of patients, mainly for
heavy menstrual bleeding and pressure symptoms.
7. Can uterine fibroid embolisation
help in infertility?
While it has been postulated that
fibroids may be a factor in infertility, the statistical evidence for this is
inconclusive. While not used as a fertility procedure, there have been many
pregnancies following uterine fibroid embolisation.
8. Will I require general anaesthesia
for uterine fibroid embolisation?
No, you will not require general anaesthesia
for the procedure. You may however be given a light sedative during the
procedure.
9. What happens to the uterine
fibroids after embolisation?
The fibroid tissue dies after the
supplying blood vessels are occluded. The body naturally absorbs the dead
tissue leaving behind scar tissue.
10. How long does it take to perform
uterine artery embolisation?
The whole procedure normally takes one
to one and a half hours to perform.
11. Do I have to stay in hospital
following the procedure?
You would typically be required to
stay in hospital at least overnight for observation, and to ensure that there
are no immediate complications following the procedure.
12. What are the complications of
uterine fibroid embolisation?
Serious complications following
uterine fibroid embolisation are rare, and occur in less than 5% of patients.
These include but are not limited to injury to the groin arteries where the
catheters are introduced, blood clot formation and infection. In 2-3% of
patients, per vaginal passage of fibroid tissue may occur. This may result in
infection or bleeding, and may require surgical removal. In 1% of patients,
there is a risk of damage or injury to the uterus possibly requiring a
hysterectomy. There is also a small risk of an allergic reaction to the
administered contrast material. Your interventional radiologist will discuss
the risks with you prior to the procedure in further detail.
13. What should I expect following the
procedure?
You would expect to experience some
pain and cramping following the procedure, which is due to death of the fibroid
tissue. This is usually most severe in the first 24 hours following the
procedure, improving rapidly in the following few days. This may be controlled
with oral medication and usually subsides in a few days. Some patients
experience mild fever and nausea up to 1 week after the procedure. This is
usually related to the body’s response to the dead fibroid tissue. Again, this
is often effectively controlled with oral medication.
14. What tests are required before
undergoing uterine fibroid embolisation?
A full gynaecological work-up is
required, and include imaging of the uterus to assess the number, location and
size of the fibroids. This is done most commonly by ultrasound, but sometimes
MRI is used.
15. How quickly can I return to my
normal activities?
Most patients are able to return to
normal activity within 1 to 2 weeks following uterine fibroid Embolisation. Some
patients occasionally take a while longer to recover.
16. Who can I speak to more about
uterine artery embolisation?
You may approach your gynaecologist,
who will then refer you to an interventional radiologist for assessment as to
whether uterine artery embolisation would be suitable for you.
17. What is the latest non-surgical
method of treating uterine fibroids?
Using the latest imaging-guided
technology, high intensity ultrasound beams may be focused-guided by an MRI
scanner, on uterine fibroids within the body. The focused ultrasound waves
cause an increase in temperature within a small spot inside the fibroid,
destroying the tissue. The body gradually removes the dead tissue, and the
procedure is repeated until the entire fibroid is obliterated.
The procedure is totally non-invasive
and requires no hospitalisation. Patients only require mild over-the-counter
medicines for relief of discomfort following treatment, and can resume normal
activity within one to two days.
MRI-guided focused ultrasound
treatment for uterine fibroids has been approved by the Food and Drug Administration
(FDA) in 2004. KK Women and Children Hospital has recently acquired this
exciting new technology is offering this mode of therapy, more details may be found on the KKWCH website: www.kkh.com.sg.
RADIOLOGICAL MANAGEMENT OF
VARICOSE VEINS
By Dr Chong Le Roy
1. What causes varicose veins?
Veins in your legs contain small
one-way valves within to help return blood to the heart. These valves open to
allow blood to flow upwards towards to heart but prevent backward flow by
closing. When the valves in the superficial veins of the leg malfunction, blood
no longer flows in an upward direction, but rather collects in the leg veins
causing them to engorge and these then become varicose veins.
2. What is EVLT and how does it work?
EVLT stands for Endovenous Laser
Treatment and is a new, minimally invasive method of treating varicose veins,
approved by the Food and Drug Administration (FDA) in 2002. A very fine laser
fibre is inserted into the varicose vein, following which the laser is fired
from within the vein. The energy from the laser causes scarring of the vein
walls, shrinking them such that blood no longer flows within. This improves the
cosmetic appearance of the leg.
3. Which doctors can perform EVLT in
Singapore?
In Singapore, EVLT is performed by
doctors specially trained and accredited in imaging-guided procedures known as
interventional radiologists*.
*Interventional radiologists are
specialists with further sub-specialty training and expertise in performing
procedures under imaging guidance using tiny instruments introduced through the
skin, without requiring open surgery. Interventional radiologists are also
trained in performing and interpreting diagnostic imaging studies such as
ultrasound, CT and MRI.
4. What are the advantages of EVLT
compared to surgery?
EVLT is an outpatient procedure
without requiring hospital stay. It is also less painful than open surgery,
with a shorter recovery period. EVLT also offers a high success rate, with
lower risks compared to open surgery. There is also minimal to no scarring
following the procedure.
5. How successful is EVLT?
EVLT has a very high success rate of
up to 93 - 98%.
6. What happens to the varicose veins
after EVLT?
The shrunken veins eventually becomes
scar tissue following EVLT, and the body uses other normal veins of the leg to
return blood back to the heart.
7. Will I require general anaesthesia
for EVLT?
No, general anaesthesia is not
required for EVLT. EVLT is performed in almost all instances under local
anaesthesia.
8. Will local anaesthesia alone be
adequate for EVLT?
The radiologist will inject local
anaesthetic along the length of the varicose vein to be treated under
ultrasound guidance using a tiny needle prior to the laser therapy. Some
discomfort may be felt during the injection of local anaesthetic, but there
should be minimal or no pain during the activation of the laser.
9. How long does the procedure take?
EVLT typically takes approximately one
hour to perform, from start to finish.
10.Do I have to stay in hospital
following EVLT?
Almost all patients go home on the
same day following the procedure with prescribed painkillers. Only in rare
instances will hospitalisation be necessary.
11. Is the laser dangerous?
The radiologist will ensure full laser
safety precautions are adhered to during the treatment. Everybody in the
treatment room (including the patient) will be required to wear special safety glasses
during activation of the laser. The laser may be dangerous if somebody looks at
the beam directly without protective glasses.
12. What are the complications of
EVLT?
Apart from mild discomfort during, and
a degree of skin bruising following the procedure, complications from EVLT are
rare. The commonest complication is vein irritation and skin numbness. The risk
of developing deep venous thrombosis is also very low at approximately 0.25% (1
in 400).
13. What should I expect following the
procedure?
There will be some bruising of the leg
following the procedure which commonly resolves within the first few weeks.
There may be a tight or pulling feeling of the leg in the first week following
the procedure, which is normal and commonly encountered following a successful
procedure.
14. How long do I have to wear
bandages for?
The bandages are worn for about a
week, following which stockings are worn for about two weeks. Your doctor will
advise you regarding the type and length of time the bandages and stockings are
required.
15. What tests are required for EVLT
treatment?
An ultrasound study of the legs would
be required prior to EVLT to assess the anatomy of the leg veins. This is
non-invasive and painless.
16. Are my varicose veins suitable for
EVLT?
About 70% of varicose veins are
suitable for EVLT treatment. Some types of varicose veins require alternative
methods of treatment. Your doctor will advise whether you would be a suitable
candidate for EVLT.
17. Can the varicose veins return
after EVLT?
There is a low chance that the
varicose veins may recur, but this is less common as compared to open surgery.
18. How quickly can I return back to my
normal activities?
Most patients are able to resume
normal activity within a few days following treatment, although it is advised
that strenuous activity and long periods of standing be avoided in the initial
weeks.
19. Who can I speak to find out more
about EVLT?
You may approach your specialist
surgeon who will then refer you to an interventional radiologist for assessment
as to whether EVLT would be suitable for you.
ROLE OF RADIOLOGY IN
HEPATITIS B SCREENING
By Dr Elizabeth Chan
Chronic hepatitis B virus infection is
a major cause of liver cancer (hepatocellular carcinoma or HCC) and liver
failure in Singapore. HCC is the fourth most common cancer in Singaporean
males. About 4 out of every 100 Singaporean residents aged between 18 and 69
years of age have chronic hepatitis B virus infection. About 4 out of 10 of
those with severe infection will eventually develop liver cirrhosis (liver
damaged by scarring from chronic infection), with an annual incidence ranging
from 2 to almost 6%.
Regular blood tests are used to
monitor the activity of the viral infection and the liver function. In
addition, one of these tests, known as serum alpha-fetoprotein level, can also
be used to screen for development of HCC. However, this is usually
supplemented with ultrasonographic imaging. The current Singapore Ministry of
Health guidelines recommend an ultrasound scan of the liver every 12 months if
the liver is normal and every 6 months if there is liver cirrhosis.
An ultrasound scan is a painless
procedure but requires fasting 4 – 6 hours prior to the procedure. During the
scan, the patient will periodically need to hold his breath which pushes the
liver down out of the rib cage and makes assessment of the liver easier.
If an abnormality is seen on the ultrasound
scan, a computer tomography (CT) scan of the liver is then indicated. This
scan requires an injection, is more expensive and exposes the patient to
radiation which makes CT scan an unsuitable screening tool. Alternatively,
magnetic resonance (MR) imaging may be used to evaluate the abnormality seen on
ultrasound scan. An MR scan will also require an injection.
STROKE IMAGING
By Dr Elizabeth Chan
Stroke is the second most common cause
of death worldwide and is the fourth leading cause of death in Singapore. In
addition, stroke is a leading cause of disability and the need for long-term
nursing care. It is important therefore that every effort is made to prevent
stroke in the first instance, and where stroke has occurred, to optimise
management to achieve good clinical and functional outcomes.
What is the difference between a
stroke and a transient ischaemic attack (TIA)?
Stroke occurs when a part of the brain
is damaged due to lack of blood supply. This may be caused by blockage of the
blood vessel, which results in cerebral infarction (death of brain cells), or a
burst brain artery (blood vessel carrying blood to the brain), which causes
intracranial hemorrhage (bleed in the brain).
By definition, the event is called a
stroke if the symptoms and signs last more than 24 hours or a TIA if symptoms
and signs are transient, that is, lasting less than 24 hours. Stoke symptoms
are usually more severe, sometimes, disabling, life-threatening or even leading
to death. In TIA’s, there is no long term complication but increase the
individual’s risk of a more disabling stroke.
What is the role of radiology in
management of strokes?
1. Determine cause of the stroke
A scan of the brain is usually
performed within 24 hours of the event to establish the cause of the stroke.
This is important because an infarct caused by blockage of the artery is
treated with medication which thin the blood. These drugs are usually not given
if the stroke is due to hemorrhage (bleeding).
Either a computer tomography (CT) scan
or magnetic resonance (MR) scan of the brain will determine the cause and which
part of the brain is affected. Both do not require an injection for the
procedure. An MR scan may show strokes earlier than CT imaging, as well as
very small strokes that may not be seen on CT scan, but is more expensive and
not as readily available as a CT scan.
2. Monitor progress of the stroke
If symptoms and signs get worse, a
repeat CT or MR scan may be useful to see if the damaged portion of the brain
is larger or if some complication has developed.
3. Evaluate possible risk factors
When the patient is better, some may
need tests such as Carotid Doppler ultrasound (assess arteries in the neck) and
echocardiogram (assess the heart) to determine the risk of developing another
stroke.
4. Assess possible complications
Sometimes, various reflex functions of
the body may be damaged as a result of a stroke. For example, the swallowing
mechanism may become uncoordinated. In this case, a barium swallow would be helpful
to see if food and water goes into the stomach or into the lungs.
RESOURCES
Singapore National Stroke Association
26 Dunearn Road
Singapore 309423
Tel: 63584138
More information on strokes can be
found at the website of the National Neuroscience Institute at the following
url:
http://www.nni.com.sg/ForPatientsandVisitors/PatientEducationPamphlets/Stroke.htm
