Ultrasound
What
is an Ultrasound?
Ultrasound uses sound waves to generate pictures of many
parts of the body. The pictures are created by applying
a warm gel to the skin and then moving a transducer (also
know as an ultrasound probe) over the body part being
examined. It is a completely safe and painless procedure.
You cannot hear or feel the sound waves. Nearly every
organ in the body can be examined by ultrasound and there
are many different types of ultrasound exams. The type
of exam will vary depending on information that your doctor
needs.
Types
of Ultrasound Exams
Obstetrical Ultrasound:
Ultrasound can be used to safely exam babies before they
are born. Early in pregnancy ultrasound is used to confirm
the well being of the fetus before you can feel the baby
moving and before your doctor can hear the heartbeat.
After about 16 weeks, when the bones and internal organs
have developed, ultrasound can assess if the baby’s
growth and development are progressing normally. Examining
babies while in the womb is completely safe and the information
provided can be very helpful to your doctor.
Abdominal
and Pelvic Ultrasound:
There are many organs in the abdomen and pelvis and the
scope of your exam will be tailored to your doctor’s
request. The right upper quadrantultrasound focuses on
the liver, gallbladder, bile ducts and pancreas. This
is one of the most commonly ordered ultrasound exams and
is the very best way to see if you have gallstones. Liver
and bile duct abnormalities are also easily seen on an
ultrasound. A renal ultrasound includes pictures of both
kidneys and the bladder. A renal ultrasound is often the
first test ordered if blood tests show that the kidneys
may not be working properly or when blood is discovered
in the urine. A pelvic ultrasound focuses on the uterus
and ovaries. Abnormal uterine bleeding or pelvic pain
are common reasons to have a pelvic ultrasound. Sonohysterography
is a new technique used to examine the inside of the uterus
and is performed after a sterile saline solution is carefully
introduced into the uterus through a tiny catheter in
the cervix. This exam can potentially better characterize
and localize an abnormality which is seen or suspected
on a routine pelvic exam.
Doppler
Ultrasound: Doppler ultrasound is a special
way of examining blood vessels and can be used to study
arteries and/or veins in any part of the body. Doppler
ultrasound can be used to detect areas of narrowing in
the arteries leading to the brain, the abdominal organs
or the extremities. Doppler ultrasound can also be used
to detect blood clots within veins which are potentially
life threatening abnormalities.
Special
Preparations
You may be asked to follow certain instructions to best
prepare for your ultrasound exam. The instructions will
vary depending on the information your doctor needs and
the type of exam you will have. Many exams require no
preparation at all.
Gallbladder:
Best performed after an 8 hour fast so that the gallbladder
is distended. Eating makes the gallbladder shrink and
makes it harder to see small gallstones. The larger upper
abdominal organs such as the liver, spleen and kidneys
are less affected by eating and are generally well seen
whether you have fasted or not.
Transabdominal
Pelvic Ultrasound: A
full bladder provides an ultrasound "window"
for seeing deep into the pelvis with the probe placed
on the lower abdomen. Your bladder should be full but
not uncomfortable. For most women, this means drinking
a few glasses of water during the hour leading up to your
exam.
Transvaginal
Pelvic Ultrasound: This exam is done with
the bladder empty. It is performed with a small ultrasound
probe placed in the vagina, often after the routine transabdominal
pelvic exam. The transvaginal pelvic exam doesn’t
let us see very far into the pelvis, but the resolution
of what we do see may be better. The two exams complement
each other and both are often performed during the same
visit.
Doppler
Exam of the Renal Arteries: The renal
arteries sit deep in the abdomen. In the unprepared patient,
bowel gas usually obscures the arteries and the exam is
unsuccessful. The exam is best performed after fasting
at least 8 hours, taking an antiflatulent such as Mylecon,
and drinking a few glasses of water just before the exam
to improve hydration. Nearly every organ in the body can
be examined by ultrasound and there are many different
types of ultrasound exams.
Exams
that do not Require Preparation
Obstetrical Ultrasound:
The amniotic fluid provides the "ultrasound window"
to see your baby. A full bladder is not necessary.
Renal
Ultrasound
Extremity
Ultrasound, including Doppler exams.
Small
parts: breast, thyroid, testicle