Basic Principles of Ultrasound

Doppler ultrasound capabilities have increased enormously in the past few years. Technology is ever changing and the ultrasound is no different and it continues to grow in versatility as more demands are placed on the technology. Today the Doppler ultrasound is an important piece of equipment in dealing with heart disease. It's time you had understood the basic principles of ultrasound.

The Doppler ultrasound reflects sound waves which evaluate the blood as it flows through the vessels. This helps your doctor evaluate the blood flow through your major arteries and veins in the neck, legs, and arms. It can show reduce blood flow caused by narrowing in the arteries as well as blockages.

These narrowing in the arteries of the neck can lead to stroke while blood clots in the legs called deep vein thrombosis can break loose and block the flow of blood in the lungs.

A handheld transducer is passed lightly over the skin and blood vessels. Sound waves are sent which are then bounced off the solids which include the blood cells. The movement of the blood cells changes the pitch of the sound waves. This is called the Doppler Effect. When there is no blood flow there is not change in the sound pitch produced.

There are four types of Doppler ultrasounds used:

1. Power Doppler - uses the newest technology and its 5 times more sensitive at detecting blood flow than the color Doppler is and it is able to obtain images other Doppler equipment can't produce. It is generally used to evaluate the flow of blood through the vessels in organs.2. Bedside Doppler - uses the change in the pitch of the sound waves to produce the information on the flow of the blood through the vessels. The doctor listens to these sounds to evaluate whether there is a narrowed or blocked blood flow. This method is used in the hospital right at the patient's bed to quickly determine blood flow.3. Color Doppler - produces a picture of the blood vessel using the traditional ultrasound methods. The Doppler sounds are converted into color which is then overlain on the blood vessel image showing the speed and flow of the blood in the vessels.4. Duplex Doppler - also uses traditional ultrasound methods to produce pictures of both the organs and the blood vessels. The computer converts these Doppler sounds into graph form that shows the speed and direction of the flow of the blood in the vessels.

The Doppler is used to:1. Detect blood clots, narrowed blood vessels, and blocked vessels throughout the entire body but especially in the legs, arms, and neck. When arteries become narrowed or blocked they can cause dizziness, paralysis, vision loss, numbness, weakness, and other symptoms of stroke.2. Look for blood clots in the deep veins of the legs that can cause swelling and pain and if left untreated lead to pulmonary embolism.3. After a stroke or similar condition evaluate the flow of blood.4. Map veins that may be candidates for blood vessel grafts.5. Determine the amount of blood reaching a kidney transplant.6. Monitor blood flow following blood vessel surgery.7. Locate arterial plaque specifically in the carotid artery which can reduce blood flow to the brain and increase the risk of stroke.

Now that you understand the basic principles of ultrasound you can see why the Doppler ultrasound is such a powerful and important tool in the treatment and diagnosis of heart disease.

Yong has been working for a leading ultrasound manufacturer for last 8 years. At At www.ultrasoundlive.com he has provide information about different types of utlrassound equipments. Visit the website to get more information about ultrasound equipment and accessories.

Fertility at 40

The first time Marie Pearson saw her seven-week-old baby's heart beat, rising and falling on the ultrasound monitor, she couldn't stop sobbing. It's an exciting moment for any expectant mother, but for Marie, the new life represented the successful culmination of a three-year struggle.

After several attempts with intrauterine insemination and in vitro fertilization injections, expensive trips to reproductive specialists in the U.S., and trying Chinese herbal medicine and acupuncture, 41-year-old Marie was finally pregnant with her second child.

"There's truly nothing like discovering you've conceived after so many disappointments and lost dreams. We're so blessed for our little miracle," says Marie, who lives in Calgary with her husband, Brian Bertsch, 41.

Full article: http://homemakers.com/Health&Fitness/womenshealth/fertility-at-40-n264494p1.html

Life Begins...
Miscarriage stories of loss, hope & help
http://born2luv.blogspot.com/

Stories of Pregnancy & Birth over 44y
- Daily blog of hope & inspiration!
http://pregnancyover44y.blogspot.com/

4,800 Stories of Pregnancy & Birth over 44y
Daily blog of hope & inspiration!
http://pregnancyover44y.blogspot.com/

Recent Keyword Searches: can wheat germ help you become pregnant, natural pregnancy chances age 43, how to get pregnant over 45, fertility old eggs, wanting to get pregnant at 44 years old, up to what age can a woman still conceive

Technique measures a woman's 'biological clock'

Photo by miamiamia
A technique has been developed by scientists to tell a woman how fast her biological clock is ticking and when menopause is likely to hit.

Sandy Martinez, a 30-year-old manager of actors, is busy building a career, but she also wants to raise a family.

She wonders how long she can put it off. "Obviously your body's not the same when you're older, so that is a concern to me," she told CTV News.

"A woman of say, 30 or 32, who's thinking about whether to press on with her career, or wants to get into a better financial situation to have a family, could be rest assured they have more time," said Dr. Hamish Wallace, one of the study's authors.

"What we have done is to come up with a method that may allow us to predict for a woman what ovarian reserves she has and at what age she is likely to experience the menopause," Wallace, a pediatric oncologist and lecturer at the University of Edinburgh, told Reuters.

The Scottish scientists say they can do this by measuring the volume of a woman's ovaries using ultrasound.

This could also tell them how many eggs a woman has left, which could have a significant impact on fertility treatments.

"The ultrasound measurement is taken to work out the volume of the ovaries. If the ovaries are larger than average for her age, then she is likely to have a later menopause and if they are smaller she is likely to have an earlier one. Essentially we try to quantify by how much, by how many years," Dr. Thomas Kelsey, a computer scientists at the University of St. Andrews, told Reuters.

Women start with an estimated 800,000 eggs, but that number declines over time.

By the time a woman reaches 37, she's down to about 25,000 eggs. At that time, the rate of decline speeds up. The ovaries shrink until almost all the eggs are depleted. At that point, menopause occurs.

That generally happens at age 50, but can happen between the ages of 42 and 58.

Wallace and Kelsey reported their findings in the medical journal Human Reproduction.

"It is going to be useful for couples who have fertility problems because it is an easy way for the fertility clinics to work out essentially whether it is worth doing IVF (in-vitro fertilization) or whatever treatment," Kelsey said.

For example, a woman with a number of fertile years ahead might be better off trying to conceive naturally or to space out fertility treatments, he said.

Conversely, if the egg supply is low, it might not be worth it, he said.

Two instances in which the diagnostic method won't work is for women taking oral contraceptives or those suffering from polycystic ovarian syndrome, which causes infertility.

The scientists are planning to do longer-term studies to track young women until they hit menopause.

"It opens the door to the possibility of screening women for early ovarian aging. These women may be at increased risk to their general health from the effects of having an early menopause," Wallace said.

But some warn against the use of this technique by perfectly healthy women.

"The difficulty of getting pregnant goes up as you get old. And the risk of miscarriage or Down's Syndrome goes up as well. So it's not just how many eggs you've got," Diane Allen of the Infertility Network.

Study: Ovarian reserve and reproductive age may be determined from measurement of ovarian volume by transvaginal sonography

Source: http://www.ctv.ca/servlet/ArticleNews/story/CTVNews/20040617/fertility_study_040617?s_name=&no_ads=

Life Begins...
Miscarriage stories of loss, hope & help
http://born2luv.blogspot.com/

Stories of Pregnancy & Birth over 44y
- Daily blog of hope & inspiration!
http://pregnancyover44y.blogspot.com/

4,550 Stories of Pregnancy & Birth over 44y
Daily blog of hope & inspiration!
http://pregnancyover44y.blogspot.com/

Recent Keyword Searches: can i get pregnant at 45?, is anovulation a symptom of menopause, ivf success stories over 40, can you get pregnant when your on perimenopause, is it harder to get pregnant when your 45, what can you do to improve the chances of your egg implanting, age woman can no longer become pregnant, can you get pregnant at age 46, can you get pregnant after 40 without fertility drugs?, change of life babies

Baby scans: do we need them?

For many women, the scan which shows their unborn squirming, kicking and sucking its thumb is one of the important milestones of pregnancy.

For the vast majority it provides reassurance that all is well, and it enables parents to prepare if all is not.

But an eminent ultrasound specialist is determined to kickstart a debate on the value of the scan within an NHS increasingly strapped for cash.

In a paper published in Ultrasounds this week, retired Dr Hylton Meire not only argues there is no scientific evidence to prove the 20-week scan is worthwhile, he also casts doubt on the reliability of the principal method of testing for Down's Syndrome - the nuchal fold measurement.

These tests do not give a yes or no answer to whether a baby has Down's, but an indication of risk. Those deemed to have a higher possibility are offered an amniocentesis, where a needle is inserted into the womb to give a much more accurate analysis.

Every amniocentesis carries a small risk of miscarriage, so women who are not carrying a disabled foetus in the first place can end up losing a perfectly healthy baby.

Using various figures, Dr Meire, formerly of King's College Hospital, calculates that as many as 3,200 healthy babies are lost in this way each year.

For every 50 live births of children with Down's Syndrome prevented, he says 160 women miscarry non-affected babies.

'Muddled measurements'

Dr Meire has reservations about aborting babies with Down's Syndrome in the first place, and admits this forms part of his hostility to testing for the condition.

The nuchal fold test involves measuring the fluid at the back of the neck of an 11-13 week old foetus.

Babies with abnormalities tend to accumulate more fluid at the back of their neck during the first three months after conception, causing this clear space to be larger than average.

Age of the mother is one of the factors taken into account when risk is being calculated, and many hospitals also carry out blood tests to give an even more accurate picture.

Low risk is a result where the chances of having a baby with Down's syndrome is less than one in 800, while high risk is anything greater than one in 300.

Dr Meire argues that blood tests notwithstanding, the test is hugely problematic because of the difficulties of measuring anything accurately on a blurry ultrasound screen.

"Women are being referred on to amniocentesis on the basis of a very flimsy test," he says.

"And I think they need to understand just how inaccurate it can be."

Jane Fisher from Antenatal Results and Choices (ARC) says Dr Meire does have a point, but that most parents are all too aware the test is fallible.

Weighing up the various risks - a one in 200 chance of carrying a child with Down's syndrome against a one in 200 chance of miscarrying after an amniocentesis - is an immensely difficult decision.

"The problem is Dr Meire wants absolutes," she says.

"The technology isn't there to provide that yet, and in the absence of it, we have to make do with what there is. But of course counselling is important, and a proper discussion about what the risks are."

Spending money

In any event, ARC stresses that screening now means fewer older mothers have an amniocentesis as a matter of course, as was the case all the way up until 2001 when the scans became available nationally.

The test is offered in around three quarters of hospitals, but not necessarily to all women. Older women are at greater risk of having a child with Down's Syndrome, and some hospitals only screen those over the age of 35 or even 38.

But the vast majority of women in the UK - 95% - are offered the 20 week anomaly scans which Dr Meire also targets in his paper.

Costing between £25 and £50 a go, the specialist says there is no evidence to prove they are worth the money.

"There's no data that shows - in regard to children living or dying or succumbing to serious illness - that these scans have any effect in population terms. No-one has been able to prove otherwise," he says.

"We need to really think about why we do these, and the money we spend on them, and ask ourselves if it's really worthwhile."

Conditions detected at 20 weeks include serious problems such as heart defects, as well as more minor conditions like cleft palate.

Obstetrics consultant Patrick O'Brien says it is very important to know in advance if a child has heart defects, as it means preparations can be made for delivery in a specialist unit if need be.

But he concedes that viewed at the level of pure statistics, it is possible to argue that scans only benefit a small minority of people. Often parents learn information which they do not necessarily need to know before the birth.

But while finding out a child is to be born with a cleft palate may not be necessity, learning through a scan means parents can be prepared for what can be a huge shock at delivery.

"They are shown pictures of what can be done and understand how easy it is to treat," says Mr O'Brien.

"I certainly wouldn't want to go back to the pre-scan days when horrified parents simply shunned the child when it was born."

"But sometimes you've also got to look at things from an individual perspective, and what it means for the parents.

"Maybe the pure joy of parents seeing their unborn child is something that's worth paying for."

Source: http://news.bbc.co.uk/1/hi/health/6948015.stm

Baby scans: do we need them?

For many women, the scan which shows their unborn squirming, kicking and sucking its thumb is one of the important milestones of pregnancy.

For the vast majority it provides reassurance that all is well, and it enables parents to prepare if all is not.

But an eminent ultrasound specialist is determined to kickstart a debate on the value of the scan within an NHS increasingly strapped for cash.

In a paper published in Ultrasounds this week, retired Dr Hylton Meire not only argues there is no scientific evidence to prove the 20-week scan is worthwhile, he also casts doubt on the reliability of the principal method of testing for Down's Syndrome - the nuchal fold measurement.

These tests do not give a yes or no answer to whether a baby has Down's, but an indication of risk. Those deemed to have a higher possibility are offered an amniocentesis, where a needle is inserted into the womb to give a much more accurate analysis.

Every amniocentesis carries a small risk of miscarriage, so women who are not carrying a disabled foetus in the first place can end up losing a perfectly healthy baby.

Using various figures, Dr Meire, formerly of King's College Hospital, calculates that as many as 3,200 healthy babies are lost in this way each year.

For every 50 live births of children with Down's Syndrome prevented, he says 160 women miscarry non-affected babies.

'Muddled measurements'

Dr Meire has reservations about aborting babies with Down's Syndrome in the first place, and admits this forms part of his hostility to testing for the condition.

The nuchal fold test involves measuring the fluid at the back of the neck of an 11-13 week old foetus.

Babies with abnormalities tend to accumulate more fluid at the back of their neck during the first three months after conception, causing this clear space to be larger than average.

Age of the mother is one of the factors taken into account when risk is being calculated, and many hospitals also carry out blood tests to give an even more accurate picture.

Low risk is a result where the chances of having a baby with Down's syndrome is less than one in 800, while high risk is anything greater than one in 300.

Dr Meire argues that blood tests notwithstanding, the test is hugely problematic because of the difficulties of measuring anything accurately on a blurry ultrasound screen.

"Women are being referred on to amniocentesis on the basis of a very flimsy test," he says.

"And I think they need to understand just how inaccurate it can be."

Jane Fisher from Antenatal Results and Choices (ARC) says Dr Meire does have a point, but that most parents are all too aware the test is fallible.
Weighing up the various risks - a one in 200 chance of carrying a child with Down's syndrome against a one in 200 chance of miscarrying after an amniocentesis - is an immensely difficult decision.

"The problem is Dr Meire wants absolutes," she says.

"The technology isn't there to provide that yet, and in the absence of it, we have to make do with what there is. But of course counselling is important, and a proper discussion about what the risks are."

Spending money

In any event, ARC stresses that screening now means fewer older mothers have an amniocentesis as a matter of course, as was the case all the way up until 2001 when the scans became available nationally.

The test is offered in around three quarters of hospitals, but not necessarily to all women. Older women are at greater risk of having a child with Down's Syndrome, and some hospitals only screen those over the age of 35 or even 38.

But the vast majority of women in the UK - 95% - are offered the 20 week anomaly scans which Dr Meire also targets in his paper.

Costing between £25 and £50 a go, the specialist says there is no evidence to prove they are worth the money.

"There's no data that shows - in regard to children living or dying or succumbing to serious illness - that these scans have any effect in population terms. No-one has been able to prove otherwise," he says.

"We need to really think about why we do these, and the money we spend on them, and ask ourselves if it's really worthwhile."

Conditions detected at 20 weeks include serious problems such as heart defects, as well as more minor conditions like cleft palate.

Sometimes you've also got to look at things from an individual perspective, and what it means for the parents - maybe the pure joy of parents seeing their unborn child is something that's worth paying for

Obstetrics consultant Patrick O'Brien says it is very important to know in advance if a child has heart defects, as it means preparations can be made for delivery in a specialist unit if need be.

But he concedes that viewed at the level of pure statistics, it is possible to argue that scans only benefit a small minority of people. Often parents learn information which they do not necessarily need to know before the birth.

But while finding out a child is to be born with a cleft palate may not be necessity, learning through a scan means parents can be prepared for what can be a huge shock at delivery.

"They are shown pictures of what can be done and understand how easy it is to treat," says Mr O'Brien.

"I certainly wouldn't want to go back to the pre-scan days when horrified parents simply shunned the child when it was born."

"But sometimes you've also got to look at things from an individual perspective, and what it means for the parents.

"Maybe the pure joy of parents seeing their unborn child is something that's worth paying for."

Source: http://news.bbc.co.uk/1/hi/health/6948015.stm

How much of the outside world can a fetus perceive?

They are iconic images of pregnancy: Expectant parents watching their squirming baby-to-be on the ultrasound screen, or a mom reclining on the couch while headphones playing Mozart hug her growing belly. But how much of this early attention is actually perceived by the developing fetus? As it turns out, it may be quite a lot.

Researchers note that fetal auditory perception has been observed at 30 weeks’ gestation; in fact, there has been much research done to demonstrate this. In 1999, researchers at the Universite de Paris V and at the University of North Carolina at Greensboro examined whether 36-to-39-week-old fetuses could perceive differences in musical notes. They found playing a single note caused fetuses’ heart rates to slow, and changing the note after a spell caused the heart rate to change again.

In a 2003 study, 38-week-old fetuses showed off their ability to recognize voices. Researchers at both Queen’s University in Canada and Zhejiang University School of Medicine in China played recordings of either the mother’s or a stranger’s voice over a loudspeaker. They discovered that the mom-to-be’s voice caused the fetus’ heart rate to increase, while the strange voice caused it to drop. This result was interpreted to show that the experiences of the fetus during gestation impact future speech processing ability.

Music and voices are among the stimuli that babies are adapted to listen to after birth, so it seems logical that these sounds would have an effect on a fetus in the womb. Some researchers, though, uncovered a surprise when fetuses reacted to something they wouldn’t be able to hear once born: an ultrasound.

Most diagnostic ultrasound scans today use pulse ultrasound, which works by emitting bursts of ultrasound energy. Dr. Paul Ogburn, an obstetrician at Stony Brook University, equates the ultrasound energy pulse to yelling down a canyon: the yell is the burst of energy, and the ultrasound energy bouncing off the fetus and coming back to the sonographer is “the echo.”

Ultrasound exposure must always conform to the principle of ALARA, or As Low As Reasonably Achievable, when obtaining the necessary pictures, explained Dr. Deborah Levine, in the Department of Radiology at Harvard’s Beth Israel Deaconess Medical Center. It is recommended that a transducer – the wand that is run across the mother’s belly – operate at three to five million hertz (cycles per second). By comparison, human hearing can only detect frequencies from 20 hertz to about 20,000. Therefore, the expectant mother cannot perceive the frequency of her ultrasound scan, but Ogburn’s research indicates that the same is not true of her baby.

Ogburn and his colleague Mostafa Fatemi, a biophysicist and engineer with the Mayo Clinic, studied fetal reactions to ultrasound waves, which travel through flesh and amniotic fluid differently than they do through the air that mediates adults’ hearing. They found that fetuses do move more frequently under ultrasound than under normal conditions, and their heart rates increase. Typical fetal movements in the third trimester range from one movement every two minutes to almost two movements a minute, they wrote, citing a prior paper. In their study, fetuses 25-to-40-weeks-old moved an average of almost three and a half times a minute when presented with pulse ultrasound.

Fatemi said that for a fetus, the experience of ultrasound is similar to the experience an adult would have at a rock concert or standing near a jackhammer. Ogburn noted that the medical community has assumed that ultrasounds are a way of eavesdropping to show the normal behavior of a fetus, but in fact the ultrasound machine itself may be subjecting the baby to unusual conditions.

“If you come crashing in with a loud machine, with ultrasound, or if you come in crashing pots and pans into the nursery, you may see a different baby than you would have seen if you snuck in quietly,” Ogburn explained.

Though Ogburn and Fatemi stressed that their research did not address the possible health implications of these findings, obstetric ultrasound is considered to be safe when the scan stays within the settings that are approved for use on fetuses, explained Harvard’s Levine — even if the procedure does interrupt a nap… or a Mozart concerto.

Source: http://scienceline.org/2007/08/20/ask-moser-ultrasound/