Reviews and News on Ultrasound Machines

The word “ultrasound” conjurers up images of fuzzy pictures and growing babies. But ultrasound machines have another face, one of precision and delicacy. This facet of ultrasound is employed when operating on one of the most sensitive organs of the body: the human eye.

Modern ultrasound has both the ability to be very precise and very controlled. The precision is self evident. The width of a sound wave is beyond tiny. Getting into small places is not a problem for a sound wave. And the length of a wave is not really an issue. To simplify it a bit, length of sound wave can be correlated to strength. And controlling the strength of the ultrasound is perhaps the most established part of the modern techniques of ultrasound.

So, given this, it is no wonder that eye surgeries use ultrasound machines. Especially in cataract surgery, ultrasound really comes into play. The principle complaint in all cataracts is a clouding of the lens. At the end of World War II, many pilots were retuning to base with eye injuries from explosions of the windshield of the planes. Surgeons at the time were unable to remove every piece. But the subsequent weeks did not show any rejections of the small bits by the eye. Therefore, it was discovered that certain kinds of materials could be introduced into the eye and the eye would not reject the material. It was but a short step from that discovery to the grinding of lenses that could replace the natural lens of the eye when clouded with a cataract.

Surgeons quickly discovered that when they opened the capsule of the eye, they had to re-establish the pressure of the anterior chamber of the eye for the surgery to be successful. Over the years many techniques were studied, but one day eye surgeon Dr. Charles Kelman went to his dentist and saw an ultrasonic probe. He saw that this small device could be readily adapted for eye surgery.

The advantage of the ultrasonic probe is that the lens can be removed without opening the capsule of the eye. Of course, the appropriate anesthetic, local or general is used, but given the small size of the incision and the need for the patient to remain still, local anesthetic is the typical choice. Basically, the procedure involves a very small incision in the cornea. A probe irrigated with a saline solution is then introduced under the cornea without opening or removing the whole cornea. The probe liquefies the natural lens, which is then aspirated out while clean saline is introduced. As the new artificial lens Is then inserted, the pressure in the eye is maintained.

Recovery time for this type of procedure is remarkably short. Many patients report improved vision only hours following the procedure, though full effects may take weeks to be realized. Patients are cautioned against bending at the waist and lifting things for about a week, but generally after that, the only reminder of the surgery is vastly improved vision.

With the technology established for HIFU or High Intensity Focused Ultrasound (see part 1 of this series), more and more uses are being found for this innovative technology. In 2004, The Food and Drug Administration approved HIFU for to treat uterine fibroids, significantly broadening the treatment options for this disease.

Cancer Applications
But it is in the treatment of cancers that HIFU finds very broad application. It has been successfully applied in the destruction of solid tumors of the bone, brain, breast, liver, kidney and prostate, just to name only a few.

The earliest use of HIFU to destroy tumors was in the case of prostate cancer. The treatment is given trans-rectally and the results are reaching the same success rates as traditional surgery. These and other similar treatments for prostate cancer greatly reduce some of the common side effects that can accompany traditional surgery, including nerve damage and the impotence which can result.

Laying aside tumor destruction aside, one of the latest innovations for HIFU is using it in conjunction with cancer drugs. There is a class of cancer drugs that can be loaded into the tumor site, but will remain in a tight bundle until released by the application of HIFU. This reduces the systemic spread of the chemotherapy agent while maximizing its concentration at the tumor site. This methodology makes it easier to keep the medicine in one spot, increase the local concentration and keep the toxic burden on the body as low as possible. This minimizes the risks risks associated with traditional chemotherapy methodologies.

The brain is protected by a blood/brain barrier that makes it difficult for some substances to get to the brain, even if you want those substances to get to the brain. It has been discovered that an application of HIFU will temporarily disable the blood/brain barrier and let needed drugs get through to the brain.

Imaging is not the only medical application for ultrasound. There is a new application that is growing in importance the medical science. Imaging ultrasounds are fairly high intensity, but the changes in that intensity are stable over time.

But if you take the same ultrasound waves, lower the overall intensity, while rapidly changing the intensity from one setting to another over time, you get an entirely different effect. These waves are called High Intensity Focused Ultrasound or HIFU. This heats and destroys pathogenic tissue rapidly. It is a very precise technique. Its precision is due to the ability of the sound waves to be focused to small widths and diameters. It can be directed by several means, but the overall modality remains the same.

Sound waves carry energy. As a sound wave passes through tissue, it generates heat. In a diagnostic ultrasound, this heat is not the goal and great pains are taken to minimize it. In HIFU, the rapid changes between frequencies make much more heat, not unlike the heat generated when you bend a piece of wire back and forth to break it. Once hot enough, the tissue becomes thermally coagulated, rendering it inactive.

It is interesting to note that if this heating is pushed too far, bubbles will be produced. This is called cavitation. These bubbles will grow larger and ultimately implode. This would increase the cell death, but it is an unpredictable process and is not desirable. There is some investigation to see if this can be harnessed, especially with the need to destroy relatively large masses of tissue, but that lies in the future.

The temperatures within the targeted tissue can rise to between sixty-five and eighty-five degrees centigrade, destroying the tissue. This can easily be combined with other treatment modalities for better long term outcomes. Overall, this treatment is valuable because it is noninvasive, generally painless, and highly controlled. It is a valuable new tool in the medical arsenal.

Real-time data on a pregnant mother and her unborn child during the course of labor was a pressing need in obstetrical science. Ultrasound came to the rescue with the development of external fetal monitors. The all-encompassing term for this type of monitoring is cardiotocography, or CTG. This refers to the fact that not one, but two pieces of data are being collected. In simple terms, the CTG is recording the fetal heartbeat and the rate of uterine contractions. These factors, when taken together, are a good indicator of how the fetus is handling the stress of labor.

There are two ultrasound transducers used in fetal monitoring, one for the fetal heart rate and the other for the contractions themselves. External monitoring is accomplished by strapping the transducing sensors to the abdomen of the pregnant mother. The heart sensor is based on Doppler methodology. The contraction transducer is a pressure sensor and measures the tension of the abdominal wall which is an indirect indicator of intrauterine pressure.

CTG must consider several factors, namely uterine contractions and all four features of fetal heart rate:

*the baseline heart rate,
*variability or changes over time,
*accelerations over time, and
*decelerations over time.

Before interpretation can begin, risk factors must be defined. They will influence the decision-making process. For example, the decision to proceed to a surgical intervention or cesarean section might be made more quickly if the patient is at higher risk for an adverse outcome.

Historically, this suite of data has been classified as “reassuring” or “non-reassuring.” Deemed not descriptive enough, these two classifications have been supplanted by these new categories.

*Category I (normal) – the tracing of all findings are indicative of normal status and labor can be allowed to proceed using standard procedures.
*Category II (indeterminate) – the tracing of all findings are not indicative of normal status but do not rise to the level that requires immediate intervention. Continued monitoring is indicated and more re-evaluations are necessary.
*Category III (abnormal) – some part of the findings indicate an abnormal status such as fetal distress that requires prompt evaluation and management, inducing but not limited to direct intervention such as a cesarean section.

At the recent annual VEITH symposium in New York, Emory University researchers revealed that ultrasound machine waves may be the next big thing in treated deep vein thrombosis, or DVT.

DVT is a blood clot that has formed in one of the larger veins of the body. Blood clots can then break off and travel through the bloodstream. If it lands in the lungs it can cause a pulmonary embolism; in the heart, a heart attack; and in the brain, a stroke. In fact, blood clots are the main cause of heart attacks and of strokes. The most frequent locations of DVT are the calf or thigh. You can be at risk for a DVT if you sit without moving for a long time, recently had surgery, fell or broke a bone, were in a car crash, or are a woman who is taking birth control pills, pregnant, or menopausal. Seniors over the age of 65 and smokers are at higher risk as well.

The more quickly the clot in a DVT can be dissolved, the less risk a patient has of injury and death. Until now, treatment for DVT has often involved either surgical removal of the clot or the use of clot dissolving medications, such as tPA (tissue plasminogen activator) or heparin.

Karthikeshwar Kasirajan, assistant professor of surgery, Emory University School of Medicine, reported that using ultrasound waves to loosen the proteins in the blood clots allowed tPA medication to penetrate into the clots faster for quicker resolution during their testing. “We now know that using ultrasound, along with the traditional method of using drugs to break up or dissolve blood clots, will help restore flow, prevent valve damage and also prevent the possibility of pulmonary embolism,” Kasirajan said. Patients in the test either had DVT or acute in-situ arterial thrombosis. There were 37 patients involved in the study.

This is a promising new use for ultrasound. With its use as a diagnostic tool well established, we are now finding many ways in which ultrasound machine waves can be used to treat diseases, sometimes the very diseases which they helped diagnose.

Because advances in technology have made ultrasound machines more affordable, a new industry has sprung up: the making of fetal keepsakes. These companies allow parents to purchase a photograph or video of their baby in utero as a keepsake. Companies who own equipment that can produce three-dimensional images are especially popular and sought after. These fetal keepsake images are far different products from the fuzzy snapshots doctors share when they are performing a diagnostic ultrasound. The exposure level is quite different as well: in the case of fetal keepsakes, ultrasound may be used for as long as an hour to capture the desired images.

The FDA considers the use of ultrasound for fetal keepsakes an unapproved use of a prescription medical device. First and foremost, ultrasound is intended to be used for diagnostic purposes. In the hands of a skilled technician working with a medical professional, an ultrasound can provide valuable information about a fetus, including diagnosing abnormalities that can be corrected even before the child is born. Secondly, ultrasound can also used to provide certain medical treatments. At higher levels, ultrasound can be used to help bone fractures heal and to treat sprained muscles. While there is no hard evidence that ultrasound can be harmful to a developing fetus, it makes sense to limit exposure to medically necessary scans.

Seeing your child’s face for the first time is an amazing experience, and since it is possible to see that face before the child is even born, it’s no wonder that some parents want to have that experience as soon as possible. While the risk of a fetal keepsake ultrasound may be minimal, no risk is worth taking unless there’s a potential benefit to be gained that is greater than the risk involved. In the case of seeing a developing face a few months early, the benefit doesn’t outweigh the risk, however small. It’s better to wait until the baby is born for that first real glimpse. After all, if you’re going to be a parent, you might as well start learning patience now.

We have all witnessed the rapid pace of technological development. We’ve seen how technology brings new tools to our lives, and makes existing tools smaller, more powerful, and less expensive. Portable ultrasound is no different. Even wealthy private individuals can purchase machines should they so desire: Tom Cruise created significant controversy when he purchased a machine for home use while wife Katie Holmes was expecting their first child.

So let’s consider two questions. First, with all the technological advances in diagnostic medicine, is the portable ultrasound machine still a valuable medical tool, or has it gone the way of the dinosaur? Advanced testing modalities, like CT scans, MRIs, and PET scans, are commonplace these days as the technology to provide them becomes more affordable. Is there still a place in the medical office for a portable ultrasound machine?

The answer is a resounding “yes!” When you need answers quickly, there is nothing like having a portable ultrasound machine in your office. Ultrasound machines can quickly provide diagnostic information, from abdominal pain to looking for blood clots in the veins to diagnosing an ectopic pregnancy. The size of the equipment  needed for CT and PET scans and MRIs makes it impossible for every office to have one on hand. In the hands of a skilled medical professional, a portable ultrasound is a powerful and sometimes instantaneous diagnostic tool.

Which brings us to our second question: what is an ultrasound good for? Most of us are most familiar with ultrasounds of developing infants, or other diagnostic uses. But technology is finding new uses for the technology at the heart of this familiar imaging device. Ultrasounds waves at a higher energy level than used for diagnostic imaging can produce very powerful results. For example, focused ultrasound energy can be used to cauterize wounds and stop bleeding, to break up kidney stones, and to treat cancer by accelerating the rate at which drugs are absorbed into the body or tumor.

In light of these new uses, and in light of the wonderful diagnostic imaging they can provide, portable ultrasound machines have a definite place in the medical office of today and tomorrow.

There are lots of different models of portable ultrasound machines for radiologists, or general physicians for that matter. During this recession, makers of medical equipment are using many cost-effective marketing strategies, making the equipment more affordable than before. Though many brands are available, many people like to go by popular names; ore choose less expensive alternatives like choosing previously-owned yet still quality equipment.

Portability of an ultrasound machine allows the physician in charge to use the machine anywhere in his hospital premises without hassle. However, besides portability, you need to look out for many things when buying portable ultrasound machines. A good machine should have:

• Relatively light weight, preferably less than 30 Kilos
• High resolution image matrix
• Micro-processor controlled
• Connectivity to 2-3 transducers simultaneously
• Should be able to use broad-band, multi-frequency transabdominal and transvaginal transducer technology
• Alpha-numeric keyboard
• 256 level gray scale
• High-resolution monitor with swivel capability
• Facility of pre and post-processing
• User-friendly set up
• Real time zooming capability Preloaded with all necessary software

Many physicians also like to have accessories like an onboard black and white thermal printer. Most dealers provide specialty training and training materials with every purchase of portable ultrasound machines.

Among many brands, still people are seen to prefer quality brands like Mindray, Toshiba, Phillips, etc., although Acuson, GE, ATL, Sequoia, etc.  are also popular. Even used machines from high quality brands are preferred over newer models, as these are usually available at far less cost than when they were initially purchased. Many dealers and manufacturers even offer guaranteed original specifications in used models.

Most online vendors offer 24/7 assistance in choosing as well as buying portable ultrasound machines. A little vigilance on your part regarding the features, price range, and some comparative study can definitely help you grab the best deal online!