Sunday, April 7, 2013

Bye Bye Biopsy: Chemicals Diagnose Cancer

FT. LAUDERDALE, Fla. (Ivanhoe Newswire) - It's believed close to 70,000 Americans will be diagnosed with a cancerous or non-cancerous brain tumor this year. Even if they're removed, there's a chance the tumors could come back. Now, doctors are using a new way to figure out if a dangerous tumor is regrowing or if something else is going on in the brain.

"I have a tumor the size of a goose egg right here in my head," Mary Grace, who had a brain tumor, told Ivanhoe.

After radiation therapy, Mary Grace had that benign tumor removed from her brain. Then, a new mass popped up in the same spot. Radiologist Dr. Robert Kagan believed it was one of two things.?

"The question here was, is this a malignant tumor caused by the radiation or is this an effect of the radiation?" Robert L. Kagan, MD, Radiologist at the MRI Scan Center, told Ivanhoe.

Tissue damage caused by radiation and cancerous tumor cells look alike, but, ""The chemical composition of radiation necrosis is a lot different than a malignant tumor," Dr. Kagan said.

?The doctor was able to determine the chemical make-up of Mary's mass with MR spectroscopy. Without an invasive biopsy or injecting dye, he uses an advanced MRI machine to figure out if the growth is cancerous. The ratio of various brain chemicals lead to a diagnosis.

"And that shows you that it is necrosis and not a tumor," Dr. Kagan explained.

Mary's cancer scare has passed and the benign brain mass is safely removed.

"And now my synapses are firing. It's like a Gatling gun," Grace said.

Dr. Kagan has one of about 200 MRI machines capable of performing state of the art MR spectroscopy in the United States. Others are located at places like Mayo Clinic, Duke University and Stanford University Medical Center. The test is not covered by insurance at this time and could cost you about $900. The doctor said MR spectroscopy is also being used to detect breast and prostate cancers in clinical trials.?

RESEARCH SUMMARY

BACKGROUND:??The causes of brain tumors are unknown.?There are only a few known risk factors.? Children who receive radiation to the head have a greater risk of developing a tumor on the brain when they are adults, as well as people who have rare genetic conditions, like neurofibromatosis or Li-Fraumeni syndrome.?These cases only represent a fraction of the 35,000 new primary brain tumors diagnosed every year.?? Age is another risk factor.? People over 65 years are diagnosed with brain cancer at a rate four times higher than younger people.? A primary brain tumor originates in the brain and they are not all cancerous.? A benign tumor is not aggressive, but can be life-threatening.?? (Source:?www.webmd.com)

SYMPTOMS:? Symptoms vary according to the type of tumor and location.? Different ares of the brain control different functions of the body, where the tumor is located will affect the symptoms.? Some tumors do not have symptoms. A common symptom is headaches.? Others can include:? seizures, changes in vision, changes in speech, balance problems, numbness or tingling in the arms or legs, problems with walking, personality changes, problems with memory, weakness in one part of the body, and the inability to concentrate.?? (Source:?www.webmd.com)

TREATMENT:? Surgery to remove the tumor is the typical first option, but some can't be removed because of the location. Chemotherapy and radiation therapy are other options to kill the tumor.? They can also be used after the surgery to kill remaining cancer cells.? For tumors that are embedded deep in the brain, a form of highly focused radiation therapy can be used to treat it, called Gamma Knife therapy.? (Source:?www.webmd.com)

NEW TECHNOLOGY:??Even if the tumor is successfully removed, there is always a chance it can come back.? Therefore, diagnostic tools are necessary.? A new noninvasive diagnostic test for measuring biochemical changes in the brain is called Magnetic Resonance (MR) spectroscopy.? Magnetic Resonance Imaging identifies the anatomical location of the tumor; MR spectroscopy compares the chemical composition of normal brain tissue with abnormal tumor tissue.? It can also be used to identify tissue changes in epilepsy and stroke. MR spectroscopy is done on the same machine as MRI.? It is a series of tests that are added to the MRI scan of the brain or spine to measure the chemical metabolism of a tumor.? It analyzes molecules like protons or hydrogen ions.? Proton spectroscopy is more common.? Several different metabolites can be used to differentiate between tumor types, including: lipid, lactate, amino acids, myoinositol, choline, creatine, and N-acetyl aspartate.? The frequency of these metabolites is measured in units called per million (ppm) and plotted on a graph as peaks of height.? The neuroradiologist can determine the type of tissue present.? It can be used to determine tumor type and aggressiveness, and it can distinguish between radiation necrosis and recurrence.? MRI and MR spectroscopy are both safe.? There are no health risks associated with the magnetic field or the radio waves used by the machine.? (Source:?www.mayfieldclinic.com/PE-MRspectroscopy.HTM)

INTERVIEW

Robert Kagan, MD, Medical Director at MRI Scan Center, talks about a new technique for MRI imaging.

Can you tell us about your MRI machine?

Dr. Kagan:??Magnetic field strength is a very important property in determining the quality of not only the images that you can get with MRI, but also the spectral or graphic analysis that you can get with Magnetic Resonance Spectroscopy (MRS). The stronger the magnet is the better the resolution. It allows us to be able to separate one structure from another and see individual structures as individual structures instead of them blending together. Also, it gives us speed increases. So, that could be a problem for certain people if we're doing imaging because we are detecting these tiny little radio wave signals that are coming out of the body. They have to add up over time. By doubling the magnetic field strength, going from 1.5 tesla to 3 tesla, which is the most powerful magnet available in America approved by the FDA, we get four times the signal. Another way to look at it is, if the scan used to take an hour it will take fifteen minutes now to get the same quality or you could take a half-hour and get twice the quality in half the time. There's always trade-offs involved.

What were you able to do with MR Spectroscopy in Mary's case?

Dr. Kagan:?Mary's case an interesting case and a great use of MRS. We can use the signal that comes from the hydrogen atoms. The human body is composed of atoms. Imagine the earth; the earth is a magnet that has a North and a South Pole. If you hold a compass out on the face of the earth it will point in the direction of the North Pole. If you could see the little atoms that make up your body, they look like miniature versions of the earth. They all have a North and a South Pole. So, when we put the human body into a magnet, all those atoms that are spinning around randomly line up with the North, South Pole of the magnet like a compass would. It just so happens that the right energy required to knock them out of alignment happens to be a radio wave. The right radio wave will cause them all to spin at the same frequency, which is called resonance. We use that resonance property to create images, which are now called MRI. Also, we can use the same signals to create a graphic representation, called spectra of the different metabolites. When looking at a MRI scan, we are looking at an anatomic display of tissue biochemistry. That's why things look different because they're different biochemical structures. You can have a tumor in your liver as big as a grapefruit and you'll never see that on the most sophisticated x-ray known to man, which is called a CAT scan, if the tumor happens to have the same density as your liver because x-rays are based on density. It's a physical characteristic. We can always see it on the MRI because tumor is not a liver; it's as simple as that. When we have a certain question, for example, we have this mass in the patient's brain that I talked about which looks like a tumor. It looks like a tumor with this little signal drop-out in the middle, which is usually a sign of necrosis. It certainly has all the characteristics of a tumor and it presses on the ventricle, but given her clinical story we know that it could be radiation necrosis vs. radiation induced tumor caused by too much radiation therapy.

So, in Mary's case, you were determining whether the tumor was benign or malignant?

Dr. Kagan:??Well, I know it's malignant if it's a tumor because it's not a meningioma, which was her original tumor. So, this is something that's malignant. Radiation therapy was used to treat the meningioma at first and when it turned out to be resistant to that type of treatment, which it usually is, they performed surgery. They cut out the tumor, but now this is a different process all together and meningiomas don't look like this. The question here was is this a malignant tumor caused by the radiation or is this an effect of the radiation, called radiation necrosis, which is not a tumor but looks like a tumor? There's a big difference if it's a malignant tumor versus if its radiation necrosis and it's not a tumor.

What did it turn out to be?

Dr. Kagan:??Well it turned out to be radiation necrosis and the only way to make that diagnosis was by using MRS. We couldn't make that diagnosis from the MRI images alone. Everything about the MRI scan told us it was one or the other and there was no way to differentiate between those two possibilities. So, here was a great use of MR spectroscopy, which is using the same hydrogen signal for those hydrogen atoms to create a spectral readout of the chemical composition of the lesion. The chemical composition of radiation necrosis is a lot different than a malignant tumor. For example, with a tumor this particular metabolite N-acetyl-aspartate (NAA), which makes up normal tissue, goes down. The other metabolite, choline, which is in cell membranes, goes up because you get a lot of destruction of cell membranes. However, with radiation necrosis we get this large increase in the lipid fraction and all those other metabolites you can hardly see. For example, in a healthy volunteer, you can see a high NAA, which is a measure of the integrity of neurons; the higher that is the better the function. It's very nonspecific, but sensitive. So, almost any bad thing that's happening in the brain will cause a decrease in NAA, which is located in a certain place on the spectral readout. Then choline is lower than NAA. What happens with a tumor is a reversal of those two. Choline goes shooting up and NAA goes down; that is a sign of a brain tumor. For example, in a malignant brain tumor, you can see choline went way up and the NAA went way down and so they reversed. However, those are very different than radiation necrosis. There's no other way to make that diagnosis except by drilling a hole in the head and going in to the brain. MRS is completely noninvasive, which is a miraculous thing.

What other uses do you have for it?

Dr. Kagan:?Most research has been done in the brain. The brain is sort of ready for prime time. We can use it. The research is for prostate. For example, there is a metabolite called citrate, which is normally very high in the prostate. That goes down when you have cancer. Choline, again, goes up because choline is a very general metabolite that's in cell membranes. Whenever there is destruction of cell membranes, it shoots up. There are certain things that are specific, like citrate for the prostate, which it hasn't all been worked out yet. This is technically difficult. It's just like MRI itself in the beginning. It was first established in the brain. It took a long time before we went to the spine and then a number of years before it went to the musculoskeletal system. Every athlete that gets injured now has to have an MRI. The musculoskeletal system acceptance took years after the central nervous system acceptance. That's how it works with medicine; you go from one organ to another organ.

After you made the diagnosis of necrosis from the radiation, what happened with Mary's brain? What did they do?

Dr. Kagan:?She went to a neurosurgeon in Miami. A very famous neurosurgeon who actually resected this and she was cured, but you couldn't have resected this if this was a malignant brain tumor. They would have just left her alone. When we knew it was benign and that it was just an effect of the radiation, it was taken out and she's been fine because it spreads if you don't take it out. So, she had brain surgery and she was cured as much as she could be. Don't forget that she still has part of her brain missing, but there's a lot of duplication of activity. There's a lot of reserved capacity in the brain. She can do quite well still.

FOR MORE INFORMATION, PLEASE CONTACT:

Robert Kagan, MD
Medical Director
MRI Scan Center
(954) 772-8000
rkaganmd@mriscancenter.com

Source: http://www.newschannel5.com/story/21892285/bye-bye-biopsy-chemicals-diagnose-cancer

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