How has technology helped to make our lives better? A Science Project about Electromagnetic Radiation in Medical Imaging (MRIs)

Electromagnetic Radiation in Medical Imagery: MRIs 

Zara Tse

MRIs History Timeline

1882- Nikola Tesla discovered the Rotating Magnetic Field in Budapest. This was a fundamental discovery in Physics.

 

1937- Columbia University Professor Isidor I. Rabi observed the quantum phenomenom dubbed nuclear magnetic resource (NMR). He recognized that the atomic nuclei show their presence by absorbing or emitting radio waves when exposed to a sufficiently strong magnetic field.

 

1046- Magnetic resonance phenomenom is discovered by Felix Bloch and Edward Purcell.

1950s- A one-dimensional MR image is created by Herman Carr. 

 

1956- All MRI machines are calibrated in 'Tesla Units'. The strength of the magnetic field is measured in Tesla or Gauss Units. The stronger the magnetic field, the stronger the amount of radio signals which can be elicited from the body's atoms and therefore the higher the quality of MRI images.

 

1971- Ramond Damadian, a physician and experimenter discovered that hydrogen signal in cancerous tissue is different from that of healthy tissue because tumors contain more water. More water means more hydrogen atoms. When the NMR machine was switched off, the bath of radio waves from cancerous tissue will linger longer then those from the healthy tissue. 

 

1972- A patent is applied which discribes the concept of using NMR machinese being used for the concept above.

 

1973- The first NMR image is produced, and was of a test tube.

 

1974- Ramond Damadian receives his patent.

 

1975- Richard Ernst proposes using the frequency and phase  encoding and Fourier transform for acquisition of MR images.

 

 

 

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MRIs History Timeline

1997/1998- Raymond Damadian builds the first MRI scanner by hand with the help of his two post-doctoral students. They achieved the first scan of a healthy human body in 1997, and a human body with cancer in 1998. Peter Mansfield improves the mathemetics behind MRI and develops an echo-planar technique, which allows images to be produced in seconds, and later became the basis for fast MR imaging.

 

1987- Real time MR imaging of the heart is developed.

 

1991- Filler and colleagues describe imaging of axonal transport of supermagnetic metal oxide particles, a technique, which later becomes important in imaging of neural tracts.

 

1993- Functional MR imaging of the brain is introduced.

 

1994- The first intraoperative MR unit is installed in the Brigham and Women's Hospital in Boston.

 

1990s- Not only research centres, and large hospitals, but also small remote hospitals, and imaging centers begin to use MRI predominately for neuroimaging and musculoskeletal imaging.

 

2000s- Cardiac MRI, Body MRI, fetal imaging, functional MR imaging are further developed and become routine in many imaging centers. Research centers make significant strides forward in imaging cartilage on high field scanners. The number of free standing MRI centers, most of which utilize low or moderate field MR scanners significantly increases. 

 

 

 

 

 

 

     - The inventor of the first MR Scanning Machine was Raymond Damadian in 1997.

 

 

HOW IT WORKS

The human body is largely made of water, which consists of hydrogen and oxygen atoms. At the center of each atom is an even smaller particle called a proton, which is sensitive to any magnetic fields. The MRI machine works on this principle.

 

Normally, the molecules are randomly arranged, but when placed in a strong magnetic field, such as a MRI scanner, they align in one direction. 

 

Once this is done, radio waves are transmitted. The protons are jostled off their axis, and spin into the same direction.

 

A computer then records how long the atoms in the different body parts take to return to their aligned positions.

 

The different tissues have different realignment times, so any abnomalitites lying within the body will have their signal picked up. Most diseases manifest themselves by an increase in water content, and the MRI is a sensitive test for the detection of diseases.

 

The scanner can detect any changes, and in conjunction with a computer, can create a detailed cross-sectional image for the radiologist.

 

 

USES& BENEFITS

RISKS& LIMITATIONS

USES& BENEFITS

 

With the development of the MRI Machine, doctors, scientist, and researchs are now able to examine the inside of the human body, without using an invasive tool.

 

There are many uses for the MRI Scan, and the following are just some examples:

  • Abnormalities of the brain and spinal cord
  • Tumors, cysts, et cetra in various parts of the body
  • Injuries or abnormalities of the joints, such as back pain.
  • Certain types of heart problems
  • Diseases of the liver and other abdominal organs
  • Causes of pelvic pain in women (e.g. fibroids, endometriosis)
  • Suspected uterine abnormalities in women undergoing evaluation for infertility

The MRI Scan has been used in these ways to detect, and prevent further development.

 

 

RISKS& LIMITATIONS

 

The powerful magnetic field will attract metal objects, which is fine if you remove any jewellery, watches, or metallic objects etc. However, heart pacemakers, defibrillation devices and cochlear implants may also malfunction or cause problems. 

This means that people with any of the above objects are cannot proceed with MRI scanning.

 

MRIs also typically costs more and may take more time to perform than other imaging modalities.

 

NEWS ARTICLE

Published in Medical News Today

Tuesday 20 October 2015 

Written by Catharine Paddock PhD

 

Hearts age differently in men and women

Changes detected in imaging scans over time reveal that the main pumping chamber of the heart ages differently in men and women, suggesting men and women may need different treatments for heart failure.
 
diagram of human heart

MRI scans showed significant differences in how men's and women's hearts change over time.

This was the finding of a federally funded study, led by Johns Hopkins University in Baltimore, MD, published in the journal Radiology.

The study is thought to be the first long-term follow-up using magnetic resonance imaging (MRI) to show how the human heart changes as it ages.

After analyzing MRI scans of the aging hearts of nearly 3,000 adults, the researchers found some significant differences in how men's and women's hearts change over time.

They conclude that while they do not know what causes these gender-related heart changes, the results explain some of the differences we see in heart failure between men and women, suggesting treatments for the condition should be sex- specific.

 

 

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NEWS ARTICLE- CONTINUED

 

The findings mainly surround changes to the main chamber of the heart - the left ventricle - which fills with blood and then pumps it out. As the heart ages, less blood enters the heart, and so less is pumped out.

The study builds on previous research that uses ultrasound to investigate how the heart changes with age. But this study, because it uses MRI scans, is able to make assessments using more detailed - and more reliable - images.

 

Left ventricle heart muscle grew in men, shrank slightly in women

Another distinguishing feature of the study is that it compares scans taken about a decade apart in the same patients. Most other studies of heart aging have tended to compare snapshots of young and old patients, which makes it difficult to rule out changes among individuals, such as lifestyle and health history.

John Eng, lead researcher and associate professor of radiological science at Johns Hopkins, notes:

"We had the opportunity to re-examine the same people after 10 years so that we could see what happened to their hearts after a decade. This is a more reliable way to assess left ventricular changes over time."

He and his colleagues found that in men, the heart muscle around the left ventricle grows and thickens with age, while in women it stays the same, or even shrinks slightly.

"Thicker heart muscle and smaller heart chamber volume both portend heightened risk of age-related heart failure," Prof. Eng explains, "but the gender variations we observed mean men and women may develop the disease for different reasons."

 

Heart filling capacity reduced with age, but more so in women

The participants in the study were aged between 54-94 and did not have any pre-existing heart disease when they enrolled. They underwent two sets of MRI scans, taken about 10 years apart between 2002-2012.

The MRI scans showed the interior and exterior of the heart in 3D, and allowed the researchers to assess size and volume of heart muscle, and from these to calculate its weight.

 

 

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NEWS ARTICLE- CONTINUED

 

 

The results showed that over 10 years, on average, the weight of the left ventricle increased in men by about 8 gms, and decreased by 1.6 gms in women.

The heart's filling capacity - reflected by the amount of blood the left ventricle can hold between heart beats - reduced in both men and women, but more so in women. In men it fell by just 10 mls, and in women by 13 mls.

Around 5 million Americans have heart failure, a condition where the heart muscle becomes "floppy" and weak and less able to pump blood around the body.

To reduce the risk of developing the disease, cardiologists prescribe drugs that boost cardiovascular performance by reducing heart muscle thickness. However, the researchers suggest this strategy may benefit men more than women.

Senior author João Lima, professor of medicine and radiological science at Johns Hopkins, concludes:

"Our results are a striking demonstration of the concept that heart disease may have different pathophysiology in men and women and of the need for tailored treatments that address such important biologic differences."

He and his colleagues also recommend further investigation of what might explain the physiological reason for the differences they discovered.

Following a heart attack, patients are advised to take certain medicines so as to reduce the risk of another one. ButMedical News Today has recently learned of a study that finds many heart attack patients are either not prescribed such medications or do not take them. It also identifies a gender gap in use of heart medications, with younger women being the least likely to be prescribed or take them.

 

 

NEWS ARTICLE- SUMMARY

 

Researchers analyzed 3000 aging adults' hearts, and found a few significant differences in how men's and women's hearts change over time.

 

The participants were aged between 54-94, and did not have any pre-existing heart diseases.

 

While the cause of these gender-related heart changes are still unknown, the results do explain some of the differences seen in heart failure between men and women.

 

Because this study uses MRI scans, images produced are more detailed and more reliable.

Many of the patients examined had already been examined 10 years ago, so this allowed the researchers to see what happened to their hearts in that decade.

 

They found that the heart muscle around the left ventricle grows and thickens with age in men, while it stays the same, or shrinks, in women.

 

Results showed that the weight of the left ventricle increased in men by 8 grams, but decreased in women by 1.6 grams.

 

The heart's filling capacity (the amount of blood the left ventricle can hold between heart beats) fell lower in women that men- it fell by only 10 mls in men, but 13 mls in women.

 

Researchers have found that certain stratergies used to reduce the development of heart failure may benefit men more than women.

 

Further investigation is recommended to find out the physiological reason for the differences the researchers discovered.

 

Patients are advised to take certain medicines after a heart attack, however, studies have shown that many of these patients are not presctibed, or do not take these medicines. A gender gap is also identified, with younger women being least likely to be prescribed or take the medicines.

 

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  • LiveScience.com, (2015). How Does an MRI Work?. [online] Available at: http://www.livescience.com/32282-how-does-an-mri-work.html [Accessed 30 Oct. 2015].
  • Medical News Today, (2015). MRI Scans: How Do They Work?. [online] Available at:http://www.medicalnewstoday.com/articles/146309.php#how_does_an_MRI_scan_work [Accessed 4 Nov. 2015].
  • NPS MedicineWise, (2015). What are the risks and benefits of MRI?. [online] Available at: http://www.nps.org.au/medical-tests/medical-imaging/for-individuals/types-of-imaging/mri-magnetic-resonance-imaging/for-individuals/risks-and-benefits [Accessed 2 Nov. 2015].
  • Paddock, C. (2015). Hearts age differently in men and women. [online] Medical News Today. Available at: http://www.medicalnewstoday.com/articles/301221.php [Accessed 12 Nov. 2015].

 

 

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