This document provides an overview of magnetic resonance imaging (MRI) and discusses its history, technical aspects, medical uses, safety considerations, comparisons to other imaging techniques, regulations, underlying physics principles, ongoing developments, and potential job opportunities. MRI is a medical imaging technique that produces detailed images of the internal structures and functions of the body without using ionizing radiation. It was developed in the 1970s and continues to be an area of active research and clinical application.

1. Or Nuclear Magnetic Resonance Imaginig (NMRI)?
Emina Džaferović, mag.fizike
Voditelj postupka akreditiranja | Case Officer
Vodeći ocjenjivač | Lead Assessor
Institut za akreditiranje Bosne i Hercegovine
Institute for Accreditation of Bosnia and Herzegovina
Hamdije Cemerlica 2/VII, 71000 Sarajevo, Bosna i Hercegovina
+387 33 721 321
eminadz@bata.gov.ba
http://www.bata.gov.ba

2. magnetic resonance imaging (MRI)
nuclear magnetic resonance imaging (NMRI)
negative connotations associated with the word nuclear in
the late 1970's
magnetic resonance tomography (MRT)
an imaging technique used primarily in medical settings to
produce high quality images of the inside of the human
body.

3. • MRI:
• gives different information about structures
in the body
• may show problems that cannot be seen
with other imaging methods

4.  the area of the body being
studied is placed inside a
special machine that
contains a strong magnet
 pictures from an MRI scan
are digital images that can
be saved and stored on a
computer for more study
 the images also can be
reviewed remotely, such as
in a clinic or an operating
room
 an MRI with an open
machine camera that
doesn't enclose entire body
 open MRI machines aren't
available everywhere
 the pictures from an open
MRI may not be as good as
those from a standard MRI
machine

5. People who get nervous in small places (are
claustrophobic) may feel better using an open MRI
machine. An open MRI machine also may be easier to use
for people who are very overweight or obese. But not all
medical centers have this kind of MRI machine.
An open MRI machine has
a larger opening compared
to a standard MRI
machine. Some have
magnets that do not
completely surround your
body. But this kind of open
MRI cannot do some types
of MRI scans.

6. Felix Bloch and Edward Purcell, both of whom were
awarded the Nobel Prize in 1952, discovered the magnetic
resonance phenomenon independently in 1946. In the period
between 1950 and 1970, NMR was developed and used for
chemical and physical molecular analysis.
History

7. In 1971 Raymond Damadian
showed that the nuclear magnetic
relaxation times of tissues and
tumors differed, thus motivating
scientists to consider magnetic
resonance for the detection of
disease. In 1973 the x-ray-based
computerized tomography (CT)
was introduced by Hounsfield.
This date is important to the MRI
timeline because it showed
hospitals were willing to spend
large amounts of money for
medical imaging hardware.
70s

8.  Magnetic resonance imaging was first demonstrated on small test tube samples
that same year by Paul Lauterbur. He used a back projection technique
similar to that used in CT. In 1975 Richard Ernst proposed magnetic
resonance imaging using phase and frequency encoding, and the Fourier
Transform. This technique is the basis of current MRI techniques. A few years
later, in 1977, Raymond Damadian demonstrated MRI called field-focusing
nuclear magnetic resonance. In this same year, Peter Mansfield developed the
echo-planar imaging (EPI) technique. This technique will be developed in later
years to produce images at video rates (30 ms / image).
Paul Lauterbur & Richard Ernst

9.  Edelstein and coworkers
demonstrated imaging of the body
using Ernst's technique in 1980. A
single image could be acquired in
approximately five minutes by this
technique. By 1986, the imaging
time was reduced to about five
seconds, without sacrificing too
much image quality. The same year
people were developing the NMR
microscope, which allowed
approximately 10 µm resolution on
approximately one cm samples. In
1987 echo-planar imaging was used
to perform real-time movie imaging
of a single cardiac cycle. In this same
year Charles Dumoulin was
perfecting magnetic resonance
angiography (MRA), which allowed
imaging of flowing blood without the
use of contrast agents.
Reducing time for imaging

10.  In 2003, Paul C.
Lauterbur of the
University of Illinois
and Sir Peter Mansfield
of the University of
Nottingham were
awarded the Nobel
Prize in Medicine for
their discoveries
concerning magnetic
resonance imaging.
Nobel Prize in the field of MRI

11.  Neuroimaging (Since many images are taken
milliseconds apart, it shows how the brain responds to
different stimuli; researchers can then study both the
functional and structural brain abnormalities in
psychological disorders)
 Cardiovascular (Its applications include assessment of
myocardial ischemia and viability, cardiomyopathies,
myocarditis, iron overload, vascular diseases and
congenital heart disease.)
 Musculoskeletal (Applications in the musculoskeletal
system includes spinal imaging, assessment of joint
disease and soft tissue tumors.)
Medical uses

12.  Liver and gastrointestinal MRI (MR
enterography provides non-invasive
assessment of inflammatory bowel
disease and small bowel tumors. MR-
colonography can play a role in the
detection of large polyps in patients at
increased risk of colorectal cancer.)
 Functional MRI (used to understand
how different parts of the brain
respond to external stimuli or passive
activity in a resting state.)
 Oncology (MRI is the investigation of
choice in the preoperative staging of
rectal and prostate cancer, and has a
role in the diagnosis, staging, and
follow-up of other tumors.)
Medical uses

13.  All patients are reviewed for contraindications prior to
MRI scanning. Medical devices and implants are
categorized as MR Safe, MR Conditional or MR
Unsafe:
 MR-Safe — The device or implant is completely non-
magnetic, non-electrically conductive, and non-RF
reactive, eliminating all of the primary potential threats
during an MRI procedure.
 MR-Conditional — A device or implant that may
contain magnetic, electrically conductive or RF-reactive
components that is safe for operations in proximity to
the MRI, provided the conditions for safe operation are
defined and observed (such as 'tested safe to 1.5 tesla' or
'safe in magnetic fields below 500 gauss in strength').
 MR-Unsafe — Objects that are significantly
ferromagnetic and pose a clear and direct threat to
persons and equipment within the magnet room.
What about safety – Is it
safe?

14.  Projectile risk
 MRI-EEG
 Genotoxic effects
 Peripheral nerve stimulation (PNS)
 Heating caused by absorption of radio waves
 Acoustic noise
 Cryogens
 Pregnancy
 Claustrophobia and discomfort
Be careful about...

15.  MRI and computed tomography (CT) are complementary imaging technologies
 CT is more widely used than MRI in OECD countries A concern is the potential for CT to
contribute to radiation-induced cancer
 In 2007 it was estimated that 0.4% of current cancers in the United States - due to CTs
performed
 An advantage of MRI is that no ionizing radiation is used and so it is recommended over
CT
 The MRI costs more than CT
 In a comparison of possible genotoxic effects of MRI compared with those of CT scans,
Knuuti et al. noted that although previous studies have demonstrated DNA damage
associated with MRI, "the long-term biological and clinical significance of DNA double-
strand breaks induced by MRI remains unknown".
 Commonly used MRI contrast agents have a good safety profile but linear non-ionic agents
in particular have been implicated in nephrogenic systemic fibrosis in patients with
severely impaired renal function.
 MRI is contraindicated in the presence of MR-unsafe implants, and although these
patients may be imaged with CT, beam hardening artefact from metallic devices, such as
pacemakers and implantable cardioverter-defibrillators, may also affect image quality.
 MRI is a longer investigation than CT and an exam may take between 20 - 40 mins
depending on complexity.
MRI versus CT

16.  This Directive (2013/35/EU - electromagnetic fields) covers all known
direct biophysical effects and indirect effects caused by electromagnetic
fields within the EU and repealed the 2004/40/EC directive. The deadline
for implementation of the new directive is 1st July 2016. Article 10 of the
directive sets out the scope of the derogation for MRI, stating that the
exposure limits may be exceeded during "the installation, testing, use,
development, maintenance of or research related to magnetic
resonance imaging (MRI) equipment for patients in the health sector,
provided that certain conditions are met." Uncertainties remain
regarding the scope and conditions of this derogation.
 http://eur-lex.europa.eu/legal-
content/HR/TXT/PDF/?uri=CELEX:32013L0035&from=EN
The European Directive on Electromagnetic Fields

17.  the interaction of matter with electromagnetic fields
 The human body is largely composed of water molecules, each
containing two hydrogen nuclei, or protons. When inside the
magnetic field (B0) of the scanner, the magnetic moments of these
protons align with the direction of the field.
 A radio frequency pulse is then applied, causing the protons to alter
their magnetization alignment relative to the field.
 Diseased tissue, such as tumors, can be detected because the protons
in different tissues return to their equilibrium state at different rates
(i.e., they have different relaxation times). By changing the parameters
on the scanner this effect is used to create contrast between different
types of body tissue.
Just a lil‘ bit of physics...

19.  MRI is based on the principle of
nuclear magnetic resonance (NMR)
 Two basic principles of NMR
 Atoms with an odd number of
protons or neutrons have spin
 A moving electric charge, be it
positive or negative, produces a
magnetic field
 Body has many such atoms that can
act as good MR nuclei (1H, 13C, 19F,
23Na)
 Hydrogen nuclei has magnetic spin
 MRI utilizes this magnetic spin
property of protons of hydrogen to
elicit imgages
Physics in short

22.  Yes and no
 In 2003, there were approximately 10,000 MRI units worldwide, and
approximately 75 million MRI scans per year performed. As the field of
MRI continues to grow, so do the opportunities in MRI.
 Specialized applications
 Diffusion MRI
 Magnetic resonance angiography
 Magnetic resonance spectroscopy
 Functional MRI
 Real-time MRI
 Interventional MRI
 Magnetic resonance guided focused ultrasound
 Multinuclear imaging
 Molecular imaging by MRI
(The) End?

23.  Radiologists
 MRI technologist
 the post processing technologist
 the health safety specialist
 MRI service technicians
 scientists trained in the basic
sciences of chemistry, biology,
and physics
 Biomedical engineers and
material scientists
 Imaging scientists
 architects to design safe and
efficient MRI centers and clinics
Job opportunities?

24. Thank you for your attention!
