Magnetic Resonance Imaging (MRI) is a technique that uses radio waves and magnetic field to create high-resolution images of tissues and organs and skeletal system within the body. It is a non-invasive way that helps doctor to diagnose a variety of problems. The MRI machine can also be used to produce 3-D images that may be observed from numerous different angles. To know more about What is an MRI, join our expert talk by Dr. Nirad Mehta, Consultant Radiologist.

1. MRI
Imaging Division
P.D. Hinduja National Hospital and
Research Centre

2. What Is It
• A test to obtain detailed images of the human
body
• No ionizing radiation – so not harmful
• Superb Soft tissue contrast
• Imaging in multiple planes

3. • Magnetic - Powerful Magnetic Field
• Resonance - Radiofrequency
• Imaging - Visualization

4. Magnetic
• Powerful Magnet (Tesla – T)
– Strength varies from 0.3 Tesla – 7 Tesla
– Doughnut / Tunnel : Higher strength but
claustrophobic
– Partially open : Lower strength, less
claustrophobic
– Hydrogen ion – proton used most commonly
• Once in the magnet, protons line up in the
direction of the magnetic field

5. Resonance
• Radiofrequency Pulse : low strength
electromagnetic pulse, generated by RF coils,
used to align these protons together
• After the pulse is switched off, the protons
slowly return to the original state
• As they return, they give off energy in form of
that is then received by special receiver coils,
which convert it into a signal

9. Imaging
• The signal received is then converted to
Images
• These are then looked at and analysed by the
Radiologist

10. Application
• Brain
• Spine
• Musculoskeletal System
• Body – especially Abdominal Organs
• Heart
• Blood vessels

11. Procedure
• Patient lies down on the table
• Table then slides into the bore of the
magnet
• Various ‘sequences’ are obtained
• Intravenous contrast injection may be
given, depending upon the condition being
investigated and the images obtained
• Patient comes out of the tunnel

13. Procedure
• As the images are obtained, lot of noise can
be heard
• Generally ear plugs are provided. Some
centres provide head phones and even music!
• No pain, no sensation.
• Patient has to lie still, as movement during the
scan can result in artefacts which can
compromise the quality of images

19. •MRI has allowed clinicians to treat, monitor,
and learn about many different diseases and
problems.
•Also, to learn how the body functions,
normally, without needing to resort to more
invasive methods like surgery.

20. • MRI treatment is a wonderful option for most
patients, but there are some people who are
not candidates.
• Those include:
– Patients with pacemakers: as the magnet from
the MRI interferes with the signal sent from the
pacemaker, and deactivates it.
– Patients who are too tall, or too obese
– Patients who have orthopedic hardware can get
distortion in the image, and the scan quality is
not as high.

21. Future
• The possibility of having very small machines
that scan specific parts of the body.
• The continuing improvements on seeing the
venous and arterial systems.
• Functional Imaging :Brain mapping while the
patient does specific tasks, allowing clinician’s
to see what part of the brain is responsible
for that task/activity.
• Improvements on the ability to do MRI’s of
the lungs.