MRI: Medical Imaging Tool of Choice

Magnetic Resonance Imaging is, without a doubt, the most powerful imaging tool available to medical professionals worldwide. It has wide application in medical diagnostic of neurological,cardiovascular, musculoskeletal and gastrointestinal diseases. The method uses very strong magnetic fields and radiofrequency energy to take a three-dimensional ‘picture’ of soft tissues that helps doctors pin point disease or anomalies. MRI is popular because of the high quality of imaging and the convenience to the patient. MRI is a non-invasive procedure, it is not painful or inconvenient to the patient, there is no initial preparation for the patient and it is a painless.

How MRI Works?

Our body is almost 65 % water by weight. Water is present in all tissues as well as in proteins and fats contained in the body. Protons,positively charged particles contained in the nucleus of the Hydrogen atoms in water, spin in random directions. Under a magnetic field these particles get aligned in some direction. They can either align in the direction of the magnetic field or in a direction opposite to it. Usually half of the protons align either way but there are a few unmatched ones that do not. When radiofrequency energy at resonance frequency is applied, the unmatchedprotons absorb this energy and reverse their direction of spin. Once the radiofrequency is turned off, the protons release the energy that they have absorbed and return to their relaxed state. This energy can be detected by radio antennas in the machine. Recorded signals vary according to the kind of tissue in which the water is contained. It is because of this variation that an MRI machine is able to take a clear picture of body organs and tissues.

MRI Technology in India

In developed countries an MRI scan is considered routine while developing countries in Asia and Africa are catching up to the trend.According to an article by Dhandhapany Ragavan, Executive Vice President, Siemens Medical Solutions published in the Indian Journal of Radiology (2008 Volume 18 Issue 3), there were 600 MRI scanning machines in India in 2008 or around 0.6 machines per million population. This number is poor as compared to other nations according to OCED statistics. China had 2 machines per million population in 2008 while developed nations are far ahead with 43.1 machines per million in Japan in 2008 and 31.52 machines per million in the United States (2010 statistics). According to Dhandhapany, high costs of machines and unavailability of technology in developing nations are factors that are responsible for this.


How MRI works by Todd A. Gould and Molly Edmonds |

Magnetic Resonance Imaging|

MRI V/s CT Scan

Both MRI and CT scanare non intrusive medical imaging techniques that produce detailed images of body parts. A CT scan uses X-rays to take pictures of the body while MRI relies on a combination of a magnetic field and radio frequency. CT scans take lesser time (around 5 minutes) while MRI scans take longer (30 minutes) to complete. Application wise, MRI scans are better at imaging soft tissues while CT is very good at imaging of bone, blood vessels and soft tissue at the same time.


CT scan VS MRI scan |

A tale of two scans | scans-which-is-better