From the 1930s, when Isidor Isaac Rabi developed a method for measuring magnetic properties of atoms, to 1977, when the first MRI of a human was performed, thanks to the cumulative efforts of many scientists, Edward Purcel, Felix Bloch, Sir Peter Mansfield, Raymond Vahan Damadian, et al., to this day, the world of MRI has been constantly evolving.
This non-invasive method has enabled multiplanar visualization of anatomic structures to greater detail than any other modality without the use of ionizing radiation. It has made soft-tissue delineation better than ever before as also the imaging of the brain and the musculoskeletal system. Newer developments include hybrid imaging like MR-HIFU, PET-MRI, MR defecography, and real-time MRI. MR spectroscopy adds pathophysiological information and is a useful tool in not only tertiary care hospitals today, but also in stand-alone imaging centers, where the preliminary diagnostic workup is happening in most cases. Functional MRI enables non-invasive functional mapping of the brain, and is a part of the diagnostic armamentarium in advanced centers handling neurological cases.
Newer innovations are targeted toward cutting down scan times. Open MRI looks at eliminating claustrophobia. There are innovations like mobile MRI that aim to provide access to more people.
The cost factor becomes the limiting criterion for deciding the magnetic field strength of the MRI machine that needs to be purchased. A 1.5-Tesla looks like the optimal choice that can cater to most of the needs of any hospital. If it is possible to purchase a 3-Tesla MRI, the image quality improvement is worth the additional expenses. If it is a super-specialty hospital doing a good load of neurological and MSK work including joint replacement surgeries, etc., then for imaging before treatment/surgical intervention and follow up, 3T offers a huge advantage. Also, cardiac MRI is best performed on 3T MRI.
Now, coming to an important issue about MR safety. The accidents at Tata ACTREC and Nair Hospital have created a panic among hospital owners and administrators due to the issue of vicarious liability. Awareness can help allay the associated anxiety. A metallic projectile is a risk, the larger the weight, the greater the pull, so while a light needle can prick the eye, one can well imagine what will happen to a heavy cylinder, the pull is much greater as the magnetic forces are stronger, just like the gravitational pull is higher for a heavier object; stretchers fly similarly! So, investing in security staff and metal detectors provides simple solutions at screening out risks. Regular drills and training of staff is a must. There should be awareness that cellphones and credit cards will be spoiled as any magnetic chip will get corrupted, adequate signages should be put up.
Similarly, piped oxygen should be made available as should MRI compatible resuscitative and anesthesia equipment. MRI-compatible wheelchairs and stretchers are to be used compulsorily. Such necessities increase the costs of running the MRI unit. More vendors are needed in the market to bring down costs.
The quenching switch should never be disabled. The staff should be educated about its use and should be informed about the humongous costs involved in re-filling helium. Providing special gowns to patients to change into can help reduce the chances of human error. An exhaustive check list to rule out risk factors is a must, e.g., only MR-compatible prosthetics must be allowed. Frequent code blue drills should be done.
While planning the MRI suite, the issue of electromagnetic interference should be tackled as well.
One should be aware of the option of refurbished machines that lower the cost to almost half; vendors who provide good after-sales service can be carefully selected. Other options include machines on lease, turn-key projects, or such mutually symbiotic projects.
In today’s age of evidence-based medicine, radiology is indispensable and MRI is now almost a must-have modality. Before setting up an MRI unit, a need-based outlook should be adopted.