Magnetic resonance imaging (MRI) is one of the most significant medical inventions. It is a non-invasive technique used to produce high-quality images of the human body’s interior using a magnetic field and radio waves.
It has brought about an unparalleled revolution in medical imaging. With the ability to provide superb soft tissue contrast; it is the imaging tool of the future.
“MRI today is an integral part of medical imaging in arriving at a diagnosis as well as in providing a roadmap to the operating surgeons,” says Dr Chandrasekhar, Senior Radiologist & COO; Yashoda Hospitals; Secunderabad; Hyderabad. “Its role is of paramount importance, especially in neuro-imaging where it has revolutionised the management of stroke, brain tumours and spine pathologies,” he adds.
The idea that worked
 “We expect to bring cutting edge technologies that will bring down scan times thereby bringing down the scanning mode time of the MRI.”Raveendran Gandhi Sr. Director- Radiology, Philips India |
When Dr Raymond Damadian, an American physician and scientist, constructed a superconducting magnet trying to produce a machine that could non-invasively scan the body, he had no idea how this would would evolve in future and become the most advanced diagnostic tool ever.
Very simply put, MRI measures the changes in radiofrequency signal of protons in our body when subjected to changing magnetic field. The main component of our body is water which is made up of hydrogen and oxygen. It is the presence of the hydrogen that allows MRI to record the movement to its subatomic particle in a given magnetic field.
Understandably then, the basic hardware components of all MRI systems are the magnet, producing a stable and very intense magnetic field. Then there are the gradient coils, creating a variable field; and radio frequency (RF) coils which are used to transmit energy and encode spatial positioning as well as a computer to controls the MRI scanning operation and process the information. There is a patient table, coolers to cool the superconducting coils and heat exchangers that complete the MRI set-up.
More energy more cost
 “Low power consumption, compact chiller without effecting image quality, zero helium boil off, compact MRI with smaller footprints are expected from next generation MRIs.”Dr Mona Bhatia HOD, Dept of Radiodiagnosis and Imaging, FEHI |
Now, to make magnets work we need energy in the form of electricity. Because the quality of the images generated by a MRI is directly related to the strength of the magnetic field aligning the spins of the atom nuclei and the power of the gradient as well as RF amplifiers they are constantly being researched to get clearer pictures. But these efforts have also led to MRIs which require increasing power supply. “Higher the magnetic field strength, the better is the image quality in terms of contrast and resolution. This helps doctors diagnose the smallest of tumours,” explains KN Umesh Kumar, Business Head – MRI, Healthcare Sector – Siemens. “Systems with high field strengths of 3 Tesla, which are often used in clinical routine by now, require high power RF amplifies and more receiving channels and hence higher energy usage,” he informs.
In addition, there are other components of the MRI equipment which add to the energy burden. The components that consume maximum energy are gradient amplifier (RF sender, RF receiver and water heat exchanger), magnet (including cryo-cooling), computation and patient table.
“The major power consuming units in an MRI are a cryo-cooler – Maintaining -260oC temperature within so that magnet remains superconducting and RF transmitters – Different MRI sequences require varying RF pulse parameters for high-resolution scanning,” explains Raveendran Gandhi, Senior Director, Radiology, Philips India. “To attain thinner slice thickness with larger coverage and faster scanning high performing gradients are needed, higher the gradient performance more will be power consumption,” he further adds.
 “Energy efficient green MRI must reduce power consumption by at least 25 to 30 per cent while not compromising on the image quality, efficiency, speed of performance etc.”Dr Chandrasekhar Sr. Radiologist & COO; Yashoda Hospitals |
Thus more powerful magnetic fields and amplifiers help to obtain images with less noise and higher resolutions. Therefore, an increase in the energy usage is expected. However, more energy use increases the total cost of ownership. Talking about the power consumed by a MRI, Dr Chandrasekhar says, “It is approximately 20,000 – 22,000 units per month including the A/C and UPS power consumption.” He says that the cost of ownership of MRI today is around Rs 1.5 – 2 lakhs a month. Concurring Dr Mona Bhatia, HOD, Department of Radiodiagnosis and Imaging, Fortis Escorts Heart Institute. Delhi says, “The cost of ownership could be estimated at approximately Rs 1-1.5 lakhs per month however values would vary depending on the equipment purchased.”
In reality, the doctors in India face the double burden of the cost of the MRI as well as the cost of ownership. Both of which are high.
Expensive but necessary
 “We will continue to work particularly on three fields to increase energy efficiency; easy siting, higher performance and lower energy usage in non-productive modes.”KN Umesh Kumar Business Head – MRI Healthcare Sector, Siemens |
There are about 1400-1500 MRI scanners in India today; and the numbers continue to grow. Although MRI is a highly sought diagnostic tool it is not available freely. “In the US there are approximately 25 MRIs per million people, in Japan there are approximately more than 40 MRIs per million people. While in India we have approximately one MRI per million people,” reveals Dr Karthik Kuppusamy, Director, MRI; India and South Asia, GE Healthcare.
These numbers are not very impressive and undeniably one of the reasons for this is the high cost of the machine. “The cost of a 1.5 Tesla MRI equipment in India can range from Rs 2 crores for a refurbished machine to up to Rs 6 crores for a new one, depending on the features,” informs Dr Chandrasekhar.
While Dr Bhatia says, “The cost of new latest state of art MRI machines vary from approximately Rs 3.5 crores (1.5 Tesla) to Rs 12 crores (high end 3 Tesla machines).”
Yet, we cannot think of radiology and imaging without MRI. It is the best way to examine the human body in-vitro. “The high expense of MRI is offset by its tremendous advantage in image analysis on account of its high contrast resolution enabling differentiation of tissues and their characteristics. This makes MRI the preferred modality for the assessment of brain, spine, abdominal and pelvic organs, breast, and musculoskeletal involvements,” Dr Bhatia explains. “In fact, its recent ability to image the heart with high temporal and spatial resolution, besides characterisation of the myocardium, are fast making MRI the modality of choice in multiple cardiovascular disorders,” she adds.
“The non ionising properties of MRI make it the preferred and safer modality to reduce long term radiation risks, particularly in vulnerable patients like children and those needing repeated follow up studies, to assess response to therapy, as in oncology. Thus, MRI today is the modality of choice for superior diagnostic image quality for better delineation, characterisation, distribution and assessment of lesions, and despite its high costs rules over most other modalities in diagnosis and follow up of patients,” she further explains.
Areas of improvement
It is clear that in future we will get MRIs that produce sharper images which also means that the energy consumption would increase. But the good news is that manufacturers are working on finding means to reduce energy consumption in MRIs. A report published in 2012, by Self-regulatory Initiative of COCIR, European Coordination Committee of the Radiological, Electromedical and Healthcare IT Industry stated that there is a direct relationship between the number of patients that can be examined by an MRI and the energy consumption. MRIs with higher patient per day ratio use more energy. As the patient per day ratio can be considered as the ‘productivity’ of the equipment, it seems appropriate to refer the energy consumed (per day) to the number of patient (per day): kWh/patient.
Thus in principle, to reduce the energy consumption per patient (kWh/p), there is the option to reduce the time per examination which increases the number of examined patients per day. The report stated that this is not a linear calculation, e.g. in the sense of higher performance level leads to shorter investigation cycles. This reduction could be achieved only by changing the defined sequences with new ones that could produce the same images in shorter time.
“Statistically, a typical MRI is ‘scanning’ and ‘becoming ready-to-scan’ for 15 per cent of the time (% hours/year) each while for another 70 per cent of the time (night) it is at standby,” informs Gandhi. “There is big scope to segregate these modes and smartly save more power while MRI is not really scanning. Moreover, when MRI is scanning, power consumption can be minimised with optimised gradient performance in combination with smarter RF designs,” he says.
Optimistic about its effort to increase energy efficiency UmeshKumar says, “At Siemens, our clear focus is to increase energy efficiency. There is scope for further improvement in areas where new sequence techniques will use less RF power and less time without any compromise on image quality.”
“Our engineering teams have identified several opportunities to reduce power consumption,” says Dr Kuppusamy. “By incorporating innovative overnight ‘sleep mode’, efficient gradient and electronics design, as well as exceptional cooling technology, our team reduced the system’s energy consumption during both operating and non-operating hours,” he explains.
Innovations to reduce power consumption
Manufacturers have taken numerous steps to make their products more energy efficient. “Innovation is the key,” says Dr Kuppusamy. “Our new MRI product is engineered to use ecomagination-certified technologies like efficient gradients, water-cooling, super capacitors and a power distribution unit, reducing power consumption by 50 per cent as compared to similar premium 1.5T competitor MRI systems. With all of these ecomagination features, these systems are intended to lower the total cost of ownership while still delivering excellent clinical performance. Other premium 1.5T systems require UPS ratings of 100-140KVA while MR360 Advance uses only 60KVA UPS,” he explains. “Advanced applications like propeller 3.0 which helps in motion correction while neuro, body & musculoskeletal imaging will help to reduce rescans. It reduces effects of patient voluntary and physiologic motion and thus reduces artefacts and rescans.” he adds.
Informing about Siemens’ innovations in energy efficiency Umesh Kumar says, “All heat-dissipating components [of MRI] are water cooled, thus reducing the load on the air conditioning system, which helps in energy saving.”
Adding further he says, “Power saving mode is available when no patients are being scanned to reduce energy consumption to a minimum while computers are kept running for doctors to review images or do post processing and stability of the system is maintained for next examination. VFD technology is used for all motors/ compressors/ chiller used in MRI systems, which helps to reduce energy consumption.”
Philips Healthcare is not behind. They have implemented PowerSave, smart power management in MRIs that only consumes energy when really needed. “PowerSave is built around two design principles: lowering the level of energy consumption when the system is not used and lowering the level of energy consumption in between scans. Our solid-state gradient amplifier design uses energy only when the system is scanning thereby lowering energy consumption in between the scans. This feature results in up to 50 per cent reduction in energy bills,” explains Gandhi.
“Philips has designed the MRI magnets with the shortest tunnel length that helps in managing RF irradiation by reducing unnecessary RF deposition on patient. Moreover, introduction of multi-transmit technology helped to a great extent in optimising performance of RF transmitters in 3T systems. Furthermore, by designing unique fully digital broadband MR technology or dStream technology in our Ingenia platform we have reduced scan time significantly which results in proportional decrease in energy consumption,” he says.
“Our MRI systems have one of the industry’s best FoV and field homogeneity that enables our customers to complete their scanning with less number of stations. In addition to this, the best homogeneity of field ensures that the number of repeat scans are minimised. Both of these enable our customers to complete their scans with the industry’s highest SENSE acceleration factor,” Gandhi further adds.
Current market
There are a number of products available in the Indian market that are energy efficient. “Energy efficient MRIs or green MRIs have been recently launched in the market,” informs Dr Chandrasekhar. “Yes, Power Save option using Zero Helium boil off and low power consumption when system not in use are available,” adds Dr Bhatia.
On the manufacturers front in 2008, GE’s Signa HDe, 1.5 Tesla MRI received the first ‘ecomagination’ status for a healthcare imaging system. By employing efficient gradient and electronics design as well as innovative water cooling technology, the Signa HDe became the most energy efficient 1.5T MRI system. GE continued its pursuit and brought out more energy efficient 1.5T MRI systems in the form of Brivo MR 355, MR 360 and Optima MR 360 Advance.
“Siemens provides a simple active cooling system (needs regular water supply) e.g. in the 1.5 Tesla MAGNETOM ESSENZA which requires very low power and eco-friendly chiller (imported) along with the 3 Tesla MAGNETOM Spectra. Hence, despite MAGNETOM Spectra being a 3T, it requires 100 KVA only, which is the same as 1.5T requirement,” informs UmeshKumar.
Talking about Phillips Healthcare’s products Gandhi says, “Principles of power management are not new to Philips MRI. All Philips systems (Iegenia and Achieva series) comply to the green product requirements for sustainability improvement, which are audited by KPMG.”
Lying in wait
The process of innovations continues. Just as we wait for the ultimate MRI which will provide images with zero noise so do we expect that next generation MRIs will be more energy efficient. “An energy efficient green MRI must reduce the power consumption by at least 25 to 30 per cent and occupy lesser space while not compromising on the image quality, efficiency, speed of performance and the equipment’s longevity,” wishes Dr Chandrasekhar. While Dr Bhatia expects, “Low power consumption, compact chiller without effecting image quality, zero helium boil off, compact MRI, and less electronics with smaller footprints,” from the next generation MRIs.
“We will continue to work particularly on three fields to increase energy efficiency; easy siting, higher performance of the systems and lower energy usage in non-productive modes,” says Umesh Kumar.
“We expect to bring cutting edge technologies that will bring down scan times thereby bringing down the scanning mode time of the MRI. In addition, through our strong R&D teams and collaboration with leading researchers across the globe we expect to take the combination of our RF-Smart technology and gradient to the next level. Lastly, we see our systems becoming increasingly cryo-efficient,” informs Gandhi.
MRI systems are complex. The future will see much improvement in the modes and functions of the system providing better diagnostic ability to doctors. It is evident that energy efficiency figures prominently in all manufacturers’ wish list. Let’s hope we get greener MRIs in the future.
- Advertisement -
