1.5T Toshiba NVA Coil
Courtesy of mricoilrepair.com
Courtesy of mricoilrepair.com
Coils: an array of channels to choose from
November 24, 2014
by Gus Iversen, Editor in Chief
When the early commercial MR scanners came out in the mid-‘80s they were single channel systems; one transmit and one receive. Since then, coils have been in a perpetual state of growth and development, and it’s all about signal to noise ratio (SNR). HCBN spoke to Randy Jones, the president of ScanMed, about the evolution of coils.
“Coils were rudimentary designs of a single resonator; a conductor loop with some capacitor on it attached to a cable,” says Jones, “You’d put that next to the part of the anatomy you wanted to scan, and voila! You’d get better imaging quality.”
Jones says GE brought the first four channel scanner to market in the ‘90s, and singlechannel coils gave way to various geometric coils, like bird cage coils. Geometric coils evolved into multiple and switchable arrays, which have more than one resonator and more than one element in a single package. Multiple elements added new quality and speed to the application of MR imaging.
“I believe the word array was borrowed from World War II technology,” says Jones. “It referred to a geometric grouping of antennas used to focus electromagnetic sensitivity profiles in early radar development.” Jones says those arrays can still be found all over the world for air traffic control amongst military applications.
Channel density: when is enough, enough?
Stuart Clarkson, the senior director of MR business with Siemens says, “It became apparent in the early ‘90s that the more coils you can put inside one of these receivers, or antennas, the better the SNR could be.” With more coils come more channels, “If I had four copper windings that were built inside one coil, that would give me the ability to get higher SNR,” says Clarkson, “but I would need four channels to look at the independent data coming from each element.”
Today Siemens is at the forefront of high end channel density exploration. Their new scanner, the MAGNETOM Prisma 3T, has 128 channels and an 80/200 gradient coil, making it a truly top of the line scanner, particularly for imaging the brain.
When asked if channel density ever becomes sufficient and stops resulting in better outcomes, Clarkson says, “Probably, but if you ask two different people you’ll get two different answers. It’s certainly not a linear scale, doubling the channels does not result in an image twice as good.”
Clarkson also explained that the availability of 128 channels is a kind of investment in the future, because although no coil currently requires 128 channels, one probably will before an end user is ready to replace their Prisma. He says it was only six or seven months ago that the FDA approved their 64-channel head coil.
The issue of coil density seems to hinge in large part on a manufacturer’s target audience. As Jones puts it, “If you’re trying to sell a reasonably priced system that’s going to do all of these anatomies that are so fundamental to MR imaging, like brain, spine, extremities, then 32-channels is enough.”
“The return on investment as you get higher channel counts becomes smaller and smaller.” Jones says if you are trying to push the envelope and break new ground in a research and academic capacity, then you’ve got to keep moving forward with increased channels. In terms of the average end user however, the majority of systems in use today, according to Jones, still feature less than 32 channels.
Toshiba is currently manufacturing 16-and 32-channel systems on both 1.5T and 3T platforms. Suresh Narayan, senior manager of Toshiba’s MR business unit, says Toshiba broadly identifies three market segments for MR; the economy segment, the core segment, and the high-end segment. Generally, their Titan 3T is suitable for high-end investors while the Titan 1.5T is a better fit for the majority of their customers.
HCBN spoke to Richard Hausmann, president and CEO of MR global business at GE, who offers an explanation to the question of channel density. “Physics will tell you that there is an advantage in behavior around 32 or 64 channels, but then additional benefit is getting smaller and smaller. But more importantly, what are the coils doing?” Hausmann says image quality is highly dependent on the design of the coils and the ways in which those coils interact with the patient’s anatomy.
“You can put a four element coil on an eight-channel system, you just won’t use them all,” says Jones at ScanMed, “You can also put a 16 element coil on an eight-channel system, then the coil design allows you to select which eight you want to use.” As a manufacturer of coils, Jones says there is a lot of latitude to put more elements in than are necessarily needed so that the technologist who uses them can pick and choose which channels to utilize.
Dr. Vossough, from Children’s Hospital of Philadelphia, says adult coils are often reimagined for use on pediatric patients. “Some coils that would have been used for an adult knee can be used for different areas of the baby.” The reason for this is, in part, because pediatric MR accessories have not historically represented a big market segment, but Vossough thinks that trend is changing.
Looking forward, Jones envisions a future where an in-channel array will be developed as a full body suit. Such a suit would be the only set of coils a physician would ever need. “The patient would wear it and you could pick channels for the entire body out of 256 or something like that,” says Jones. “I really think that’s where we’re headed.” Jones cites several reasons why such technology is not yet on the market and engineering capability is not among them. “We haven’t had the appropriate speed, or price of electronics, or physician sign-off to make it worthwhile,” says Jones, “Not to mention reimbursement.”
Coil repair—options abound
Single coils for head/neck/spine imaging represent a prime example of channel customization. Depending on which part of the anatomy a physician is interested in looking at, they can activate the corresponding parts of the coil. Jay Miller, the president of IMRIS, says they have been making a lot of headway with wireless, disposable coils. Those coils offer a solution to coil maintenance, which can lead to workflow problems if a piece of equipment fails.
Clarkson at Siemens says, “If a coil breaks down we will immediately ship one out to the customer so they can keep working. We will take back the broken coil, do a post-mortem on it, assess it and see if we can repair it.”
Toshiba has service warehouses across the country. “If a coil is broken the turnaround time is 24 hours,” says Narayan. Almost every Toshiba system sold today includes their 16-channel flexible coil, which can be used for imaging any part of the body so, “If your muscular skeletal imaging coil breaks down, “ says Narayan, “you can immediately use the 16-channel flex coil to replace it.”
ScanMed repairs coils as an independent service organization. When asked why ISOs are as good (or better) than manufacturers, Jones says, “The answer depends on the certifications, capabilities, and the knowledge of the company. If they can diagnose, electronically repair, aesthetically refurbish, and offer validation and warranty, then why not?” Of course, not all independent service options can offer all of that. Jones says anyone can start a company calling themselves coil repair experts, and the ineptitude of so many of them actually do a disservice to his business because clients don’t know better. Jones emphasizes the importance of ISO certification 13485 and FDA approval saying, “If you Google ‘MR coil repair,’ more than fifty percent of the results do not have that stuff.”
Wes Solmos, Coils Account Manager for MRIcoilrepair.com, describes his company as the only one in the market that can handle full coil repair under one roof. He would agree with Jones’ sentiment; “The big thing our customers like is that we’re medically certified,” says Solmos, “A broken surface coil that we need to reverse engineer and 3-D print mechanical parts for? We can handle that.”
Jones says a broken coil can mean many things. Sometimes it’s a simple electronic component failure which can be easy to find and correct. Other times it’s something more involved, like a complex connector head that has been dropped and broken.
“A lot of times we see broken pins in the output cable connector,” says Solmos, “Those are the pins that connect a coil to the actual system or tabletop.” Occasionally Solmos and his colleagues see twenty-year-old coils, “but those come a little bit more from our international business.” He says they function on the same RF theory and that makes servicing them possible.
Names in boldface are Premium Listings.
Domestic
Robert Costa, Oxford Instruments Service, LLC, CA
DOTmed 100
Ray McClellan, MRI Technical Services Inc, GA
Randal Walker, BC Technical, IL
DOTmed 100
Charlie Lewis, BC Technical, IL
Mike Ghazal, Zetta Medical Technologies LLC, IL
Wes Solmos, Creative Foam Medical Systems, IN
DOTmed Certified
Robert Manetta, Nationwide Imaging Services Inc, NJ
DOTmed Certified
DOTmed 100
International
Mads Vittrup, AGITO Medical, Denmark
DOTmed Certified
DOTmed 100
Cicero Oliveira, Kuf Electronics, Brazil
“Coils were rudimentary designs of a single resonator; a conductor loop with some capacitor on it attached to a cable,” says Jones, “You’d put that next to the part of the anatomy you wanted to scan, and voila! You’d get better imaging quality.”
Jones says GE brought the first four channel scanner to market in the ‘90s, and singlechannel coils gave way to various geometric coils, like bird cage coils. Geometric coils evolved into multiple and switchable arrays, which have more than one resonator and more than one element in a single package. Multiple elements added new quality and speed to the application of MR imaging.
“I believe the word array was borrowed from World War II technology,” says Jones. “It referred to a geometric grouping of antennas used to focus electromagnetic sensitivity profiles in early radar development.” Jones says those arrays can still be found all over the world for air traffic control amongst military applications.
Channel density: when is enough, enough?
Stuart Clarkson, the senior director of MR business with Siemens says, “It became apparent in the early ‘90s that the more coils you can put inside one of these receivers, or antennas, the better the SNR could be.” With more coils come more channels, “If I had four copper windings that were built inside one coil, that would give me the ability to get higher SNR,” says Clarkson, “but I would need four channels to look at the independent data coming from each element.”
Today Siemens is at the forefront of high end channel density exploration. Their new scanner, the MAGNETOM Prisma 3T, has 128 channels and an 80/200 gradient coil, making it a truly top of the line scanner, particularly for imaging the brain.
When asked if channel density ever becomes sufficient and stops resulting in better outcomes, Clarkson says, “Probably, but if you ask two different people you’ll get two different answers. It’s certainly not a linear scale, doubling the channels does not result in an image twice as good.”
Clarkson also explained that the availability of 128 channels is a kind of investment in the future, because although no coil currently requires 128 channels, one probably will before an end user is ready to replace their Prisma. He says it was only six or seven months ago that the FDA approved their 64-channel head coil.
The issue of coil density seems to hinge in large part on a manufacturer’s target audience. As Jones puts it, “If you’re trying to sell a reasonably priced system that’s going to do all of these anatomies that are so fundamental to MR imaging, like brain, spine, extremities, then 32-channels is enough.”
“The return on investment as you get higher channel counts becomes smaller and smaller.” Jones says if you are trying to push the envelope and break new ground in a research and academic capacity, then you’ve got to keep moving forward with increased channels. In terms of the average end user however, the majority of systems in use today, according to Jones, still feature less than 32 channels.
Toshiba is currently manufacturing 16-and 32-channel systems on both 1.5T and 3T platforms. Suresh Narayan, senior manager of Toshiba’s MR business unit, says Toshiba broadly identifies three market segments for MR; the economy segment, the core segment, and the high-end segment. Generally, their Titan 3T is suitable for high-end investors while the Titan 1.5T is a better fit for the majority of their customers.
HCBN spoke to Richard Hausmann, president and CEO of MR global business at GE, who offers an explanation to the question of channel density. “Physics will tell you that there is an advantage in behavior around 32 or 64 channels, but then additional benefit is getting smaller and smaller. But more importantly, what are the coils doing?” Hausmann says image quality is highly dependent on the design of the coils and the ways in which those coils interact with the patient’s anatomy.
“You can put a four element coil on an eight-channel system, you just won’t use them all,” says Jones at ScanMed, “You can also put a 16 element coil on an eight-channel system, then the coil design allows you to select which eight you want to use.” As a manufacturer of coils, Jones says there is a lot of latitude to put more elements in than are necessarily needed so that the technologist who uses them can pick and choose which channels to utilize.
Dr. Vossough, from Children’s Hospital of Philadelphia, says adult coils are often reimagined for use on pediatric patients. “Some coils that would have been used for an adult knee can be used for different areas of the baby.” The reason for this is, in part, because pediatric MR accessories have not historically represented a big market segment, but Vossough thinks that trend is changing.
Looking forward, Jones envisions a future where an in-channel array will be developed as a full body suit. Such a suit would be the only set of coils a physician would ever need. “The patient would wear it and you could pick channels for the entire body out of 256 or something like that,” says Jones. “I really think that’s where we’re headed.” Jones cites several reasons why such technology is not yet on the market and engineering capability is not among them. “We haven’t had the appropriate speed, or price of electronics, or physician sign-off to make it worthwhile,” says Jones, “Not to mention reimbursement.”
Coil repair—options abound
Single coils for head/neck/spine imaging represent a prime example of channel customization. Depending on which part of the anatomy a physician is interested in looking at, they can activate the corresponding parts of the coil. Jay Miller, the president of IMRIS, says they have been making a lot of headway with wireless, disposable coils. Those coils offer a solution to coil maintenance, which can lead to workflow problems if a piece of equipment fails.
Clarkson at Siemens says, “If a coil breaks down we will immediately ship one out to the customer so they can keep working. We will take back the broken coil, do a post-mortem on it, assess it and see if we can repair it.”
Toshiba has service warehouses across the country. “If a coil is broken the turnaround time is 24 hours,” says Narayan. Almost every Toshiba system sold today includes their 16-channel flexible coil, which can be used for imaging any part of the body so, “If your muscular skeletal imaging coil breaks down, “ says Narayan, “you can immediately use the 16-channel flex coil to replace it.”
ScanMed repairs coils as an independent service organization. When asked why ISOs are as good (or better) than manufacturers, Jones says, “The answer depends on the certifications, capabilities, and the knowledge of the company. If they can diagnose, electronically repair, aesthetically refurbish, and offer validation and warranty, then why not?” Of course, not all independent service options can offer all of that. Jones says anyone can start a company calling themselves coil repair experts, and the ineptitude of so many of them actually do a disservice to his business because clients don’t know better. Jones emphasizes the importance of ISO certification 13485 and FDA approval saying, “If you Google ‘MR coil repair,’ more than fifty percent of the results do not have that stuff.”
Wes Solmos, Coils Account Manager for MRIcoilrepair.com, describes his company as the only one in the market that can handle full coil repair under one roof. He would agree with Jones’ sentiment; “The big thing our customers like is that we’re medically certified,” says Solmos, “A broken surface coil that we need to reverse engineer and 3-D print mechanical parts for? We can handle that.”
Jones says a broken coil can mean many things. Sometimes it’s a simple electronic component failure which can be easy to find and correct. Other times it’s something more involved, like a complex connector head that has been dropped and broken.
“A lot of times we see broken pins in the output cable connector,” says Solmos, “Those are the pins that connect a coil to the actual system or tabletop.” Occasionally Solmos and his colleagues see twenty-year-old coils, “but those come a little bit more from our international business.” He says they function on the same RF theory and that makes servicing them possible.
DOTmed Registered MRI Coils 2014 Companies
Names in boldface are Premium Listings.
Domestic
Robert Costa, Oxford Instruments Service, LLC, CA
DOTmed 100
Ray McClellan, MRI Technical Services Inc, GA
Randal Walker, BC Technical, IL
DOTmed 100
Charlie Lewis, BC Technical, IL
Mike Ghazal, Zetta Medical Technologies LLC, IL
Wes Solmos, Creative Foam Medical Systems, IN
DOTmed Certified
Robert Manetta, Nationwide Imaging Services Inc, NJ
DOTmed Certified
DOTmed 100
International
Mads Vittrup, AGITO Medical, Denmark
DOTmed Certified
DOTmed 100
Cicero Oliveira, Kuf Electronics, Brazil