Pediatric Sedation in MR Imaging | Pros & Cons
Acquiring a high-quality magnetic resonance imaging (MRI) exam requires patient cooperation to reduce movement and breathing. This can be difficult, however, when imaging young children and neonates, who can’t cooperate with breath-holding instructions and have difficulty remaining still long enough for the scan to be completed.
Sedation is often necessary with these patients, but this comes with its own challenges. Avoiding anesthesia and sedation can save patients and their parents from undue anxiety, complications and improve the overall experience.
Lorna Browne, MD, a pediatric radiologist at Children’s Hospital Colorado, is passionate about making pediatric MRI easier and safer for kids. Her goal is to achieve anesthesia- and sedation-minimized exams that limit IVs and contrast injections as much as possible.
Kristan Harrington is an MRI technologist at Children’s Healthcare of Atlanta, and an MRI Education and Safety Consultant and business partner with Bill Faulkner at William Faulkner & Associates.
“Our goal as technologists is to sedate as little as possible,” says Harrington. “It’s my job to make sure that I optimize for image quality, while minimizing the amount of time the child is under sedation or anesthesia, and to get the patient’s scan done as quickly, safely and comfortably as possible.”
Scan acceleration techniques and free-breathing sequences
The MRI practice at Children’s Hospital Colorado incorporates free-breathing sequences, despite the challenges involved in acquiring them. “Anesthesia/sedated exams are beautiful because they are motion free. Doing non-sedated, free-breathing images is harder and sometimes takes longer, and the risk is that they maybe motion limited,” says Dr. Browne.
To acquire sequences that produce images equal in quality to breath-hold sequences, Dr. Browne often uses radial K-space acquisitions that are motion insensitive. She says this has transformed their ability to perform free-breathing acquisitions with excellent imaging quality.
“When we recently compared our free-breathing T1 and T2 sequences with our traditional breath-hold sequences, we found that our awake or sedated free-breathing sequences actually performed better than our previous anesthesia breath-hold sequences. So that was very reassuring that we were on the right track with our non-sedation protocols,” she says.
Harrington calls these free-breathing techniques “innovative, especially for neonates.”
“It has a huge impact on the successful diagnostic capability of cardiac and abdominal imaging. Free-breathing techniques are extremely powerful as far as image quality,” she says.
At Children’s Healthcare of Atlanta, Harrington and her colleagues also implement a variety of scan acceleration and motion reduction techniques to shorten scan times and the time the kids are in the scanner.
A comfortable MRI experience
Traditionally, some children received anesthesia up to the age of seven or eight years of age. Dr. Browne and her colleagues at Children’s Colorado are trying to reduce this age to under four years. Children’s Colorado uses several non-traditional methods to facilitate this process, including therapy dogs to soothe patients when they receive IV lines for contrasted studies. The MRI suite also provides ambient lighting and MR compatible virtual reality goggles to make the patient’s entry into the scanner less scary for kids.
“If necessary, we can make them completely unaware of the machines and the equipment, and instead totally immersed in a virtual world experience,” she explains.
The Children’s Hospital Colorado radiology department also works to avoid sedation in neonates. “In the first three months, and up to six months, we try not to use any anesthesia/sedation,” says Dr. Browne. “To achieve this, we work closely with the NICU staff to bring babies down hungry and tired, as they are more likely to sleep through the exam once they are fed just before the MRI.”
Outpatient exams in babies are also scheduled for evenings when the babies are more likely to be approaching a natural sleep cycle. Intravenous contrast administration is avoided as much as possible to prevent waking the sleeping babies. Dr. Browne reports they have had great success doing these exams without sedation.
She says they often know if they’ve acquired diagnostic-quality images within 15 minutes, and they repeat the images if needed. “Usually, we can get diagnostic exams in one sleep setting, but occasionally we may need to do some more sequences at a later appointment if the baby wakes and can’t get back to sleep again,” she explains.
Harrington uses a distraction tactic developed by Dr. Elvira Lange, a former Associate Professor of Radiology at Harvard Medical School, founder of “Comfort Talk” – a drug-free method to reduce patient pain and anxiety on the exam table – and author of “Patient Sedation without Medication.”
“It’s like a low hypnosis technique. We use a distractor by saying something like, ‘I’m bringing the table down now,’ as we bring the table up. It’s quite a phenomenal thing,” she explains.
Sometimes they invite the kids and their parents to visit the MRI suite days before their exam so they know what to expect and staff can assess their comfort levels.
During the scan, the MRI technologists give pediatric patients as much control as possible to help them feel comfortable in the environment. At the time of the scan, they also explain what is happening to help the kids understand the situation. Like adult patients, children can squeeze a “communication ball” to talk to the tech any time during the exam.
Cross-departmental communication
Communication among the NICU staff, child-life specialists, anesthesiologists and parents is critical to ensuring the process goes smoothly in order to reduce the need for anesthesia.
“Parents are usually agreeable to this, even though it means they might be in the hospital for a longer period of time and potentially come back a second time, just to avoid anesthesia,” says Dr. Browne. “It takes longer to do this and requires patience, but it’s in the best interest of the patient.”
Harrington agrees. “It starts with the parents. When they first arrive, we make sure the parent is comfortable with the situation and understands that we’re going to do everything we can to avoid sedation. Then the parents work with our nursing staff, the technologists and the radiologists as a collective team,” she says.
Safety at every step
To improve MRI safety and avoid the risks of alarm fatigue that may be encountered in the MRI setting, in 2017 Children’s Hospital Colorado MRI department led a transition to an entirely ferrous-free MRI environment – the first of its kind in the country. This was a significant culture shift for the hospital, but Dr. Browne says the effort was worth it.
“When everyone in the MRI unit is entirely ferrous-free, there are fewer alarms sounding. And that means when the alarms do alert you to the presence of metal, it precipitates an additional check to ensure those entering the MRI environment are truly ferrous-free,” she explains.
The MR technologists at Children’s Healthcare of Atlanta also perform a “full stop/final check,” as outlined in the latest version of the ACR Manual on MR Safety, to confirm the patient’s identification and ensure completion of all pre-scan screening before they enter Zone IV, where the MRI magnet is always “on.”
“Now, when an alarm does go off, people pay attention. It’s an immediate cause for a pause to figure out what is going on and minimize all risk associated with it,” says Harrington.
Harrington and Dr. Browne both believe these initiatives are ushering in a new era of forward-thinking MRI safety when imaging neonates and children.
“We’re in an exciting time of pediatric MR imaging,” says Dr. Browne. “Vendors are coming up with great techniques to make MR imaging faster, free-breathing and without contrast. I think the future’s really bright in pediatric radiology.”