In some communities such as New York and Los Angeles, pediatric imaging is spread all over the city, where each medical system has its own special pediatric branch. In Cincinnati, however, pediatric health care is focused in one location: Cincinnati Children’s Hospital Medical Center.
Within that center of care are the Cincinnati Children’s radiology department and the University of Cincinnati’s Imaging Research Center (IRC). With 35 clinical pediatric radiologists, seven PhD physicists, and the latest imaging technology, Cincinnati Children’s is helping to diagnose the most complex disease states in pediatric medicine and conducting clinical research for the benefit of kids today—and tomorrow.
Kids Are Not Little Adults
Lane Donnelly, MD, is the radiologist in chief at Cincinnati Children’s, as well as professor of radiology and pediatrics at the University of Cincinnati College of Medicine (UCCM).
|Lane Donnelly, MD|
When performing pediatric imaging examinations, Donnelly noted that it is important to keep in mind that kids are not little adults.
“It’s not that they have the same problems as adults, but just smaller. The disease sets of kids are completely different than adults, and they’re also very age-specific within children. For example, the differential diagnosis for a liver mass in a 2-day-old is completely different than the differential diagnosis in a 12-year-old.”
Another example of the importance of age is the research of Scott K. Holland, PhD, Professor of Radiology, Pediatrics and Physics at UCCM. Holland is also the director of the Pediatric Neuroimaging Research Consortium (PNRC), one of the research arms of Cincinnati Children’s.
|Scott K. Holland, PhD|
Holland and his colleagues at the hospital have performed functional MRI (fMRI) and diffusion tensor imaging (DTI) studies in more than 500 children between the ages of 5 and 18, as well as adults. By using a series of language tasks during the fMRI scanning, Holland has recorded normal brain activity at different ages. These scans revealed that the distribution of brain activity associated with semantic and tactic language processing actually changes with age. Having this database of normal brain activation can be helpful to neurosurgeons for pediatric patients of a corresponding age.
In epileptic seizure surgery candidates, for example, Holland’s work can assist in determining whether the patient’s brain has reorganized, whether the brain activity is in the typical location, or whether the brain activity has been moved by the epileptic focus. Perhaps most importantly, comparative imaging studies can also inform surgeons if the damaged area can be safely resected without impacting language function.
To accomplish their research projects and clinical tasks, Cincinnati Children’s main hospital and its community centers are equipped with the latest imaging equipment and facilities, including:
- 10 MRI scanners (two of which are 3 Tesla units) and one 7 Tesla for research with animal models;
- 3 CT scanners, including one 64 slice;
- 1 PET/CT;
- 17 ultrasound machines; and
- 3 interventional suites.
The 35 radiologists and seven physicists use their facilities to perform and interpret more than 170,000 pediatric imaging examinations per year.
Alternatives to Sedation
While having the latest technology gives Cincinnati Children’s staff the best tools for diagnosis, it takes more than having a 3T scanner to obtain a quality MR image from an infant or a frightened toddler. Even the most well-behaved children will require specific technology, extra staff, and, sometimes, sedation.
“Sedation is an unavoidable thing for the performance of some imaging examinations,” Donnelly said. “There are some kids in particular, the 2- and 3-year-olds, where there’s absolutely no way, most of the time, that they’re going to cooperate with doing an MR or even a CT. So, sedation is a necessary thing, and imaging can be done very safely if you have the appropriate staff, types of drugs, and facilities.”
MRI May Help Predict Success of Cochlear Implants
Scott K. Holland, PhD, is leading a large-scale outcome study that uses fMRI to predict whether cochlear implant surgery will be successful in congenitally deaf infants. If the resulting data proves to be accurate, Holland’s fMRI research protocol may one day become a standard MRI screening tool in medical centers that now perform cochlear implant surgery in young children.
Testing infants for hearing loss is now more common, since The American Society for Speech and Hearing issued a consensus statement saying that every newborn infant in the country should be tested for hearing before they leave the delivery room.
Infants with congenital deafness typically have a sensory neural hearing loss that occurs when the electrical signal from the cochlea to the brain is broken in some way. Cochlear implant surgery can often fix this problem and allow children to develop relatively normal speech and language abilities—but not always.
Holland explained, “It’s a little bit of a mystery about why 10% to 30% of the kids who get these implants fail to learn speech and language. We think it’s because the central auditory system is not able to process the inputs or it’s not getting the inputs.”
The fMRI brain scans performed in implant candidates can help clinicians to see if the auditory nerve is intact, whether the cochlea is intact, and can even detect a response at the level of the brain stem from an auditory stimulus.
Surgeons try to facilitate early language development by implanting cochlear implants in patients as early as possible. The FDA approves the surgery for patients as young as 1 year old. However, physicians cannot truly know the surgery’s full success until the child is actually talking—or not—2 years later.
Holland’s outcome study will attempt to determine whether fMRI scans performed before implantation can help clinicians predict how successful the cochlear operation will be, hopefully saving children from receiving unnecessary surgery.
In addition to a sedation program that includes full anesthesia, life support, and properly trained staff, Cincinnati Children’s has also invested in devices to divert the attention of children away from the noise and closed-in feeling of a bore hole.
For MR, young patients are given specially designed video goggles, allowing kids to focus on cartoons during acquisition. For the CT exams, the Cincinnati Children’s has installed a device that projects dazzling light shows inside of the gantry, which can distract the children and help them to relax.
In addition, the hospital employs child life specialists that can coach and play with the kids during CT, MR, and fluoroscopic studies.
Donnelly believes that these devices and programs have been a great benefit. “It’s pretty amazing,” he said. “Historically, we could never get a kid under 7 to cooperate with an hour-long MR, and now we can sometimes scan kids as young as 3. They can just wear the goggles and watch the movie. Some kids even complain when they have to come out.”
Having a 64-slice CT can also be advantageous for imaging a young child. Although 16-slice scanners are already fast, the 64 CT’s speed and shorter scan time may further aid in reducing sedations, since patients need to remain still for a smaller window of time.
Donnelly credits the implementation of these devices and child life specialists for decreasing the number of sedations by 33% for kids under age 7 who undergo CT or an MRI.
In addition to aiding in avoiding pediatric sedation, the hospital’s 64-slice CT scanner helps radiologists to see smaller structures. Of course, Donnelly and his staff are well aware of the risks of exposing children to the CT’s radiation and try to minimize that exposure in several ways.
“The best way to avoid the dose of a CT scan is not to have it,” Donnelly said. “Making sure that a CT is the appropriate protocol is something that we all struggle with, especially with the increased reliance on imaging being a part of what goes on in an emergency department.” Consequently, one of the ways that radiologists keep CT radiation exposure in check is by being aware of the appropriateness criteria and using alternative modalities like ultrasound when possible.
When CT is appropriate, technologists adjust several parameters. “Smaller people need less radiation to create the same quality of picture as a larger person does. That’s the basic principle. So you can adjust your parameters by lowering your tube current or your mAs,” Donnelly said. He also recommends utilizing breast shields and utilizing the CT’s automated exposure control with a ceiling limit.
At the same time that the radiology team is helping diagnose complex cases with their advanced imaging techniques, they may also be contributing to a wide array of research being conducted by the Imaging Research Center and Holland’s Pediatric Neuroimaging Research Consortium (PNRC).
PNRC is focused on pediatric radiology, but also includes participants from neurology and neurosurgery, otolaryngology, psychiatry, and psychology. There are ongoing projects in epilepsy, deafness, traumatic brain injury, bipolar disorder, and sleep apnea.
The following is just a brief summary of some of the research projects currently under way at the IRC and PNRC:
- Donnelly is one of the pioneers of cine MRI, sometimes known as MRI sleep studies. The technique images anatomic images as well as moving images of the airway. Cine MRI’s main advantage is that it gives clinicians the ability to make surgical decisions based on a dynamic view of airway obstructions in pediatric patients with obstructive sleep apnea (OSA). Subsequent research with specialists in otolaryngology, pulmonary medicine, and sleep medicine has produced recommendations for the future surgical treatments of pediatric patients with persistent OSA.
- Weihong Yuan, PhD, research assistant professor of radiology at the University of Cincinnati College of Medicine, is using parameters from DTI studies to discover whether children with hydrocephalus have predictors for when it would be most beneficial for them to be shunted. If shunted too early, the shunt may later prove to be unnecessary; if shunted too late, brain damage may occur.
- Alan Brody, MD, is leading a team that is utilizing CT scanners to aid in the early detection of cystic fibrosis (CF). Brody’s recent research shows that CT scans can reveal the structural changes associated with CF before the functional changes are identified by standard pulmonary function tests.
In addition, Holland is working on a large research project funded by the National Institute on Deafness and Other Communication Disorders. The project involves performing fMRI scans in congenitally deaf infants and evaluating them for cochlear implant surgery. If proven successful, the exam could become a new protocol for every medical center performing pediatric cochlear implants.
Holland’s cochlear implant surgery research is just one example of how Cincinnati Children’s is making use of the latest high field magnets for clinical research.
Asked whether radiologists will one day have a clinical need for the ultra high field 20T MRIs that are currently being used in animal research, Holland points out that the clinical 3T magnets today allow radiologists to perform exams that were not possible only 10 years ago; for example, advanced imaging spectroscopy methods that can show the metabolism of a tumor.
“So, do we need it? I don’t know, but since we have it, we’ll figure out how to use it. Then, probably as a result, children will live longer, and we’ll be able to detect their cancer sooner, treat it more effectively, and follow that treatment a little more accurately.”
Tor Valenza is a staff writer for Medical Imaging. For more information, contact .