Autism and the Use of MRI

Abstract

In this paper, the relationship between autism spectrum disorder (ASD) and the use of magnetic resonance imaging will be discussed. Autism is a very common neurodevelopment disorder with many different symptoms. Diagnosing and treating autism can be challenging because of how different every case of ASD truly is. Early detection is important for getting ahead on treating the symptoms that go along with ASD to create more positive outcome for the patients. Using MRI can open the doors for doctors and researchers to learn even more about this disorder and how to treat it. The studies discussed in this paper will explain how the use of structural MRI can allow physician to see how an autistic patient’s brain size and appearance differs from typically developing individuals, and the use of functional MRI can be used to compare the brain’s activity. Sleep fMRI is also discussed in how it can help with early detection in children. Overall, the discussion is about how MRI can better the understanding, detection, and treatment of ASD.

Autism and the Use of MRI

Autism spectrum disorder (ASD) is a neurodevelopment condition that has a wide variety of symptoms that can effect a patient’s social skills, speech or other ways of communication, and also can include different repetitive behaviors. One third of children with autism are nonverbal, and there are also many children that have gastrointestinal disorders, anxiety, and attention deficit hyperactive disorder (ADHD) along with many other symptoms. The conditions of ASD are very diverse because every case can be so unique because of different genetic and environmental blends can effect an ASD patient’s conditions. Around 1 in 68 children are effected by autism, and boys are much more likely to have the disorder.

Diagnosing autism can become a process; usually, if a parent or physician is concerned of ASD being a possibility, they will do a general screening which is normally suggested to the parents of infants anyway. After the screening, if there is a strong possibility of the patient having autism, the doctor will do a complete evaluation to confirm the diagnosis of the patient (Autism Speaks, n.d.). According to Shen et al (2013), early detection is critical because the earlier ASD is diagnosed positive results are more likely to happen when treating impairments. Most of the time diagnosing and understanding autism is only done by observation or screening, but with radiology, doctors are now seeing the signs of autism with magnetic resonance imaging (MRI) which could lead to an earlier detection.

There are multiple types of MRI that can help with these studies. Structural MRI is used to understand the anatomy of the brain. The data received from structural MRI can explain shape, size, and white and gray matter within the brain. Structure can be very important when understanding function of the brain, and this is why structural MRI is so useful. The next form of MRI is used for mostly neural activity rather than anatomy. Functional MRI can use tasks or something visual to stimulate the brain, and then doctors can compare the changes of neural function and compare the results with other patients. Using these two functions of MRI can help doctors or researchers understand normal or unusual brain function. Also, fMRI and structural MRI aid in the research or treatment involving neurological disorders (Center for Functional MRI, n.d.).

Throughout this first study, the use of structural MRI for studying autism is discussed; also, the comparison of the brain between patients with ASD and typical developing individuals. With the help of MRI, doctors can study the brain without anything invasive and allows researchers or doctors to view the structural changes of patients with ASD. These studies look for the differences between patients with autism and how their brain growth persists the older they get using structural MRI. With structural MRI, the brain volume in children with autism can be observed and compared. Multiple scans were performed on young children throughout the ages of a year and a half to five years who all were confirmed to have autism at around the age of four years old, and the researchers also performed scans on children without autism. When the scans were studied, it was found that most children with ASD had a cerebrum and many other divisions of the brain that were enlarged by the time the patient was two and a half. These studies have found that young children with autism have atypical enlargement of brain volume compared to normal developing children (Chen, Jiao, & Herskovits 2011). According to (Chen et al., 2011), the enlargement seems to relate to an increase in “gray-matter (GM) and white-matter (WM) volumes.”

Although enlargement is found within children, it is vague if whether or not the enlargement continues as the child gets older. Although the enlargement is seen within children, there have also been reports of autistic adults with substantially smaller parts of the brain within the corpus callosum. Throughout these MRIs, many differences and abnormalities were seen throughout the scans. Consistent abnormalities were seen throughout the patients’ white matter, frontal and temporal lobes, as well as other parts of the brain (Chen et al., 2011). Pointing out the abnormalities becomes difficult because the symptoms of ASD cannot be found as a result of one specific part of the brain; the multiple symptoms of autism could be explained by certain neural systems and how they perform together (Dichter, 2012). These studies are an example of how magnetic resonance imaging can assist doctors in identifying they physical differences between patients with ASD and typically developing individuals (Chen et al., 2011).

In the next study reviewed, they researched the relationship between extra-axial fluid and children who develop autism spectrum disorder. This study differs because the children involved in the study had not yet been diagnosed with autism. The study began with 64 infants, 41 of who were high risk because they had sibling with ASD. The other 23 participants had no relatives with the disorder and were considered low risk. Throughout the case, the number of participants decreased to 55 children (33 high risk and 22 low risk). The participants were scanned three times during sleep using a 3 Tesla Siemens TIM Trio MRI system from the ages of six months to 24 months. After the series of scans were complete, there seemed to be a trend with the high risk children. Some of the high risk children who participated in the study had similarities within the subarachnoid space. According to Shen et al. (2013), the children had “the presence of ‘prominent extra-axial fluid.’ Extra-axial fluid is characterized by excessive cerebrospinal fluid (CSF).” After the scans were completed and the children were old enough to be diagnosed, ten of the high risk children were classified to have ASD at 24 months old, and eight of them were officially diagnosed at 36 months old. Eight of the other children who were high risk had developmental delays, and only three children from the low risk group had developmental delays, but none of them were diagnosed with ASD.

There are many features that extra axial fluid and autism spectrum disorder share. Shen et al. (2013) explained that these traits include “enlarged head circumference early in life, higher rate in boys than girls, and a co-occurrence with seizures.” Although there has been no previous relationship between ASD and extra axial fluid, increased cerebrospinal fluid has been found in patients with autism. After this study and research was conducted, the results concluded that if the presence of the significant amount extra axial fluid has not gone away by the time the child is two years old that it could be a possible symptom of autism in children. This study would not have been possible without the use of MRI and also shows how imaging could help with early detection of children with autism. (Shen et al., 2013). This study showed how certain things that were seen in children with ASD could potentially be seen before the normal time of diagnosis.

According to Dichter (2012), MRI (fMRI) “has proven to be a useful tool to investigate aberrant neurobiological function in ASDs because of its excellent contrast properties, spatial resolution, and temporal resolution.” Although fMRI can be very useful, it can become difficult when performing the scans on children. Children are not able to undergo functional MRI because the scans cannot be completed if they are awake or alert because the procedure must be done with the patient completely still. FMRI has become possible to perform the procedure with children by doing the scan during nature sleep which is known as sleep fMRI. This allowed doctors to understand more about an autistic child’s brain function in which they have been unable to do before. FMRI is allowing doctors to see some of the earliest signs of autism which is vital for the future of a child with ASD (Pierce 2011). According to Pierce (2011), sleep fMRI can allow doctors to make a diagnosis even earlier than they thought possible and will allow treatment to occur much sooner.

With autism spectrum disorder being so common and the diversity of behaviors with autistic children, the use of MRI is opening the doors for doctors to detect the early signs and to understand even more about the disorder. Structural MRI and functional MRI can both play very important roles for studying ASD. Structural MRI allows researchers to observe the differences between brain volume in typical developing children and in children with autism, and functional MRI allows doctors to review brain activity and function. Sleep fMRI is also becoming the way for doctors to make even earlier detection because it allows them to perform scans on patients at a much younger age. With the research being done and early detection becoming even more possible, advances in imaging are creating a clearer picture of what parts of the brain are different for children and adults with ASD and how this effects their brain activity. With imaging, individuals with ASD can have the possibility of more positive treatment because of even earlier detection, and doctors can have a better ability of understanding autism and the parts of the brain it effects.

References

Autism Speaks. (n.d.). What is autism? Retrieved from https://www.autismspeaks.org/what- autism Chen, R., Jiao, Y., & Herskovits, E.H. (2011, May). Structural MRI in autism spectrum disorder. Pediatric Research, 69(5 pt 2), 63R-68R. doi: 10.1203/PDR.0b013e318212c2b3 Center for Functional MRI. (n.d.). What is fMRI? Retrieved from https://fmri.ucsd.edu/Research/whatisfmri.html Dichter, G.S. (2012, September 14). Functional magnetic resonance imaging of autism spectrum disorders. Dialogues Clinical Neuroscience. 14(3), 319-351. Pierce, K. (2011, March 22). Early functional brain development in autism and the promise of sleep fMRI. Brain research, 1380, 162-174. doi: 10.1016/j.brainres.2010.09.028. Shen, M.D., Nordnal, C.W., Young, G.S., Wooton-Gorges, S.L., Lee, A., Liston, S.E., Harrington, K.R., Ozonoff, S., & Amaral, D.G. (2013). Early brain enlargement and elevated extra-axial fluid in infants who develop autism spectrum disorder. Brain: A journal of neurology, 136, 2825-2835. doi: 10.1093/brain/awt166

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