NEWS FROM RSNA 2018

Snoring Poses Greater Cardiac Risk to Women

Obstructive sleep apnea (OSA) and snoring may lead to earlier impairment of cardiac function in women than in men, according to a study presented at RSNA 2018. Moreover, the findings suggested that OSA may be vastly underdiagnosed among snorers. A common but dangerous sleep disorder, OSA causes an increased risk for left ventricular and, more rarely, right ventricular dysfunction in the heart.

OSA is the most common type of sleep apnea. It occurs when the throat muscles intermittently relax and block the airway while a person sleeps. While there are several symptoms of OSA—such as gasping for air during sleep, waking with a dry mouth, morning headache, and irritability—loud snoring is a common sign. Complications of OSA may include daytime fatigue and sleepiness, complications with medications and surgery, and cardiovascular problems.

Researchers investigated cardiac function in relation to diagnosed OSA and self-reported snoring from data available through UK Biobank. A national and international health resource, UK Biobank is open to researchers and follows the health and well-being of 500,000 volunteer participants. Its aim is to improve the prevention, diagnosis, and treatment of a wide range of serious and life-threatening illnesses.

For this study, data from 4,877 UK Biobank participants who had received a cardiac MRI were analyzed. The patients were allocated to three study groups: those with OSA (118 patients), those with self-reported snoring (1,886 patients), and those who are unaffected—without OSA or snoring (2,477 patients). There were 396 individuals who did not meet research criteria.

“Our analysis showed that in both genders of the OSA and snoring groups there was an increase in left ventricular mass, meaning that the walls of the heart’s main pumping chamber are enlarged, making the heart work harder,” said lead author Adrian Curta, MD, a radiology resident at Munich University Hospital in Munich, Germany. “We also found that men showed an increase in the ejection fraction of both ventricles.”

Ejection fraction is the percentage of the heart chamber’s total volume that is pumped out with each heartbeat.

When the researchers compared the snoring group with the unaffected group, they found a more significant difference in the left ventricular mass in women than in men. The cardiac changes in the self-reported snorers point to earlier impairment and might be an indication of undiagnosed OSA.

“We found that the cardiac parameters in women appear to be more easily affected by the disease and that women who snore or have OSA might be at greater risk for cardiac involvement,” Curta said. “We also found that the prevalence of diagnosed OSA in the study group was extremely low. Together with the alterations in cardiac function in the snoring group, it leads us to believe that OSA may be grossly underdiagnosed.”

The findings suggest that the transition from snoring to OSA is an evolving process that is associated with left ventricular hypertrophy, an independent predictor for increased adverse events and in-hospital mortality in many procedures. Curta stresses that it’s important for people who snore to get screened for OSA, and cautioned that those with OSA should be properly treated.

“I would encourage people who snore to ask their partner to observe them and look for phases during sleep when they stop breathing for a short while and then gasp for air,” Curta said. “If unsure, they can spend the night at a sleep lab where breathing is constantly monitored during sleep and even slight alterations can be recorded.”

Treatment is dependent on the cause of an individual’s OSA, Curta noted. Weight loss, for example, can often improve OSA in overweight individuals. Apart from that, there are surgical techniques and special machines that keep the upper airways open at nighttime by applying continuous positive airway pressure.

Since this was a population study, the researchers hope to conduct further studies to gain more insight into the gender differences associated with snoring and OSA.

Youth Football Changes Nerve Fibers in Brain

MRI scans show that repetitive blows to the head result in brain changes among youth football players, according to a study presented at RSNA 2018. Football has been the subject of much scrutiny in recent years due to growing concerns over the long-term consequences of repetitive head impacts. Players who show signs of concussion are typically removed from games, but many hits to the head are subconcussive—below the threshold of a concussion—and, therefore, don’t cause any immediate symptoms. There is rising concern that youth football players who experience these collisions in practices and games may be vulnerable to their effects.

“The years from age 9 to 12 are very important when it comes to brain development,” said study lead author Jeongchul Kim, PhD, from Wake Forest School of Medicine in Winston-Salem, North Carolina. “The functional regions of the brain are starting to integrate with one another, and players exposed to repetitive brain injuries, even if the amount of impact is small, could be at risk.”

Kim and colleagues studied the results of these collisions on youth football players using a novel MRI method that looks at the strain evident on white matter tracts—the bundles of nerve fibers that carry information between different areas of the brain.

“The focus here was on deformations of these fiber bundles,” Kim said. “Changes from collisions might cause elongation or contraction of these bundles.”

Twenty-six male youth football players with an average age of 12 years underwent MRI studies before and approximately three months after the season was over. For comparison, 22 similarly aged boys who did not participate in contact sports had MRIs on the same schedule. The MRI results showed that the football players developed changes in the corpus callosum, a critically important band of nerve fibers that connects the two halves of the brain. The primary role of the corpus callosum is to integrate cognitive, motor, and sensory functions between the two sides of the brain. There were signs of greater axial strain (contraction) in some parts of the corpus callosum, and indications of radial strain (expansion) in other parts.

“The body of the corpus callosum is a unique structure that’s somewhat like a bridge connecting the left and right hemispheres of brain,” Kim said. “When it’s subjected to external forces, some areas will contract and others will expand, just like when a bridge is twisting in the wind.”

The results suggest that repetitive subconcussive head impacts associated with participation in youth contact sports could lead to changes in the shape of the corpus callosum during this critical time of brain development. Kim cautioned, however, that more evidence is needed to confirm the findings. His group intends to continue studying the players, when possible, to see if any additional deformation occurs.

The ultimate goal of the research, Kim said, is to provide guidelines for safe football play. MRI may have a role in that process by helping to determine if and when an athlete is able to return to play after a head injury. PET, an imaging technique that can detect signs of inflammation in the brain, is also potentially useful in this regard, according to Kim.

“It’s best to detect changes at the earliest possible time,” he said.

Online Gaming Addiction in Men Affects Brain’s Impulse Control

Researchers using fMRI have found differences in the brains of men and women who are addicted to online gaming, according to a study presented at RSNA 2018.

“Internet use is an integral part of the daily lives of many young adults, and a loss of control over internet use could lead to various negative effects,” said the study’s senior author, Yawen Sun, MD, a diagnostic radiologist in the department of radiology of Ren Ji Hospital, affiliated with the Shanghai Jiao Tong University School of Medicine in Shanghai, China. “Internet gaming disorder (IGD) has become a major public health concern worldwide among both adolescents and young adults.”

IGD is a condition characterized by compulsive playing of online games to the exclusion of other interests. Individuals with IGD often suffer significant impairment or distress and may experience negative effects at work, in school, or in relationships because of the amount of time they spend playing. They also show symptoms of withdrawal when not playing. While some evidence exists that IGD is more prevalent among men, there is little existing research on differences in the structure and function of the brains of men and women with the disorder.

The researchers studied 32 men and 23 women with IGD. They performed resting-state fMRI on the study participants, along with 30 male and 22 female age-matched healthy controls. Resting-state fMRI allows a view of the brain activity when it is not focused on a particular task. The study looked at relationships between brain activity as seen on fMRI and scores on the Barratt Impulsiveness Scale-11, a commonly used test to assess behavioral inhibition.

The results illuminated key differences between the men and women with IGD. Men with IGD showed alterations in regional- and network-level brain function. In particular, they had lower brain activity in the superior frontal gyrus, an area of the brain’s prefrontal lobe that is important for impulse control. The women with IGD did not exhibit any of these brain alterations.

“Our findings demonstrated that alterations in cerebral activity are observed in men with IGD, but not in women with IGD, and that the lower brain activity in the superior frontal gyrus in men with IGD may be associated with higher impulsivity,” Sun said.

This and other differences apparent in the study suggest that IGD may interact with gender-specific patterns of brain function in men and women. Different rates of maturation in men’s and women’s brains could also contribute to gender-specific alterations in IGD, Sun noted. For instance, the prefrontal cortex, which has a central role in executive function and inhibition, matures later in men.

“Men have shown lower levels of impulse control in comparison with women, and their impulse control also increases more gradually,” she said. “Given the role of inhibitory control in the initiation of IGD, young men may tend to experiment with pathological internet use to a greater degree than young women do.”

A dysfunctional prefrontal cortex, specifically in men with IGD, may be associated with high impulsivity, a finding partly consistent with those of previous studies of substance addiction. The research adds to a growing body of literature linking the behavioral problems associated with IGD to those found in individuals with substance abuse issues.

“However, it remains unclear whether the functional and structural brain changes found in IGD are gaming-induced or precursors for vulnerability,” Sun said. “I think future research should focus on using functional MRI to identify brain susceptibility factors relating to the development of IGD.”

Internet, or online, gaming has grown tremendously over the past decades. It includes social gaming, mobile gaming, and multiplayer gaming, which generates billions of dollars in revenue in the United States alone. Recent surveys have reported that there are more than 55 million online console gamers in the United States. According to data measurement company Nielsen, 162 million people, or roughly one-half of the US population, live in a household with a video game console.

These news items are based on press materials provided by RSNA at RSNA2018 in Chicago.