Blog Search Results

MRI shows that lower pulmonary gas exchange in the lungs of long-COVID patients may be associated with cognitive symptoms, according to a study to be presented at the RSNA annual meeting in Chicago. “This is the first time that MRI has been used to jointly assess lung and brain function to investigate their relationship in long COVID," Staab said, in an RSNA statement. About 17% of adults in the U.S. have experienced a post-COVID condition commonly referred to as long COVID, according to estimates. Difficulty concentrating ("brain fog"), changes in sense of smell or taste, fatigue, joint or muscle pain, and dyspnea (shortness of breath) are among the symptoms, which can persist for weeks, months, or even years. In pulmonary gas exchange, oxygen moves from the lungs to the bloodstream, while carbon dioxide moves from the bloodstream to the lungs. In the study, Staab and colleagues used an advanced technique that uses xenon-129 (Xe-129) gas with MRI to measure this gas exchange. They recruited 10 women (median age: 52 years old) who had persistent dyspnea and/or fatigue following on average 31 months after acute COVID-19 infection. Participants underwent hyperpolarized Xe-129 pulmonary MRI, structural and functional brain MRI, pulmonary function tests, and cognitive tests." Perceived cognitive difficulties were measured using Patient-Reported Outcomes Measurement Information System, and objective cognitive performance was assessed using the National Institutes of Health Toolbox V3 Cognition Battery, the researchers noted. Individuals in the study were plotted with the x-axis being rank of pulmonary gas exchange. The black dots show the pulmonary gas exchange ratio (red blood cell to tissue plasma ratio, RBC:mem) on the left y-axis and the blue dots are the cognition scores on the right y-axis. Gas exchange maps of three representative patients from a low, medium, and high pulmonary gas exchange. Image courtesy of RSNA. The analysis showed that lower pulmonary gas transfer ratios detected by MRI were related to cognitive dysfunction – specifically in executive function and processing speed. Lower gas exchange on MRI was also related to lower gray matter and white matter volumes, Staab noted. “There was a range of cognitive difficulties among the patients in the study. Some were mild and indicated slight dysfunction, while others were more serious and indicated that some patients have slow thinking and trouble concentrating several times per day," he said. "This relationship could be a compensatory mechanism where lower lung function is compensated by higher cardiac output and higher brain perfusion. It's also a possibility that the disease mechanism that impairs pulmonary gas exchange also leads to higher brain perfusion through downstream vascular injury in both lung and brain," Staab said. The study is unique in that it combined multiple advanced imaging types to study a multiorgan relationship in a disease population and larger studies are needed to investigate the associations, added senior study author Sean Fain, PhD, also of the University of Iowa. "If these findings can be generalized to the long-COVID population, the study suggests that there may be a causative relationship between cognitive dysfunction and lung dysfunction, suggesting a potential treatment strategy using methods that target improved gas exchange," Fain said.

Radiologists, neuroscientists, and biomedical engineers have identified a new clinical marker that could be associated with concussions from youth contact sports such as tackle football, research to be presented December 1 at RSNA 2024 suggests. Christopher Whitlow, MD, PhD. Called aperiodic activity, the marker reflects brain cortical excitability, a vital part of brain function, according to Christopher Whitlow, MD, PhD, of Wake Forest University School of Medicine in Winston-Salem, N.C. "Our study opens the door to new ways of understanding and diagnosing concussions, using this novel type of brain activity that is associated with concussion symptoms," Whitlow said in an RSNA statement. "It highlights the importance of monitoring kids carefully after any head injury and taking concussions seriously." The study indicated that concussions appear to cause slowed aperiodic activity in areas of the brain where cortical excitability plays a key role in cognitive functions such as learning and memory, information processing, decision-making, motor control, wakefulness, and sleep, according to the researchers. "Most previous neuroscience research has focused on rhythmic brain signaling, which is also called periodic neurophysiology," lead author and presenter Kevin Yu, a neuroscience student at Wake Forest, said in the statement. "On the other hand, aperiodic neurophysiology refers to brain signals that are not rhythmic." For the study, the investigators combined a clinical evaluation tool for concussions called the Post-Concussive Symptom Inventory with pre- and post-season resting-state magnetoencephalography (MEG) data from 91 high school football players, of whom 10 were diagnosed with a concussion. MEG is a neuroimaging technique that measures the magnetic fields that the brain's electrical currents produce. Data were source-imaged, frequency-transformed, and parameterized using specparam, the team noted, adding that they used linear mixed models to examine the effects of concussion on pre- to post-season changes in neurophysiological activity. They also conducted colocalization of the resulting beta-weight maps with 19 neuromaps atlases using autocorrelation-preserving null permutations. "This study is important because it provides insight into both the mechanisms and the clinical implications of concussion in the maturing adolescent brain," said co-lead author Alex Wiseman, PhD, of Fraser University in Burnaby, British Columbia, Canada. The team observed aperiodic activity present in areas of the brain that contain chemicals linked with concussion symptoms like impaired concentration and memory. For their neuroradiology poster session, Yu and colleagues noted changes in the superior-frontal cortices, with the concussion-aperiodic relationship strongest in brain regions with high normative densities of cholinergic and noradrenergic neurotransmitter systems. "Reduced excitability is conceptually a very different brain activity change than altered rhythms and means that a clear next step for this work is to see whether these changes are related to effects of concussion on the brain's chemistry," Wiseman added.

The American Society for Radiation Oncology (ASTRO) has released an updated radiation therapy guideline for rectal cancer. The guideline was published November 25 in Practical Radiation Oncology . It includes new data on patient selection and best practices from clinical trials published since the prior guideline was issued in 2020, the society said. Key recommendations include the following: Neoadjuvant radiation therapy is recommended for patients with stage II or III rectal cancer to reduce their risk of locoregional recurrence rather than after surgery. Organ preservation through total neoadjuvant therapy followed by nonoperative management, or neoadjuvant chemoradiation followed by local excision, may present alternatives to radical surgery for select patients. Updated recommendations also describe regimens to treat patients at higher risk of recurrence who would likely benefit from an intensified treatment approach. The guideline is a collaboration between ASTRO and the American Society of Clinical Oncology (ASCO) and the Society of Surgical Oncology (SSO), and it is endorsed by the European Society for Radiotherapy and Oncology (ESRO) and the Royal Australian and New Zealand College of Radiologists (RANZCR).