MRI Scans May Help Reveal Subtle Brain Changes in CF Patients
MRI scans may help to reveal subtle changes in certain areas of the brain among people with cystic fibrosis (CF), a study found.
The affected areas are involved in mood and cognition, which were found to be altered relative to people without the genetic disease.
“CF patients exhibited significant anxiety and depression symptoms and impaired cognitive abilities, and brain regions regulating such functions showed altered brain structural integrity,” the researchers wrote.
Low levels of oxygen in tissues — a condition known as hypoxia — appeared to be a key factor.
“Tissue changes may contribute to symptoms resulting from ongoing hypoxia accompanying the condition,” the investigators wrote, calling for “integration of mental health screening and early identification and targeted treatment of CF patients.”
The study, “Regional brain tissue changes in patients with cystic fibrosis,” was published in the Journal of Translational Medicine by a team of researchers in the U.S.
Those living with CF may feel emotionally unwell, and are more likely to have mood disorders such as anxiety and depression, research has shown. While such disorders may have an origin in the brain, no studies have looked at changes in the brain tissues of patients with CF.
Now, a team from the University of California Los Angeles (UCLA) launched a study involving three men and two women with CF, all patients at UCLA’s Adult Cystic Fibrosis Center. The participants had a mean age of 29.7. The study also included 15 controls — 10 men and five women without CF — with a mean age of 33.9, who were recruited through advertisements at the UCLA campus and the Los Angeles area.
“Subtle brain tissue changes are often challenging to visualize on routine brain magnetic resonance imaging (MRI),” the researchers wrote, noting that even the use of T1-weighted and T2-weighted imaging often fails to work well. T1-weighted and T2-weighted imaging refer to different ways used to produce images on MRI.
To detect such subtle changes, the researchers thought of using two techniques.
One is T1-weighted voxel-based morphometry, which can measure the relative proportion of gray matter — which contains the cell bodies of nerve cells — to other tissues in a specific brain area. The other is T2-weighted relaxation, which can measure free-water content to detect tiny changes in brain structures.
“Such MRI techniques are simple and rapid,” and use data from routine, non-invasive MRI scans, the scientists added.
To start, the researchers looked at differences in mood disorders between the two groups. They found that both anxiety — measured using the Beck anxiety inventory — and depression, as assessed using the Beck depression inventory, were more severe in patients with CF than in controls.
Cognitive performance — measured using the Montreal Cognitive Assessment (MoCA) — was a mean 1.7 points lower in patients with CF than in controls (26.5 vs. 28.2), a statistically significant difference. The MoCA test evaluates various cognitive domains, including attention and concentration, memory, language, conceptual thinking, calculations, and orientation. The threshold for abnormal scores in this study was a score under 26.
Next, the researchers looked at the grey matter content inside certain areas of the brain.
MRI scans revealed an increase in grey matter content in multiple areas of the brain of people with CF, indicating injury to brain tissues. These included the cerebellum, hippocampus, amygdala, basal forebrain, insula, and frontal and prefrontal cortices. These regions are key in functions such as mood, cognition, motor coordination, memory, and sleep/wake states.
Other areas in the temporal and occipital cortices — two of the major lobes of the cerebral cortex of the brain — had a decrease in gray matter content compared with controls.
Multiple brain areas also had lower T2-weighted relaxation values in those with CF than in controls, which according to the investigators indicates acute injury. These included the cerebellum, cerebellar tonsil, prefrontal and frontal cortices, as well as the insula.
“Patient[s] with CF showed significant brain structural changes …. indicative of tissue injury, in brain regions that control cognitive, autonomic, and mood functions,” the researchers wrote. Of note, autonomic function is involuntary body functions such as heartbeat, breathing, and digestion.
“To increase the life span and life quality of CF individuals, detection of brain changes are of utmost importance,” the team wrote, noting that “the altered brain regions we encountered in CF patients have a considerably important role in their cognitive and mood wellbeing.”
“With a high incidence of psychological symptoms in adult CF patients, this study highlights the importance for improved early identification and management strategies for adult CF patients,” the team wrote.
As for study limitations, they mentioned its small sample size and the low resolution of T2 images. But they said further research on the use of brain MRI scans could have an impact on patient care.
“Identifying the structural brain changes associated with cognitive and mood deficits in CF patients may provide new insights into healthcare management and long-term clinical strategies,” they concluded.