Fractional Anisotropy Varies with Age, Cognition, and Depression in Patients with Sickle Cell
Poster No:
2184
Submission Type:
Abstract Submission
Authors:
Elizabeth Meinert-Spyker1, Tales Santini2, Sharadhi Umesh Bharadwaj1, Charles Jonassaint2, Meryl Butters2, Olubusola Oluwole2, Enrico Novelli2, Tamer Ibrahim2, Sossena Wood1
Institutions:
1Carnegie Mellon University, Pittsburgh, PA, 2University of Pittsburgh, Pittsburgh, PA
First Author:
Co-Author(s):
Introduction:
Sickle cell disease (SCD) is a genetic condition causing abnormal hemoglobin formation, chronic hemolysis, anemia, poor perfusion, and decreased oxygen delivery. As neurological function relies on adequate blood and oxygen, SCD patients often experience neurological complications from tissue damage [1]. These complications may lead to cognitive deficits experienced by patients with SCD starting at a young age [2]. Diffusion tensor imaging (DTI) characterizes white matter microstructure and connectivity in the brain. The sensitivity of this imaging technique may help predict SCD disease progression. The fractional anisotropy (FA) metric from DTI measures tissue organization and directional coherence and has been associated with cognitive function [3] and depression [4], which is highly prevalent in SCD. However, the association between FA metrics and mental health outcomes has not been examined in this population. This study examines the associations between FA values, age, cognitive performance, and depressive symptoms in adults with SCD patients and healthy controls.
Methods:
24 healthy controls (aged 38±15, F=16) and 24 patients with SCD (aged 35±13, F=15) were included. Patient subtypes include HbSS, HbSC, and HbSβ+ thalassemia. DTI data was acquired with a 7T MRI scanner (MAGNETOM, Siemens) and a customized 16Tx/32Rx head coil [5,6]. The sequence parameters were: 64 directions with a b-value of 1ms/µm2, 2 acquisitions without diffusion gradients (with and without reversed phase encoding direction), TE/TR=80/10031 ms, and total acquisition time 11:33 min. Preprocessing of the data was conducted with the softwares MRtrix [7] and FSL [8]. Tract-based spatial statistics [9] was used to compare diffusion metrics. The average FA value for each participant was calculated over the JHU ICBM-DTI-81 white-matter labels atlas. On the day of their MRI scans, participants self-reported depression (Center for Epidemiological Studies-Depression (CES-D)) and anxiety (Generalized Anxiety Disorder-7). They also completed cognitive tests, including the digit symbol substitution test (DSST). Pearson correlations tested associations between FA values, age, cognition, and depression/anxiety for all participants and patients/controls separately. Correlations with absolute values 0.3-0.49 were considered moderate, ≥0.5 were strong. P<0.05 indicated significant moderate/strong correlations.
Results:
Overall correlations were found between FA values and age, DSST scores, and the CES-D. Across both groups, higher age was associated with lower FA values (r(46)=-0.52, p<0.01; Figure 1), while higher FA was associated with higher DSST scores, indicating faster processing speed (r(45)=0.49, p<0.01; Figure 2a). Increasing CES-D scores, indicating worse depressive symptoms, were also associated with lower FA values (r(45)=-0.41, p<0.01; Figure 2b). For patients with SCD, the correlation between age and FA was stronger, r(22)=-0.64, p<0.01, compared to controls, r(22)=-0.54, p<0.01. Correlations between DSST scores and FA values were similar between patients (r(21)=0.46, p=0.03) and controls (r(22)=0.48, p=0.02). For correlations with the CES-D, only patients had a moderate negative correlation (r(21)=-0.46, p=0.03).
Conclusions:
Prior research suggests adults with SCD show accelerated white matter aging compared to non-SCD counterparts [10]. This is supported by data from this study showing stronger correlations between lower FA and age in the SCD participants compared to controls. This study also identified correlations between FA, cognitive function, and depressive symptoms. To our knowledge, this is the first 7T MRI study to examine correlations between FA, age, DSST performance, and depression severity in SCD patients and controls. Next, we will explore correlations between specific cognition and depression-related brain regions and FA in SCD. This can provide further insights into SCD's neurological effects.
Disorders of the Nervous System:
Psychiatric (eg. Depression, Anxiety, Schizophrenia)
Higher Cognitive Functions:
Executive Function, Cognitive Control and Decision Making
Lifespan Development:
Aging
Neuroanatomy, Physiology, Metabolism and Neurotransmission:
White Matter Anatomy, Fiber Pathways and Connectivity 1
Novel Imaging Acquisition Methods:
Diffusion MRI 2
Keywords:
Aging
Anxiety
Cognition
MRI
Psychiatric
WHITE MATTER IMAGING - DTI, HARDI, DSI, ETC
Other - Sickle Cell Disease
1|2Indicates the priority used for review
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