A Combined Brain Structural And Cerebral Blood Flow MR Imaging Study In Systemic Lupus Erythematosus

Objective:To investigate the alteration of brain structural and cerebral blood flow (CBF) in systemic lupus erythematosus (SLE) patients using voxel-based morphometry and arterial spin labeling (ASL)-MRI, and to explore their clinical significance in reflecting the cognitive impairment in SLE patients.Methods and materials:Seventy-six SLE patients and eighty age- and sex-matched healthy controls underwent conventional MRI, the three-dimensional high-resolution T1 structural and ASL examinations. Neuropsychologic tests were performed in all subjects. Independent sample-t test was used to detect clinical markers, gray matter volume and CBF differences between SLE and healthy controls groups, respectively. Finally, a voxel-based correlation was carried out correlate the maps of gray matter or CBF with neuropsychologic tests and clinical markers.Results:52.6% SLE patients showed abnormal findings in conventional MRI, and the most frequent abnormality was white-matter hyperintensities. In comparison with healthy controls, SLE patients showed significant reduced gray matter volume in bilateral frontal gyrus, cingulate gyrus, left temporal gyrus and right insula, reduced CBFs in bilateral frontal gyrus, cingulate gyrus. insula and temporal gyrus (P< 0.05, FWE corrected). The result of the gray matter volume and CBFs maps had a strong positive correlation in spatial (r=0.60, P<0.001). Voxel-based correlation correlate the maps of gray matter or CBF with neuropsychologic tests and clinical markers showed that reduced gray matter volume and CBF of multiple brain areas negatively correlated with NCT-A score (r=-0.23～-0.38, P<0.05), reduced gray matter of some area also negatively correlated with SDT scores (r=-0.23～-0.42, P<0.05). Multiple regression showed that reduced gray matter volume of multiple brain areas negatively correlated with serum creatinine level and disease duration. While global mean CBF was positively correlated with serum creatinine level.Conclusion:This study combined structural and functional MR imaging to investigate the alteration of brain structural and CBF in SLE patients. Most patients presented abnormal MRI findings of cerebral small vessel diseases, and the most frequent abnormality was white-matter hyperintensities. We further found a significant reduction in gray matter volume and CBF, which was correlated with cognitive dysfunction.Objective:Chronic kidney disease is very common in SLE patients, and kidney and brain similar high-flow and low-resistance circulation, therefore, this study was focused on exploring the impact of chronic kidney disease on brain structural and cerebral blood flow in SLE patients, and their clinical significance in reflecting the cognitive impairment in SLE patients with chronic kidney disease.Methods and materials:Seventy-six SLE patients were divided into 2 groups according to the estimated glomerular filtration rates (eGFR):CKD group, defined as eGFR<60 mL/min/1.73 m2, and control, defined as eGFR≥60 mL/min/1.73 m2 (NonCKD group). All patients underwent MRI scan and neuropsychologic tests examination. Independent sample-t test was used to detect clinical markers, gray matter volume and CBF differences between CKD and NonCKD groups, respectively. According to the result of independent sample-t test, the main different brain regions between the two groups were selected as region of interests to correlated with neuropsychologic tests and clinical markers. Partial correlation was performed to analyze the association between mean CBFs and clinical markers.Results:In comparison with NonCKD group, CKD patients showed significant reduced gray matter volume in bilateral medial frontal gyrus, orbital frontal cortex and medial cingulate gyrus, while elevated CBFs in bilateral precuneus, hippocampus, thalamus, middle occipital gyrus, left central gyrus, left putamen and right angular (P<0.01, FDR corrected). CKD had a worse cognitive function, higher serum creatinine and urea levels, and lower hemoglobin level. Correlation analysis showed that the four main ROI of reduced gray matter volume were negatively correlated with serum creatinine and urea levels, and medial cingulate gyrus was positively correlated with DST score. In additon, the mean CBFs of the gray matter, white matter and global brain were significantly negatively correlated with hemoglobin level.Conclusion:SLE patients with chronic kidney disease had a more significant brain atrophy and worse cognitive function. However, the CBF was elevated due to anemia. These suggested that kidney impairment was associated with brain structural and cerebral blood flow in SLE patients, which clinicians need to pay close attention to the brain changes among lupus nephritis patients.