Quantitative MRI Study On Neuromyelitis Optica Spectrum Disorder And Multiple Sclerosis

Part ? Analysis of cerebral blood flow in normal appearing white matter in relapsing-remitting multiple sclerosisPurpose: To investigate whether cerebral blood flow (CBF) is abnormal in normal appearing white matter (NAWM) using 3D pseudocontinuous arterial spin labeling(3D pCASL) and its relationship with clinical data.Materials and Methods: Twenty-nine relapsing-remitting MS (RRMS) and seventeen age, sex-matched healthy control subjects were prospectively and consecutively enrolled and performed MRI including T2 weighted image (T2WI),3-dimensional fast spoiled gradient echo (3D FSPGR) and 3D pCASL. Regions of interest (ROIs) in centrum semiovale and periventricular NAWM were manually outlined to obtain the average CBF values. Two independent samples t-test was conducted for comparisons between RRMS and healthy control group in centrum semiovale and periventricular NAWM. Person and spearman correlation analysis were used to assess the relation between clinical data and CBF values for RRMS group.Results: Compared to healthy control subjects, CBF values were significantly reduced both in centrum semiovale and periventricular NAWM in RRMS(centrum semiovale NAWM: 32.5452 ± 4.5848 vs 35.4865±5.7968,p=0.036;periventricular NAWM: 30.7788 ± 4.1746 vs 34.053 ± 4.4821,p=0.006). In RRMS group, no relationships were found between CBF values and clinical data ( age, age of first onset, onset frequency, disease duration and expanded disability status scale score).Conclusion: Our 3D pCASL results showed reduced perfusion in NAWM in RRMS group indicating that there exists potential hemodynamic abnormality in NAWM and hemodynamics may play a pivotal role in pathogenesis of RRMS patients.Part ? Differentiation of neuromyelitis optica spectrum disorder from multiple sclerosis using dynamic contrast-enhanced MRIPurpose: Neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis(MS) are inflammatory demyelinating diseases of central nervous system. NMOSD has different pathophysiology, approaches to treatment, prognosis and pathogenesis from MS. Therefore, early accurate identification of the two disorders plays a vital role in choice of optimum treatment strategies and prognosis. The primary purpose of this study is to investigate whether blood-brain barrier (BBB) permeability can be used to differentiate NMOSD and MS using dynamic contrast-enhanced MRI(DCE-MRI) and its relationship with clinical characteristics.Materials and Methods: Thirty-six NMOSD patients and thirty-six MS patients were prospectively and consecutively enrolled from September 2014 to May 2016. All participants had performed MRI including axial T2-weighted image (T2WI), coronal T2 FLAIR, 3-dimensional fast spoiled gradient echo (3D-FSPGR) and DCE-MRI.Regions of interest in lesions, normal appearing white matter (NAWM), normal appearing grey matter (NAGM) and thalamic grey matter (TGM) were manually outlined to obtain volume transfer constant (Ktrams) values. Mann-Whitney U-test were conducted for comparisons between MS and NMOSD group in lesions, NAWM,NAGM and TGM. Receiver operating characteristic (ROC) curve were applied to obtain the optimal cut-off value reflecting sensitivity and specificity to differentiate MS from NMOSD group.Results: Significantly higher Ktrans values were found in lesions and NAGM in MS group when compared with NMOSD (0.0046 ± 0.0037 vs 0.0033 ± 0.0030,p=0.000 for lesions and 0.0033 ± 0.0023 vs 0.0021 ± 0.0010,p=0.004 for NAGM). However,no significant differences were found in NAWM and TGM between MS and NMOSD groups (0.0038 ± 0.0020 vs 0.0037 ± 0.0018,p=0.731 for NAWM; 0.0013± 0.0012 vs 0.0011± 0.0009,p=0.612 for TGM). ROC curve showed that the predicted probability for aquaporin-4 antibodies (AQP4-Ab) +Ktrans values in lesions and NAGM reached the largest area under the ROC curve (0.953) and had the best diagnostic cut-off value(0.7335).Conclusion: Our research emphasized the importance of BBB pathology in distiguishing MS and NMOSD patients. Therefore, BBB permeability, measured by DCE-MRI can further help differentiate MS and NMOSD and afford in vivo insight into the pathology of the two disorders.