骨性膝关节炎病人脑功能MRI改变与手术前后疼痛的相关性研究

The correlation between altered brain fMRI and pain perception before and after operation in patients with knee osteoarthritis

目的旨在分析人工膝关节置换术(TKA)后仍存在慢性中重度疼痛的骨性膝关节炎(KOA)病人脑功能的改变与手术前后疼痛的相关性。方法纳入2016年12月—2017年5月在南京鼓楼医院住院的KOA病人18例[男1例,女17例,平均年龄(65.4±7.7)岁]及正常对照14例[(男1例,女13例,平均年龄(64.9±5.6)岁],获取3D T1WI及静息态功能磁共振成像(rs-fMRI)影像,运用低频振幅(ALFF)及格兰杰因果关系分析(GCA),以Z变换后获得的zALFF值代表血氧水平依赖(BOLD)信号变化强度,并以Z变换格兰杰因果关系(zGC)值表示兴趣区(ROI)到全脑及全脑到ROI的有效连接。采用双样本t检验比较2组静息状态下的脑功能活动差异。并采用Pearson相关检验分析zGC值与TKA手术前后疼痛视觉模拟评分(VAS)的相关性。结果 KOA病人右侧丘脑zALFF值显著减低(P<0.05, GRF校正),从右侧丘脑到右侧中央前回、中央后回、顶上小叶、楔前叶的有效连接增强,从右侧顶上小叶、楔前叶到右侧丘脑的有效连接减低(P<0.05, GRF校正)。术后VAS评分与右侧丘脑到右侧中央后回间的有效连接zGC值呈正相关(r=0.624, P=0.006);术前VAS评分与右侧楔前叶到右侧丘脑间的有效连接zGC值呈负相关(r=-0.527, P=0.024)。结论 KOA导致的长期慢性疼痛会引起脑功能的改变,进而影响治疗后的疼痛感知,因而术前脑功能检查有助于识别术后慢性疼痛高危病人。

Objective The purpose of this study was to analyze the relationship between brain function and pain perception before and after total knee arthroplasties(TKA)in patients with knee osteoarthritis(KOA)and post-operative moderate and severe pain.Methods Eighteen patients with knee osteoarthritis(male n=1,female n=17,average age:65.4±7.7 years)and 14 normal control(NC)subjects(male n=1,female n=13,average age:64.9±5.6 years)from Nanjing Drum Tower Hospital were enrolled during December 2016 to May 2017.3D T1WI sequence and resting-state functional MRI(rsfMRI)sequence were collected.Amplitude of low-frequency fluctuation(ALFF)and Granger causality analysis(GCA)were used in the processing of resting-state fMRI.The Z-transformed ALFF(zALFF)was used to represent the change intensity of BOLD signal.The Z-transformed Granger causality(zGC)was used to characterize the effective connectivity from region of interest(ROI)to the whole brain and from whole brain to ROI.Comparisons between two groups were performed by using the independent two-sample t-test analysis.The Pearson correlation analysis between the zGC value and the Visual Analogue Scale(VAS)score before and after TKA was carried out.Result The zALFF of right thalamus in KOA patients decreased significantly(P<0.05,GRF correction)compared with the NC group.Increased effective connectivities were observed from right thalamus to right central anterior gyrus,central posterior gyrus,superior lobes,and praecuneus,while decreased effective connectivities were observed from right superior lobes and praecuneus to right thalamus(P<0.05,GRF correction).The postoperative VAS score was positively correlated with the effective connectivity from right thalamus to right central posterior gyrus(r=0.624,P=0.006).The preoperative VAS score was negatively correlated with the effective connectivity from right praecuneus to right thalamus(r=-0.527,P=0.024).Conclusion Chronic pain caused by KOA leads to changes in brain function and then affected the pain perception after TKA.Brain function examination before surgery may help to identify patients at high risk of postoperative chronic pain.