mDIXON-Quant序列、弥散加权成像对骶髂关节炎分期定量诊断的价值

Value of mDIXON-Quant sequence, diffusion-weighted imaging in quantitatively diagnosing the sacroiliitis stages

目的探讨mDIXON—Quant序列、弥散加权成像（DWI）对强直性脊柱炎（AS）骶髂关节炎分期的定量诊断价值。方法收集2015年4月至2016年12月天津市第一中心医院临床确诊AS患者51例，根据Bath强直性脊柱炎疾病活动指数（BASDAI）评分及实验室指标分为早期急性期（20例）、慢性活动期（31例）两组，同时期于天津市招募25名健康志愿者作为健康对照组。均行MRI常规序列及mDIXON—Quant序列、DWI扫描。应用mDIXON—Quant序列脂肪分数（FF）图、DWI表观弥散系数（ADC）图测量早期急性期组、慢性活动期组骨髓水肿区及健康对照组关节面下骨髓FF值、ADC值，对组间FF值、ADC值进行比较。结果早期急性期组、慢性活动期组骨髓水肿区及健康对照组关节面下骨髓ADC值分别为（1．07±0．20）×10^-3mm^2／s、（1．00±0．22）×10^-3mm^2／s、（0．25±0．07）×10^-3mm^2／s，早期急性期组、慢性活动期组骨髓水肿区ADC直分别与健康对照组比较，组间差异皆有统计学意义（P〈0．01），但早期急性期组、慢性活动期组间骨髓水肿区ADC值差异无统计学意义（P=0．394），即ADC值不能对骶髂关节炎早期急性期和慢性活动期进行分期；组问FF值差异皆具有统计学意义（P〈0．01），且慢性活动期组骶髂关节骨髓水肿区脂肪含量高于早期急性期组。结论mDIXON—Quant序列能对骶髂关节炎早期急性期、慢性活动期进行定量诊断，且诊断价值优于DWI，对临床诊疗及预后具有指导意义。

Objective To evaluate the value of mDIXON-Quant sequence, diffusion-weighted imaging （ DWI ） in quantitative diagnosing of the sacroiliitis stages in patients with ankylosing spondylitis （AS）. Methods Based on the Bath Ankylosing Spondyfitis Activity Index （BASDAI） and laboratory parameters, a total of 51 patients were diagnosed with AS. They were divided into two groups as early active group （n =20） and chronic active group （n = 31 ）, and at the same time, 25 healthy people from Tianjin were included as control group. The regular MRI sequences and mDIXON-Quant sequence, DWI were obtained. The apparent diffusion coefficient （ADC） and fat-signal fraction （FF） value of bone marrow with edema of the sacroiliac joints in early active group and chronic active group and of subchondral bone marrow of sacroiliac joint in control group all were measured by ADC maps and FF maps. Mean （FF, ADC） values were compared between groups. Results The ADC value of the early active group, chronic active group and the control group is （1.07 ±0.20） ×10^-3mm^2/s, （1.00±0.22）×10^-3mm^2/s, （0.25 ±0.07）×10^-3mm^2/s, respectively, and the differences of ADC value between early active group and control group, chronic active group and control group were significant （ P 〈 0.01 ） , but the difference of the ADC value between early active group and chronic active group was not significant （ P = 0. 394 ）. That is to say, the ADC value can＇t distinguish the early active group and chronic active group. The differences of FF value between groups was significant （P 〈 0.01 ） , and the FF value of bone marrow with edema in chronic active group were higher than that in early active group. Conclusions The mDIXON-Quant sequence can quantitatively diagnose early active group and chronic active group, and the diagnostic value is better than DWI. Thus, it can provide guidance for clinical treatment and prognosis.