[667] - Evidence That New Focal Fat
Lesions Follow Resolution of Spinal Inflammation in AS but Existing
Lesions Are More Likely To Resolve with TNF Blocking
Agents.
Praveena
Chiowchanwisawakit,
MD1,Robert GW Lambert, F.R.C.P.(C)2,Walter P
Maksymowych, MD, FRCPC3. 1Mahidol University,
Bangkok, Bangkok,2University of Alberta, Edmonton,
Alberta,3Medical Research Centre, University of Alberta,
Edmonton, AB
Purpose: MRI of the spine in SpA frequently shows focal fat
lesions in the spine on T1W scans, especially at vertebral corners
(VC) and adjacent to the vertebral endplate. Its histopathological
basis and pathophysiological implications remain unclear. Adipose
tissue has been shown capable of expressing proinflammatory
cytokines. It is assumed that VC Fat reflects post-inflammatory
change but there have been no prospective studies that have
actually tested this hypothesis. We aimed to test the hypothesis
that an active vertebral corner inflammatory lesion (CIL) on
baseline MRI is more likely to evolve into a de novo VC Fat
lesion on TIW scans than a VC which demonstrates no inflammation on
baseline MRI.
Method: MRI scans were performed at baseline and 2 years in
61 AS patients of whom 28 received TNF blocking agents in open
label follow up of clinical trials while 33 received either TNF
blocking agents (n = 16) or standard therapy (n = 17) in an
observational cohort. We recorded VC fat lesions, defined as
increased signal in bone marrow on T1W MRI, and CIL, defined as
increased signal on STIR MRI, at anterior and posterior VC on any
central sagittal slice. Via televideoconference, reference images
were developed in which VC fat lesions and CIL were assigned by
consensus amongst an international MRI working group. VC Fat
lesions and CIL were independently recorded dichotomously
(present/absent) from lower C2 to the upper sacrum of the spine.
Anonymized MRI scans were assessed independently by 2 readers who
were blinded to treatment and time point. The primary analysis was
based on concordant data (VC fat, CIL) and compared the development
of new VC Fat lesions according to the presence of a CIL on
baseline MRI and its persistence/resolution on follow up MRI. We
also tested the effect of treatment on baseline VC fat lesions.
Proportions were compared by Fisher's exact test.
Results: New VC Fat lesions developed significantly more
frequently in those VC with (32/83 (38.6%)) as compared to those
without (69/2647 (2.6%)) inflammation on baseline MRI in the
anti-TNF group (p<0.0001). This was less evident in
the standard therapy group (1/14 (7.1%) vs 8/1161 (0.7%), p = NS).
New VC Fat lesions developed significantly more frequently from CIL
that resolved compared to VC with persistent or no CIL in the
anti-TNF therapy group (p<0.0001). These differences
were again less evident in the standard therapy group. VC Fat
lesions present on baseline MRI resolved significantly more
frequently after TNF blocker (47/247 (16%)) compared to standard
treatment (5/94 (5.1%)) (p = 0.005).
Table. Number (percentage) of new VC Fat lesions.
Conclusion: New VC Fat lesions occur more frequently at
sites of prior inflammation, especially after inflammation has
resolved following institution of anti-TNF. Existing VC Fat lesions
are also more likely to resolve with anti-TNF.
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AS脊柱炎症消退后出现新发灶性脂肪病变而旧病变可能被TNF拮抗剂消除
Chiowchanwisawakit P, et al. ACR 2010. Present
No:667.
目的: SpA脊柱MRI常在T1加权像(T1W)中发现灶性脂肪病变,特别是在椎体角(VC)和相邻椎体终板。其病理组织学基础和病理生理学意义尚不清楚。脂肪组织能表达促炎细胞因子。VC脂肪病变可能是一种炎症后改变,暂无前瞻性研究对这种假说加以证实。本研究旨在证实基线期MRI活动性椎体角炎症病变(CIL)与无炎症的VC相比,是否更可能进展为T1W中的脂肪病变。
方法: 61例AS患者在基线期和2年后进行MRI扫描,其中28例在开放性临床试验中使用TNF拮抗剂,另外33例患者在观察性队列中使用TNF拮抗剂(16例)或常规治疗(17例)。VC脂肪病变定义为T1W MRI骨髓中信号增强,CIL定义为STIR MRI信号增强。一个国际MRI工作组通过电视会议对MRI进行会诊,一致确定VC脂肪病变和CIL。采用两分法(有/无)记录C2至骶椎的VC脂肪病变和CIL。2名阅片者进行独立盲态评估。根据基线期MRI是否存在CIL,及其在随访MRI中持续存在或消退,比较新发VC脂肪病变的产生情况。同时检测治疗对基线期VC脂肪病变的影响。采用Fisher精确检验进行比较。
结果: 在TNF拮抗剂治疗组,与基线期MRI无炎症的VC相比,有炎症的VC更常出现新发VC脂肪病变(32/83 (38.6%) vs 69/2647 (2.6%),p<0.0001)。这种差异在常规治疗组中并不明显。在TNF拮抗剂治疗组,与持续存在或无CIL的VC相比,CIL消退的VC更常出现新发脂肪病变(p<0.0001)。这种差异在常规治疗组中同样不明显。与常规治疗相比,TNF拮抗剂治疗后基线期存在的VC脂肪病变更常消退(47/247 (16%) vs 5/94 (5.1%), p = 0.005)。
表
新发VC脂肪病变的数目(百分比)
|
治疗
|
CIL
消退
|
CIL
持续
存在
|
无CIL
|
VC脂肪变+
|
抗TNF
|
16
(20.8)
|
1
(5.0)
|
41
(1.3)
|
VC脂肪变-
|
抗TNF
|
61
(79.2)
|
19
(95.0)
|
2578
(98.7)
|
VC脂肪变+
|
传统治疗
|
1
(11.1)
|
0
|
8
(0.7)
|
VC脂肪变-
|
传统治疗
|
8
(88.9)
|
5
(100)
|
1153
(99.3)
|
结论: 新发VC脂肪病变更常发生于之前存在炎症的部位,特别是在TNF拮抗剂使炎症消退后。已有VC脂肪病变可能被TNF拮抗剂清除。
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