脊柱结核磁共振成像增强扫描的意义

陆通，何花，张琴，续梦玲，杨虹，郭玉林*

脊柱结核磁共振成像增强扫描的意义

陆通1，何花2，张琴1，续梦玲1，杨虹1，郭玉林2*

目的通过分析脊柱结核的磁共振成像(magnetic resonance imaging，MRI)影像表现，提高对脊柱结核的诊断、认识。材料与方法回顾性分析经活检和手术病理检查证实的57例脊柱结核患者的MRI影像资料，分析脊柱结核MRI平扫及增强扫描影像表现。结果57例患者中颈椎结核5例、胸椎结核12例、腰椎结核24例，颈椎合并胸椎3例，胸椎合并腰椎8例，腰椎合并骶椎5例。单椎体受累2例，相邻2个椎体受累41例，3个及3个以上椎体受累14例。43例椎间隙狭窄或消失，40例脓肿形成。增强扫描41例病灶区域明显强化，16例弱强化或无强化。57例患者均接受1～3月不等强化多联抗结核化疗治疗。15例患者术前多次行MR增强扫描检查，12例患者影像学表现不同程度好转，3例无明显变化。结论MRI增强扫描对早期诊断脊柱结核及指导临床治疗有着重要的应用价值。

结核，脊柱；磁共振成像；影像表现

脊柱结核是肺外骨关节结核中最常见的类型。近年来由于耐药、多重耐药结核菌菌株的逐渐增多，给治疗带来了很大困难[1]。患者表现出病程较长，临床症状较重、就诊较晚、椎体破坏明显的特点，给患者及其家庭带来了较大的痛苦和沉重的经济负担。手术是目前治疗脊柱结核的主要手段。尽早治疗能给患者带来较大获益，因此早期诊断脊柱结核对治疗至关重要。笔者回顾性分析了57例经活检和手术病理检查证实的脊柱结核患者的磁共振成像(magnetic resonance imaging，MRI)平扫及增强扫描影像资料，探讨MRI增强扫描检查在脊柱结核诊断中的价值，旨在提高对脊柱结核的诊断认识，为临床治疗、评估提供可靠依据。

1 材料与方法

1.1 临床资料

收集我院2015年1月至2016年5月经活检、手术证实为脊柱结核的57例患者。其中，男性30例，女27例，年龄8～68岁，平均(39.1±24.6)岁。入组标准：(1)经平片、CT、临床诊断为脊柱结核；(2)患者临床资料完整；(3)接受脊柱结核手术治疗或活检患者。排除标准：(1)患者配合欠佳，图像不清晰影响诊断者；(2)无完整病理结果者。患者临床主要表现为病变部位疼痛如颈部、腰背部及腰骶部疼痛；结核中毒症状：低热、乏力、午后盗汗、体重下降；脊髓或神经受压症状：腰疼、下肢放射性疼痛等。

1.2 检查方法与设备

本研究采用Philips Achiva 1.5 T超导型磁共振扫描仪。颈椎采用表面线圈，胸、腰段采用脊柱专用线圈。扫描序列：TSE序列T1WI (TR 450 ms，TE 15 ms)、TSE序列T2WI (TR 3500 ms，TE 120 ms)和抑脂T2WI (TR 3000 ms，TE 100 ms)，层厚3～4 mm，层间距1 mm。增强扫描：对比剂采用钆双胺注射液，注射剂量15 ml，流率2 ml/s。经肘静脉注射后行轴位、矢状位、冠状位T1WI扫描。

1.3 图像分析

图像处理采用GE公司SUN Workstation 4.3工作站的Functool 5.4.07软件。

2 结果

本组研究中脊柱结核MRI表现如下：(1)椎体及附件骨质破坏：57例患者均有不同程度椎体骨质，MRI增强扫描41例骨质破坏区明显强化，11例强化不明显，5例无强化。多数病变椎体增强后呈明显强化，信号不均匀，病变边缘信号更高，与正常椎体分界较清晰(图1、2)。(2)椎间盘表现：57例患者中43例椎间隙狭窄或消失。39例椎间盘受累，间盘正常形态消失变扁，边缘模糊，MRI表现为T1WI低信号，T2WI呈高信号或者混杂信号，增强扫描呈不均匀强化。椎间盘完全破坏时常与病变椎体界限不清，受累椎间盘内常伴有小脓肿形成。(3)寒性脓肿形成表现：40例脓肿形成，MRI表现为T1WI呈低信号，T2WI呈高信号，大多数脓肿范围较广，跨越多个椎体，脓肿与周围组织边界较清楚，少数边界不清。椎前和后纵韧带下脓肿冠状位、矢状位呈“哑铃状”。增强扫描呈明显环形或多房形强化，囊壁强化明显，囊内信号大多均匀、无强化(图3～5)。(4)15例患者治疗前后行MR增强扫描检查，12例患者病变强化程度、范围、水肿较前减弱(图6、7)，3例无明显变化。

3 讨论

脊柱结核是最常见的脊柱感染性病变，胸腰椎交界附近是脊柱结核好发部位。脊柱结核一般为结核杆菌由肺部病灶通过血行播散而借机会感染[2-3]。脊柱结核多椎体的前中部受累，这可能与椎体血液微循环系统有关[4]。椎体前中部、终板是微循环的终末血管，结核细菌容易在此处停留、繁殖，因而是脊柱结核的好发部位[5]。脊柱结核早期多数患者往往无任何临床症状，X线及CT常无阳性发现。MRI对水含量、蛋白及脂肪等成分变化非常敏感，可以发现脊柱结核早期病灶，增强扫描对病变范围、病变成分显示更清晰。

3.1 MR增强扫描对病变范围显示

典型的脊柱结核主要表现为相邻椎体骨质破坏、椎间隙变窄、椎间盘受累破坏及椎旁脓肿形成。结核病灶的确定主要有两条途径：一是CT与MRI等影像学检查；二是术中肉眼观察[6]。术前评估病灶主要依赖影像学检查，主要是CT和MRI检查，MR增强扫描可清晰显示脊柱结核病变范围。椎体的骨质破坏最常见的表现为病变累及2个或2个以上椎体，以靠近椎体上下缘为主，多呈溶骨性破坏，表现为“吻型”破坏。在T2WI由于病变椎体骨髓炎性水肿，椎体内含水成分增加，表现出高信号，信号往往不均匀。病变早期无干酪样坏死、钙化、死骨等改变时增强扫描多均匀强化，合并上述改变时强化往往不均匀[7]。椎体骨质破坏明显时，大多同时伴有椎体的塌陷、成角畸形，椎体塌陷成角与骨质破坏程度有关。明显的塌陷、成角畸形可压迫硬膜囊甚至脊髓引起腰疼、腿疼、腿麻等神经压迫症状。MR表现为局部突向椎管T1WI低信号，T2WI不均匀混杂高信号影。增强扫描后多呈不均匀强化，合并脊髓压迫时可有脊髓水肿。脊柱结核多伴椎间隙变窄、间盘破坏，MR表现为T1WI低信号，T2WI多为不均匀混杂高信号，病变间盘与相邻椎体界限模糊，增强扫描多呈不均匀强化。脊柱结核椎旁寒性脓肿是本病的特征性改变，椎旁脓肿多呈弧形，跨越相邻2个或多个椎体。腰大肌脓肿多呈梭形或哑铃形，部分脓肿内可见多房分隔。MR多表现T1WI等低信号，T2WI不均匀高信号或高低混杂信号，边界较清楚，增强扫描多呈环状强化，囊内成分信号往往均匀，无明显强化。椎旁软组织受累表现为软组织水肿、炎症表现，多累及椎体周围常沿韧带下及硬膜外扩散，MR表现为T2信号增高、信号欠均匀，增强扫描病变边界显示更加清晰。

3.2 MR增强扫描对结核病变成分的显示

图1 、2 患者，男性，64岁，术后病理证实为胸椎结核。图1 T1增强矢状位示：胸11～12椎体骨质“吻型”破坏，椎体明显不均匀强化，骨质破坏边缘呈明显线样强化(箭示)；图2 T1冠状位示：椎体两侧见弧形肉芽肿形成(箭示) 图3～5 患者，男性，54岁，术后病理证实为颈椎结核。图3 T1WI：颈2～3椎体形态正常，局部不均匀低信号。椎体前方、椎管内见弧形低信号脓肿影，椎管继发狭窄，脊髓受压(箭示)；图4 T2WI：颈2～3椎体不均匀稍高信号。椎体前方见均匀高信号脓肿影，椎管内脓肿信号不均(箭示)；图5 T1增强：颈2～3椎体明显不均匀强化，椎前及椎管内脓肿壁明显强化，脓液无强化(箭示) 图6、7 患者，男性，56岁，术后病理证实为胸椎结核，患者术前接受1个月抗结核治疗。轴位T1增强示椎体前方脓肿壁强化较前减弱，周围软组织水肿减轻(箭示)(图6为治疗前，图7为治疗后)Fig. 1, 2 Patient, male, 64-year-old, proved to be thoracic tuberculosis after surgery. Fig.1 T1 enhanced sagittal displayed that the thoracic 11-12 vertebral body bone "kiss type" damage, the vertebral body was obviously uneven strengthen, bone destruction edge showed a line-like enhancement (arrow); Fig.2 Coronal showed arcuate granuloma formation on both sides of the vertebral body (arrow). Fig.3—5 Patient, male,54-year-old, proved to be cervical tuberculosis after surgery. Fig.3 T1WI: Cervical 2-3 vertebral morphology normal, local uneven low signal.In the vertebral body, in the spinal canal, there were signs of low signal abscess, spinal canal stenosis and spinal cord compression (arrow);Fig.4 T2WI: Cervical 2-3 vertebral body slightly uneven high signal. In the anterior part of the vertebral body, there was a uniform high signal sign of the abscess (arrow); Fig.5 T1 enhancement: Cervical 2-3 vertebral body was obviously uneven enhancement, vertebral and spinal abscess wall was significantly enhanced, pus without reinforcement (arrow). Fig. 6, 7 Patient, male, 56-year-old, confirmed by pathology after surgery for thoracic tuberculosis and received preoperative anti-tuberculosis treatment for one month. The enhancement of T1 in the anterior wall of the vertebral body was weaker than before,and the surrounding soft tissue edema was reduced (arrow) (before treatment in Fig.6, after treatment in Fig.7).

脊柱结核病程长，病变成分变化复杂。MR对软组织显示优势明显，对结核病变成分显示亦有价值。(1)对干酪样坏死物质与寒性脓肿显示与区别：干酪样坏死物质成分复杂，MR表现T1WI多呈低信号，T2WI不均匀高信号或高低混杂信号。因干酪样坏死物质富含脂质成分，在压脂序列上相应高信号会表现为低信号。寒性脓肿边界往往较清楚，脓肿壁信号较高，脓液信号均匀。寒性脓肿常由干酪样坏死物质液化形成[8]，因此寒性脓肿可以认为是干酪样坏死物质进一步发展。MRI对液性成分的变化非常敏感，T2WI呈明显高信号，因而寒性脓肿信号更高、更均匀。当然同一患者干酪样坏死物质与寒性脓肿两种病理表现可同时存在。(2)对钙化、死骨的显示：MR对钙化不敏感，T1WI及T2WI均表现为低信号，增强扫描无强化。死骨在MR表现为T1WI及T2WI低信号，信号均匀，但是死骨周围T2WI表现为不均匀较高信号，增强扫描死骨不强化，而周围组织多有强化。钙化、死骨在MR表现上非常相似，二者常难以鉴别。CT在钙化与死骨显示上有优势，二者均呈高密度，但是钙化密度往往更高，因而MR平扫、增强扫描、CT三者结合起来可以加以区别[9]。(3)对结核肉芽肿的显示：结核肉芽肿中纤维肉芽组织增生，MR表现为T1WI呈低信号，T2WI呈高信号，T1WI增强扫描后增生肉芽组织边缘呈不均匀强化[8]。结核病灶往往出现干酪样坏死物质、钙化、死骨、结核肉芽肿、脓肿多种病理成分同时存在，造成MR信号表现多样、复杂。

3.3 MR增强扫描对结核病变活动期判断、评估

脊柱结核活动期临床常表现为：结核中毒症状如低热、乏力、盗汗等；贫血症状、血沉升高等。大部分脊柱结核患者术前需接受1个月左右抗结核化疗治疗。当临床症状缓解，贫血状况好转、血沉恢复正常，无明显手术禁忌后行手术治疗[10]。本组研究中40例患者均接受1～3个月不等强化多联抗结核化疗治疗。所有患者经强化抗结核化疗之后临床症状减轻或消失，血沉等实验室检查指标好转或恢复正常后接受手术治疗。其中有15例患者治疗前后行MR增强扫描检查，比较前后影像表现发现：椎体骨质破坏、脓肿强化程度、范围、周围组织炎性水肿与结核活动期临床表现及实验室化验检查存在一定关联。临床症状较重、血沉等化验检查高者病变椎体数量多，骨质破坏更加明显，寒性脓肿往往更大。增强扫描强化程度更明显、范围往往也较大。经强化抗结核化疗之后，12例患者影像学表现不同程度好转，3例无明显变化。MR影像表现上：(1)病变椎体骨髓水肿、范围均有不同程度缩小；病变椎体骨质破坏边缘T2WI较高信号减低；寒性脓肿壁T2WI信号减低，脓肿内病变信号较治疗表现趋于均匀；所有患者周围组织炎性水肿明显缩小，部分患者周围肌肉组织炎性水肿消失。(2)增强扫描病变椎体骨髓水肿、范围缩小较平扫更明显；病变椎体骨质破坏区强化程度均有不同程度降低；寒性脓肿壁强化边界更清晰，周围炎性反应减轻。患者临床表现、实验室检查与影像学表现相符合。临床症状减轻、实验室检查、影像学表现好转往往提示患者已经不在结核活动期，可根据临床评估无手术禁忌证可行手术治疗。

综上所述，MRI对蛋白、水含量、脂质等成分显示良好[11]，对检出早期无症状X线、CT检查阴性的早期脊柱结核患者意义重大。MRI矢状位、冠状位对病变的累及范围、椎管内侵犯、脊髓压迫情况有较大帮助[12-13]。增强扫描对脊柱结核病变受侵范围显示、结核病变成分显示与区别、病变活动期判断均有重要价值。同一患者多次MR椎体增强扫描检查前后对照比较对于结核病变活动期判断、结核化疗效果评估具有非常重要的价值。本组研究中脊柱结核患者抗结核治疗化疗中多次接受MR椎体增强扫描进行前后对比病例数尚较少，因而MR椎体增强扫描对结核活动期判断、化疗效果评估需加大病例数进一步研究、探讨。

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The significance of MRI enhanced scan in the spinal tuberculosis

LU Tong1, HE Hua2, ZHANG Qin1, XU Meng-ling1, YANG Hong1, GUO Yu-lin2*1School of Clinical Medicine, Ningxia Medical University, Yinchuan 750004, China
2Department of Radiology, General Hospital of Ningxia Medical University, Yinchuan 750004, China

Objective:To improve the diagnosis of spinal tuberculosis by analyzing the MRI imaging findings of spinal tuberculosis.Materials and Methods:MRI imaging data of 57 patients with spinal tuberculosis confirmed by biopsy and surgery and pathology were analyzed retrospectively. The findings of MRI plain scan and enhanced scan images of spinal tuberculosis were analyzed.Results:Fifty-seven cases of cervical tuberculosis in 5 cases, 12 cases of thoracic tuberculosis, 24 cases of lumbar spine tuberculosis. Cervical vertebrae complicating thoracic vertebrae were 3 cases. Thoracic vertebrae complicating lumbar were 8 cases. Lumbar complicating sacral vertebrae were 5 cases. Only one vertebrae was involved in 2 cases, two vertebraes were involved in 41 cases, more than three vertebraes were involved in 14 cases. There were stenosis or disappearance of intervertebral space in 43 cases and 40 cases had cold abscess. There were obviously enhanced in 41 cases and weak or no enhanced in 16 cases by MR enhanced scan. 57 patients were treated with 1-3 months by the combination of multiple anti-tuberculosis chemotherapy. MR scan was performed more than 2 times in 15 patients before operation. 12 patients' imaging performances were better than that of anti-tuberculosis chemotherapy and 3 cases were not.Conclusion:MRI enhanced scan has important application value in diagnosis and treatment of spinal tuberculosis.

Tuberculosis, spinal; Magnetic resonance imaging; Imaging performance

21 Dec 2016, Accepted 21 Feb 2017

作者单位：
1.宁夏医科大学临床医学院，银川750004
2.宁夏医科大学总医院放射科，银川750004

郭玉林，E-mail：guoyulin66@163.com

2016-12-21

接受日期：2017-02-21

R445.2；R681.5

A

10.12015/issn.1674-8034.2017.06.007

陆通, 何花, 张琴, 等. 脊柱结核磁共振成像增强扫描的意义. 磁共振成像,2017, 8(6): 436-440.

*Correspondence to: GuoYL, E-mail:guoyulin66@163.com