布氏杆菌性脊柱炎的MRI、CT表现
2016-11-28杨军妍丁世斌宋继业
张 鹏,杨军妍,丁世斌,宋继业
(沈阳市第六人民医院放射科,辽宁 沈阳 110006)
◁肌肉骨骼影像学▷
布氏杆菌性脊柱炎的MRI、CT表现
张 鹏,杨军妍,丁世斌,宋继业
(沈阳市第六人民医院放射科,辽宁 沈阳 110006)
目的:探讨布氏杆菌性脊柱炎的MRI及CT表现,以提高该病的诊断水平。方法:回顾性分析已确诊的43例布氏杆菌性脊柱炎的MRI及CT表现。结果:①43例行MRI扫描,检出椎体炎32例,表现为椎体内大片状异常信号影24例,8例椎体边缘小斑片影;椎间盘炎及终板炎10例;2例骶髂关节面异常信号;23例合并有椎旁受累。②19例行CT检查,其中椎体破坏11例,表现为椎体周缘小破坏灶、边角缺如、大片状缺损等,病灶周边增生硬化;椎间盘炎伴膨出8例;合并椎小关节面增生硬化4例,骶髂关节炎1例。③累及单个椎体5例(11.6%),2个及2个以上椎体受累30例(69.8%);腰椎病变32例,以L4、L5椎体发病率最高(53.1%)。结论:布氏杆菌感染致脊柱炎有较为特征的CT及MRI表现,对于侵及椎体的早期病变,MRI检出率优于CT。
脊柱炎;磁共振成像;体层摄影术,X线计算机
布氏杆菌病是布氏杆菌引起的人畜共患的传染的变态反应性疾病。近些年,我国布氏杆菌病疫情呈上升趋势,该病常侵袭骨关节系统,脊椎受累引起脊柱炎[1],患者被迫处于固定体位,临床极易误诊为脊柱结核及其他疾病而延误治疗时机。熟悉布氏杆菌病的流行病学特点和脊柱炎的影像学改变,对该病的早期诊断和治疗具有重要的意义。本文回顾性分析43例布氏杆菌病合并脊柱炎的CT、MRI表现,并加以总结,旨在提高对改病的认识。
1 资料和方法
1.1 一般资料
收集本院2012年6月—2014年10月间就诊的布氏杆菌病患者43例,男34例,女9例,年龄18~76岁,中位年龄53岁。大部分患者居住在农村、牧区,均有不同程度的牛、羊接触史或未经消毒、灭菌的乳品及食用涮牛羊肉史。所有病例均有不同程度的间断发热、多汗、乏力、脊柱疼,病史半个月至半年不等,5例压迫脊髓一侧或双侧下肢麻木或疼痛,1例形成顽固性神经根痛。
1.2 实验室检查
本组43例患者布氏杆菌血清凝集试验均呈阳性,滴度>1∶160,血培养布氏杆菌均呈阳性。其中12例穿刺活检由病理确诊。
1.3 仪器及扫描方法
43例全部行MRI扫描,采用GE 0.5T磁共振扫描仪,使用颈部、腰部、盆腔线圈,采用SE及FSE序列,常规行矢状位、轴位扫描,33例加用压脂序列。扫描参数:T1WI,TR 500ms,TE 20ms;T2WI,TR 4 000ms,TE 150ms,层厚5mm,层距5mm,14例行增强扫描,对比剂采用Gd-DTPA,按0.2mmol/kg给药。
19例行CT检查,采用GE Lightspeed 16 CT扫描机,层厚1.25mm×16mm,层间隔1.0mm,螺距1.375,管电压140 kV,电流250mA。
2 结果
2.1 病变部位
43例布氏杆菌性脊柱炎中,累及单个椎体5例(11.6%,5/43),2个及 2个以上椎体受累 30例(69.8%,30/43),其中颈椎病变6例,胸椎4例,骶髂关节2例,腰椎病变32例(1例为腰椎、骶髂关节同时受累),腰椎L4、L5椎体受累最多(53.1%,17/32),合并椎旁及椎管内软组织影23例。
2.2 CT表现
19例CT检查者中,4例CT检查无明显异常,其余病例伴有不同程度骨质增生,合并椎体周缘多发小破坏灶6例(图1,2),周围多伴有增生硬化;椎体膨胀或大片状缺损2例;椎体边角缺如3例;椎间盘炎变、膨出8例,其中椎间隙变窄、相邻椎体骨密度增高3例;合并椎小关节面增生硬化4例,5例脊柱旁可见软组织密度影,1例骶髂关节面增生硬化。
图1,2 布氏杆菌性脊柱炎。图1a~1d:L2~L3病灶。图1a,1b:轴位CT示椎体破坏呈多灶性、边缘型、虫蚀样改变(箭),椎体缘骨质增生硬化(箭头);图1c,1d:MRI矢状位示病变椎体T1呈低信号,T2呈高信号(箭),椎间隙无明显狭窄。图2a~2f:L3~L5病灶。图2a,2b:腰椎侧位像及CT重建显示椎体无明显变形,L3~L4椎间隙轻度变窄,L4椎体前缘角缺如(箭),椎体边缘新生骨赘,似“花边椎”;图2c:CT轴位示椎体局灶性骨质破坏并增生硬化(箭);图2d,2e:MRI矢状位示病灶T2呈等、高混杂信号,T1呈低信号,椎体相邻终板骨质破坏(箭),椎体前软组织影T2呈高信号、T1呈低信号(箭头);图2f:T1增强示病变椎体明显较均匀强化,椎体前缘脓肿腔形成,椎前韧带受侵。
Figure 1,2. Brucellar spondylitis.Figure 1a~1d:L2~L3lesions.Figure 1a,1b:Axial CT shows that vertebral destruction were multifocal,edge type,Insect alteration(arrow),vertebral body bone hyperplasia sclerosis(arrowhead).Figure 1c,1d:Sagittal T1-weighted image shows low signal and T2-weighted image shows high signal of involved L2~L3vertebral bodies(arrow),without obvious stenosis of intervertebral space.Figure 2a~2f:L3~L5lesions.Figure 2a,2b:Lumbar lateral radiography and CT reconstruction show no significant changes in vertebral body, the intervertebral space of L3~L4is slightly narrowed,L4vertebral angle is absent(arrow),with vertebral osteophyte,like“vertebral lace”.Figure 2c:Axial CT of the vertebral body with focal bone destruction and proliferation and sclerosis(arrow).Figure 2d,2e:MRI sagittal position shows that the lesions were hypointense on T1WI and mixed signal of hyperintensity on T2WI,adjacent end plate bone was destruction(arrow), anterior vertebral body soft tissue was low signal on T1WI and high on T2WI(arrowhead).Figure 2f:T1enhancement shows that the lesions were significantly enhanced,and the anterior vertebral body abscess cavity was formed,and the prevertebral ligament was invaded.
2.3 MRI表现
43例MRI检查者中,24例椎体(累及2个或2个以上)呈片状异常信号,其中T1呈低信号,T2及压脂序列呈高信号12例(图1),T2呈混杂高信号8例(图2),4例呈长T1、等T2信号;8例椎体边缘小斑片影,呈长T1、长T2信号;椎间盘异常信号及合并终板炎10例,其中椎间隙变窄及椎体融合7例,椎间隙正常3例;23例合并椎旁软组织影(图2,3),5例侵入椎管内压迫脊髓(图3,4);2例骶髂关节面异常信号。14例Gd-DTPA增强检查病变椎体、椎间盘及椎旁软组织影呈明显强化(图2,4)。
2.4 布氏杆菌脊柱炎CT及MRI检出率
43例布氏杆菌脊柱炎中,MRI检出 43例(100%,43/43),CT见椎体异常改变15例 (78.9%,15/19)。
3 讨论
布氏杆菌病又称马耳他热、波浪热,是人畜共患的疾病,国内多见于东北和西北牧区,羊是主要传染源,近年来出现上升的趋势。主要有3类人群易感染:在农牧区有病畜接触者;与含菌培养标本接触的实验室工作人员;饮用过未经消毒灭菌达标的乳品或食用过未熟牛羊肉的人群。近年来城市多因进食乳制品或涮羊肉致发病率有所上升,成为食物源性疾病[2]。
布氏杆菌病临床表现为低热、乏力、盗汗、食欲不振、贫血,还伴有其它脏器感染,以呼吸系统和生殖系统感染为主,肝、脾、淋巴结肿大,游走性全身肌肉和大关节痛。布氏杆菌可以侵及脊柱的任何部位,腰椎受侵最常见,慢性患者统计可达76.09%,伴相应神经根放射痛或脊髓受压症状,极少因硬膜外脓肿而致截瘫[3]。临床分期为急性期、亚急性期及慢性期。急性期指患病3月以内,椎体病理改变为以炎性充血水肿为主,呈弥漫性骨髓水肿,含水量增加,进而骨质破坏、坏死,脓液向周围扩散,引起软组织脓肿;亚急性期指患病3月到1年;慢性期指患病1年以上。后两者病理改变为骨破坏与骨修复并存,脓液吸收,组织细胞增生,骨髓内增殖性结节和肉芽肿形成[4]。
布氏杆菌病的主要病理变化为渗出变性坏死改变、增生性改变、肉芽肿形成,肉芽肿进一步发生纤维化,最后造成组织器官硬化[4-5],3种病理改变可循急性期向慢性期依次交替发生和发展。
图3,4 布氏杆菌性脊柱炎。图3a~3f:C3~C4病灶(治疗前后)。图3a,3b:MRI矢状位示病变椎体、椎间盘(箭头)及椎管内硬膜外脓肿(箭)T2呈明显高信号,T1呈低信号;图3c:MRI轴位示软组织影侵入椎管内,形成流注脓肿,硬脊膜囊受压(箭);图3d:CT重建示C3~C4椎体间隙轻度狭窄,椎体无明显破坏、变形;图3e,3f:治疗2月后复查MRI,病变椎体信号减低(箭),脓肿明显吸收。图4a~4d:T11病灶。图4a,4b:MRI矢状位显示病变椎体T1呈低信号,T2呈高信号;图4c:GD-DTPA增强示病变椎体明显较均匀强化(箭);图4d:轴位见椎管内硬膜外软组织肿块,呈明显强化,硬脊膜囊受压移位(箭)。
Figure 3,4. Brucellar spondylitis.Figure 3a~3f:C3~C4lesions(before and after treatment).Figure 3a,3b:Sagittal T2-weighted image reveals significant increase and T1-weighted image reveals decrease of signal intensity of involved C3~C4disc(arrowhead)and adjacent vertebral bodies with epidural abscess(arrow).Figure 3c:Axial MRI shows soft-tissue invading the spinal canal,and forming abscess,dural sac compression(arrow).Figure 3d:CT reconstruction shows that the C3~C4vertebral space was mild stenosis,no obvious damage and deformation of the vertebral body.Figure 3e,3f:Two months after treatment,the signal of involved vertebral column is reduced(arrow)and the abscess is obvious absorbed.Figure 4a~4d:T11lesion.Figure 4a,4b:Sagittal T1-weighted image reveals decrease and T2-weighted image reveals increase of signal intensity.Figure 4c:GD-DTPA enhanced lesions are obviously homogeneous enhancement(arrow).Figure 4d:The axial position shows that the soft tissue mass of the spinal canal was significantly enhanced,with thecal sac compression(arrow).
3.1 CT改变
布氏杆菌病性脊柱炎影像学表现按侵犯部位分为椎体炎和椎间盘炎,当二者同时受累时不能明确区分,以椎体病变为主称椎体炎,以椎间盘受累为主称椎间盘炎,部分侵犯韧带及椎体附件。椎体炎中以腰椎居多,本组病变多累及两个以上椎体,L4、L5椎体受累约占53.1%,与文献报道接近[6-8]。
CT表现为椎体内2~5mm的多发、类圆形破坏灶,椎体中心和边缘均可被侵犯,较大的病灶呈“岛屿状”[5],周边有明显的增生硬化带,新生骨中又见新破坏灶。本组15例中9例分布于椎体边缘,呈虫蚀样骨质破坏,1例较大破坏灶内见小死骨形成,未见明确椎体压缩征象。有4例椎小骨关节面增生硬化,5例椎体边缘形成唇状骨赘,骨桥形成,可能与发病年龄较大及时间较长、炎症反复刺激有关。
3.2 MRI改变
本组T1为低信号、T2加权脂肪抑制像为高信号12例,信号较均匀,对应病理过程基于骨髓的渗出与水肿改变,表明病程处于椎体炎急性期或进展期;有12例表现为不均匀一信号,其中T2呈混杂信号8例,等信号4例,与急性期信号相比T1为更低信号,提示合并骨质增生硬化改变,病程处于亚急性期或慢性期。
3.3 CT与MRI比较
椎间盘病变及椎旁软组织影显示上,MRI较CT有优势。前者表现为椎间隙明显变窄,椎间盘呈长T1、长T2信号,部分相邻椎体有融合趋势,表明处于椎间盘炎晚期。本组有23例病变侵及椎旁,MRI表现为梭形或条状异常信号,位于椎体前方、两侧及后方,呈中等T1、T2混杂高信号,增强后病变边缘不均匀强化,6例见脓腔形成,5例重症者形成流注脓肿,侵犯椎管内成硬膜外脓肿。
在检出率方面,以椎体病变为主,MRI可发现骨质破坏前的早期感染及骨髓水肿,同时能良好显示骨髓腔受累范围,对脓肿的部位和大小及伸向软组织内的窦道在T2WI上清晰可见,有利于指导手术,明显优于普通X线及CT检查。MRI显示骨质硬化、骨赘和骨桥形成等表现信号混杂,不如CT显示清晰。与Arkun等[9]报道椎旁韧带钙化不同,本组病例无明显钙化,也可能与CT组病例较少有关。对于MRI及CT影像特征改变没有相关统计学分析,有待于进一步研究。本组8例患者临床症状轻,发病缓慢,多无明显全身中毒症状,CT及MRI仅于椎体边缘见轻微的骨质破坏,因椎体骨髓脂肪使得感染容易局限,不易扩散[10],此类患者临床预后较好。由此可见影像学检查为临床治疗及预后可提供有价值的信息。
3.4 鉴别诊断
布氏杆菌侵及脊柱的影像表现需要与脊柱结核鉴别,两者共同点是受累椎体破坏,椎间隙变窄或消失,可形成椎旁脓肿,特别在病变早期很难鉴别。但两者也有不同之处,布氏杆菌性脊柱炎骨质破坏进展迅速,骨质增生出现早,脊椎结核牵涉胸腰段和更多椎体,椎体变形明显,可见到沙粒样死骨,呈“跳跃性”侵犯,脓肿壁薄而光滑,明显强化、界限清楚[11-12]。本病还需与强直性脊柱炎鉴别,强直性脊柱炎亦可出现椎体前角骨质侵蚀,椎体边缘硬化,小关节模糊或关节间隙消失,椎体边缘的韧带出现钙化,但椎管内异常信号往往不明显,间盘不受累,椎旁多无脓肿形成。
总之,布氏杆菌性脊柱炎的CT影像特征改变为相邻椎体局灶性边缘性骨质破坏,椎体破坏同时伴有明显的骨质增生硬化,呈“花边椎”,无脊柱畸形。MRI能更早发现脊椎的异常变化,脊椎炎急性期T1加权像呈低信号,T2呈高信号,亚急性期及慢性期受侵椎体在T1和T2加权像上表现为不均一信号,与急性期相比T1信号增强。MRI还能清晰显示椎旁软组织异常信号。布氏杆菌性脊柱炎临床中经常有误诊漏诊现象,加强对布氏杆菌性脊柱炎的CT 及MRI影像学改变的认识,同时结合病史、地域特点,进行必要的实验室检查,从而不断提高对该病诊断的准确性。
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MRI and CT findings of brucellar spondylitis
ZHANG Peng,YANG Jun-yan,DING Shi-bin,SONG Ji-ye
(Department of Radiology,the Sixth Hospital of Shenyang,Shenyang 110006,China)
Objective:To study MRI and CT findings of brucellar spondylitis caused and to improve lever of the clinical diagnosis.Methods:We analyzed CT and MRI findings of 43 patients with brucellar spondylitis retrospectively.Results:①Forty-three patients underwent routine MRI scan.There were 32 cases of vertebral bodies,a large patch of abnormal signal of vertebral body shadow 24 cases,8 cases of vertebral body margin small patch shadow;Intervertebral disc inflammation and endplate inflammation in 10 cases;2 cases of sacroiliac joint surface anomaly signal;23 lesion beside of vertebral body.②Ninteen patients underwent CT examination,including vertebral body destruction in 11 cases,vertebral peripheral small focal damage,a large patch of defects,edge horn were absent,hyperplasia of lesions around the hardening;Intervertebral disc inflammation and bulging with 8 cases;4 cases merge vertebral hyperplasia of small joint surface hardening,1 case of sacroiliac arthritis.③Five cases involved one vertebral body(11.6%),two or more vertebral bodies involved in 30 cases(69.8%),32 cases in the lumbar spine,L4,L5vertebral rate was highest(53.1%).Conclusion:CT and MRI findings in brucellar spondylitis are characteristic.Comparing to CT,detectable rate of MRI is higher,especially in early stage of cases with vertebral body affected.
Spondylitis;Magnetic resonance imaging;Tomography,X-ray computed
R681.51;R445.2;R814.42
A
1008-1062(2016)04-0278-04
2015-09-10
张鹏(1981-),男,辽宁沈阳人,主治医师。E-mail:zp1106@sina.com
杨军妍,沈阳市第六人民医院放射科,110006。E-mail:yang.jyan@163.com