颞下颌关节髁突囊样变的多模态影像学分析

Multimodal imaging analysis of the cyst like lesion of condyle in temporomandibular joint

目的分析颞下颌关节髁突囊样变的锥形束CT、螺旋CT、MRI及核素骨显像影像学特点,为其诊疗提供影像学依据。方法回顾性纳入2018年1月至2020年12月就诊于解放军总医院口腔颌面外科,经锥形束CT影像检查发现髁突囊样变并进行螺旋CT、MRI检查和核素骨显像的患者32例,其中男性12例,女性20例,年龄(33.9±12.5)岁(16~65岁)。分析髁突囊样变在锥形束CT、螺旋CT、MRI影像及核素骨显像的特点,根据囊样变表面骨质是否有缺损,分为A型和B型;根据囊样变是否伴髁突骨髓水肿样病变(bone marrow edema-like lesions,BML)分为Ⅰ型(有)和Ⅱ型(无)。分析BML、关节盘移位及骨代谢异常的发生率及与囊样变的关系。结果32例患者的64侧关节影像中34侧有髁突囊样变,6侧为多发,共42处。囊样变最大径为(3.7±1.8)mm,范围为1.0~12.4 mm;A型囊样变24侧,B型囊样变10侧。锥形束CT检出率[95.2%(40/42)]与螺旋CT检出率[100%(42/42)]的差异无统计学意义(校正χ^(2)=0.51,P=0.474)。MRI检出率为80.1%(34/42),其中对2 mm以下的囊样变检出率为3/11。囊样变侧与无囊样变侧颞下颌关节的关节盘移位情况差异有统计学意义(χ^(2)=7.80,P=0.005)。MRI显示囊样变侧[17.6%(6/34)]与无囊样变侧[3.3%(1/30)]伴有BML的差异无统计学意义(校正χ^(2)=2.04,P=0.153);但A型囊样变中Ⅰ型占比[25.0%(6/24)]与B型囊样变中Ⅰ型占比(0/10)的差异有统计学意义(P=0.024)。核素骨显像显示髁突囊样变侧26侧骨代谢浓聚,无囊样变侧5侧骨代谢浓聚,分布差异有统计学意义(χ^(2)=22.82,P<0.001)。结论多排螺旋CT可早期发现颞下颌关节髁突囊样变,髁突囊样变的影像学表现与大关节有所不同,其形成机制可能并非单一的机制,根据其病变分型其形成机制可能有所不同。

Objective To investigate the imaging features of condylar cystic degeneration of temporomandibular joint(TMJ)by cone-beam CT(CBCT),spiral CT,MRI and radionuclide bone imaging.Methods From January 2018 to December 2020,thirty-two patients with cyst-like lesions of condylein temporomandibular joint were examined by CBCT,spiral CT,MRI and radionuclide bone imaging at the Department of Oral and Maxillofacial Surgery in General Hospital of Chinese PLA.There were 12 males and 20 females involved,aged from 16 to 65 years with an average age of(33.9±12.5)years.The characteristics of CBCT,spiral CT,MRI and radionuclide bone imaging were analyzed.Condylar cyst like lesions were classified as type A and type B based on the presence or absence of surface bone defects.Condylar cyst like lesions were classified as typeⅠ(yes)and typeⅡ(no)according to the accompanying bone marrow edema-like lesions of the condyles.The incidence of condylar bone marrow edema,disc displacement and abnormal bone metabolism were analyzed.Results A total of 64 joint images of 32 patients were included,including 34 sides with TMJ cyst-like lesion and 6 sides with multiple cyst-like lesions,the total cyst-like lesions were 42.The largest diameter of cyst-like lesion ranged from 1.0 to 12.4 mm,with an average length of(3.7±1.8)mm.There were 24 cases of type A TMJ cyst like lesion and 10 cases of type B cyst-like lesion.The detection rate of CBCT was 95.2%(40/42)and that of spiral CT was 100%(42/42),there was no significant difference(Calibration Chi-square=0.51,P=0.474).The detection rate of nuclear magnetic resonance was 80.1%(34/42),and the detection rate of cyst-like lesions less than 2 mm was 3/11.In the cyst like lesion side,there were 9 sides with anterior disc displacement with reduction,20 sides with anterior disc displacement without reduction.In the non-cyst like lesion side,10 sides with anterior disc displacement with reduction and 6 sides with anterior disc displacement without reduction.There was a significant difference in the displacement of the disc between cyst-like and non-cystic lesion side(χ^(2)=7.80,P=0.005).MRI showed that 6 cases of cystic side[17.6%(6/34)]had bone marrow edema-like lesions(all type A),1 case of non-cyst like lesions side[3.3%(1/30)]had bone marrow edema-like lesion,there was no significant difference between cystic and non-cystic lesions(Calibration Chi-square=2.04,P=0.153).There was a significant difference between type A and B cystic lesions(Fisher exact probability method,P=0.024).Radionuclide bone imaging showed abnormal bone metabolism in 26 patients in the cyst-like lesion side and 5 patients in the non-cyst like lesion side(χ^(2)=22.82,P<0.001).Conclusions Multi-slice Spiral CT could detect the cyst-like lesion of TMJ condyle in the early stage,which is different from the large joint.And the formation mechanism may vary from the different classifications.