甲状腺结节的血管化特征与微血管密度的相关性及其临床意义
吕秀芳1,王延海2,孙丹立3,孙秋艳4
1丹东国际旅行卫生保健中心 2中国医科大学附属盛京医院
3丹东疾控中心慢病所 4 丹东市第一医院
(摘 要)
目的:观察不同性质的甲状腺结节的血管化特征及其微血管密度变化,进而探讨其鉴别结节良恶性质的可行性。
方法:回顾分析了我院经手术病理证实的112例患者,共计128个结节,其中男性49例共计51个结节,女性63例共计77个结节。观察结节的大小、纵横比值、形态、边界、内部回声、有无钙化等二维形态特征。采用半定量的方法对病灶内部的彩色多普勒血流信号的数量予以分级,对病灶内部血流分布予以分型。采用免疫细胞化学方法以CD34标记病灶内部的微血管内皮细胞,并半定量方法计算微血管的密度。
结果:所有128个结节中病理恶性的结节81例,病理非恶性的结节47例。病理恶性与非恶性结节在低回声、不规则形态、不清晰的边界、纵横比≥1、是否有微小钙化等超声声像图特征方面均有显著差异。甲状腺结节内部血流信号的分级显示,约78.12%是相对多血供的,21.88%的结节为少血供的。多血供的结节中恶性结节占64%,良性结节占36%。病理恶性的病灶中,约52.3%呈现病灶中心型或周边环绕的血管分布,约10.9%呈现为病灶内无血管;在病理非恶性的结节中,29.7%呈现病灶中心型或周边环绕的血管分布,约7.0%呈现为病灶内无血管。病理恶性的病灶内部MVD值显著低于病理非恶性病灶内部的MVD值,差异非常显著。
结论:甲状腺结节的低回声、边界不清晰及微小钙化在鉴别病理恶性结节中拥有较好的敏感性与较高的特异性。结节中心部位的血流增多是值得关注的声像图特征,但不能作为鉴别诊断的关键性依据。结节内部新生微血管的密度与彩色多普勒的血流分级或分型之间存在不一致的现象,其机理尚待进一步研究。
关键词:甲状腺癌,结节,彩色多普勒,微血管密度
Relationship and its Clinical Significance of Nodular Vascularity
and MVD in the Thyroid Gland
Abstract
Objective It was designed to investigate the possibility of differentiating thyroid nodular malignacy, through observation on its changes of intra-vascularity and microvessel density.
Methods Altogether 112 patients with 128 thyroid nodules, which were confirmed by operation and pathology, were retrospectively analyzed. Among these patients, there were 49 males with 51 nodules and 63 females with 77 nodules. Two dimentional features about the nodular size, aspect ratio, shape, boundary, inner echogenicity and microcalcifications were carefully observed and measured. Color Doppler flow imaging (CDFI) signals inside the nodular lesions were graded semi-quantitatively, and the distribution of CDFI signals were classified as graded types. Moreover, the value of microvessel density (MVD) was semi-quantitatively measured and calculated through microvessel endothelium labelled by immunocytochemical method with CD34.
Results Of all these 128 nodules, there were 81 nodules proved to be patological malignacy, which the other 47 nodules being pathologically non-malignant. There were significant differences between malignant nodules and non-malignant nodules in low inner echogenicity, irregular shape, indistinct boundary, value of aspect ratio great than or equal to 1 and inner microcalcifications.it was showed by intranodular graded Doppler flow signals that about 78.12% of the nodules were hypervascularity, the other 21.88% were hypovascular. Among thoses thyroid nodules with hypervascularity, 64% were malignant and 36% were benign. Moreover, of those malignant nodules, approximately 52.3% showed polycentric or surrounding flow signals, while about 10.9% of them showed hypovascular inside the nodules. On the contrast, of those nonmalignant nodules, only 29.7% manifested as polycentric or surrounding flow signals, and 7.0% as hypovascular inside the nodules. It was also demonstrated that values of MVD inside the malignant nodules were significantly higher than that of the nonmalignant nodules.
Conclusion The above results suggested that low echogenicity, indistinct boundary and intranodular microcalcifications may have better specificity and sensitivity. Increased polycentric or surrounding Doppler flow signals were important sonographic features, but should not be considered as key poit for differential diagnosis. There was obvious inconformity between intranodular MVD and intranodular Doppler flow gradings and types, which mechnisms should also be further investigated.
Key words: Thyroid carcinoma, nodule, color Doppler flow imaging, microvessle density
甲状腺结节的血管化特征与微血管密度的相关性
及其临床意义
甲状腺癌在临床各类肿瘤中发生率增长最快也是最常见的内分泌肿瘤【1】。目前,彩色多普勒超声的广泛应用虽然极大地提高了甲状腺结节的临床检出率,但其在结节良恶性质的鉴别中的作用颇多争议。有学者观察了甲状腺结节内部与周边血管的数量、形态分布甚至血流动力学参数的变化在鉴别结节性质中的意义,提出甲状腺恶性结节通常表现为穿入结节内部的中央型血流形态,而良性结节则多表现为环绕结节的周围型血流形态【2】。进一步的研究发现,甲状腺良、恶性结节间的血流形态存在明显交叉的现象,可以因结节大小、慢性疾病等因素而难以鉴别,结节越大其特异性相对越高【3,4】。本研究的目的是探讨不同性质的甲状腺结节的血管化特征及其可能的微血管病理形态学基础,进而观察其判定甲状腺结节良恶性质的可行性。
材料与方法
一、研究对象
2015年4月至2018年3月在我院检查并经手术病理证实的甲状腺结节112例患者,共计128个结节。其中男性49例,年龄28-65岁,平均34±11岁,共计51个结节;女性63例,年龄32-76岁,平均41±13岁,共计77个结节。所有被观察的甲状腺结节均在5-20mm范围内。排除标准①小于5mm或大于20mm的结节不纳入观察范围;②有明确液性暗区,且液性暗区超过结节30%的结节均不计入观察范围;③患有甲亢、结节性甲状腺肿或桥本氏甲状腺炎病史的患者;④接受过I131治疗或微创介入治疗的患者。
二、仪器与方法
1、所用仪器:彩色多普勒超声仪器采用美国GE公司的Logic E9超声诊断仪,线阵探头,6-15MHz;百胜公司MyLab90超声诊断仪,线阵LA523探头,频率4-13MHz。
2、二维超声观察甲状腺结节的位置、大小、边缘、形态、内部回声、有无钙化和结节纵横比比值。参照Rosario P【5】的方法对病灶结节内部及周边血管分布的形态给予分型,并对病灶结节内部血管分布的数量予以分级。血管分型方法:Ⅰ型,内部有血流信号,周边少许血流信号;Ⅱ型,周边有环绕或包绕的血流信号;Ⅲ型,内部无血流信号。血流分级的方法:0级,内部未见彩色血流信号或仅可测得点状血流信号;Ⅰ级,内部可见彩色血流信号,短棒状彩色血流少于2条或点状彩色血流少于5个;Ⅱ级,内部可见较丰富的彩色血流信号,短棒状彩色血流多于2条呈粗大、杂乱排列,或点状彩色血流多于5个。
3、免疫组织化学染色及MVD检测:标本经5um连续切片,60℃烘烤过夜,分别做HE染色及免疫组化染色,CD34单抗1:100稀释,EnVision两步法对CD34染色。参照Weidner等【6】的方法测算微血管密度(micro vessel density,MVD),先在低倍镜(10×10)下全面观察切片以确定瘤内血管密度最高处,再在高倍镜(10×40)下选取癌巢细胞与结缔组织区别明显的的任何一个染色阳性内皮细胞或内皮细胞簇作为一个血管计数,每张标本记录5个视野的微血管数,取其平均值为该病例的MVD值。
三、统计学处理
使用SPSS19.0统计软件包,计数资料采用X2检验,计量资料采用t检验,非参数检验采用秩和检验,P<0.05为差异有显著意义。
结 果
一、甲状腺结节的病理类型与超声声像图:
所有128个结节中病理恶性的结节81例,分别为甲状腺乳头状上皮细胞癌58例,滤泡状上皮细胞癌12例,未分化癌7例,髓样癌4例;病理非恶性的结节47例,分别为结节性甲状腺肿24例,腺瘤23例。病理恶性结节中共有约59.38%(76/128)表现为低回声和形态不规则,约53.9%(69/128)表现为边界不清晰,41.4%(53/128)表现为纵横比≥1,约53.13%(68/128)表现为有微小钙化灶;病理非恶性结节中,28.13%(36/128)表现为低回声,18.74%(24/128)表现为形态不规则,4.68%(6/128)表现为边界不清晰,15.62%(14/128)表现为纵横比≥1,25%(32/128)出现微小钙化。统计分析表明,病理恶性与非恶性结节在低回声、不规则形态、不清晰的边界、纵横比≥1、是否有微小钙化等超声声像图特征方面均有显著差异见(表1、2)。
表-1 甲状腺结节超声声像图特征与病理组织学类型的相关性(例)
声像图特征 |
例数 |
病理恶性 乳头状癌 滤泡状癌 髓样癌 未分化癌 |
病理非恶性 腺瘤 结节性甲状腺肿 |
|||||
低回声 |
是 |
112 |
55 |
10 |
7 |
4 |
18 |
18 |
|
否 |
16 |
3 |
2 |
0 |
0 |
5 |
6 |
形态 |
规则 |
23 |
2 |
1 |
2 |
0 |
12 |
11 |
|
不规则 |
105 |
56 |
11 |
5 |
4 |
11 |
13 |
边界 |
清晰 |
53 |
5 |
3 |
2 |
2 |
19 |
22 |
|
不清晰 |
75 |
53 |
9 |
5 |
2 |
4 |
2 |
纵横比 |
≥1 |
67 |
36 |
9 |
5 |
3 |
3 |
11 |
|
﹤1 |
61 |
22 |
3 |
2 |
1 |
20 |
13 |
钙化灶 |
未见钙化 |
16 |
4 |
2 |
2 |
0 |
6 |
2 |
|
微小钙化 |
91 |
51 |
8 |
5 |
4 |
14 |
18 |
|
粗大钙化 |
11 |
3 |
2 |
0 |
0 |
3 |
4 |
表2不同性质的甲状腺结节声像图特征占比比较(n=128)
声像图特征 |
例数 |
病理恶性 |
病理非恶性 |
|
低回声 |
是 |
112 |
59.38%(76/128)* |
28.13%(36/128) |
形态 |
不规则 |
105 |
59.38%(76/128)** |
18.74%(24/128) |
边界 |
不清晰 |
75 |
53.9%(69/128)** |
4.68%(6/128) |
纵横比 |
≥1 |
67 |
41.4%(53/128)* |
15.62%(14/128) |
钙化灶 |
微小钙化 |
91 |
53.13%(68/128)* |
25%(32/128) |
组间比较:* p<0.05,p<0.01
二、甲状腺结节的MVD、血流分型、血流分级与病理类型间的关系
甲状腺结节内部血流信号的分级显示,约78.12%(100/128)是相对多血供的,21.88%(28/128)的结节为少血供的。若按照结节的性质分类,多血供的结节中恶性结节占64%,良性结节占36%。若将病理恶性的结节根据其不同的组织学类别予以比较,血流分级Ⅰ、Ⅱ 级的结节中,甲状腺乳头状癌比例最高,约占36.72%(47/128),滤泡状癌、髓样癌及未分化癌所占比例分别为5.46%(10/128)、3.13%(4/128)和2.34%(3/128);而在病理非恶性的血流分级Ⅰ、Ⅱ 级的结节中,甲状腺腺瘤约为14.06%(18/128),结节性甲状腺肿约为14.06%(18/128),(见表3)。
从病灶结节内部的血管血管形态和分布状态比较,病理恶性的病灶中,约52.3%(67/128)呈现病灶中心型或周边环绕的血管分布,约10.9%(14/128)呈现为病灶内无血管;在病理非恶性的结节中,29.7%(38/128)呈现病灶中心型或周边环绕的血管分布,约7.0%(9/128)呈现为病灶内无血管(见表3)。
病灶结节内部微血管密度(MVD)测定结果显示,病理恶性的病灶内部MVD值显著低于病理非恶性病灶内部的MVD值,差异非常显著。
表-3 甲状腺结节MVD、血流数量分级、血管形态分型与病理组织学类型的相关性(例)
CDFI |
例数 |
病理恶性 乳头状癌 滤泡状癌 髓样癌 未分化癌 |
病理非恶性 腺瘤 结节性甲状腺肿 |
||||||
血流信号 数量分级 |
0 |
28 |
11 |
2 |
3 |
1 |
5 |
6 |
|
Ⅰ |
51 |
12 |
7 |
4 |
3 |
8 |
|