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乳腺导管原位癌的磁共振特征与病理对照关系

2016-05-14张惠锋杨慧芬杜芳郝亮

中国现代医生 2016年6期
关键词:磁共振成像

张惠锋 杨慧芬 杜芳 郝亮

[摘要] 目的 探讨非肿块的乳腺导管原位癌(DCIS)的MRI表现与病理分级之间的相关性。 方法 回顾性分析我院2012年9月~2015年9月经手术病理证实的DCIS 67例患者并与MRI影像表现进行对照分析。 结果 在67例DCIS病例中,乳腺导管原位癌的非肿块样强化以线样(34.3%)和局灶(26.8%)强化为主,两组的病理VanNuys分级以Ⅲ级为主,各占26.8%和17.9%。组内差异有统计学意义。内部强化特征以混杂(38.8%)和均匀(31.3%)强化为主,两者病理分级分别以Ⅲ级(31.3%)和Ⅱ级(14.9%)为主,组内差异有统计学意义。曲线类型以平台型21(31.3%)和廓清型(58.2%)为主,病理分级廓清型以Ⅲ级(58.2%)为主,差异有统计学意义。 结论 非肿块样DCIS MRI的形态、强化特征和曲线类型与病理分级有密切相关性。

[关键词] 乳腺导管原位癌;磁共振成像;BI-RADS;病理分级

[中图分类号] R737.9;R445.2 [文献标识码] B [文章编号] 1673-9701(2016)06-0084-04

Comparison between magnetic resonance and pathology in ductal carcinoma in situ patients

ZHANG Huifeng1 YANG Huifen2 DU Fang1 HAO Liang1

1.Department of Radiology,Hangzhou Hospital of Traditional Chinese Medicine,Hangzhou 310007,China;2.Department of Breast Surgery,Hangzhou Hospital of Traditional Chinese Medicine,Hangzhou 310007,China

[Abstract] Objective To evaluate the correlation between characteristics of Magnetic Resonance Imaging(MRI) and pathological classification, ductal carcinoma in situ(DCIS) patients were observed. Methods Sixty seven DCIS patients verified by surgery pathology from September, 2012 to September, 2015 were retrospectively analysed, and were compared to characteristics of MRI image. Results In 67 cases, non-masslike enhancement lesions were observed mainly. 34.3% of linear ductal enhancement and 26.8% focal enhancement occupied among the non-masslike enhancement lesions, respectively. And the corresponding rate of pathological VanNuys classification was 26.8% and 17.9% respectively. Intra group statistical significance was approached. 38.8% of mixed reinforcement and 31.3% of homogeneous enhancement occupied in internal schedule of reinforcement. The Ⅲ pathology grade occupied 31.3% and Ⅱ grade accounted for 14.9%. Intra group statistical significance was approached in Ⅲ pathology grade, meanwhile,no significance was found in Ⅱ pathology grade. Platform 21 type(31.3%) and dissection(58.2%) type mainly showed in the dynamic enhancement curves, with Ⅲ pathology grade(58.2%) majorly found among dissection type. Statistical significance was approached. Conclusion Closely correlation between characteristics of Magnetic Resonance Imaging(MRI) and pathological classification was approached in ductal carcinoma in situ (DCIS) patients, in non-masslike enhancement lesions, internal schedule of reinforcement.

[Key words] DCIS;MRI;BI-RADS;Pathology grade

乳腺癌发病率有逐年上升的趋势[1],乳腺癌最常见的病理类型为浸润性乳腺导管癌,它一般由于乳腺导管原位癌(ductal carcinoma in situ,DCIS)未被及早发现,逐步发展而成[2]。研究表明,病理学上,高级别的DCIS发展为浸润性导管癌和局部复发的危险性显著高于非高级别[3,4],因此如何早期发现乳腺导管原位癌以及如何进一步分析MRI表现与病理学分级的相关性成为临床迫切解决的问题。

1 资料与方法

1.1 一般资料

回顾性分析我院2012年9月~2015年9月经术后病理证实的单纯性DCIS 67例,所有患者术前均行过乳腺MR动态增强扫描检查,患者均为女性,年龄35~75岁,平均(56.37±13.42)岁。临床均未扪及肿块,局部皮肤增厚8例,乳头溢血性液6例,仅表现局部胀痛4例,其余49例均无明显临床症状。

1.2 设备与检查方法

磁共振检查采用Philip Intera 1.5T双梯度超导磁共振成像系统。患者俯卧于专用乳腺八通道相控阵表面线圈上,使双侧乳房自然悬垂于线圈洞穴内。扫描参数:TSE-T1WI ,TR764 ms,TE7.2 ms,层厚3 mm,层间距0.6 mm,FOV340×340 mm,矩阵312×442;TSE-T2WI,TR5100 ms,TE115 ms,层厚3,层间距0.6,FOV340×340 mm,矩阵378×510;Tirm-T2WI TR4500 ms,TE64 ms,层厚3,层间距0.6 mm,FOV340×340 mm,矩阵314×320;DWI采用EPI序列,TR11780 ms,TE75 ms,层厚3 mm,层间距0.6 mm,FOV340×340 mm,矩阵230×175,b值0,500,700,1000 s/mm2;动态增强扫描采用Flash-3D 脂肪抑制T1WITR5.2 ms,TE1.6 ms,层厚1 mm,层间距0 mm,FOV340×340 mm,矩阵320×342,翻转角(FA)10°,相位编码为左右方向,单期扫描时间约为60 s,共扫描6个期像,第一与第二期像扫描间隔30 s,增强采集时间416 s。增强扫描经肘正中静脉留置静脉留置针,0.2 mL/kg,经高压注射器注射钆喷酸葡胺(GD-DTPA),速率0.2 mL/s。

1.3 影像资料分析及病理学分级

磁共振影像分析是由2名专门从事乳腺研究的放射科医师,在确定DCIS但不知病理分级的情况下,根据磁共振成像乳腺影像报告与数据系统(BI-RADS)(第5版,2013年)的标准进行影像描述[5]。描述包括,病灶形态、强化特征、信号强度-时间曲线特征[6]。DCIS形态为非肿块样强化(NME)局灶、线样、叶段、区域、多区域、弥漫[7];内部强化特征为均匀、混杂、集丛状、簇环状;信号强度-时间曲线分为增强早期和延迟期,增强早期为第一个2 min或在曲线趋势开始改变时的强化模式,分为慢、中等、快速,延迟期为2 min后或在曲线开始变化后的强化模式,分为流入型、平台型、廓清型[8]。病理分级:根据细胞核的形态及有无坏死的VanNuys组织学分级,组织病理学上根据细胞核的异型程度、管腔内坏死、核分裂象和钙化将DCIS分为Ⅰ~Ⅲ级别[9]。

1.4 统计学处理

采用SPSS14.0统计学软件进行分析,计数资料采用χ2检验,P<0.05为差异有统计学意义。

2 结果

67例DCIS病例非肿块样强化中,按照新版BI-ARDS标准进行影像描述中非肿块样强化以线样(34.3%)(封三图5)和局灶(26.8%)强化为主,两者的病理VanNuys分级以Ⅲ级为主各占26.8%和17.9%,差异有统计学意义。强化特征以混杂强化(38.8%)和均匀强化(31.3%)为主,两者病理分级分别以Ⅲ级(31.3%)和Ⅱ级(14.9%)为主,差异有统计学意义。弥散加权图像显示为明显的弥散受限特征(封三图6)。曲线类型以平台型21(31.3%)和廓清型(58.2%)为主(封三图7、8),病理分级廓清型以Ⅲ级(38.8%)为主,差异有统计学意义。

表1 67例DCIS的NME和病理学分级相关性[n(%)]

3 讨论

乳腺导管原位癌指癌细胞只出现在上皮层内,而未破坏基底膜,或侵入其下的间质或真皮组织.更没有发生浸润和远处转移[10]。多发生于终末导管小叶单位,通常起源于一个导管束,可沿导管进行播散,是乳腺癌较常见的类型之一,也是浸润性乳腺癌的早期阶段[11]。治愈率高,复发率低。因此早期发现、早期诊断成为临床刻不容缓的需求。乳腺X线摄影作为一种乳腺疾病常规筛查手段,对于DCIS检出以微钙化为主要表现,然而对于乳腺呈致密型的腺体组织,这种微钙化显示率不到10%,限制其在DCIS检出率[12]。磁共振检查虽然费用高、时间长是其不足外,但是其无辐射、高清的软组织分辨率、多角度成像、多参数成像的优势是其他检查设备无法替代的。随着磁共振技术的不断发展,超高场磁共振广泛应用于临床后,动态增强技术、弥散加权成像以及软件的发展带来减影技术、动态曲线的获取,从而对乳腺的检查优势越来越明显,所以磁共振对乳腺病变的辅助诊断已经越来越广泛地应用于临床,尤其对于DCIS病例以非肿块表现为主,磁共振发挥了乳腺X线摄影无法取代的作用[13]。DCIS患者的病理VanNuys组织学分级是临床判断恶性程度及预后的可靠指标,是预示是否复发和临床放疗化疗治疗的评判手段之一。高级别的分类具有较高的浸润趋势,肿瘤切除术后有较高的复发率且高级别DCIS术后复发时间显著短于非高级别类型[14]。如能在手术前明确诊断,将为临床个性化治疗提供重要的参考依据。如果术前可以借助影像学手段来无创性提供较为确切的病理分级标准,对临床医师手术方式的选择提供了不可或缺的指导手段。

磁共振的形态、强化特征和曲线类型是否与病理分级相关报道并不一致,但多数的报道均与Rahbar等[15]报道的一致。MRI动态增强表现与不同核级别相关,高级别DCIS更容易出现恶性病变的强化模式,而非高核级别则很少出现。病理基础考虑肿瘤血管化程度、血管壁对对比剂的渗透性及肿瘤间质内压力三方面因素[16]。本研究对病理为Ⅲ级的病变明显高于Ⅰ级和Ⅱ级的病变,并且形态集中表现在线样和局灶,而强化方式也以混杂为主,曲线类型以廓清型为特征。可能由于肿瘤的细胞异形性明显,细胞沿着导管壁或导管局部异常增生性生长,且肿瘤的细胞致密,间质减少,毛细血管内皮不完整,存在通透性增高,动-静脉的分流加剧,导致混杂的强化模式和曲线类型呈廓清型表现为主。但是仍不能忽视的问题是DCIS本身就有导管内膜生长,而未突破基底膜的病变,其形态和强化模式及曲线类型分类在其他类型不占优势,导致其他类型的样本数量过小,可能无法得到真实的统计学意义。

扩散加权成像是目前唯一能观察活体分子微观运动的成像方法,在乳腺病变鉴别诊断中具有较高价值[17,18]。乳腺的弥散加权图像及ADC值的测定目前临床应用比较广泛,对乳腺良恶性的判断起到不可低估的作用。有学者证实乳腺癌患者的弥散受限程度即ADC值与其细胞的致密度呈明显正相关[19-21]。本组DCIS患者的弥散明显受限,在弥散加权图像上呈明显高信号。

综上所述,DCIS在MRI表现为非肿块样强化为主。磁共振的形态、强化特征和曲线类型与病理分级有差异。MRI在DCIS的组织学分级有优势作用,有着临床应用价值,但其准确性还要等巨大的样本量进一步支持。

[参考文献]

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(收稿日期:2015-10-08)

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