【作者】 张辉；

【导师】 邹利光；

【作者基本信息】 第三军医大学 ， 影像医学与核医学， 2010， 硕士

【摘要】 目的:建立大鼠乳腺癌模型,研究诱发性大鼠乳腺癌CT平扫、CT增强和CT灌注成像(CT perfusion imaging, CTPI)表现,探讨CTPI与肿瘤病理分级、组织类型和微血管密度(microvascular vessel density, MVD)的相关性,进一步明确CTPI对乳腺癌的诊断价值。方法:清洁级饲养40天龄Wistar雌性大鼠35只,体重在110～140 g之间。取芝麻油100 ml,置于60℃恒温水浴箱加热10分钟,将1 g二甲基苯蒽(DMBA)加入其中搅拌直至溶解,35只大鼠分4批分别用10 mg/ml的DMBA新鲜溶液进行灌胃,一周后,同样的方法与剂量进行第二次灌胃,按肿瘤诱发的时间不同随机分为A(10-15周)、B(16-20周)、C(21-25周)3组。将诱发肿块的大鼠腹腔注射6 ml/kg水合氯醛麻醉,四肢仰卧位固定于固定板四角,切开腹股沟皮肤,暴露股静脉,24 G静脉留置针穿刺并妥善固定,观察并记录大鼠乳腺肿块诱发情况。将大鼠固定板置于CT扫描床,定位线调至肿块中心位置,扫描范围将肿块完全包裹,分别进行64排螺旋CT平扫、CT增强扫描和CTPI检查,扫描数据传送至CT专用AW 4.3图像后处理工作站,采用其预装的CT perfusion 3软件中的body tumor软件处理数据,得到CTPI参数血流量(blood flow, BF)、血容量(blood volume, BV)、平均通过时间(mean transit time, MTT)、表面通透性(permeability surface, PS),并计算时间密度曲线(time-desity curve, TDC)。扫描完毕后,灌注法固定标本,取乳腺肿瘤组织进行HE染色、Ⅷ因子相关抗原免疫组化染色(SABC法)和免疫荧光染色,观察乳腺肿瘤病理类型,采用热点法计数MVD,低倍镜下(×100)寻找3个高密度血管区(热点),3个视野分别在高倍镜下(×200)计数,以其平均数表示微血管密度。结果:35只大鼠中30只大鼠成功诱发乳腺肿块,其中乳腺增生性疾病8只,乳腺癌22只,乳腺肿瘤和增生性疾病总的诱发成功率为85.7%,乳腺癌诱发成功率为62.9%。乳腺增生性疾病均为单发,22只乳腺癌有5只诱发2个肿块,且均为恶性。肿块最小的为0.2×0.3 cm,最大的为3.6×2.7 cm,乳腺增生性疾病肿块平均大小为(1.19±0.28)×(1.39±0.28)cm,乳腺癌平均大小为(2.27±0.17)×(1.56±0.12) cm,肿块<2 cm时,恶性率为50%,肿块2～3 cm时恶性率为60%,当肿块>3 cm时恶性率达到100%,其恶性率有统计学差异(P<0.05)。22只大鼠乳腺癌按组织类型分,包括浸润性导管癌6只,浸润性小叶癌6只,其他类型腺癌10只;按分化程度分,包括高分化癌1只,中分化癌15只,低分化癌6只。大鼠乳腺癌平扫CT均值为62.54±4.42 Hu,多表现为软组织密度肿块,肿块形态不规则或呈分叶状,部分肿块密度不均匀,其中5个较大肿块中央处可见液化坏死区。恶性程度高的肿块表现为浸润性、不均衡生长,边界不清,毛刺征少见,所有肿块均未见钙化。增强扫描CT均值为101.31±5.33 Hu,与平扫CT值比较平均升高38.77±1.79 Hu,主要表现为均匀强化或环状不均匀强化,少数肿块表现为弥散分布的斑点或小斑片强化灶,动态增强表现符合“快进快出”的特点,即动脉期病灶迅速强化,延迟2 S后强化程度消退较快。TDC曲线类型分析,流出型(5只大鼠)和平台型(4只大鼠)的乳腺肿瘤全部为乳腺癌,平坦型TDC(2只大鼠)全部为乳腺增生性疾病,19只大鼠表现为流入型TDC,其中乳腺癌占68.4%(13只),乳腺增生性疾病占31.6%(6只),乳腺癌与乳腺增生性疾病TDC曲线类型之间有显著性差异(P<0.05)。乳腺癌中央区与边缘区的BF、BV、MTT、PS分别为20.00±44.45 ml/min/100g,151.72±93.43 ml/min/100g;0.80±1.09 ml/100g,9.55±7.88 ml/100g;9.67±10.48 sec,2.43±1.64 sec;6.55±9.64 ml/min/100g,15.70±12.19 ml/min/100g。乳腺癌组呈边缘高灌注表现,BF、BV、PS均高于中央区,MTT低于中央区,差异均有统计学意义(P<0.05)。中分化和低分化乳腺癌BF、BV、MTT、PS分别为115.30±15.46 ml/min/100g,256.52±132.19 ml/min/100g;9.76±9.00 ml/100g,10.35±4.56 ml/100g;2.49±1.90 sec,2.42±1.00 sec;13.86±8.91 ml/min/100g,22.68±17.12 ml/min/100g。乳腺增生性疾病的BF、BV、MTT、PS分别为42.96±32.42 ml/min/100g, 2.17±1.36 ml/100g,4.89±5.78 sec,8.45±6.23 ml/min/100g。乳腺癌BF、BV显著高于乳腺增生性疾病(P<0.05),BF、BV在不同分化程度肿瘤之间有显著差异(P<0.05);乳腺癌MTT显著低于乳腺增生性疾病(P<0.05),但在不同分化程度肿瘤之间无显著差异(P>0.05),乳腺癌与乳腺增生性疾病的PS无显著性差异(P>0.05)。不同组织类型灌注参数之间无显著相差(P>0.05)。乳腺癌BF、BV、PS与MVD的相关性随肿瘤分化程度的降低呈升高趋势,两者之间呈显著正相关(r=0.701,P=0.000;r=0.441,P=0.015;r=0.521,P=0.003)。结论:1.二甲基苯蒽(DMBA)灌胃大鼠乳腺癌诱发成功率高,多发生于第一、二对乳腺,大鼠诱发性乳腺癌是CT灌注成像研究适合的动物模型。2.乳腺肿瘤CT平扫表现为形态不规则或呈分叶状的软组织密度影,所有肿块均未见钙化。增强后明显不均匀强化,动态增强表现符合“快进快出”的特点,与人乳腺癌CT平扫及增强表现相似。3.乳腺癌TDC曲线多表现为流出型和平台型,根据TDC曲线类型可进一步判断大鼠乳腺肿块良恶性。4.乳腺癌BF、BV高于乳腺增生性疾病,呈高灌注表现,可以作为乳腺肿块良恶性诊断和肿瘤分化程度的参考指标。乳腺癌MTT显著低于乳腺增生性疾病(P<0.05),乳腺癌与乳腺增生性疾病PS无显著性差异(P>0.05)。5.乳腺癌BF、BV、PS与MVD的相关性随肿瘤分化程度的降低呈升高趋势,两者之间呈显著正相关,CT灌注成像有助于反映肿瘤组织血管化程度。更多还原

【Abstract】 ObjectiveEstablish animal model of rat breast cancer and study the induced rat breast cancer CT scan, CT enhancement and CT perfusion imaging (CTPI) performance, investigate the correlation of CTPI with tumor grade, histological type microvascular vessel density (MVD), and further identify the diagnostic value of CTPI on breast cancer.MethodsThirty-five female Wistar rats were arranged, with the age of 40 days and the weight of 100~140 g. 100 ml sesame oil was heated in 60℃thermostatic waterbath for 10 mins. Added 1 g 7, 12-dimethylben(a)anthracene (DMBA) into the heated sesame oil and stired to dissolve. Thirty-five rats were divided into 3 groups by the induced time of breast cancer, included A (10~15 weeks), B (15~20 weeks), and C (20~25 weeks). Each rat was administrated intragastrically with 10 mg/ml DMBA.The induced rats were anesthetized by intraperitoneal injection of 6 ml/kg chloral hydrate, fixed on the fixing plate. Inguinal skin was slitted to paracentesis the femoral vein by 24 G intravenous catheter needle. Fixing plate was put in CT scanner table and localized appropriately. Each rat was performed 64-slice spiral CT routine scan, enhanced scan and CTPI. Scanning data was delivered to CT exclusive image post-processing workstation of AW 4.3, and post-processed by body tumor software installed in CT perfusion 3 to obtain CTPI parameters of blood flow (BF), blood volume (BV), mean transit time (MTT), permeability surface (PS), as well as time density curve (TDC).After CT examination and perfusion-fixation procedure, tissues of breast tumor were performed HE stain and FactorⅧrelated antigen immunohistochemisty (SABC method) and immunofluorescence to observe the pathological type of tumors. Initially, 3 hyperdense vascular area (hotspot) were chosen under low power lens (×100), and then calculated under high power lens (×200). The average data was obtained to evaluate MVD. ResultsThirty breast tumors were successfully induced in 35 rats, 8 were benign and 22 were malignant. The total achievement ratio of induced breast lump was 85.7%, and the achievement ratio of induced breast cancer was 62.9%. All lumps of breast proliferative disease were solitary, 5 in 22 of breast cancer were induced two lesion of malignant lump. The size of tumor between 0.2×0.3 cm and 3.6×2.7 cm, the mean size of breast proliferative lump was (1.19±0.28)×(1.39±0.28) cm, and the mean size of breast cancer was (2.27±0.17)×(1.56±0.12) cm. When the size of lump small than 2 cm, the malignant ratio was 50 %; between 2 and 3 cm, the ratio was 60 %; large than 3 cm, the ratio was 100 %. There was significant difference between each other (P<0.05). The pathological type of breast cancer included infiltrating ductal breast cancer (n=6), infiltrating lobular carcinoma (n=6), and other types of adenocarcinoma (n=10). The differentiation of breast cancer included well differentiated (n=1), moderately differentiated (n=15) and poorly differentiated (n=6). The mean CT value of breast cancer was 62.53±4.42 Hu, showed as soft tissue. The morphology of tumor was irregular or lobulated. The density of some tumor was asymmetrical, and showed central necrosis in 5 comparatively large tumors. The high degree malignant tumor showed invasive growth, obscure boundary,few spicule sign and none calcification. The mean CT value of breast cancer was 101.31±5.33 Hu in CT enhanced scanning, 38.77±1.79 Hu higher than CT routine scanning. It showed that well-distributed enhancement or circularity uneven enhancement, and some showed dispersed spots or small patches enhanced lesions, accorded with“quick-in-quick-out”feature.Both outflow-type (5 rats) and platform-type (4 rats) TDC were malignant, flat-type (2 rats) TDC were benign. 19 rats showed inflow-type TDC, included 68.4% (13 rats) malignant and 31.6% (6 rats) benign. The type of TDC had significant differences (P<0.05) between benign and malignant.The BF、BV、MTT and PS of breast cancer central region and marginal region were 20.00±44.45 ml/min/100g,151.72±93.43 ml/min/100g;0.80±1.09 ml/100g,9.55±7.88 ml/100g;9.67±10.48 sec,2.43±1.64 sec;6.55±9.64 ml/min/100g,15.70±12.19 ml/min/100g. Breast cancer showed marginal hypertransfusion, BF, BV and PS were higher than centre area, MTT lower than centre area, and it had significant difference (P<0.05). The BF、BV、MTT and PS of moderately differentiated and poorly differentiated breast cancer were 115.30±15.46 ml/min/100g, 256.52±132.19 ml/min/100g; 9.76±9.00 ml/100g, 10.35±4.56 ml/100g; 2.49±1.90 sec, 2.42±1.00 sec; 13.86±8.91 ml/min/100g, 22.68±17.12 ml/min/100g. And The BF、BV、MTT and PS of breast proliferative disease were 42.96±32.42 ml/min/100g, 2.17±1.36 ml/100g, 4.89±5.78 sec, 8.45±6.23 ml/min/100g. BF and BV of malignant were higher than benign (P<0.05), and varied by the tissue differentiation (P<0.05). MTT of malignant was lower than benign (P<0.05), but showed no significant differences by malignant differentiation (P>0.05). There was no significant difference of PS between malignant and benign (P>0.05). The positive correlation of MVD with BF, BV and PS heightened while the differentiation decreased (P<0.05). The positive correlation of MVD with BF, BV and PS heightened while the differentiation decreased (P<0.05).Conclusion⑴Induced rat breast cancer is a suitable model for CT perfusion study.⑵CT routine scanning of rat breast cancer showed the same feature of human breast cancer, included character of irregular morphology, lobulated, soft tissue liked density, obvious enhancement and“quick-in-quick-out”.⑶Breast cancer TDC always showed outflow-type and platform-type, it can help to different the benign and malignant breast tumor.⑷BF and BV of breast cancer are higher than benign and skeletal muscles. It can be used as reference index for diagnosis and differential diagnosis of breast cancer.⑸CTPI is conducive to reflect tumor differentiation, and closely associated with microvascular vessel density of tumor.更多还原