基于生成对抗网络的乳腺MRI图像生成

乳腺癌磁共振成像(nuclear magnetic resonance imaging,MRI)数据由于不同医院采集方式不同、设备不同或病人等自身原因,会存在同一病人不同序列缺失的问题。目前主流的图像生成对抗网络Pix2Pix和Cycle-consistency是医学图像生成的两种主要模式,这类方法要求不同MRI序列数据配对出现,难以处理存在缺失的数据,此外,该类方法往往关注整幅图像的生成质量,缺少对疾病诊断更有价值的病灶区域的生成质量的监控。针对以上问题,该文受配准网络(RegGAN)自适应对准图像空间分布的启发,设计了一种新的基于特征增强的双注意力配准生成对抗网络DA-RegGAN。该网络在生成器中引入卷积注意力模块,使网络更注重病灶的学习;在判别器中添加梯度正则化约束,主要解决网络训练不稳定容易出现模式崩溃的现象,使网络生成包含更清晰的病灶细节全局图。该文在1697幅乳腺数据上开展消融实验、不同图像生成算法间的对比实验、肿瘤分类实验,进一步验证了方法的有效性。与原始RegGAN比,全局图像生成质量和局部病灶图像生成质量均得到提升,局部图像质量较原始PSNR提升了0.518,SSIM提升了0.021;全局图像质量较原始PSNR提升了0.584,SSIM提升了0.020。

母猪泌乳周期:生理上和管理上的矛盾

１前言哺乳动物用母畜消化产物所合成的乳汁来养育其幼仔。因此只要母畜具有充足的营养，它们即可成功地繁殖。而且，由于哺乳动物具有消耗体内贮备以供给乳汁合成的能力，母畜摄食的中断不会立即停止对幼仔的食物供应。不仅哺乳动物的生存环境有很大的变异，而且出生时的...

Clinical study of digital mammography,contrast-enhanced MRI as well as their combination in the diagnosis of breast cancer

Objective： To compare the effectiveness of digital mammography and MRI in the detection and diagnosis of breast cancer and to assess the value of these modalities as well as the combination of the two. Methods： Sixty-seven patients with surgery and pathology proved breast lesion （malignant, n = 32; benign, n = 46） underwent digital mammography and MRI, the pulse sequences included T1WI, T2WI, diffuse weighted imaging （DWI）, and dynamic contrast-enhanced MRI before surgery. Of the results of these two modalities, all lesions were classified into 5 groups according to BI-RADS classification, and the imaging findings were correlated to histopathology. The sensitivity and specificity of each modality as well as the combination of the two were calculated. Results： Of these 78 breasts lesions, The sensitivity was 78.13%% （25/32） for digital mammography and 93.75% （30/32） for MRI （P 〉 0.05）. The specificity was 73.91%% （34/46） and 89.13% （41/46） accordingly （P 〈 0.05）, both of them showed statistical difference. The sensitivity and specificity was 98.63% and 97.16% respectively as these two modalities were used in combination. Conclusion： Digital mammography in combination with MRI is helpful in the diagnosis of breast cancer, the sensitivity and specificity was enhanced when compared to that of single modality.

Correlation of VEGF expression,angiogenesis and carcinomatous change in breast tumors

Objective: The aim of the study was to detect the expression of vascular endothelial growth factor (VEGF) and microvessel density (MVD) in breast benign tissues and malignant tumors to clarify the relationship between VEGF expression, angiogenesis and breast carcinoma occurrence. Methods: The expression of VEGF and MVD in 79 cases of invasive ductal breast carcinoma, 79 corresponding para-cancer normal tissues from primary invasive breast carcinomas, 35 breast carcinoma in situ, 23 breast atypical hyperplasia and 56 breast fibroid tumor were examined by immunohistochemistry staining (SP-method). Results: The positive rate of VEGF and MVD value increased significantly with the increase of the malignant degree of breast tissues (P = 0.000). In breast carcinoma group, the positive rate of VEGF and MVD value with lymph node metastasis were higher than those without lymph node metastasis (P = 0.011 and P = 0.023). A significant higher expression of VEGF and MVD value were observed as the clinical stage increased (P = 0.035 and P = 0.012). The MVD value was higher in VEGF positive group than negative group (P = 0.000). Conclusion: The combining detection of VEGF expression and MVD is helpful for evaluating malignant degree of breast carcinoma. Angiogenesis in breast tumors and occurrence of breast carcinoma might be correlated with the expression of VEGF.

Antiangiogenic therapy for breast cancer: current status and future perspectives

Tumor angiogenesis plays an important role in the growth, invasion and metastasis of breast cancer, therefore re-cently a very active area of breast cancer research involves the addition of antiangiogenic therapy. Numerous clinical studies for several antiangiogenic agents have recently been conducted in breast cancer patients and have shown clinically significant improvement in outcomes. This review gives a brief background to breast cancer angiogenesis, also focusing on current prog-ress in the field of antiangiogenic therapy for breast cancer and issues regarding future therapeutic development.

Progress in the study of cancer-associated retinopathy in breast cancer patients

Cancer-associated retinopathy (CAR) typically has a sudden or progressive onset of severe visual loss and an ominous association with an occult malignancy which contains breast cancer. Pathologically, CAR is the degeneration of photoreceptors. But the precise mechanism has not been fully established, CAR may result from autoimmune mediated apoptosis. And in recent years, there also have been some results demonstrating that tumor derived angiogenic factors such as VEGF may also confer the development of CAR, which may offer novel avenues for the therapeutic intervention in CAR. Early initiation of immunosuppressive therapy is critical for vision preservation. Future developments in rapid identification and longitudinal quantification of antibody levels would enable individualized management in these patients. The goal of this review was to analyze the epidemiology, the clinical features, the diagnosis and management of retinopathy in the context of recent advances in the elucidation of breast cancer-associated retinopathy (BCAR) pathogenesis.

Anti-angiogenesis effect of generation 4 polyamidoamine/vascular endothelial growth factor antisense oligodeoxynucleotide on breast cancer in vitro

Objective:To study the effects of the generation 4 polyamidoamine/vascular endothelial growth factor antisense oligodeoxynucleotide(G4PAMAM/VEGFASODN) compound on the expressions of vascular endothelial growth factor(VEGF) and its mRNA of breast cancer cells and on the inhibition of vascular endothelial cells. Methods:We examined the morphology of G4PAMAM/VEGFASODN compound and its pH stability,in vitro transfection efficiency and toxicity,and the expressions of VEGF and its mRNA. Methyl thiazolyl tetrazolium assay was used to detect the inhibitory function of the compound on vascular endothelial cells. Results:The compound was about 10 nm in diameter and was homogeneously netlike. From pH 5 to 10,it showed quite a buffered ability. The 48-h transfection rate in the charge ratio of 1:40 was 98.76%,significantly higher than that of the liposome group(P<0.05). None of the transfection products showed obvious toxicity on the cells. The expressions of both VEGF protein and its mRNA after G4PAMAM/VEGFASODN transfection decreased markedly. Conclusion:With a low toxicity,high safety,and high transfection rate,G4PAMAM/VEGFASODN could be a promising gene vector. Specifically,it inhibits VEGF gene expression efficiently,laying a basis for further in vivo animal studies.