Volume 19, Issue 10

Computer-aided classification of benign and malignant masses on mammograms is attempted in this study by computing gradient-based and texture-based features. Features computed based on gray-level co-occurrence matrices (GCMs) are used to evaluate the effectiveness of textural information possessed by mass regions in comparison with the textural information present in mass margins. A method involving polygonal modeling of boundaries is proposed for the extraction of a ribbon of pixels across mass margins. Two gradient-based features are developed to estimate the sharpness of mass boundaries in the ribbons of pixels extracted from their margins. A total of 54 images (28 benign and 26 malignant) containing 39 images from the Mammographic Image Analysis Society (MIAS) database and 15 images from a local database are analyzed. The best benign versus malignant classification of 82.1%, with an area (A/sub z/) of 0.85 under the receiver operating characteristics (ROC) curve, was obtained with the images from the MIAS database by using GCM-based texture features computed from mass margins. The classification method used is based on posterior probabilities computed from Mahalanobis distances. The corresponding accuracy using jack-knife classification was observed to be 74.4%, with A/sub x/=0.67. Gradient-based features achieved A/sub x/=0.6 on the MIAS database and A/sub z/=0.76 on the combined database. The corresponding values obtained using jack-knife classification were observed to be 0.52 and 0.73 for the MIAS and combined databases, respectively.

本研究尝试通过计算基于梯度和基于纹理的特征，对乳腺X线图像上的良性和恶性肿块进行计算机辅助分类。使用基于灰度共生矩阵（GCM）计算的特征，评估肿块区域所拥有的纹理信息与肿块边缘存在的纹理信息相比的有效性。提出了一种涉及边界多边形建模的方法，用于提取跨肿块边缘的像素带。开发了两种基于梯度的特征来估计从肿块边缘提取的像素带中边界的锐度。共分析了54幅图像（28幅良性，26幅恶性），其中39幅来自乳腺X线图像分析学会（MIAS）数据库，15幅来自本地数据库。使用从MIAS数据库图像中基于GCM的肿块边缘纹理特征，获得了最佳的良性/恶性分类准确率82.1%，受试者工作特征（ROC）曲线下面积（A_z）为0.85。所使用的分类方法基于马氏距离计算的后验概率。使用刀切法分类的相应准确率为74.4%，A_x=0.67。基于梯度的特征在MIAS数据库上达到A_x=0.6，在组合数据库上达到A_z=0.76。使用刀切法分类得到的相应值对于MIAS数据库和组合数据库分别为0.52和0.73。

This paper provides methodology for fully automated model-based image segmentation. All information necessary to perform image segmentation is automatically derived from a training set that is presented in a form of segmentation examples. The training set is used to construct two models representing the objects-shape model and border appearance model. A two-step approach to image segmentation is r...

本文提供了一种全自动的基于模型的图像分割方法。执行图像分割所需的所有信息都是从以分割示例形式提供的训练集中自动推导出来的。训练集用于构建代表物体形状模型和边界外观模型的两个模型。采用两步法进行图像分割...

Intravascular ultrasound (IVUS) provides direct depiction of coronary artery anatomy, including plaque and vessel area, which is important in quantitative studies on the progression or regression of coronary artery disease. Traditionally, these studies have relied on manual evaluation, which is laborious, time consuming, and subject to large interobserver and intraobserver variability. A new techn...

血管内超声（IVUS）直接描绘冠状动脉解剖结构，包括斑块和血管面积，这对于冠状动脉疾病进展或消退的定量研究非常重要。传统上，这些研究依赖于手动评估，费时费力，且观察者间和观察者内变异较大。一种新技术...

While laparoscopes are used for numerous minimally invasive (MI) procedures, MI liver resection and ablative surgery is infrequently performed. The paucity of cases is due to the restriction of the field of view by the laparoscope and the difficulty in determining tumor location and margins under video guidance. By merging MI surgery with interactive, image-guided surgery (IIGS), the authors hope ...

虽然腹腔镜用于多种微创手术，但微创肝脏切除和消融手术并不常见。病例稀少是由于腹腔镜视野受限，以及视频引导下难以确定肿瘤位置和边缘。通过将微创手术与交互式图像引导手术相结合，作者希望...

Orbital soft-tissue motion analysis aids in the localization and diagnosis of orbital disorders. A technique has been developed to objectively quantify and visualize motion in the orbit during gaze. T1-weighted MR volume sequences are acquired during gaze and soft-tissue motion is quantified using optical flow techniques. The flow field is visualized using color-coding: orientation of the flow vec...

眼眶软组织运动分析有助于眼眶疾病的定位和诊断。我们开发了一种技术，用于客观量化和可视化注视期间眼眶内的运动。在注视过程中获取T1加权MR体积序列，并使用光流技术量化软组织运动。流场通过颜色编码可视化：流动矢量的方向...

During interactive image-guided surgery (IIGS), a surgeon uses data from medical images to help guide the surgical procedure. At Vanderbilt University, an IIGS software system called Orion has been developed which is capable of displaying up to four 512/spl times/512 images and the current surgical position using an active optical tracking system. Orion is capable of displaying data from any tomog...

在交互式图像引导手术（IIGS）中，外科医生利用医学图像数据来指导手术过程。范德比尔特大学开发了一套名为Orion的IIGS软件系统，该系统能够使用主动光学跟踪系统显示多达四个512×512的图像和当前手术位置。Orion能够显示来自任何断层扫描...

The problem of progressive lossless image coding is addressed. A nonlinear decomposition for progressive lossless compression is presented. The decomposition into subbands is called rank-order polynomial decomposition (ROPD) according to the polynomial prediction models used. The decomposition method presented here is a further development and generalization of the morphological subband decomposit...

本文解决了渐进式无损图像编码的问题。提出了一种用于渐进式无损压缩的非线性分解方法。根据所使用的多项式预测模型，这种子带分解被称为秩次多项式分解（ROPD）。这里提出的分解方法是形态学子带分解的进一步发展和推广...