Changing concepts of colonic polyps: clinical and radiographic implications

The relationship of colonic polyps to carcinoma of the colon provides a basis for their importance. Recent advances in the detection of colonic polyps, including double contrast barium examination and colonoscopy, have provided a method for more extensive study of colonic polyps. Studies using these newer techniques indicate that many traditional concepts of colonic polyps were inaccurate. The relationships of polyp size to histology, polyp location to age, and the phenomenon of colon polyp clustering are important to both the immediate treatment of the polyp and to the long-term follow-up of the patient. The use of hemoccult stool screening as a technique for screening for colonic pathology is also of significance to the radiologist. The changing relationships of various parameters of colon polyps bring into question the utility of many of the currently recommended screening procedures for colon pathology. Undoubtedly, this will impact on the practice of radiology.     

Multiresolutional modification of speech signals for listeners with hearing impairment

A new method, the multiresolutional modification algorithm (MMA), which modifies speech signals in frequency and time domains, is proposed for listeners with hearing impairment and early clinical results are reported. Unlike other methods, this algorithm modifies the wavelet coefficients of the speech signal in order to obtain a modified version of the original signal instead of modifying the speech waveform itself. The speech signal is first divided into subbands using an 11-level quadrature mirror filter (QMF) bank. These subbands are then modified using the modification algorithm. Finally, the inverse Wavelet transform is applied to these modified subband coefficients in order to reconstruct a modified version of the input signal. The efficacy of the MMA was evaluated using subjects with hearing impairment and subjects with no such impairment. Listening tests showed that the proposed algorithm increases the quality and intelligibility of the modified speech over the well-known modification algorithms.     

结肠巨大息肉内镜下治疗安全性的探讨

【目的】介绍内镜下治疗结肠巨大息肉（〉2．5cm）的经验,探讨其安全性及并发症的防治。【方法】常规做肠道准备,采用电子肠镜下直视操作,应用圈套器直接套扎或分块套扎带蒂和亚蒂巨大息肉;应用针形电切刀,切割巨大息肉基底部或无蒂息肉表面;应用内镜注射针,在无蒂息肉基底部黏膜下注射肾上腺素盐水,使局部黏膜肿胀、隆起,再分块切除。并与普通息肉组比较,两者的疗效及并发症。【结果】462例结肠巨大息肉患者,共968枚息肉,均成功切除。与普通息肉组相比较,两组一次性切除与二次性切除及分块切除息肉数有显著性差异（P〈0．01）;两组并发症比较（出血、肠壁电凝损伤、肠道感染）有显著性差异（P〈0．01）。【结论】内镜下高频电切术治疗结肠巨大息与普通组比较并发症多,风险大,但术前充分准备、严格掌握适应证,术中耐心细致操作,术后严密观察,结肠巨大息肉电凝术是安全,可靠的。     

Hyoscine butylbromide administered at the cecum increases polyp detection: a randomized double-blind placebo-controlled trial

Background and study aims: Removal of colonic polyps prevents progression of colonic neoplasia. Miss rates of polyps range from 5?% to 32?%. The effect of colonic contractility on polyp detection has not been studied adequately. Hyoscine butylbromide results in colonic spasmolysis and may improve polyp detection.Patients and methods: Patients undergoing colonoscopy for standard indications were included and randomized to receive either 20?mg hyoscine butylbromide or placebo at cecal intubation. Operators were blind to the intervention. Data on indication, preparation, sedation, colonoscope type, times of insertion/withdrawal, polyps, and failure were recorded. The primary end point was the number of polyps detected per patient. Secondary endpoints were adenoma detection rate and polyp detection rate. Results: A total of 303 patients received hyoscine butylbromide and 298 received placebo. More polyps per patient were identified in the hyoscine group than in the placebo group (0.91 vs. 0.70; P?=?0.044). Adenoma detection rate and polyp detection rate were higher in the hyoscine arm but not significantly different (27.1?% vs. 21.8?% [P?=?0.13] and 43.6?% vs. 36.6?% [P?=?0.08], respectively). After adjusting for confounding variables, the odds of detecting any polyp were 1.56 higher in the hyoscine than the placebo group (95?% confidence interval [CI] 1.09?-?2.21, P?=?0.014). The adjusted odds of detecting any adenoma were 1.62 higher in the hyoscine group compared with the placebo group (95?%CI 1.09?-?2.42, P?=?0.017). There were no differences in baseline characteristics between the groups. No adverse colonoscopy-related events were recorded. One patient experienced transient tachycardia without sequelae.Conclusions: Hyoscine butylbromide administered at the cecum aids polyp detection. Further studies are required to determine the contribution of colonic spasm to polyp miss rates.     

175例结肠镜诊断和治疗结肠息肉的临床分析

目的分析结肠息肉大小及分布特点,探讨色素结肠镜对结肠良性息肉的诊断及氩离子体凝固术(APC)、高频电凝电切术、内镜黏膜切除术(EMR)和钛夹术治疗良性息肉的临床疗效。方法收集2015年12月-2016年6月在该院消化科住院行内镜及病理诊断为良性结肠息肉且行治疗的175例患者资料。结果通过普通内镜和染色内镜检查,结肠良性息肉以单发性息肉为多;结肠在多部位有多发息肉类型为多;左半结肠中的直肠和乙状结肠息肉数较多且息肉直径较小,右半结肠中的升结肠息肉较少且直径较大,色素内镜有助于微小息肉和小息肉的诊断,染色检查提高了结肠多发息肉的检出率。结论色素内镜可以提高息肉检出率,尤其是多发息肉检出率,减少漏诊率,有助于良性息肉的鉴别诊断;依据结肠单发和多发息肉结合息肉大小选择APC、高频电凝电切术或者EMR其中一种内镜治疗或联合2种内镜治疗方法,疗效明确、手术安全,以APC息肉切除术最常用。     

SAR image classification based on alpha-stable distribution

We propose a classification algorithm that utilizes the alpha-stable distribution to model the texture features of synthetic aperture radar (SAR) images. The SAR image is first decomposed by stationary wavelet transform (SWT). After that, the alpha-stable distribution is applied to model the high-frequency subband coefficients of the image at each decomposition scale. A regression-type method is then used to estimate the alpha-stable distribution parameters, which form a feature vector that fully describes the texture. Finally, a SAR image classification algorithm is derived by exploiting this feature vector based on the support vector machines (SVM) approach. Because different combinations of alpha-stable distribution parameters contribute to differences in classification precision, a multilevel SVM (MSVM) classification algorithm is also presented to address the issue. Experimental results indicate that the proposed SAR image classification algorithm is effective and the MSVM algorithm improves the classification performance. Moreover, our proposed algorithm has low computational cost as only a small number of the alpha-stable distribution parameters are processed.     

Computer-aided detection for CT colonography: update 2007

Computed tomographic colonography (CTC) is an emerging technique for polyp detection in the colon. However, lesion detection can be challenging due to insufficient patient preparation, chosen CT technique or reader imperfection. The primary goal of computer-aided detection (CAD) for CTC is locating possible polyps, and presenting the reader with these polyp candidates. Other goals are sensitivity improvement and reduction of reading time and inter-observer variability. The multistep CAD procedure typically consists of segmentation of the colonic wall (e.g. region growing); selection of intermediate polyp candidates (curvature analysis, sphere fitting, normal analysis, slope density function ...); classification of final candidates for detection and listing suspicious polyps (location, size and volume). Remaining task for the radiologist is the validation or rejection of the polyp candidates. State-of-the-art CAD systems should require minimal or even no user interaction for the extraction of the colonic wall, offer a computation time less than 10-20 min and high sensitivity and specificity for different polyp sizes and shapes, with a low number of false positives. These systems have the potential to increase radiologist's performance and to decrease inter-reader variability. Besides CAD key techniques we also discuss new developments in CAD and describe recent applications facilitating CTC.     

结肠息肉内镜下黏膜切除术后迟发性出血的危险因素分析

目的探讨行结肠息肉内镜下黏膜切除术(EMR)后发生迟发性出血的相关危险因素。方法回顾性分析2016年1月-2018年12月在该院行结肠息肉EMR治疗的328例患者的临床资料。以是否发生迟发性出血分为两组(出血组和未出血组),对比两组患者临床指标的差异,采用Logistic回归模型分析EMR术后迟发性出血的独立危险因素。结果328例患者中发生术后迟发性出血22例(6.71%)。两组患者的年龄、高血压、肝硬化、抗凝药服用史、体质指数(BMI)、息肉大小、息肉形态和息肉数量比较,差异均有统计学意义(P<0.05);多因素Logistic回归分析显示,高血压、抗凝药服用史、息肉大小、息肉形态与迟发性出血发生存在密切关系(P<0.05)。结论结肠息肉患者合并高血压、长期服用抗凝药、息肉大小和息肉形态是发生EMR术后迟发性出血的独立危险因素。     

251例结肠息肉切除术后再发危险因素分析

目的 探讨结肠息肉切除术后再发的危险因素。方法 回顾性分析251例结肠息肉切除术后患者再发的危险因素。结果 男性、结肠息肉部位多发于全结肠、息肉个数>10个均为结肠息肉再发的危险因素（P值分别为0.009、<0.001、0.028）。再发组（160例）癌胚抗原水平高于未再发组（P=0.014）,而年龄、同型半胱氨酸水平...     

Improved medical image fusion based on cascaded PCA and shift invariant wavelet transforms

Purpose

In the medical field, radiologists need more informative and high-quality medical images to diagnose diseases. Image fusion plays a vital role in the field of biomedical image analysis. It aims to integrate the complementary information from multimodal images, producing a new composite image which is expected to be more informative for visual perception than any of the individual input images. The main objective of this paper is to improve the information, to preserve the edges and to enhance the quality of the fused image using cascaded principal component analysis (PCA) and shift invariant wavelet transforms.

Methods

A novel image fusion technique based on cascaded PCA and shift invariant wavelet transforms is proposed in this paper. PCA in spatial domain extracts relevant information from the large dataset based on eigenvalue decomposition, and the wavelet transform operating in the complex domain with shift invariant properties brings out more directional and phase details of the image. The significance of maximum fusion rule applied in dual-tree complex wavelet transform domain enhances the average information and morphological details.

Results

The input images of the human brain of two different modalities (MRI and CT) are collected from whole brain atlas data distributed by Harvard University. Both MRI and CT images are fused using cascaded PCA and shift invariant wavelet transform method. The proposed method is evaluated based on three main key factors, namely structure preservation, edge preservation, contrast preservation. The experimental results and comparison with other existing fusion methods show the superior performance of the proposed image fusion framework in terms of visual and quantitative evaluations.

Conclusion

In this paper, a complex wavelet-based image fusion has been discussed. The experimental results demonstrate that the proposed method enhances the directional features as well as fine edge details. Also, it reduces the redundant details, artifacts, distortions.

     

k-means based hybrid wavelet and curvelet transform approach for denoising of remotely sensed images

This article presents a new technique for denoising of remotely sensed images based on multi-resolution analysis (MRA). Multi-resolution techniques provide a coarse-to-fine and scale-invariant decomposition of images for image processing and analysis. The multi-resolution image analysis methods have the ability to analyse the image in an adaptive manner, capturing local as well as global information. Further, noise, as one of the biggest obstacles for image analysis and for further processing, is effectively handled by multi-resolution methods. The article aims at the analysis of noise filtering of image using wavelets and curvelets methods on multispectral images acquired by the QuickBird and medium-resolution Landsat Thematic Mapper satellite systems. To improve the performance of noise filtering, an iterative thresholding scheme and a hybrid approach based on wavelet and curvelet transforms are proposed for restoring the image from its noisy version. Two comparative measures are used for evaluation of the performance of the methods for denoising. One of them is the peak signal-to-noise ratio and the second is the ability of the noise filtering scheme to preserve the sharpness of the edges. By both of these comparative measures, the hybrid approach of curvelet and wavelet for heterogeneous and homogeneous areas with iterative threshold has proved to be better than the others. Results are illustrated using QuickBird and Landsat images for proposed methods and compared with wavelets and curvelet-based denoising.     

超声在儿童结肠息肉诊断中的应用价值

目的探讨超声对儿童结肠息肉的诊断价值及其超声声像图特征。方法回顾性分析342例术前进行超声检查并经结肠镜及病理证实的结肠息肉患儿的超声表现。结果 342例患儿中男244例,女98例。224例(65.5%)患儿发病年龄为3～6岁。单发息肉333例,位于乙状结肠226例,直肠41例,余段结肠66例。多发息肉9例,共33枚。息肉最大5.3cm×1.7cm×3.1cm,最小0.6cm×0.5cm×0.5cm。超声诊断332例(97.1%),超声表现均为中等回声结节,其内部可探及小囊腔且CDFI血供丰富,可探及蒂血流及息肉内部树枝状血流。<1cm的息肉囊腔及蒂结构不明显,但CDFI可探及明确的血流信号。16例患儿超声检出合并继发肠套叠,表现为同心圆征象,套入起始部肠腔内可探及息肉回声。其中14例患儿息肉位于降结肠及结肠脾曲。结论超声诊断儿童结肠息肉方便、无创、无放射性且检出率高,是血便患儿首选检查方法。结肠息肉超声声像图具有特异性,不易与其他病变混淆,在儿童一般不需鉴别诊断。     

结直肠息肉经内镜摘除术后并发出血的危险因素分析

目的分析结直肠息肉经内镜摘除术后并发出血的危险因素。方法以该院收治的342例行内镜摘除术治疗的结直肠息肉患者为研究对象,统计该组患者经内镜摘除术后并发出血的发生率。并将该组患者分为并发出血组和未并发出血组,以术后并发出血为因变量,以可能诱发患者术后出血的相关因素(性别、年龄、合并糖尿病、合并高血压、高血脂史、饮酒史、息肉发生位置、息肉病理分型、息肉大小、息肉形态和息肉数量)为自变量,先进行单因素回归分析,再运用Logistic回归分析工具进行多因素分析。结果该组342例患者术后并发出血的发生率为7.60%(26/342)。单因素分析结果显示,并发出血组患者合并高血压者比例高于未并发者(P0.05),合并高血脂史者比例高于未并发者(P0.05),息肉直径2.0 cm者比例高于未并发者(P0.05),息肉形态有蒂息肉者比例高于未并发者(P0.05)。多因素分析结果显示,高血压、合并高血脂、息肉直径2.0 cm、息肉形态有蒂息肉均为结直肠息肉经内镜摘除术后并发出血的危险因素(P0.05)。结论结直肠息肉经内镜摘除术后并发出血的危险因素包括高血压、合并高血脂、息肉直径2.0 cm、息肉形态为有蒂息肉。     

基于非下采样双树复轮廓波变换的小波纹理特征识别肺良恶性结节CT图像

目的 观察基于非下采样双树复轮廓波变换（NSDTCT）的小波纹理特征在识别肺良恶性结节CT图像中的应用价值。方法 从肺结节患者的CT图像中分别提取基于NSDTCT和基于Contourlet变换的小波纹理参数,对高维纹理参数采用单因素分析、Lasso回归等方法进行降维。对降维后的纹理参数分别构建诊断良恶性肺结节的支持向量机分类诊断模型,绘制ROC曲线,比较2种方法的诊断效能。结果 采用NSDTCT方法,基于经Lasso降维且自变量数目较少的纹理参数构建的诊断模型分类效果最好,判断良恶性肺结节的准确率为98.37%,AUC为1.00;采用Contourlet变换方法,基于全部提取纹理参数构建的模型分类效果最好,诊断准确率为56.05%,AUC为0.73;2个模型的ROC曲线的AUC差异有统计学意义（Z=6.430,P<0.001）。结论 基于NSDTCT的纹理分析方法对判断良恶性肺结节的准确性较高。     

Characterization of colonic polyps at conventional (nonmagnifying) colonoscopy after spraying with 0.2 % indigo carmine dye

BACKGROUND AND STUDY AIMS: Japanese endoscopists have devised a classification system based on mucosal crypt patterns which is helpful for distinguishing between hyperplastic polyps, adenomas, and invasive cancers at colonoscopy. The aim of this study was to assess how well the various types of colonic polyp could be distinguished using conventional colonoscopes after spraying with 0.2 % indigo carmine dye. PATIENTS AND METHODS: The endoscopic appearances of all colonic lesions were assessed in 476 unselected patients using normal-resolution, nonmagnifying colonoscopes after spraying with 0.2 % indigo carmine dye. RESULTS: A total of 709 lesions were found in the 476 patients, and histology was available for 673 of these lesions: 187 lesions were found to be non-neoplastic (128 hyperplastic, 2 juvenile, 30 inflammatory, and 27 classified as "others"); 467 lesions were adenomatous; and 19 lesions were carcinomas. Of the 467 adenomas, 377 were tubular, 77 were tubulovillous, 8 were villous and 5 were serrated; 423/467 were correctly identified (sensitivity 91 %). Of the 187 non-neoplastic lesions, 153 were correctly classified (specificity 82 %). A total of 343 of the 377 tubular lesions were correctly identified as tubular adenomas (sensitivity 90 %), and 46 of the 77 tubulovillous lesions were correctly identified. CONCLUSIONS: Standard colonoscopy with dye spraying can be used to differentiate colonic polyps. Magnification is not always necessary to distinguish neoplastic from nonneoplastic colonic lesions. This finding could result in resource savings in colonoscopic screening.     

生存素及血管内皮生长因子在结肠腺瘤性息肉及腺癌中的表达

目的 探讨非家族性大肠腺瘤性息肉及腺癌中生存素（Survivin）及血管内皮生长因子（VEGF）的表达，为预测腺瘤性息肉癌变提供理论基础。方法 收集我院2004年1月至2005年12月大肠腺瘤性息肉及腺癌标本，利用免疫组化技术分别检测40例腺瘤性息肉，40例大肠腺癌及相应的正常黏膜对照中Survivin、VEGF的表达情况。结果 Survivin、VEGF的表达强度均依次为腺瘤黏膜对照组＜腺癌黏膜对照组＜腺瘤组＜腺癌组， Survivin 及VEGF在正常黏膜与腺瘤性息肉及腺癌中的表达依次增强，且均有统计学意义（均P＜0.01）。结论 VEGF在腺瘤的增生、癌变、肿瘤的形成、生长和血管形成中起重要作用； Survivin可能是大肠腺瘤发展及癌变过程中的重要促进因子，对于预测大肠腺瘤癌变可能性及化学干预有重要意义。     

西北某地内镜下诊治小儿结直肠息肉的临床研究

目的探讨西北某地结肠镜对小儿结肠息肉的诊断和治疗价值。方法对2015年1月-2016年12月诊断的112例1~18岁患者的结肠镜检查及治疗资料进行回顾性分析。在该项研究中评估的临床变量包括:性别,年龄,症状,发病年龄的症状,息肉的识别年龄,间隔时间之间的症状和内镜诊断结肠息肉,结肠息肉和/或结直肠癌家族史。息肉的特征还包括:数量,形态类型,直径,组织学和分布。笔者对人口统计,临床过程,实验室检查结果,内镜和病理组织学特征,治疗和结果进行了分析。结果在112例患者中,年龄中位数为6.9岁,其中男占64.3%(72/112)。所有患者有便血的症状,只是小部分患者有腹痛症状、肛门息肉和腹泻。9.8%(11/112)轻度贫血,贫血的患者都有6个多月的便血症状,与息肉部位无关。91.9%(103/112)的患者被确定为幼年性息肉,炎性息肉为7.1%(8/112),0.9%(1/112)被确定为腺瘤。1.8%(2/112)的患者有结肠息肉的家族史,无结直肠癌家族史。结论该地区儿童结直肠息肉发病率较高。男性明显多于女性。小部分患者有家族性结直肠息肉病史无结直肠癌家族史。小部分便血患者有轻度贫血。息肉主要位于直肠和乙状结肠。幼年型息肉为主要病理类型,其次为炎性息肉和腺瘤。腺瘤可能位于直肠和乙状结肠以外的其他地方。     

Two cases of colonic adenomatous polyps accompanied by a migrated surgical suture

A 56-year-old man and a 70-year-old woman, with histories of left colectomy and appendectomy respectively, were admitted to our hospital. In both cases, colonoscopy showed a pedunculated colonic polyp in the ascending colon, and a silk suture became visible in the stalk during polypectomy. The histological diagnosis was adenoma. These two cases constitute the first report of colonic adenomatous polyps accompanied by suture migration.     

Endoscopic polypectomy in the colon (author's transl)]

A report is given on the endoscopic removal of 81 polyps of the colon by means of high frequency diathermy. This procedure proved to be without risk to the patient and has largely replaced surgical removal by laparotomy as the method of choice today. Total removal of the polyp with subsequent histological examination is naturally imperative to avoid unnecessary subsequent radical surgical procedures. Since most colonic carcinomas arise in the base of a polyp, polypectomy represents a true prophylactic measure and, in some cases, a therapeutic one.     

Wavelet optimization for content-based image retrieval in medical databases

We propose in this article a content-based image retrieval (CBIR) method for diagnosis aid in medical fields. In the proposed system, images are indexed in a generic fashion, without extracting domain-specific features: a signature is built for each image from its wavelet transform. These image signatures characterize the distribution of wavelet coefficients in each subband of the decomposition. A distance measure is then defined to compare two image signatures and thus retrieve the most similar images in a database when a query image is submitted by a physician. To retrieve relevant images from a medical database, the signatures and the distance measure must be related to the medical interpretation of images. As a consequence, we introduce several degrees of freedom in the system so that it can be tuned to any pathology and image modality. In particular, we propose to adapt the wavelet basis, within the lifting scheme framework, and to use a custom decomposition scheme. Weights are also introduced between subbands. All these parameters are tuned by an optimization procedure, using the medical grading of each image in the database to define a performance measure. The system is assessed on two medical image databases: one for diabetic retinopathy follow up and one for screening mammography, as well as a general purpose database. Results are promising: a mean precision of 56.50%, 70.91% and 96.10% is achieved for these three databases, when five images are returned by the system.