多层螺旋CT仿真结肠镜诊断直、结肠病变

目的: 研究多层螺旋CT(MSCT)仿真结肠镜诊断结肠病变的临床价值.材料和方法: 应用MSCT对63例患者行一次屏气全结肠容积扫描,包括直结肠癌39例,息肉19例,多憩室2例,慢性结肠炎2例,纤维脂肪瘤1例.除憩室、慢性结肠炎2例外,均经手术和常规结肠镜活检病理证实.用工作站软件获取仿真结肠镜CTVC、多平面重建MPR、表面遮盖显示SSD和透明显示Raysum等图像进行分析比较.结果: MSCTVC能够显示结肠癌的大体分型、大于5.0mm的癌结节和溃疡;有利于显示大于3.0mm的息肉检出,与常规结肠镜比较直结肠癌肿检出率为100%;直结肠息肉检出率为92.3%.MPR能直观反映息肉和癌肿处肠壁及肠周受侵状况,对癌肿肠周受侵判断正确率达100%.结合SSD更有助于对假阳性的鉴别.Raysum在显示癌肿的长度上占优势,判断正确率达100%,结论: MSCTVC、MPR、SSD、Raysum检查结肠占位性病变的临床应用价值各有不同,4种后处理技术的结合,更有助于病变的检出与病变的定位、定性.MSCT仿真结肠镜将为直结肠病变的检查开创新的临床途径.     

多层螺旋CT在诊断结肠病变中的应用

目的；研究MSCT结肠检查4种后处理成像技术及其临床应用价值。方法：应用MSCT对37例患行一次屏气全结肠段容积扫描，包括结肠癌14例，结肠息肉16例，慢性结肠炎5例，结节型回盲辨误诊息肉1例，结肠多发憩室1例。除1例憩室外，均经手术和／或纤维结肠镜检查活检病理证实。在工作站获取多平面重建（MPR）、CT仿真结肠镜（CTVC）、三维表面遮盖显示（3D－SSD）、四维透明显示（4D－Raysum)4种后处理图像并进行比较。结果：CTVC有利于息肉的检出，本组显示最小息肉直径为3.5mm，与纤维内镜比较息肉的总检出率为86．5％。MPR能直观反映息肉和癌肿处理壁及肠周侵犯情况，对癌肿肠周侵犯判断正确率达100％，同时有助于结肠正常结构、粪块及肿瘤鉴别。4D－Raysum较3D－SSD、MPR及CTVC在显示癌肿长度上占优势，判断正确率可达100％，亦优于钡灌肠检查。结论：MPR、CTVC、3D－SSD、4D－Raysum检查结肠病变临床应用价值各有不同，4种后处理技术的结合更有利于结肠病变的诊断。     

CT仿真结肠镜与三维重建相结合对结肠病变的诊断价值

目的探讨多排螺旋CT仿真结肠镜与三维重建相结合在结肠病变中的临床应用价值。方法分析26例CT仿真结肠镜的病例并经纤维结肠镜及临床手术病理证实的病例：结果结肠癌7例(其中1例伴有息肉)、结肠炎5例、结肠息肉6例、结肠憩室1例、结肠镜未见异常4例、结肠镜显示不满意3例：其中，纤维结肠镜所见的息肉均被仿真结肠镜所显示.纤维结肠镜所不能到达的肠腔被仿真结肠镜发现肿瘤1例：结肠炎症可表现为黏膜展平，管腔狭窄，呈渐进性改变，对点状出血不能显示、结论cT仿真结肠镜结合三维重建作为一种非侵入性的新检查方法，弥补了纤维结肠镜和结肠造影的不足。     

成人肠套叠MSCT病因学诊断价值

目的 探讨MSCT对成人肠套叠病因学诊断价值.方法 对40例MSCT诊断成人肠套叠并经手术治疗患者的CT、手术及病理资料进行回顾性分析.结果 小肠套叠12例,结肠套叠18例,回盲部肠套叠10例,手术均发现有原发病变.良性病变14例(35.0％),恶性病变26例(65.0％),小肠套叠主要为良性病变(58.3％),结肠套叠主要为恶性肿瘤(88.9％),回盲部肠套叠良恶性病变各占一半.良性病变以息肉、腺瘤和脂肪瘤多见(71.4％),恶性病变以结肠癌和淋巴瘤多见(88.5％).原发病术前CT检出率77.5％ (31/40),术后回顾CT检出率87.5％ (35/40).回顾性分析,CT平扫和增强的原发病检出率分别为73.3％ (22/30)和90.9％ (20/22).术后判断CT检出的35例原发病性质,正确31例,错误3例,l例未能判断,准确率88.6％ (31/35).结论 MSCT对成人肠套叠及其病因学诊断具有重要临床价值.     

结肠肿瘤病变的多层螺旋CT内窥镜技术及临床运用

结肠癌已经成为第3位常见肿瘤和工业国家第2位的癌症致死的原因，越来越受到高度重视。早期发现肿瘤或肿瘤前期病变，成为结肠肿瘤防治的重要方面。大多数的结肠癌被认为起源于很长时间缓慢发展的良性腺瘤样息肉，且可以通过结肠镜切除而得到防治。怎样及时准确地发现肿瘤前期病变是结肠肿瘤病变研究的重点。对结肠病变的检查方法有大便隐血实验、乙状结肠镜、结肠镜和气钡双对比灌肠造影等。CT结肠镜或称为虚拟结肠镜技术在1994年首先由Vininv等提出，随着CT技术的不断发展，CT结肠镜技术越来越成熟，尤其是近年来多层CT的出现，使其诊断准确性得到肯定，认为CT结肠镜技术是一种有效的、在结肠癌高危无症状病人中发现结肠肿瘤的有效工具。本文就结肠内窥镜技术的情况综述如下。     

多层螺旋CT结肠成像技术的应用

结肠癌是老年人群发病率和病死率最高的恶性肿瘤之一,大多数结肠癌被认为起源于腺瘤性息肉,结肠筛选检查可发现腺瘤性息肉和早期癌瘤,能有效降低结肠癌的发病率和病死率。螺旋CT结肠成像术(CT Colonography,CTC)因操作简便、无创伤,被认为是一种行之有效的结肠筛选检查方法。特别是,随着多层螺旋CT(multi-slice spiral CT,MSCT)的应用和技术的不断改进,CTC的图像质量和分析能力有了明显的改善,CTC对于发现1cm以上息肉的敏感性和特异性与结肠镜近似,在结肠检查中显示了显著优势。本文重点介绍CTC检查技术、进展和在结肠癌筛选中的价值。     

多种技术结合优化CT结肠造影后处理程序

目的 评价CT结肠造影(CTC)后处理方法对结肠病变检出的有效性,并总结了结肠CTC检查后处理的最优化程序.方法 分别应用多平面重建、表面重建、透明重建、仿真内窥镜和管腔展开等后处理方法,对42例经电子结肠镜或手术病理证实的结肠病变患者的结肠充气CTC数据进行分析.结果 42例患者共检出22枚息肉,28例结肠癌(2例肠壁局限性增厚,26例共28个肿块)和8例结肠炎性病变.对3种类型病变的检出率,多平面重建分别为81.8%、100%和100%;仿真内窥镜分别为100%、100%和87.5%;表面重建分别为36.4%、92.9%和62.5%;透明重建分别为45.5%、92.9%和62.5%.管腔展开技术对所检病变的显示率达100%.结论 采用优化程序对CTC数据进行后处理并结合多种后处理技术可提高CTC的诊断效率和准确率.     

结肠癌和结肠息肉的多排螺旋CT检查进展

结肠癌和结肠息肉是结肠常见疾病,其影像学检查方法有多种,各有优缺点。近年来随着多排螺旋CT(multi-detector spiral CT,MSCT)的技术进步,特别是后处理软件不断改进,在诊断结肠病变方面取得了巨大进展。本文就MSCT在结肠癌和结肠息肉的研究进展作一综述。     

16层螺旋CT仿真结肠镜的临床应用价值探讨

目的：探讨16层螺旋CT仿真内镜结合其它后处理技术诊断结肠病变的临床应用价值。方法：32例结肠癌、结肠息肉和结肠憩室患者行结肠充气螺旋CT扫描,利用随机附带软件进行结肠仿真内镜、多平面重组和容积再现技术等观察,并与纤维结肠镜结果比较。结果：所有病例均获得满意的结肠后处理图像,仿真内镜结合多平面重组和容积再现技术,对结肠病变作出了准确的定量和定性诊断。结论：16层螺旋CT仿真内镜及其后处理技术对结肠病变的显示具有与结肠镜相似的敏感性和特异性,且能提供比结肠镜更丰富的诊断信息。     

多层螺旋CT对结肠癌的诊断价值

目的探讨多层螺旋CT(MSCT)对结肠癌的诊断价值。方法对检查中的36例疑为结肠癌的患者行低张水或3%泛影葡胺充盈结肠,进行MSCT平扫及增强扫描,以横断面为主,结合多平面重组(MPR),观察肿瘤部位、形态、大小及周围侵犯及转移情况,作出诊断及分期,并与术后病理对照。结果乙状结肠5例,升结肠12例,横结肠6例,降结肠8例,盲肠5例;大体病理呈息肉型或肿块型18例,溃疡型6例,浸润型或狭窄型12例。术前诊断与术后结果符合率100%。术前CT分期与术后分期总符合率91.1%。结论 MSCT在结肠癌检查中具有独特的优越性,是一种快速、安全、无创伤且较准确的检查方法。     

Colorectal cancer: role of CT colonography in preoperative evaluation after incomplete colonoscopy

PURPOSE: To evaluate computed tomographic (CT) colonography in patients with clinical suspicion of colorectal cancer and in whom colonoscopy was incomplete. MATERIALS AND METHODS: After incomplete colonoscopy, 34 patients underwent CT colonography before and after intravenous injection of iodinated contrast agent, in supine and prone positions. Twenty patients with no evidence of colon cancer after complete colonoscopy were included as a control group. Sensitivity and specificity of CT colonography were determined for detection of cancers, polyps, and metastases to liver. RESULTS: In 29 patients, surgery revealed 30 colorectal cancers (three synchronous cancers) and two ischemic lesions of the descending colon. Colonoscopy missed 10 colorectal cancers and three synchronous cancers; all were detected with CT colonography. Sensitivity and specificity for detection of colorectal cancer were 56% and 92%, respectively, for incomplete colonoscopy and 100% and 96%, respectively, for CT colonography (P <.01). Sensitivity and specificity of CT colonography in detection of polyps were 86% and 70%, respectively, for diameters of 5 mm or less; 100% and 80%, respectively, for 5-10-mm diameters; and 100% for diameters greater than 10 mm. Spiral CT of the liver revealed four metastases (2-5 cm); sensitivity and specificity were 100% and 43% for nonenhanced scans and 100% for contrast-enhanced scans (P <.01). CONCLUSION: In this selected group of patients, CT colonography provided complete information to properly address surgery of colorectal cancer and treatment of liver metastases.     

Occlusive colon carcinoma: virtual colonoscopy in the preoperative evaluation of the proximal colon

PURPOSE: To evaluate the use of preoperative virtual colonoscopy to examine the proximal colon in patients with distal occlusive carcinomas, defined as cancers that cannot be traversed endoscopically. MATERIALS AND METHODS: Twenty-nine patients with occlusive colorectal carcinomas underwent preoperative virtual colonoscopy with use of a standard protocol. Patients with acute bowel obstruction were excluded. Results of virtual colonoscopy were compared with the findings of preoperative colonoscopy, preoperative barium enema examination, intraoperative colon palpation, histopathologic outcome, and postoperative colonoscopy and barium enema examination, where possible. RESULTS: Virtual colonoscopy helped identify all 29 occlusive carcinomas and demonstrated two cancers and 24 polyps in the proximal colon. Both synchronous cancers were confirmed intraoperatively and resected. Postoperative conventional colonoscopy in 12 patients confirmed 16 polyps identified at virtual colonoscopy and demonstrated two subcentimeter polyps missed at virtual colonoscopy. Postoperative barium enema examination was performed in two patients and helped confirm two polyps identified at virtual colonoscopy. Virtual colonoscopy successfully demonstrated the proximal colon in 26 of 29 patients examined compared with preoperative barium enema examination, which failed to adequately demonstrate the proximal colon in any patient examined. CONCLUSION: Virtual colonoscopy is a feasible and useful method for evaluating the entire colon before surgery in patients with occlusive carcinomas.     

Usefulness of CT colonography in the preoperative evaluation of patients with distal occlusive colorectal carcinoma

PURPOSE: To evaluate the role of preoperative virtual colonoscopy to study the proximal colon in patients with distal occlusive carcinomas, diagnosed by conventional colonoscopy. MATERIAL AND METHODS: We examined 19 patients aged 46 to 83 years (13 men and 6 women) with distal occlusive colorectal carcinomas diagnosed by conventional colonoscopy, who were preoperatively studied with virtual colonoscopy. Patients with acute bowel obstruction were excluded. Results were compared with the findings of preoperative conventional colonoscopy and barium enema examination, intraoperative colon palpation, histopathologic outcome, postoperative conventional colonoscopy and barium enema examination. RESULTS: Virtual colonoscopy identified all 19 distal occlusive colon carcinomas and 22 synchronous lesions, 2 cancers (prevalence 10,6%) and 20 polyps (prevalence 68,4%). Both synchronous cancers were confirmed intraoperatively by direct palpation. Postoperative conventional colonoscopy, which was performed in 18 patients, confirmed the presence of 15 polyps in 12 patients. Three subcentimeter polyps were removed during conventional colonoscopy and were missed at virtual colonoscopy. Two polyps shown by virtual colonoscopy were not found at conventional colonoscopy. Postoperative barium enema was performed in three patients and confirmed three polyps identified at virtual colonoscopy. Preoperative barium enema was performed in five patients and failed to adequately demonstrate the proximal colon. Virtual colonoscopy showed a sensitivity of 87% and a specificity of 75%. CONCLUSIONS: Virtual CT colonoscopy can be considered an important diagnostic technique to evaluate preoperatively the proximal colon in patients with distal occlusive carcinomas,as it gives better results than barium enema or conventional colonoscopy, as well as being well tolerated and less invasive.     

多层螺旋CT扫描在结直肠癌诊断和术前分期中的应用价值

目的:评价多层螺旋CT扫描(MSCT)在结直肠癌诊断和术前分期中的应用价值。方法:回顾性分析经手术或常规结肠镜活检病理证实的40例结直肠癌的多层螺旋CT表现,并与病理结果对照。结果:病理证实结直肠癌40例(其中盲肠癌6例,升结肠癌3例,横结肠癌3例,降结肠癌5例,乙状结肠癌1例,直肠癌22例),多层螺旋CT检出了全部结直肠癌,敏感性为100%,总的分期准确率为80%(32/40),B期分期准确率为83.3%(15/18),C期分期准确率为66.7%(8/12),肿瘤浆膜外侵犯的敏感性和特异性分别为95%(36/34)和50%(2/4),淋巴结转移的敏感性和特异性分别为60%(12/20)和90%(9/10)。结论:多层螺旋CT扫描(MSCT)可以有效地显示结直肠癌的部位、大小和形态、确定中晚期结直肠癌的侵犯范围、远处转移及淋巴结转移等,从而更准确地诊断并进行术前分期,具有较高的临床应用价值。     

多层螺旋CT在结直肠癌诊断中的价值

目的 探讨多层螺旋CT(MSCT)在结直肠癌诊断中的价值.方法 回顾性分析经手术病理证实的42例结直肠癌MSCT资料,所有病例均做多平面重组(MPR),部分病例加做曲面重组(CPR)、表面遮盖法重组(SSD) 、仿真结肠镜成像(CTVC)、透明重建(Raysum),将MSCT表现与手术和病理结果进行比较.结果 MSCT对结直肠癌的检出率为100%,定性准确率100%;对肿瘤向邻近组织侵犯诊断准确率为82.9%(29/35),腹部脏器转移诊断准确率为100%(7/7),淋巴结转移诊断敏感性为71%(22/31)而特异性为100%.结论 MSCT扫描结合多种重建技术能明确结直肠癌的诊断,对临床治疗有指导作用.     

多排螺旋CT双体位检查对结直肠癌术前评估的价值再探

目的:探讨多排螺旋CT(MSCT)双体位检查对结直肠癌术前分期的价值.材料和方法:搜集102例经肠镜确诊的直肠癌患者行MSCT仰卧、俯卧位扫描,扫描前清洁肠道,并经肛门注气,扫描范围从膈顶至耻骨联合下缘.102例结直肠癌患者全部经肠镜或手术病理证实,全部病例均有手术、术前MSCT、术后病理等完整资料参与分期研究,将影像诊断结果与手术病理结果进行对照.结果:MSCT总的分期准确率82.4%(84/102),判断T、N、M分期的准确率分别是93.1%(95/102)、83.3%(85/102)、99.0%(101/102),判断淋巴结转移的敏感性和特异性分别为93.9%和88.7%.结论:MSCT双体位扫描对直肠癌的术前分期有重要价值,有助于判断肿瘤浆膜外侵犯及区域淋巴结转移情况.     

Colon cancer: comprehensive evaluation with 64-section CT colonography using water enema as intraluminal contrast agent-a pictorial review

Sixty-four-section CT colonography with water enema combines intracolonic neutral contrast agent with high-resolution CT images of the abdomen. Owing to submillimeter isotropic voxels, high-quality reformatted images are obtained. High-resolution images offer added value for the detection and localization of colonic lesions, evaluation of the local extent of the disease, and depiction, if any, of synchronous colorectal lesions and distant metastases. Sixty-four-section CT colonography with water enema has a major role in the evaluation of patients with colon cancer before planning therapy. It can be used to complement failed or incomplete colonoscopy and investigate the colon in elderly patients.     

Colonoscopy with computed tomography with volume reconstruction. The results and a comparison with endoscopy and surgery

PURPOSE: Virtual CT colonoscopy is a novel technique whose diagnostic accuracy and clinical yield are currently investigated. Several studies have shown its capabilities in detecting colon and rectal cancers. We report the results of a preliminary experience with the volume rendering technique and compare CT colonoscopy with endoscopy and surgery. MATERIAL AND METHODS: Our series consisted of 25 patients with colon cancer confirmed at endoscopy and/or surgery. All examinations were carried out with a spiral CT scanner Philips Tomoscan AVE1. Intestinal preparation was adequate in all patients, consisting in gas insufflated immediately before acquisition, after the injection of 100 mL iodinated contrast agent. All examination were performed in prone position using axial 5 mm slices with 5 mm table feed (pitch 1) and 2 mm reconstruction index; 120 kV and 200-250 mA were used. Images were transferred to a workstation (Easy Vision, Philips, release 4.2.1.1) for processing. We acquired multiplanar (MPR) and virtual endoscopic images with volume rendering; the selected threshold was -250 to -600 Hounsfield Units. Virtual endoscopic images could be obtained in 23 of 25 cases. The results of the radiological study were compared with endoscopic and surgical findings in 25 and 17 cases, respectively. RESULTS: Endoscopy and surgery detected 46 lesions: 29 were malignant and 17 benign. Axial CT and MPR alone detected 35 lesions (76%), 29 of them malignant and 6 benign. The 11 benign lesions missed by axial CT ranged 6-8 mm in diameter. There were no false positives. CT colonoscopy alone detected 66 lesions, but 22 of them were false positive due to residual stool in the colon (21 cases) and to residual barium in the colon (1 case). Combining CT colonoscopy and axial and MPR images enabled to correct the false positive diagnoses made by CT colonoscopy alone and to decrease the false negative ratio of axial and MPR images. Forty-one of 44 lesions (93%) were detected. Thirty-seven lesions were found in the 17 surgical patients; 34 of them were correctly identified combining CT colonoscopy and axial and MPR findings, while endoscopy detected only 31 lesions. Thus, CT had 92% sensitivity, versus 83% of fiberoptic endoscopy. CONCLUSION: In this preliminary experience volume rendering CT colonoscopy exhibited high sensitivity in detecting colon cancers, but their correct evaluation and characterization can be obtained if axial and MPR studies are combined. Further investigation and technological developments are necessary to define the yield of this new technique.     

Virtuelle Koloskopie mit der Mehrschichtcomputertomographie

SUBJECT: Using multi-slice computed tomography (MSCT) large body areas can scanned with high spatial resolution. In this study, MSCT was employed for virtual colonoscopy in various pathologies of the colon. MATERIALS AND METHODS: For MSCT a Somatom Plus 4, Volume Zoom scanner, (Siemens, Forchheim) was employed, equipped with four parallel detector rows. Twenty-five patients were included in this trial, prior to colonoscopy or partial colon resection. After cleaning the colon, distension was achieved by insufflation of room air using a rectal tube. The parameters of acquisition and reconstruction were as follows: collimation 4 x 1 mm and 4 x 2.5 mm respectively; tube charge per slice: 140-160 mAs; pitch 5-6; i.v. contrast medium: 120 ml Ultravist 300 (Schering) with a flow rate of 3 ml/s; delay: 35 s. For 3D reconstruction we used edge-enhanced volume rendering, virtual colonoscopy and extraluminal views of volume-rendered images. RESULTS: Nine polyps and four of five colon carcinomas were detected using MSCT virtual colonoscopy. In three patients with ulcerative colitis virtual coloscopy revealed morphological alterations compatible with this disease. In two of four patients with multiple diverticula of the colon the true extent of the disorder could be assessed in virtual colonoscopy. CONCLUSION: Utilizing virtual MSCT colonoscopy polyps and cancer of the colon can be reliably detected, if proper cleaning and distension is provided. On axial images alone smaller polyps may be assessed. The high z-axis resolution of MSCT offers superior conditions for CT-based virtual colonoscopy.     

MR colonography in patients with incomplete conventional colonoscopy

PURPOSE: To assess dark-lumen magnetic resonance (MR) colonography for the evaluation of colonic segments in patients in whom conventional colonoscopy could not be completed. MATERIALS AND METHODS: Institutional review board approval and written informed consent were obtained. Within 24 hours of incomplete conventional colonoscopy, 37 patients (22 women, 15 men; age range, 25-63 years) underwent MR colonography. Contrast material-enhanced T1-weighted three-dimensional images were collected after rectal administration of water for colonic distention. Data from MR colonography were evaluated by two radiologists. With a three-point scale, image quality was characterized in terms of colonic distention (1 = good; 2 = moderate, diagnostic; and 3 = poor, nondiagnostic) and presence of artifacts (1 = none; 2 = moderate, diagnostic; and 3 = extensive, nondiagnostic). Depiction of colorectal disease was assessed according to the following colonic segments: cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum. RESULTS: Four patients had history of colorectal cancer, and each had undergone partial colonic resection of two segments. Hence, 214 segments were evaluated. Conventional colonoscopy failed in assessment of 127 of 214 potentially visible colonic segments in the 37 patients. MR image quality was rated diagnostic in 35 patients and permitted assessment of 206 of 214 potentially visible segments. Nondiagnostic image quality in two patients was attributed to inadequate distention of prestenotic colonic segments owing to high-grade tumor stenosis. All inflammation- and tumor-induced stenoses and all five polyps identified at conventional colonoscopy in poststenotic segments were correctly detected at MR colonography. However, MR-based assessment of prestenotic segments revealed two lesions suspected of being carcinoma, five polyps, and four segments affected by colitis. CONCLUSION: MR colonography proved reliable in evaluating the majority of colonic segments inaccessible with conventional colonoscopy. The identification of additional disease at MR colonography underscores the need for a second diagnostic step in the setting of incomplete conventional colonoscopy.