64层螺旋CT仿真内窥镜检查结、直肠病变的临床价值分析

目的探讨64层螺旋CT仿真内窥镜对结、直肠疾病的诊断价值。方法对120例临床高度怀疑结、直肠疾病的患者分别采用仿真内窥镜（CTVE）和纤维常规结肠镜进行检查，统计CTVE诊断结果，并与常规纤维肠镜（CC）的病理诊断结果进行对比分析。结果本文120例患者中有4例患者因为肠道准备不足，而未获得满意的诊断结果，其余116例患者均获得了满意诊断结果。其中常规纤维肠镜诊断显示结、直肠癌52例，结、直肠息肉24例，慢性结、直肠炎22例，溃疡结、直肠炎12例，正常6例。其中常规CT仿真结肠镜诊断结果显示结、直肠癌48例，结、直肠息肉22例，慢性结、直肠炎18例，溃疡结、直肠炎8例，正常20例。结论64层螺旋CT仿真内窥镜技术作为一种相对无创的检查方法，具有扫描速度快，高分辨率，检查无创性等优势，可作为结、直肠疾病检查的一种重要手段。     

结直肠癌病变部位与单体位扫描的关系在减少CT剂量中的对照研究

目的探讨不同部位结直肠癌病变显示清晰程度与扫描体位(仰卧位和俯卧位)的关系,为减少CT结肠成像(CT colonography,CTC)检查剂量、选择最佳单体位扫描提供理论依据。资料与方法对52例结直肠癌患者术前行CTC,均行仰卧位及俯卧位检查,将CTC结果与纤维肠镜和手术病理对照。结果52例结直肠癌中,病变位于直肠27例,肛管3例,乙状结肠9例,降结肠3例,横结肠4例,升结肠6例,均为单发病灶。病变位于直肠25例(92.59%)(χ2=32.72,P<0.05),位于乙状结肠9例(100%)(χ2=8.42,P<0.05)。俯卧位上肠管充气明显,病变显示清晰,优于仰卧位,差异具有统计学意义;病变位于横结肠4例(100%)(χ2=4.5,P<0.05),仰卧位肠管充气明显,病变显示清晰,优于俯卧位,差异具有统计学意义。升降结肠病变在仰卧位(9/9)及俯卧位(9/9)上肠管充气效果相同,均显示清晰,差异无统计学意义;肛管癌在仰卧位(0/3)及俯卧位(0/3)上均显示欠佳,由于病例数少,差异无统计学意义。CT显示浆膜面受侵的诊断正确率为85.71%,CT诊断淋巴结转移的假阳性率为25%,假阴性率为12.90%,远...     

64层螺旋CT结肠成像在结直肠癌术前定位及T分期中的应用价值

目的探讨64层螺旋CT结肠成像(CTC)在结直肠癌术前定位及T分期中的应用价值。方法对59例结直肠癌患者行CTC检查,应用后处理工作站Colon软件进行图像分析,并以手术病理结果为标准,评价CTC对结直肠癌术前定位及T分期的准确率。结果 59例结直肠癌中,3例位于盲肠,9例位于升结肠,5例位于横结肠,7例位于降结肠,14例位于乙状结肠,21例位于直肠。CTC对结直肠癌术前定位及T分期诊断的准确率分别为94.9%(56/59)和88.1%(52/59)。CTC评价浆膜外侵犯的敏感度、特异度、阳性预测值、阴性预测值分别为97.7%(42/43)、81.3%(13/16)、93.3%(42/45)、92.9%(13/14)。结论 64层螺旋CTC在结直肠癌术前定位及T分期的诊断中具有重要的价值。     

16层螺旋CT及后处理技术对大肠病变的诊断价值

目的：探讨16层螺旋CT及后处理技术对大肠病变的诊断价值。方法：回顾性分析经手术和/或纤维肠镜活检病理证实的63例大肠病变的16层螺旋CT及后处理影像资料。结果：63例大肠病变中结直肠癌44例;息肉6例;血吸虫病肉芽肿7例,其中3例恶变;内分泌癌1例;脂肪瘤2例;阑尾黏液囊肿2例及黏液性囊腺瘤1例。63例的多平面重组（MPR）、表面遮盖显示（SSD）、仿真内镜（VE）、结肠平铺显示（PE）及透明化显示（Raysum）等后处理技术的诊断符合率分别为98.4%、68.3%、85.7%、85.7%及71.4%,MPR分别与SSD、VE、PE及Raysum之间比较差异具有统计学意义（数值分别为χ2=2.019,P〈0.05;χ2=1.518,P〈0.05;χ2=1.518,P〈0.05;χ2=1.699,P〈0.05）。结论：16层螺旋CT及后处理技术对大肠病变具有较高诊断价值,MPR显示病灶更佳,检出率更高,是纤维肠镜重要的补充检查手段,而各种后处理技术在诊断中应用价值各异,应相互结合。     

腹部CTA和CTC及融合图像在结、直肠肿瘤的临床应用价值

目的:探讨64层螺旋CT血管造影(CT angiography,CTA)和CT结肠成像(CTcolonography,CTC)及融合图像在结、直肠肿瘤的临床应用价值。方法:对50例临床诊断为结、直肠肿瘤的患者行腹部CT平扫及增强扫描,将原始图像进行CTA和CTC重建,再将CTA和CTC图像进行融合,得到能同时显示结、直肠肿瘤和肿瘤供血血管的三维融合图像。结果:本组50例结、直肠肿瘤,均经病理证实。共发现结、直肠癌性病灶42个,其中39个病灶清楚显示肿瘤供血血管,3个病灶未显示肿瘤供血血管;非癌性病灶12个,仅有1个病灶显示其供血血管。癌性病变和非癌性病变显示肿瘤供血血管的比例有显著的统计学差异(χ2=34.72,P<0.01)。肿瘤供血血管对诊断结、直肠癌的灵敏度为92.9%,特异度为91.7%,假阴性率为7.1%,假阳性率为8.3%,阳性预测值为97.5%,阴性预测值为78.6%。肿瘤供血血管的出现在不同分化程度的癌性病变之间没有统计学差异,(χ2=0.67,P<0.05)。结论:腹部CTA和CTC及融合图像可以直观地显示病变的解剖部位和肿瘤供血血管,为结、直肠肿瘤的定位诊断和术前风险评估提供可靠的信息。     

MSCT结合CTC技术对外伤性脑脊液鼻漏的定位研究

目的：探讨MSCT结合CTC技术在外伤性脑脊液鼻漏漏口定位中的价值。方法：选取16例外伤性脑脊液鼻漏患者，术前经多层螺旋CT结合脑池造影进行检查定位，总结检查技术要点，分析其影像表现特征，并与手术结果进行对比。结果：16例CT均显示颅底骨质改变。其中13例经CTC可直接显示漏口位置，与手术所见完全一致。2例结合鼻棉拭测定进行扫描，可显示漏口位置，与手术所见一致。1例CTC仅发现1处漏口，手术发现为2处漏口。结论：MSCT结合CTC技术是CSF鼻漏漏口定位的一种安全、有效的检查手段，对CSF鼻漏的手术治疗具有重要意义，是术前应首选的检查方法。     

18 F-FDG PET/CT显像探测原发肿瘤病灶的临床价值

目的探讨^18F-脱氧葡萄糖(FDG)PET/CT显像寻找原发肿瘤病灶的价值。方法对临床诊断转移瘤患者31例行唧CT显像，将其诊断结果与手术、活组织检查及临床随访结果对照。结果29例患者唧CT显像准确显示其原发灶，分别为结、直肠癌7例，肺癌13例，甲状腺癌3例，子宫恶性肿瘤4例，胰腺癌和鼻咽癌各1例。1例PET/CT检查未能确定其原发灶。另1例临床诊断为肾上腺转移瘤的患者，PET/CT显像为良性肿瘤，经CT动态增强检查及实验室检查证实。结论PET／CT显像对寻找转移瘤原发灶有重要价值。     

18F-FDG PET/CT显像在结直肠癌术前分期中的价值

目的探讨18F-FDG PET/CT在结直肠癌术前TNM分期中的应用价值。资料与方法 33例疑结直肠肿瘤患者均于手术治疗前行全身PET/CT扫描,将患者PET/CT检查结果与手术病理学检查结果进行比较分析。结果 PET/CT诊断结直肠癌原发灶的敏感性、准确性分别为100%和96.97%;PET/CT对术前结直肠癌侵犯局部浆膜、淋巴结转移、远处转移及TNM分期的准确性分别为75.00%、78.12%、96.87%和71.87%,经Kappa一致性检验,PET/CT上述诊断结果与手术病理学检查结果具有较好的一致性(0.429,0.559,0.920,0.619,P均<0.05)。结论结直肠癌18F-FDG PET/CT术前检查,是结直肠癌的术前临床分期中有效的影像学评价手段。     

大肠癌16层CT仿真内镜与电子肠镜对照研究

目的:评价多层螺旋CT仿真内镜对大肠癌的临床诊断价值.方法:采用16层螺旋CT对156例大肠癌患者在肠内充气1000～1500 ml后行快速容积扫描,在图像工作站采用后处理软件行仿真内镜成像,检查结果与电子肠镜及手术病理结果进行对照.结果:156例中仿真内镜共检出肿瘤146个,检出率为93.6%;电子肠镜检出肿瘤139个,检出率为89.1%.仿真内镜对肿块型和混合型大肠肿瘤的判断较肠镜准确,两种方法的分型符合率分别为98.5%、88.6%和88.2%、77.1%;肠镜对浸润型及溃疡型大肠肿瘤的判断较仿真内镜准确,两种方法的分型符合率分别为96.9%、100%和87.5%、95.2%.仿真内镜对右半结肠癌的定位诊断符合率高于肠镜,对左半结肠癌的定位诊断符合率与肠镜无明显差异.结论:仿真内镜可从任意角度及远、近两端分别观察肿瘤的形态特征,对病变定位准确,并可判断肿瘤浸润范围,有很好的临床实用价值.     

16层螺旋CT多模式图像重建对结肠、直肠癌的诊断价值

目的探讨16层螺旋CT图像后处理技术在结肠、直肠癌诊断中的应用价值。方法对84例结肠、直肠癌患者进行全腹容积扫描,在工作站分别行多平面重建(MPR)、表面遮盖显示(SSD)、透明法显示(Raysum)、最大密度投影(MIP)及仿真内窥镜(CTVE)重建成像,并与结肠镜及手术病理对照。结果16层螺旋CT能准确地显示肿瘤的大体分型,诊断符合率为100%。病变部位包括升结肠12例,盲-升结肠2例,横结肠10例,降结肠16例,乙状结肠15例,直-乙状结肠6例,直肠23例。各种图像后处理技术在显示结肠外形,肠腔内外情况,病变的形态、范围、供血及浸润程度等细节方面价值各有不同。结论16层螺旋CT作为一种快捷、安全、准确的检查方法,对结-直肠癌的诊断具有很高的应用价值。     

Detection of flat colorectal polyps at screening CT colonography in comparison with conventional polypoid lesions

Background Although the screening of small, flat polyps is clinically important, the role of CT colonography (CTC) screening in their detection has not been thoroughly investigated. Purpose To evaluate the detection capability and usefulness of CTC in the screening of flat and polypoid lesions by comparing CTC with optic colonoscopy findings as the gold standard. Material and Methods We evaluated the CTC detection capability for flat colorectal polyps with a flat surface and a height not exceeding 3 mm (n = 42) by comparing to conventional polypoid lesions (n = 418) according to the polyp diameter. Four types of reconstruction images including multiplanar reconstruction, volume rendering, virtual gross pathology, and virtual endoscopic images were used for visual analysis. We compared the abilities of the four reconstructions for polyp visualization. Results Detection sensitivity for flat polyps was 31.3%, 44.4%, and 87.5% for lesions measuring 2-3 mm, 4-5 mm, and ≥6 mm, respectively; the corresponding sensitivity for polypoid lesions was 47.6%, 79.0%, and 91.7%. The overall sensitivity for flat lesions (47.6%) was significantly lower than polypoid lesions (64.1%). Virtual endoscopic imaging showed best visualization among the four reconstructions. Colon cancers were detected in eight patients by optic colonoscopy, and CTC detected colon cancers in all eight patients. Conclusion CTC using 64-row multidetector CT is useful for colon cancer screening to detect colorectal polyps while the detection of small, flat lesions is still challenging.     

The effect of diagnostic confidence on the probability of optical colonoscopic confirmation of potential polyps detected on CT colonography: prospective assessment in 1,339 asymptomatic adults

OBJECTIVE: We sought to evaluate the effect of interpreter confidence on the likelihood that a lesion detected on CT colonography (CTC) will correspond to a matched polyp seen on optical colonoscopy. SUBJECTS AND METHODS: Same-day CTC and optical colonoscopy were performed on 1,339 asymptomatic adults. A standard matching algorithm for polyp size and location was used. For each potential polyp detected on CTC, the level of diagnostic confidence was prospectively rated on a 3-point scale (1, least certain; 2, intermediate; and 3, most certain). RESULTS: For CTC-detected lesions 6 mm or larger, diagnostic confidence levels of 1, 2, and 3 corresponded to matched polyps on optical colonoscopy in 33.3% (45/135), 50.0% (103/206), and 66.8% (157/235) of cases, respectively (p < 0.01). Similar trends were present for categories of lesions that measured 6-7 mm, 8-9 mm, and 10 mm or larger, rising to a match rate of 82.1% (55/67) for lesions 10 mm or larger that were diagnosed with a level-3 confidence rating. The likelihood that a matched polyp was adenomatous increased with greater levels of diagnostic confidence. Of note, level-3 confidence for lesions measuring 8-9 mm on CTC more often yielded a matching neoplasm on optical colonoscopy than level-1 or level-2 confidence for lesions measuring 10 mm or larger (60.3% [35/58] vs 20.8% [10/48]; p < 0.0001). CONCLUSION: Greater diagnostic confidence for an individual lesion detected on CTC correlates with a significantly increased likelihood that a matching polyp will be found on optical colonoscopy and that this matched polyp will be neoplastic. Although polyp size represents the primary criterion for CTC screening algorithms, this data could help guide the decision to opt for noninvasive CTC surveillance versus optical colonoscopy for polypectomy.     

CT colonography versus colonoscopy in the follow-up of patients after diverticulitis - a prospective, comparative study

AIM: To assess whether computed tomography colonography (CTC) is a viable alternative to colonoscopy or double contrast barium enema in the follow-up of patients after diverticulitis. MATERIAL AND METHODS: Fifty patients underwent CTC followed immediately by colonoscopy. Results were blinded to the examiners. Findings of diverticular disease and patient acceptance were evaluated. RESULTS: Bowel preparation and distension were good in the majority of CTC and colonoscopy examinations. Diverticular disease was found in 96% of patients at CTC and in 90% at colonoscopy. The rate of agreement between CTC and colonoscopy for diverticular findings in the sigmoid colon was good (kappa=0.64). No complications were seen. Patients found colonoscopy more uncomfortable (p<0.03), more painful (p<0.001), and more difficult (p<0.01) than CTC. Of the patients favouring one examination, 74% preferred CTC. CONCLUSION: CTC appears to have a better diagnostic potential for imaging of diverticular disease-specific findings, when compared with colonoscopy. Also, CTC was less uncomfortable and was preferred by a majority of patients. CTC seems to be a reasonable alternative in follow-up of patients with symptomatic diverticular disease.     

Inclusion of computed tomographic colonography on pre-operative CT for patients with colorectal cancer

Objectives

To evaluate the impact of the inclusion of computed tomographic colonography (CTC) involving faecal tagging and no laxatives on the computed tomography (CT) study routinely used in staging patients with colorectal cancer.

Methods

CTC was performed on 25 patients who had a diagnosis of colorectal carcinoma, with pathological correlation. Researchers recorded the accuracy of the CTC for staging colorectal cancer, as well as any changes to the plans for surgery based on this exam. The patients’ tolerance of the preparation required and the quality of the exams was also evaluated.

Results

All exams were well-tolerated, and only one had unsatisfactory quality. CTC identified all the carcinomas and had an overall accuracy of 80%, 60.1% and 100% for the evaluation of tumour depth, lymph nodes and metastases respectively. CTC identified all polyps greater than 9 mm. Following CTC, changes to surgical plans were observed in 20.8% of the cases, all with incomplete optical colonoscopies.

Conclusions

CTC proved useful for the pre-operative evaluation of patients with a diagnosis of colorectal carcinoma, affecting plans for surgery in a expressive number of patients with an incomplete colonoscopy.     

Indikationen und Ergebnisse der CT-Kolonographie: von der Vorsorge bis zum symptomatischen Patienten

CT colonography (CTC) is also referred to as virtual colonoscopy and is being used with increasing frequency in radiological practice. While there are still no generally accepted, clear-cut indications for its use in mass colorectal cancer screening, there is evidence that this investigation is useful in patients in whom colonoscopy has not been successful or who have known stenotic lesions in the colon. Recent results of significant comparative studies of CTC and conventional colonoscopy will have some influence on the future place of CTC in screening for cancer of the bowel; they show the great potential of CT-aided bowel examination.     

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.     

CT-Kolonographie in der t?glichen Praxis

CLINICAL/METHODICAL ISSUE: Colorectal cancer is a major public health challenge in Austria and Germany. As the participation in dedicated colonoscopy screening programs is rather low, the question of alternative methods is raised again and computed tomography (CT) colonography seems to be a gentle alternative with a very high patient acceptance. STANDARD RADIOLOGICAL METHODS: In recent years CT colonography (CTC) has been established besides conventional colonoscopy as a radiological method for the investigation of the entire colon. From axial two-dimensional images three-dimensional images can be generated, allowing a virtual flight through the colon which is why this technique is also known as virtual colonoscopy. METHODICAL INNOVATIONS: The technique of CTC has been improved continuously during recent years. On the one hand the steady decrease in the layer thickness (currently ≤?1?mm) has improved the resolution of volume data sets and on the other hand there has been significant progress in postprocessing. PERFORMANCE: Numerous studies have recently shown that the significance of CTC in the detection of advanced adenomas is similar to conventional colonoscopy. ACHIEVEMENTS: Meanwhile CT colonography is now a routine investigation method established in both symptomatic and asymptomatic patients (screening). PRACTICAL RECOMMENDATIONS: Study data now clearly show that CTC, as an alternative to conventional colonoscopy, is a powerful method for investigation of colorectal cancer. To achieve good results adequate preparation including fecal tagging, standardized technical procedures during the investigation and expertise in both 2D and 3D reading are essential.     

Computed tomographic colonography (CTC) performance: one-year clinical follow-up

AIM: Computed tomographic colonography (CTC) represents a valuable advance in imaging technology for patients with colonic symptoms who are unfit for or fail to complete investigation with conventional techniques of colonoscopy or barium enema. The aim of this study was to examine whether CTC was sufficient to exclude colorectal cancer in such a population. As our patients were unfit for or unable to complete conventional investigations, we used 1 year clinical follow-up to exclude colonic malignancy. MATERIALS AND METHODS: CTC examination was performed using multi-slice CT in patients fitting pre-determined criteria. All patients who had completed 12 months of follow-up after CTC were included. Data were extracted from patient records and lack of presentation within the 12 months following a negative CTC was assumed to equate to lack of colorectal cancer at initial investigation. RESULTS: One hundred and twelve patients underwent CTC with a median age of 78 years (range 39-95) and median follow-up of 18 months (range 12-26). CTC detected 7 colorectal cancers, with 3 false positives and 1 false negative, giving a sensitivity of 87.5% and specificity of 97.1% for the detection of colorectal cancer. CONCLUSIONS: CTC is a good imaging tool for the exclusion of colorectal cancer in a population unfit for or unable to complete colonoscopy or barium enema, with reasonable sensitivity and specificity for detection of colorectal cancer. However, the optimum investigative strategy for fitter symptomatic individuals is still debated and should be clarified by the results of ongoing randomised controlled trials.     

Miss rate of colorectal cancer at CT colonography in average-risk symptomatic patients

Objectives

Computed tomographic colonography (CTC) is a less burdensome alternative to colonoscopy in excluding colorectal cancer (CRC) in symptomatic patients. We evaluated the proportion of patients who underwent CTC in whom CRC was missed.

Methods

Patients who had undergone CTC in the period 1 January 2007 to 1 January 2011 were merged with all cases of CRC recorded in the Cancer Registry between 1 January 2007 and 1 July 2011 to identify all patients who had undergone CTC less than 2 years before CRC had been diagnosed.

Results

In 53 out of 1,855 patients who had undergone CTC, CRC was diagnosed. Of these, 40 patients had suspected CRC and 5 had large polyps at CTC. In five patients with an indeterminate mass, further investigation confirmed malignancy. One cancer in the caecum was missed because of poor distension. Two cancers were missed: one in the distal rectum and one in the ascending colon. Sensitivity of CTC for CRC was 94.3 % (95 % CI 88–100 %). The true miss rate, excluding the inadequate distended study, was 2 out of 53 (3.8 %).

Conclusion

This study shows that the miss rate for CTC is low, which means that CTC is accurate in excluding CRC in symptomatic patients at a relatively low risk of CRC.

Key Points

? The miss rate for colorectal cancer (CRC) on CT colonography (CTC) is low. ? CTC is accurate at excluding CRC in symptomatic patients. ? CTC is the method of choice in symptomatic patients to exclude CRC.     

The use of minimal preparation computed tomography for the primary investigation of colon cancer in frail or elderly patients

AIM: To assess the place of computed tomography (CT) of the colon in frail or elderly patients with symptoms suggestive of colon cancer. METHOD: A total of 195 patients (median age 76 years) underwent CT of the abdomen and pelvis following the administration of positive oral contrast medium but no bowel preparation. All had symptoms suggestive of colon cancer. CT findings were classified as normal/diverticular disease (DD), possible colon cancer, definite colon cancer or extracolonic pathology. Accuracy of CT was assessed against patient outcome. Association between symptoms and colon cancer was assessed by chi-squared test. RESULTS: There were 47 deaths and median follow up for those alive was 16 months. Overall sensitivity of CT was 100% and specificity 87% for detection of colon cancer. One hundred and ten normal/DD CT examinations had no significant bowel lesion on follow up. Of 12 cases defined as 'definite cancers' on CT, there were nine colon cancers, two extracolonic cancers, and one normal. Of 23 'possible cancers' on CT, there were two colon cancers, three DD masses and 18 normal/DD. Fifty examinations had extracolonic findings including 33 (17%) cases of significant abdominal disease. CT findings led to a halt in investigations in 115 cases (59%), colonoscopy in 18 (9%) cases and surgery in 16 (8%) cases. None of the symptoms present showed a significant association with colon cancer (all P > 0.05). CONCLUSION: Minimal preparation CT is a non-invasive and sensitive method for investigating colon cancer in frail or elderly patients. It has a 100% negative predictive value and also detects a large number of extracolonic lesions.