16排螺旋CT胃癌术前T分期的诊断价值

目的利用16排螺旋CT双期增强扫描对胃癌进行T分期并与病理对照,确定多排螺旋CT(multi-detec-tor row CT,MDCT)在术前T分期中的作用。资料与方法经胃镜证实的62例患者(63个病灶),术前采用16排螺旋CT平扫和动脉期、门静脉期双期增强扫描,随后根据5 mm层厚横断面图像情况重组薄层动脉期和门静脉期多平面重组(multiplanar reconstruction,MPR)图像,由两名资深放射科医师共同完成T分期,术后与病理对照。结果 MDCT结合MPR技术后对胃癌的检出率为96.7%,其中对早期胃癌的检出率为66.7%,进展期胃癌的检出率为100%。胃癌的MDCT大体分型准确率为88.9%。63个胃癌MDCT术前T分期总体准确率为71.4%,其中早期胃癌准确率为33.3%,进展期胃癌准确率为75.4%。结论采用MPR后处理技术的MDCT配合动态增强扫描对进展期胃癌的检出、大体分型和T分期准确率明显提高。     

多层螺旋CT平扫及双期增强扫描在胃癌T分期的临床价值

目的探讨多层螺旋CT平扫及双期增强扫描在胃癌T分期中的临床应用价值。方法利用多层螺旋CT平扫及双期增强扫描前瞻性的对胃癌术前T分期,并与术后病理结果进行对照分析。结果对照组织病理检查结果,其中pT1 7例,占15.22%;pT2 14例,占30.43%;pT3 23例,占50.00%;pT4 2例,占4.35%;各期MDCT分期结果中轴位对T1、T2、T3、T4诊断的准确率分别为42.86%、78.57%、78.26%、50.00%;轴位结合MPR对T1、T2、T3、T4诊断的准确率分别为85.71%、85.71%、91.30%、100.00%;比较两者对胃癌分期的准确率可以发现轴位结合MPR对早期胃癌(T1)的诊断准确率明显高于单纯轴位,且差异具有统计学意义。轴位检查的T分期总的准确率为71.74%,过低分期率为19.57%,过高分期率为8.70%;轴位结合MPR检查的T分期总的准确率为89.13%,过低分期率为4.35%,过高分期率为6.52%;经统计学分析发现轴位结合MPR的T分期准确率明显高于轴位,而过低分期率则明显低于轴位,且差异具有统计学意义。结论多层螺旋CT平扫及双期增强扫描能对胃癌术前T分期做出较准确的评估,尤其是在胃癌T3期、T4期分期的准确率比较高。     

MSCT三期增强扫描和后处理技术对胃癌术前分期的评价

目的:探讨多层螺旋CT(MSCT)对胃癌的影像学诊断及其对术前分期的价值。方法:对49例胃癌患者行16层螺旋CT三期增强扫描后,用多平面重建(MPR)和CT仿真内镜(CTVE)等后处理技术对胃癌CT图像进行术前分期评价,并与术后病理分期对照,以术后病理分期为金标准。结果:MSCT T分期:T1期诊断准确率75.00%(6/8),T2、T3、T4期准确率分别为70.59%(12/17)、68.42%(13/19)、80.00%(4/5);N分期:N0期68.75%(11/16),N1期准确率为59.10%(13/22),N2期63.64%(7/11)。M分期中除1例左锁骨上淋巴结转移未行该部位的CT扫描不计入统计之列外,其余48例M分期的准确率为M0为90.91%(40/44),M1为50.00%(2/4)。结论:16层螺旋CT三期增强扫描结合多平面重建和CT仿真内镜等后处理技术对胃癌分期的准确率较高,值得临床推广。     

多层螺旋CT诊断胃癌的临床应用价值分析

目的探讨多层螺旋在诊断胃癌中的临床应用价值。方法对46例胃癌患者进行多层螺旋CT平扫及双期增强扫描,与手术后病理确诊结果进行对比分析。结果 46例胃癌患者检出率达100.00%,按照手术病理检查结果和胃癌Borrmann分型可以发现其中肿块型胃癌8例,局限溃疡型胃癌15例,浸润溃疡型胃癌16例,弥散浸润型胃癌7例。多层螺旋CT与手术病理检查结果比较显示总体判断准确率为63.04%。对照组织病理检查结果,其中pT1 7例,占15.22%;pT2 14例,占30.43%;pT3 23例,占50.00%;pT4 2例,占4.35%;各期MDCT分期结果中轴位对T1、T2、T3、T4诊断的准确率分别为42.86%、78.57%、78.26%、50.00%;轴位结合MPR对T1、T2、T3、T4诊断的准确率分别为85.71%、85.71%、91.30%、100.00%;比较两者对胃癌分期的准确率可以发现轴位结合MPR对早期胃癌(T1)的诊断准确率明显高于单纯轴位,且差异具有统计学意义(2=3.97,P0.05)。结论多层螺旋CT平扫及双期增强扫描能对胃癌术前T分期做出较准确的评估,具有重要的临床价值。     

多排螺旋CT仿真胃镜在T1和T2分期胃癌鉴别诊断中的应用

目的 探讨64排螺旋CT在T1和T2分期胃癌的鉴别诊断中的作用.方法 回顾性分析术前常规胃镜检查和MDCT检查的149名(男女=9653;32～86岁,平均62岁)155例原发性胃癌病灶为研究对象.为了得到良好的MDCT仿真胃镜图像扫描前用产气粉使胃适当充盈,通过前臂静脉注入非离子型造影剂120 ml,速率为2～3 ml/s,药物进入后60 s开始进行横断位扫描.所有胃癌经手术及术后病理证实T1和T2分期原发性胃癌(92例为T1期,63例为T2期),MDCT检查和手术日期之间的间隔为16 d.通过MDCT横断面和MPR方法进行术前T分期的评估及肿瘤浸润深度评价,通过类似于胃镜的MDCT VE图像进行胃腔内病变区胃黏膜形态特点的分析.结果 MDCT对T1和T2分期原发性胃癌的横断面和MPR重建及VE图像对胃癌检出率各为71%(65/92)、80%(74/92)、96%(88/92)和90%(57/63)、97%(61/63)、98%(62/63).在T1和T2分期胃癌的3.75 mm层厚横断面和MPR图像检出率(P<0.05)有统计学差异.92例早期胃癌中3.75 mm层厚横断面图像对黏膜层病变的诊断率为63.8%(30/47)、黏膜下病变的诊断率为77.7%(35/45),MPR图像对黏膜层病变的诊断率为65.9%(31/47)、黏膜下病变的诊断率为95.6%(43/45)(P<0.05).63例T2期原发性胃癌中横断面图像对肌层和浆膜层病变的诊断率各为88.8%(32/36)和92.5%(25/27),MPR图像对肌层和浆膜层病变的诊断率各为94.4%(34/36)和100%(27/27)(P>0.05).VE方法能清楚地显示横断面图像和MPR图像均未能发现的IIa+IIc型4例,IIc型6例,IIa型3例,IIa+IIb型1例,I型1例胃癌.结论 MDCT横断面图像和MPR图像加上VE图像对术前T1及T2期胃癌可提供较高的诊断准确率,有效地指导手术方案的选择.     

能谱CT多向调整多平面重组在术前评估胃癌T分期中的价值

目的 探讨能谱CT成像联合多向调整多平面重组(MPR)在术前评估胃癌T分期中的价值.方法 搜集经术前病理确诊为胃癌并行腹部能谱CT扫描的患者65例,男49例,女16例,年龄22 ～ 84岁,中位年龄58.3岁;对常规混能及最佳单能量图像进行横轴位、冠状位、矢状位及多向调整MPR,后者以同层显示最大范围胃癌病变为佳;依据不同的重建图像进行T分期评估.结果 术后病理证实T1期4例,T2期12例,T3期33例,T4期16例.常规混能轴位图像及最佳单能量轴位图像分别联合冠状位、矢状位、多向调整MPR对胃壁T分期的总的准确性分别为78.5％、81.5％ 、83.1％ 、87.7％;80.0％、84.6％、89.2％、92.3％;联合不同的重建方法在不同部位胃癌T分期诊断中的效能不同.结论 能谱CT联合多种MPR迸一步提高了胃癌T分期诊断的准确性.     

多层螺旋CT多平面重组对进展期胃癌毗邻器官侵犯的评价

目的:回顾性分析多层螺旋CT多平面重组(MPR)对进展期胃癌侵犯毗邻组织器官的评价。方法:此次回顾性研究得到医院道德与伦理委员会的准许并豁免知情同意。40例经手术病理证实的T3、T4期胃癌且在我院采用多层螺旋CT经服产气粉和水(500~1000ml)充分扩张胃后行低张动态增强扫描的患者入选此次研究。由两名经验丰富的放射诊断医生分别依据横断位及MPR图像通过协商对肿瘤病灶的显示和肿瘤对邻近器官的侵犯进行回顾性分析及侵犯范围的评估并经协商一致。采用McNemar检验比较横断图像和MPR图像对显示原发肿瘤侵犯邻近器官的准确性有无差别,P<0.05认为有统计学意义。结果:MPR图像对40名进展期胃癌患者T分期的准确率是90.00%(36/40),显著高于横断位图像的67.50%(27/40)(P=0.004)。MPR和横断位对胃癌T4期(胃癌灶对邻近器官侵犯)诊断的敏感性分别为83.33%和44.44%、特异性分别为95.45%和86.36%,MPR显示邻近器官侵犯范围优于横断位图像。结论:较之轴位CT图像,多层螺旋CT的MPR图像能提高胃癌对胃周邻近组织器官局部侵犯检测的准确性,提供更多的胃癌灶与毗邻器官解剖关系的信息。     

MSCT对胃癌术前TN分期的临床应用价值

目的探讨MSCT检查在胃癌TN分期的临床应用价值。方法回顾性分析我院2011年1月~2014年12月经病理或手术证实的50例胃癌患者的MSCT平扫及双期增强扫描资料,并与术后病理结果对照,评价MSCT在胃癌TN分期的临床应用价值。结果 MSCT胃癌T分期诊断的总体准确率为74%(37/50),其中对T1、T2、T3和T4期判断的特异度分别为75.0%、73.3%、71.4%、80.0%,敏感度分别为75.0%、68.5%、75.0%、80.0%。MSCT胃癌N分期诊断的总体准确率为71.7%(33/46),其中对N0、N1、N2期判断的特异度分别为73.3%、71.4%、70.0%,敏感度分别为73.3%、68.2%、77.8%。结论 MSCT对胃癌术前TN分期的诊断具有较高准确性,可以为临床选择治疗方案、评估预后提供重要的参考价值。     

多层螺旋CT多平面重组对胃癌术前T和N分期价值并与病理对照

目的前瞻性研究多层螺旋CT多平面重组(MPR)在胃癌术前T、N分期中的价值。资料与方法经本院医学伦理委员会批准,在与所有受检者签署书面知情同意书后,对连续44例经胃镜活检证实的胃癌患者,采用多层螺旋CT在服产气粉和水(500～1000ml)充分扩张胃后行低张动态增强扫描,其中39例手术的病例入选此次研究。由一名放射诊断医师采用交互方式实时MPR确定能较好地显示病灶和毗邻组织器官结构关系的成像方位进行重组。由两名经验丰富的放射诊断医师分别依据横断位及MPR图像通过协商对肿瘤的显示和T、N分期进行评价,并与病理组织结果对比。采用McNemar检验比较横断图像和MPR图像对原发肿瘤的显示以及T和N分期的准确性有无差别,P<0.05认为有统计学意义。由一名即将参与手术的外科医师评估横断位和MPR图像对传递诊断信息的效率。结果对原发胃癌病灶的检出率,横断图像和MPR图像分别是94.9%(37/39)和97.6%(38/39)。MPR评估胃癌灶对胃壁侵犯深度(T分期)的准确性为87.2%(34/39),较横断图像的61.5%(24/39)高(P=0.002)。MPR对淋巴结转移评价(N分期)的准确性为69.2%(27/3...     

胃癌螺旋CT三期、双期和单期增强的比较研究

目的　探讨提高胃癌分期准确性的最佳螺旋CT检查方法。方法　胃癌螺旋CT三期增强 96例 ,双期增强取三期的前两期 ,门脉期增强仅取三期的门脉期 ,中间期薄层增强并MPR 97例 ,分别与手术病理进行对照。结果　胃癌螺旋CT三期、双期、中间期薄层并MPR和门脉期增强扫描的TNM分期准确性分别为 82 .3 %、77.1%、80 .4%和 75 .0 %。结论　胃癌术前分期首选螺旋CT三期增强 ,其次为中间期薄层增强并MPR。     

Diagnostic accuracy of multidetector row computed tomography in T- and N staging of gastric cancer with histopathologic correlation

PURPOSE: To evaluate the diagnostic accuracy of multidetector row computed tomography (MDCT) for the preoperative T- and N staging of gastric cancer. MATERIALS AND METHODS: Eighty-four consecutive patients with gastric cancer underwent preoperative MDCT. Except for 15 patients who did not undergo surgery, 69 patients were included in our study. Two radiologists independently evaluated the T- and N staging on the axial CT images alone and in combination with the MPR images. For N staging, the new TNM and Japanese classifications were independently used. Differences in staging accuracy for T- and N staging were assessed using the McNemar test. RESULTS: The overall T staging accuracy of the axial and combined axial and MPR images was as follows: 67% (47 of 70 cancers) versus 77% (54 of 70 cancers) (P=0.039). The overall N staging accuracy of the axial and combined axial and MPR images was as follows: 59% (41 of 69 cancers) versus 67% (46 of 69 cancers) (P=0.180, Japanese classification) and 54% (37 of 69 cancers) versus 59% (41 of 69 cancers) (P=0.109, TNM classification). CONCLUSIONS: Using MPR images enables more accurate preoperative T staging of gastric cancer, but not for N staging in either classification system.     

64层螺旋CT结合多平面重建诊断早期胃癌的价值

目的探讨64层螺旋CT横断位结合多平面重建（MPR）对早期胃癌的检出价值。方法回顾性分析30例经病理证实的早期胃癌的CT影像特征,由2名有经验的放射诊断医师分别评估轴位及MPR重建图像对早期胃癌的检出率,意见不同时通过协商达成一致。结果30例患者中,轴位图像检出18例,其检出率18／30;结合MPR图像检出26例,检出率26／30,两者之间的检出率差异有统计学意义（P=0．020）;单纯CT横断位图像T分期准确性为26．67％（8／30）,结合MPR图像T分期准确性为63％（19／30）,两者比较差异有统计学意义（χ2=8．148,P=0．004）。结论64层螺旋CT横断位结合MPR图像能提高早期胃癌的检出率及术前分期的准确性。     

Diagnostic value of multidetector row CT in rectal cancer staging: comparison of multiplanar and axial images with histopathology

AIM: Although magnetic resonance (MR) imaging is widely used for rectal cancer staging, many centres in the UK perform computed tomography (CT) for staging rectal cancer at present. Furthermore in a small proportion of cases contraindications to MR imaging may lead to staging using CT. The purpose of this study was to evaluate the accuracy of current generation multidetector row CT (MDCT) in local staging of rectal cancer. In particular the accuracy of multiplanar (MPR) versus axial images in the staging of rectal cancer was assessed. MATERIAL AND METHODS: Sixty-nine consecutive patients were identified who had undergone staging of rectal cancer on CT. The imaging data were reviewed as axial images and then as MPR images (coronal and sagittal) perpendicular and parallel to the tumour axis. CT staging on axial and MPR images was then compared to histopathological staging. RESULTS: MPR images detected more T4 and T3 stage tumours than axial images alone. The overall accuracy of T-staging on MPR images was 87.1% versus 73.0% for axial images alone. The overall accuracy of N staging on MPR versus axial images was 84.8% versus 70.7%. There was a statistically significant difference in the staging of T3 tumours between MPR and axial images (p<0.001). CONCLUSION: Multidetector row CT has high accuracy for local staging of rectal cancer. Addition of MPR images to standard axial images provides higher accuracy rates for T and N staging of rectal cancer than axial images alone.     

Gastric cancer: preoperative local staging with 3D multi-detector row CT--correlation with surgical and histopathologic results

PURPOSE: To prospectively evaluate accuracy of multi-detector row computed tomographic (CT) images for preoperative staging of gastric cancer by using surgical and histopathologic results as reference standards. MATERIALS AND METHODS: This study had institutional review board approval; informed consent was obtained from all patients. Multi-detector row CT included acquisition of virtual gastroscopy images after air distention and contrast material-enhanced dynamic transverse and multiplanar reformation (MPR) images after water distention. Fifty-five consecutive patients with gastric cancer (38 men, 17 women; age range, 37-84 years; mean age, 63 years) underwent preoperative CT. All received 6 g of gas-producing crystals before unenhanced CT scanning for gastric distention and virtual gastroscopy. Patients drank 800-1000 mL of tap water to establish a background for dynamic contrast-enhanced CT scans. Images were obtained in late arterial, portal venous, and delayed phases with start delays of 40, 70, and 150 seconds, respectively. All patients underwent surgery. CT findings were compared with surgical and histopathologic results. Differences in accuracy of transverse and MPR images for T and N staging were assessed with the McNemar exact test. Statistical significance was inferred at P < .05. RESULTS: Detection rates of primary tumors with transverse images, MPRs, and combinations of MPR and virtual gastroscopy images were 91% (50 of 55), 96% (53 of 55), and 98% (54 of 55), respectively. Overall accuracy in assessment of tumor invasion of the gastric wall (T stage) was significantly better with MPR images (89% [49 of 55]) than with transverse images (73% [40 of 55]) (P < .01). Overall accuracy for lymph node (N) staging was 78% (43 of 55) with MPR images and 71% (39 of 55) with transverse images. This difference was not significant (P = .103). CONCLUSION: Multi-detector row CT with combined water and air distention can improve the accuracy of preoperative staging of gastric cancer. MPRs yield significantly better overall accuracy than transverse images for tumor staging but not for lymph node staging.     

The diagnostic value of multiplanar reconstruction on MDCT colonography for the preoperative staging of colorectal cancer

The purpose of this study was to determine whether multiplanar reconstruction (MPR) images can improve the accuracy of MDCT-based colorectal cancer preoperative staging by receiver-operating characteristic (ROC) analysis. Fifty-five patients with colorectal cancer underwent contrast-enhanced CT colonography using an 8- or 16-row scanner. Two separate interval reviews of the axial MDCT datasets with/without MPR images (coronal and sagittal) were performed independently by two radiologists blinded to both the colonoscopic and histopathologic results. At each review session, the radiologists were asked to determine the colorectal cancer TNM stage within the context of differentiating ≤T3 from T4, N0 from ≥N1 and M0 from M1 using a five-point confidence scale. The radiologists’ performance for staging the colorectal cancer using axial CT datasets with/without MPR images was evaluated using ROC analysis. Sensitivities, specificities and interobserver agreement were assessed. When MPR images were added, significant improvement was achieved by both radiologists for differentiating N0 from ≥N1 in terms of both A_Z (0.651 to 0.769; 0.573 to 0.713) and specificity (26.7 to 69.2%; 23.1 to 76.9%) (P<0.05). For T staging, ROC analysis failed to show a significant improvement in terms of differentiating ≤T3 from T4 for either radiologist (P>0.05), but a significant improvement in the specificity (70 to 90%; 80 to 92%) was achieved by one radiologist (P<0.05). In terms of the M staging, a significant improvement in the Az (0.844 to 0.996) was observed for the combined interpretation of the axial and MPR images by one radiologist (P<0.05). Furthermore, substantial or almost perfect interobserver agreement was achieved for all TNM stagings for the combined interpretations (κ=0.641–0.866), whereas only fair to substantial agreement was achieved for the axial images alone (κ=0.337-0.707). In conclusion, the combined interpretation of the axial and MPR MDCT images significantly improved the local staging of colorectal cancer compared with assessments based on axial images alone.     

螺旋CT及E-cad表达在胃癌术前分期中的价值

目的探讨CT扫描及E-cad表达相结合在胃癌术前分期诊断中的意义。方法应用CT增强扫描对66例胃癌进行术前分期;对66例胃切除标本进行E-cad表达分析,与手术及术后病理结果对照,以探讨二者在胃癌术前分期中的价值。结果 CT增强扫描对胃癌T分期准确度为81.8%,N分期准确度为89.4%,综合判断CT对于胃癌肿瘤原发灶、淋巴结和转移情况分期（TNM分期）准确度为80.3%。胃癌组织中E-cad表达阳性率为65.15%。胃癌病理分期Ⅲ、Ⅳ期者其癌组织的E-cad阳性表达率明显高于Ⅰ、Ⅱ期（P〈0.05）;浸润深度为T3、T4胃癌患者其癌组织的E-cad阳性表达率明显高于浸润深度为T1、T2者（P〈0.01）。结论 CT增强扫描及E-cad检测都有利于胃癌术前分期的判断,两者结合有利于提高分期诊断的准确率。     

Diagnostic performance of 64-MDCT and 1.5-T MRI with highresolution sequences in the T staging of gastric cancer: a comparative analysis with histopathology

Purpose

This study was undertaken to compare the accuracy of magnetic resonance (MR) imaging and 64-slice multidetector computed tomography (64-MDCT) in the T staging of gastric carcinoma in comparison with histopathology.

Materials and methods

Forty patients with an endoscopic diagnosis of gastric carcinoma underwent preoperative MR imaging and 64-MDCT, both of which were performed after i.v. injection of scopolamine and water distension of the stomach. In the MR imaging protocol, we acquired T2-weighted turbo spin-echo (TSE) sequences, true fast imaging steady-state free precession (true-FISP) and gadolinium-enhanced T1-weighted volumetric interpolated breath-hold examination (VIBE) 3D sequences. Contrastenhanced CT scans were obtained in the arterial and venous phases. Two groups of radiologists independently reviewed the MR and 64-MDCT images. The results were compared with pathology findings.

Results

In the evaluation of T stage, 64-MDCT had 82.5% and MR imaging had 80% sensitivity. Accuracy of MR imaging was slightly higher than that of 64-MDCT in identifying T1 lesions (50% vs 37.5%), whereas the accuracy of 64-MDCT was higher in differentiating T2 lesions (81.2% vs 68.7%). The accuracy of MR imaging and 64-MDCT did not differ significantly in the evaluation of T3-T4 lesions (p>0.05). Understaging was observed in 20% of cases with MR imaging and in 17.5% with 64-MDCT.

Conclusions

MR imaging and 64-MDCT accuracy levels did not differ in advanced stages of disease, whereas MR imaging was superior in identifying early stages of gastric cancer and can be considered a valid alternative to MDCT in clinical practice.     

64排螺旋CT对胃印戒细胞癌淋巴结转移的诊断价值

目的：评价64排螺旋CT对胃印戒细胞癌淋巴结转移的诊断价值。方法：回顾性分析总结40例胃印戒细胞癌患者的CT平扫及三期动态增强扫描资料,并与手术病理结果对照。结果：本组病例术后淋巴结转移情况为N0期16例,N2期6例,N3期为11例,CT以淋巴结长径〉6mm为阳性标准,发现NO期16例、N1期7例、N2期5例及N3期4例,其中CT各N分期特异性在76．5％-94．7％之间,但是对N2及N3分期的敏感性欠佳（分别为28．6％和33．3％）。转移淋巴结特点为静脉期和延迟期强化明显,虽高于动脉期强化,但是之间无统计学意义上的差异（P〉0．05）。结论：64排螺旋CT对胃印戒细胞癌转移淋巴结的诊断及N分期有帮助,其诊断特异性较高,但是准确性和敏感性均有待提高。     

Preoperative T and N staging of colorectal cancer: accuracy of contrast-enhanced multi-detector row CT colonography--initial experience

PURPOSE: To evaluate the accuracy of contrast material-enhanced multi-detector row computed tomographic (CT) colonography for preoperative staging of colorectal cancer. MATERIALS AND METHODS: Forty-one patients with colorectal carcinoma underwent preoperative contrast-enhanced multi-detector row CT colonography. Images were obtained in the arterial (start delay of 35 seconds) and portal venous (start delay of 70 seconds) phases. The arterial phase was focused on the suspected region of neoplasm, whereas the venous phase included the whole abdomen and pelvis. Two radiologists independently evaluated the depth of tumor invasion into the colorectal wall (T) and regional lymph node involvement (N) on transverse CT images alone and in combination with multiplanar reformations (MPRs). Disagreements were resolved by means of consensus. CT findings were compared with pathologic results, which served as the reference standard. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were assessed. Differences in accuracy for T and N staging were assessed by using the McNemar test. RESULTS: In T staging, overall accuracy was 73% when transverse images were evaluated alone and 83% when they were evaluated in combination with MPRs. This difference was not significant. N staging was associated with an overall accuracy of 59% with transverse images alone and 80% with combined transverse and MPR images (P <.01). CONCLUSION: Contrast-enhanced multi-detector row CT colonography is an accurate technique for preoperative local staging of colorectal tumors.