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Abstract Objective This metanalysis aimed to evaluate the sensitivity and specificity of computed tomography colonography in colorectal polyp detection. Methods A literature search was performed in the PubMed and Web of Science databases. Results A total of 1,872 patients (males 57.2%, females 42.8%) aged 49 to 82 years old (mean age 59.7 ± 5.3 years) were included in this metanalysis. The estimated sensitivity of computed tomography colonography was 88.4% (46.3-95.7%, coefficient of variation [CV]=28.5%) and the estimated specificity was 73.6% (47.4-100.0%, CV=37.5%). For lesions up to 9mm, the sensitivity was 82.5% (62.0-99.9%, CV =25.1%) and the specificity was 79.2% (32.0-98.0%, CV=22.9%). For lesions>9mm, the sensitivity was 90.2% (64.0-100.0%, CV=7.4%) and the specificity was 94.7% (80.0-100.0%, CV=6.2%). No statistically significant differences in sensitivity according to the size of the lesion were found (p=0.0958); however, the specificity was higher for lesions>9mm (p<0.0001). Conclusions Most of the studies analyzed in the present work were conducted before 2010, which is about a decade after computed tomography colonography started being indicated as a screening method by European and American guidelines. Therefore, more studies aimed at analyzing the technique after further technological advancements are necessary, which could lead to the development of more modern devices.
Resumo Objetivo Esta meta-análise teve como objetivo avaliar a sensibilidade e especificidade da colonografia por tomografia computadorizada na detecção de pólipos colorretais. Métodos Foi realizada uma pesquisa bibliográfica nas bases de dados da PubMed e da Web of Science. Resultados Um total de 1.872 pacientes, 57,2% homens e 42,8% mulheres, com idades entre 49 a 82 anos de idade (média de 59,7 ± 5,3 anos) foram incluídos nesta meta análise. A sensibilidade da colonografia por tomografia computadorizada foi estimada em 88,4% (46,3-95,7%; coeficiente de variância [CV]=28,5%) e a especificidade em 73,6% (47,4%-100,0%; CV=37,5%). Para lesões de até 9mm, a sensibilidade foi de 82,5% (62,0-99,9%; CV=25,1%) e a especificidade de 79,2% (32,0-98,0%; CV=22,9%). Para lesõesmaiores que 9mm, a sensibilidade foi de 90,2% (64,0-100,0%; CV=7,4%) e a especificidade de 94,7% (80,0-100,0%; CV=6,2%). Não houve diferença estatisticamente significante entre as sensibilidades por tamanho da lesão (p=0,0958), porém a especificidade foi maior em lesões acima de 9mm (p<0,0001). Conclusão A maioria dos estudos analisados no presente trabalho foi realizada antes de 2010, cerca de uma década depois que a colonografia por tomografia computadorizada passou a ser indicada como método de triagem pelas diretrizes europeias e americanas. Portanto, são necessários mais estudos com o objetivo de analisar a técnica apósmaiores avanços tecnológicos, o que poderia levar ao desenvolvimento de dispositivos mais modernos.
Subject(s)
Humans , Male , Female , Middle Aged , Aged , Aged, 80 and over , Colorectal Neoplasms/diagnosis , Adenocarcinoma/diagnosis , Colonography, Computed Tomographic/statistics & numerical dataABSTRACT
Objective To evaluate the feasibility of adaptive statistical iterative reconstruction-V (ASIR-V) to improve image quality in low-dose CT colonography.Methods A series of thirty artificial polyps were established by ligation in an isolated segment of porcine colon.Volume data was acquired on Revolution CT scanner (GE,USA) with High Definition scan mode and different scan parameter combinations:120 kVp with different mAs (10,30,50,70,90,100,120,140,160,180,200,220,240,260,respectively).Images were reconstructed with six different ASIR-V levels of 0 (filtered back projection,FBP),10％,30％,50％,70％ and 90％.Two radiologists were blinded to measure and analyze the objective data independently,including image noise (SD),signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR).The kappa test was used to assess interobserver agreement in subjective image quality score.ICC test was used to examine the consistency of the measurements between two observers.SD,SNR,CNR were performed for statistical analysis in different tube current and different levels of ASIR-V using variance analysis (ANOVA).Results Interobserver agreement for subjective image quality score was good with a kappa value of 0.683.The variation of the tube current(r =0.734,P =0.000) and ASIR-V level(r =0.220,P =0.044) is related to the subjective score of image quality.Under the condition of the same tube current,image quality score of 50％ ASIR-V reconstruction was the highest.Two objective data consistency is good.The differences of image noise (F =423.58,P ＜ 0.05),SNRs(F =124.26,P ＜ 0.05) and CNRs (F =1 030.17,P ＜ 0.05) of different tube current and different levels of ASIR-V reconstruction were statistically significant.In the same tube current,with increased levels of ASIR-V,image noise reduced,CNRs increased.Only in 10,120,140,160,220,240,260 mA,the differences of SNRs were statistically significant(F =8.75-31.36,P ＜ 0.05).For the same level of ASIR-V reconstruction,with the increase of tube current,the image noise decreased,SNR and CNR increased gradually.Conclusions In the CT colonography,the application of ASIR-V algorithm can significantly reduce the noise and enhance the image contrast noise ratio and improve image quality.ASIR-V algorithm with 50％ has better performance in reducing CT image noise.
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Objective To study the feasibility of applying electronic cleaning to intestinal contents tagging by diatrizoate meglumine for single-source dual-energy CT colonography with sequential acquisitions and volume scanning.Methods Twenty-four volunteers had fine effect of intestinal contents tagging by diatrizoate meglumine,good colorectal distension effect,fine image quality of dual-energy fusion colorectal images,and with informed consents were enrolled in this study.The single-source dual-energy CT colonography with sequential acquisitions and volume scanning was performed with an Acquilion ONE 320 row CT scanner,tube voltage 135 kVp/80 kVp.The intestinal contents conducted the dual-energy electronic cleaned based on decomposition of intestinal contents tagging by diatrizoate meglumine,soft tissue and air.The intestinal contents in one segment of intestinal lumen being 100％ electronically cleaned served as the basic standard,the electronic cleaning effects were divided into the 5 grades:excellent,good,moderate,fair and poor;and grade 1-3 were effective fecal electronic cleaning.Results The grade 1,2,3,4,5 of electronic cleaning effect for solid as the main intestinal contents were 22.2％,53.3％,17.8％,6.7％ and 0％ respectively;and which of electronic cleaning effect for liquid as the main intestinal contents were 47.5％,47.5％,5.0％,0％ and 0％ respectively.The together total effective electronic cleaning of intestinal contents was 97.9％ and the electronic cleaning effect was good.Conclusion Electronic cleaning could be used in the intestinal contents tagging by diatrizoate meglumine for single-source dual-energy CT colonography with sequential acquisitions and volume scanning.
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Objective To study the compliance of examinees,and effectiveness of colorectal distension with partially automated and individualized insufflation of air for dual-energy CT colonography.Methods Forty-six healthy adult volunteers without history of conditions affecting gastrointestinal motor function were enrolled in this study.One day before CT examination,volunteers were asked to orally administered 60 mL 4% diatrizoate meglumine five times for fecal tagging.Air was insufflated by using an inflator in a partially automated and individualized manner.The volunteers were initially asked to assume the right lateral decubitus position,then slowly turn to the supine position.Insufflation rate began at 1.5 L/min,and decreased to 0.5 L/min at later stage.The necessity and volume of air insufflation were decided according to effectiveness of colorectal distension on CT scout images,self-reported sensation of volunteers,and intestinal pressure.Dual-energy CT scanning was performed,and dual-energy blended images were acquired.Compliance of volunteers was statistically analyzed.The effectiveness of colorectal segments distension was statistically analyzed by using Kruskal-Wallis H test.Results No abdominal pain,bloating,nausea or vomiting were noted in the 46 volunteers.All volunteers easily accepted colorectal insufflation of air,with grade 1 compliance.The effectiveness of colorectal distension of grades 1,2,3 and 4 were 0%,2.1%,5.1% and 92.8%,respectively.The difference of effectiveness of colorectal segments distension had no statistical significance(χ2=6.19,P=0.288).The effectiveness of insufflation was poor in 6 colorectal segments,including 2 in sigmoid colon and 2 in rectum.Effectiveness of insufflation was suboptimal in 14 colorectal segments,including 4 in descending colon,4 in sigmoid colon,and 3 in rectum.Conclusion Compliance of examinees with partially automated and individualized insufflation of air for dual-energy CT colonography is excellent,with good effectiveness of colorectal distension.
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Objective To comparative study the effect on colorectal cleansing of CT colonography with gulping down 10 mg bisacodyl before or 1 h after oral taking 2 liter polyethylene glycol .Methods Forty participants with informed consent were appor‐tioned to group A ,group B randomly ,20 cases in each group .On the day before CT colonography ,participants in group A oral took 20 mL of 40% W/V barium sulfate prior to 3 mealtime ,and 20 mL of 60% diatrizoate meglumine diluted in 250 mL of water after supper ,then gulped down 10 mg bisacodyl enteric‐coated tablets 1 hour before oral taking 2 liter polyethylene glycol electrolyte so‐lution .Participants in group B were the same as that in group A ,with the exception of gulping down 10 mg bisacodyl enteric‐coated tablets 1 hour after oral taking 2 liter polyethylene glycol electrolyte solution .Cleansing efficacy of stool and fluid ,and attenuation value of remainder fluid between the two groups were analyzed statistically .Results In group A ,score of cleansing efficacy of stool (1 .96 ± 0 .11) was lower than that in group B (2 .01 ± 0 .12) ,segments with good cleansing efficacy of stool (87/120 segments , 72 .50% ) was higher than that in group B (83/120 segments ,69 .17% ) ,the difference was not statistically significant (P>0 .05) .In group A ,score of cleansing efficacy of fluid (1 .50 ± 0 .06) was lower than that in group B (1 .53 ± 0 .06) ,segments with good cleansing efficacy of fluid(113/120 segments ,94 .17% ) was higher than that in group B (111/120 segments ,92 .50% ) ,the differ‐ence was not statistically significant (P>0 .05) .Attenuation value of remainder fluid [(729 ± 29)HU ] in group A was higher than that in group B[(653 ± 25)HU] ,the difference was statistically significant(P<0 .05) .Conclusion Gulping down 10 mg Bisacodyl before or after oral taking 2 liter polyethylene glycol has no effect on cleansing of stool and fluid ,with good cleansing efficacy .The former has better cleansing efficacy of fluid ,is beneficial to detecting polyps for CT colonography .
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[Abstract ] Objective To compare the accuracy between regular computed tomography colonography (CTC)and dual-energy CTC in lesion detection.Methods Twenty-eight patients with clinical suspicious space occupying lesions of the colon were selected.All patients were underwent dual-energy mode contrast-enhanced CT scan and the data were reconstructed with colonography and dual-energy iodine maps methods.The diameter,enhanced computed tomography (CT)value and iodine value were measured.The results of colonoscopy and pathology were taken as gold standard.The sensitivity, specificity,accuracy,positive predictive value and negative predictive value of regular CTC and dual-energy CTC were compared.Variance analysis was performed for measurement data comparison among groups and chi-square test was used for count data analysis.Results Among 28 patients,colorectal lesions were detected in 24 cases by regular CTC,of which four cases were false-positive and one case was false-negative confirmed by colonoscopy and pathology.Colorectal lesions were detected in 20 cases by dual-energy CTC,of which no false-positive and one case was false negative confirmed by colonoscopy and pathology.The contrast enhanced CT value of polyps,adenoma,adenocarcinoma and stool was (38.54± 6.82),(49.16±7.31 ),(52.61 ±5 .93 )and (34.00±1 .41 )Hu,respectively.The enhanced value of adenoma and adenocarcinoma was significantly higher than that of polyps and stool,the differences were statistically significant among groups (F = 10.760,P = 0.001 ).There was no significant difference between polyps and stool (t=1 .44,P =0.188).The sensitivity of regular CTC and dual-energy CTC in lesion detection was 95 .6% (95 %cofidence interval(CI ):77.9%-99.2%)and 95 .6% (95 %CI :77.9%-99.2%),respectively.The specificity was 42.8% (95 %CI :15 .4%-93.5 %)and 100.0% (95 %CI :47.9%-100.0%).Conclusion Compared with traditional CTC,dual-energy CTC would distinguish lesions from stool,help differentiate between benign and malignant tumors and further increase the accuracy of CTC diagnosis.
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Contrast-enhanced computed tomography colonography (CE-CTC) is a useful guide for the laparoscopic surgeon to avoid incorrectly removing the colonic segment and the failure to diagnose of synchronous colonic and extra-colonic lesions. Lymph node dissection and vessel ligation under a laparoscopic approach can be time-consuming and can damage vessels and organs. Moreover, mesenteric vessels have extreme variations in terms of their courses and numbers. We describe the benefit of using an abdominal vascular map created by CE-CTC in laparoscopic colorectal surgery candidates. We describe patients with different diseases (colorectal cancer, diverticular disease, and inflammatory bowel disease) who underwent CE-CTC just prior to laparoscopic surgery.
Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Colectomy/methods , Colon/blood supply , Colonography, Computed Tomographic/methods , Colorectal Neoplasms/pathology , Contrast Media , Laparoscopy/methods , Lymph Node Excision/methods , Neoplasm Staging/methodsABSTRACT
OBJECTIVE: To compare the CT colonography (CTC) and double-contrast barium enema (DCBE) for colonic evaluation in patients with renal insufficiency. MATERIALS AND METHODS: Two sequential groups of consecutive patients with renal insufficiency who had a similar risk for colorectal cancer, were examined by DCBE (n = 182; mean +/- SD in age, 51 +/- 6.4 years) and CTC (n = 176; 50 +/- 6.7 years), respectively. CTC was performed after colon cleansing with 250-mL magnesium citrate (n = 87) or 4-L polyethylene glycol (n = 89) and fecal tagging. DCBE was performed after preparation with 250-mL magnesium citrate. Patients with colonic polyps/masses of > or = 6 mm were subsequently recommended to undergo a colonoscopy. Diagnostic yield and positive predictive value (PPV) for colonic polyps/masses, examination quality, and examination-related serum electrolyte change were retrospectively compared between the two groups. RESULTS: Both the CTC and DCBE were positive for colonic polyps/masses in 28 (16%) of 176 and 11 (6%) of 182 patients, respectively (p = 0.004). Among patients with positive findings, 17 CTC and six DCBE patients subsequently underwent a colonoscopy and yielded a PPV of 88% (15 of 17 patients) and 50% (3 of 6 patients), respectively (p = 0.089). Thirteen patients with adenomatous lesions were detected in the CTC group (adenocarcinoma [n = 1], advanced adenoma [n = 6], and non-advanced adenoma [n = 6]), as compared with two patients (each with adenocarcinoma and advanced adenoma) in the DCBE group (p = 0.003). Six (3%) of 176 CTC and 16 (9%) of 182 DCBE examinations deemed to be inadequate (p = 0.046). Electrolyte changes were similar in the two groups. CONCLUSION: In patients with renal insufficiency, CTC has a higher diagnostic yield and a marginally higher PPV for detecting colorectal neoplasia, despite a similar diagnostic yield for adenocarcinoma, and a lower rate of inadequate examinations as compared with DCBE.
Subject(s)
Female , Humans , Male , Middle Aged , Analysis of Variance , Barium Sulfate , Colonic Polyps/diagnosis , Colonography, Computed Tomographic , Colorectal Neoplasms/diagnosis , Contrast Media , Enema , Predictive Value of Tests , Renal Insufficiency/complications , Risk Factors , Sensitivity and SpecificityABSTRACT
BACKGROUND/AIMS: Colorectal cancer, one of the most common cancers in developed countries, is curable when diagnosed at an early stage. However, for better screening, both a test that patients will tolerate and diagnostic accuracy are required. We compared patient experiences and preferences between computed tomographic (CT) colonography and conventional colonoscopy (CC) under conscious sedation. METHODS: Patients referred to the gastrointestinal clinic for CC were enrolled to also undergo CT colonography prior to CC. After each procedure, patients completed a questionnaire in which variables, such as abdominal pain, abdominal discomfort, and loss of dignity, were assessed using a 7-point Likert scale, with the highest score representing the worst experience. To verify response stability, a telephone questionnaire followed within 24 h after each procedure. Patients were then asked about their preference for CT colonography or CC. RESULTS: Data were collected from 51 patients who fulfilled all requirements, including CT colonography, CC, the two questionnaires after each procedure, and a follow-up questionnaire. Severity of abdominal pain, abdominal discomfort, and a loss of dignity were reported to be higher in CT colonography than in CC (p<0.01). In addition, the preference for CC was significantly higher than that for CT colonography (p<0.01). CONCLUSIONS: Although CT colonography is a safe and noninvasive screening test for colorectal cancer, further study is required to increase patient acceptance.
Subject(s)
Female , Humans , Male , Middle Aged , Colonography, Computed Tomographic/methods , Colonoscopy/methods , Colorectal Neoplasms/diagnosis , Diagnosis, Differential , Mass Screening/methods , Patient Acceptance of Health Care/psychology , Patient Satisfaction , Prospective Studies , Surveys and QuestionnairesABSTRACT
OBJECTIVE: This preliminarily study was designed to determine and to compare the efficacy of two commercially available barium-based fecal tagging agents for CT colonography (CTC) (high-density [40% w/v] and low-density [4.6% w/v] barium suspensions) in a population in Korea. MATERIALS AND METHODS: In a population with an identified with an average-risk for colorectal cancer, 15 adults were administered three doses of 20 ml 40% w/v barium for fecal tagging (group I) and 15 adults were administered three doses of 200 ml 4.6% w/v barium (group II) for fecal tagging. Excluding five patients in group I and one patient in group II that left the study, ten patients in group I and 14 patients in group II were finally included in the analysis. Two experienced readers evaluated the CTC images in consensus regarding the degree of tagging of stool pieces 6 mm or larger. Stool pieces were confirmed with the use of standardized CTC criteria or the absence of matched lesions as seen on colonoscopy. The rates of complete fecal tagging were analyzed on a per-lesion and a per-segment basis and were compared between the patients in the two groups. RESULTS: Per-lesion rates of complete fecal tagging were 52% (22 of 42; 95% CI, 37.7-66.6%) in group I and 78% (28 of 36; 95% CI, 61.7-88.5%) in group II. The difference between the two groups did not reach statistical significance (p = 0.285). The per-segment rates of complete tagging were 33% (6 of 18; 95% CI, 16.1%-56.4%) in group I and 60% (9 of 15; 95% CI, 35.7%-80.3%) in group II; again, the difference between the two groups did not reach statistical significance (p = 0.171). CONCLUSION: Barium-based fecal tagging using both the 40% w/v and the 4.6% w/v barium suspensions showed moderate tagging efficacy. The preliminary comparison did not demonstrate a statistically significant difference in the tagging efficacy between the use of the two tagging agents, despite the tendency toward better tagging with the use of the 4.6% w/v barium suspension.
Subject(s)
Adult , Female , Humans , Male , Middle Aged , Administration, Oral , Barium/administration & dosage , Colon/diagnostic imaging , Colonography, Computed Tomographic/methods , Colonoscopy , Colorectal Neoplasms/diagnosis , Contrast Media/administration & dosage , Feces , SuspensionsABSTRACT
BACKGROUND/AIMS: CT colonography is a rapid and safe imaging method for detecting polyps in the colon and rectum. We assessed the efficacy of CT colonography in colorectal polyp detection. METHODS: We prospectively studied 84 subjects (mean age 55.7+/-11.1 years; 52 men, 32 women) undergoing CT colonography followed by colonoscopy. Based on the results of CT colonography, all polyps were classified by size (any size, and those larger than 5, 7, and 10 mm) and were checked for location, morphology, and histological characteristics. We determined the sensitivity and specificity of CT colonography using colonoscopy as a reference standard with a segmental unblinding method. RESULTS: A total of 56 lesions were identified in 26 of 79 subjects undergoing both CT colonography and conventional colonoscopy. The sensitivities of CT colonography for polyps of any size, and larger than 5, 7, and 10 mm were 60.7%, 70.5%, 75.9%, and 81.8%, respectively. The per-subject sensitivities of CT colonography for the polyps of any size, and larger than 5, 7, and 10 mm, were 80.7%, 95.0%, 93.3%, and 90.9%, respectively. The per-subject specificities of CT colonography for polyps were 86.8%, 89.8%, 95.3%, and 100.0%, respectively. The sensitivities of CT colonography for flat, sessile, and pedunculated polyps were 30.8%, 85.0%, and 90.0%, respectively. CONCLUSIONS: CT colonography is a useful diagnostic method for screening colorectal neoplasias larger than 7 mm diameter, showing 75.9% sensitivity and 71.0% positive predictive value.
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Humans , Male , Colon , Colonic Neoplasms , Colonography, Computed Tomographic , Colonoscopy , Mass Screening , Polyps , Prospective Studies , Rectum , Sensitivity and SpecificityABSTRACT
PURPOSE: We sought to evaluate the clinical usefulness of CT colonography (CTC) after incomplete conventional colonoscopy (CC) for occlusive colorectal cancer (CRC) according to the tumor location. MATERIALS AND METHODS: Seventy-five patients with occlusive CRC underwent subsequent CTC immediately after incomplete CC. Fifty-nine patients had distal CRC and 16 had proximal colon cancer. Experienced radiologists prospectively analyzed the location, length, and TNM staging of the main tumor. The colorectal polyps in the remaining colorectum and additional extraluminal findings were also recorded. Sixty-seven patients underwent colorectal resection. We retrospectively analyzed the surgical outcome and correlated CTC and CC findings. RESULTS: The overall accuracies of tumor staging were: T staging, 86%; N staging (nodal positivity), 70% (80%); and intra-abdominal M staging, 94%. Additional colonic polyps were found in 23 patients. Six synchronous carcinomas were detected (9%); three in the proximal colon and three in the distal colon of occlusion. Clinically significant localization errors at CC were noted in 8 patients (12%, 5 proximal colon cancers and 3 distal CRCs) and were corrected by CTC. After CTC, the surgeons modified the initial surgical plan in 11 cases (16%). CONCLUSION: In occlusive CRC, CTC is not only useful in the evaluation of the proximal bowel, but can also provide surgeons with accurate information about staging and tumor localization. CTC is recommended when endoscopists encounter occlusive CRC, regardless of tumor location.
Subject(s)
Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Colonography, Computed Tomographic/methods , Colonoscopy/methods , Colorectal Neoplasms/pathology , Neoplasm Staging , Reproducibility of ResultsABSTRACT
OBJECTIVE: To investigate the diagnostic value of CT colonography for the detection of colorectal polyps. MATERIALS AND METHODS: From December 2004 to December 2005, 399 patients underwent CT colonography and follow-up conventional colonoscopy. We excluded cases of advanced colorectal cancer. We retrospectively analyzed the CT colonography findings and follow-up conventional colonoscopy findings of 113 patients who had polyps more than 6 mm in diameter. Radiologists using 3D and 2D computer generated displays interpreted the CT colonography images. The colonoscopists were aware of the CT colonography findings before the procedure. RESULTS: CT colonography detected 132 polyps in 107 of the 113 patients and conventional colonoscopy detected 114 colorectal polyps more than 6 mm in diameter in 87 of the 113 patients. The sensitivity of CT colonography analyzed per polyp was 91% (41/45) for polyps more than 10 mm in diameter and 89% (101/114) for polyps more than 6 mm in diameter. Thirteen polyps were missed by CT colonography and were detected on follow-up conventional colonoscopy. CONCLUSION: CT colonography is a sensitive diagnostic tool for the detection of colorectal polyps and adequate bowel preparation, optimal bowel distention and clinical experience are needed to reduce the rate of missing appropriate lesions.
Subject(s)
Adult , Aged , Aged, 80 and over , Humans , Middle Aged , Colonic Polyps/diagnosis , Colonography, Computed Tomographic/methods , Colonoscopy/methods , Colorectal Neoplasms/diagnosis , Contrast Media/administration & dosage , False Negative Reactions , False Positive Reactions , Follow-Up Studies , Image Processing, Computer-Assisted , Imaging, Three-Dimensional , Iohexol/analogs & derivatives , Observer Variation , Predictive Value of Tests , Radiographic Image Enhancement/methods , Retrospective Studies , Sensitivity and SpecificityABSTRACT
BACKGROUND/AIMS: The purpose of this study is to evaluate the efficacy of CT colonography (CTC) in comparison with colonoscopy for the detection of colorectal adenomatous polyp in asymptomatic adults. METHODS: A total 208 asymptomatic adults underwent successive CTC and colonoscopy, on the same day. RESULTS: On the analysis of adenomatous polyps per subject, the sensitivity of CTC was 90% (9/10) in case of polyps > or =10 mm in size, and 67.7% (21/31) in case of polyps > or =6 mm in size. Those values of colonoscopy were 100% and 93.5%, respectively. The per-patient specificity of CTC was 98.0% (194/198) in case of polyps > or =10 mm in size and 88.1% (156/177) in case of polyps > or =6 mm in size. CTC missed 4 (3 flat adenomas and, 1 sessile adenoma) out of 17 adenomatous polyps > or =10 mm in size in 2 subjects. CONCLUSIONS: In asymptomatic adults, the sensitivity of CTC for detecting adenomatous polyps was lower than that of colonoscopy, particularly for the small lesions below 10 mm in size, and also for the flat adenomas > or = 10 mm in size. However, CTC showed a high sensitivity and specificity for detecting the subjects with clinically important colorectal adenomatous polyps > or = 10 mm in size. These results suggest that CTC has potential as a screening method for colorectal neoplasm.
Subject(s)
Adult , Humans , Adenoma , Adenomatous Polyps , Colonography, Computed Tomographic , Colonoscopy , Colorectal Neoplasms , Mass Screening , Polyps , Prospective Studies , Sensitivity and SpecificityABSTRACT
PURPOSE: We wished to compare CT colonography with conventional colonoscopy for the detection of colorectal polypoid lesions, and we wanted to evaluate the role of IV contrast-enhanced CT colonography for the differentiation between benign polypoid lesions and malignant polypoid lesions. MATERIALS AND METHODS: Thirty-four consecutive patients underwent CT colonography prior to conventional colonoscopy. Precontrast prone-position CT images and postcontrast supine position CT images were obtained and the virtual colonoscopic images were reconstructed. Axial, sagittal and coronal images with virtual colonoscopic images were prospectively interpreted for the presence, size and morphologic features of colorectal polypoid lesions, and then these findings were compared with the colonoscopic findings. The degree of enhancement of colorectal polypoid lesions was measured by subtracting the attenuation values obtained with precontrast and postcontrast CT images for the differentiation of benignity and malignancy of the colorectal polypoid lesions. RESULTS: Among 75 colorectal polypoid lesions identified on conventional colonoscopy, 49 neoplasms were found on CT colonography, and the overall detection rate was 65.3%. Detection rate of lesions smaller than 10 mm was 52.1% (24/46), and the detection rate for lesions equal to or larger than 10 mm was 86.2% (25/29). Morphologic features of the sessile type lesions on CT colonography were well correlated with those noted on colonoscopy, but the stalks were not identified in 6 of 13 polyps on CT colonography. There was no statistical correlation between benignity and malignancy and the degree of contrast enhancement on CT colonography. CONCLUSION: CT colonography is a useful modality for the detection of colorectal polypoid lesions equal to or larger than 10mm, and it well demonstrates the morphologic features, except for the stalk of pedunculated polyps. However, CT colonography cannot differentiate benignity from malignancy.