Computed Tomography Colonography as a Sensible Option for Colorectal Cancer Screening: Evidence Based on Metanalysis / Colonografia por tomografia computadorizada como uma opção sensível para o rastreamento do câncer colorretal: Evidências baseadas em metanálise

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.

Colonografia por tomografia computadorizada versus colonoscopia óptica no rastreamento do câncer colorretal: uma revisão sistemática / Computed tomographic colonography versus optical colonoscopy in colorectal cancer screening: a systematic review

Objetivo: comparar, por meio de uma revisão sistematizada, a colonografia por tomografia (CTC) versus colonoscopia óptica (CO) em relação ao rastreamento e vigilância do câncer colorretal (CCR). Método: foram analisados estudos em inglês e português sobre CTC e CO realizados em humanos adultos de ambos os sexos, publicados no MedLine/PubMed (National Library of Medicine) e no Scielo (Scientific Eletronic Library Online) no período entre 1990 a 2013. A busca incluiu combinações de palavras-chave (Colonoscopy, Cólonoscopic surgery, virtual Colonoscopy, CT Colonography) com boolianos AND e OR. Os critérios de inclusão foram ensaios clínicos controlados e randomizados, estudo de revisão, revisões sistemáticas com ou sem metanálise, consenso, pacientes adultos, pacientes assintomáticos ou sintomáticos. Os critérios de exclusão foram pacientes inapropriados e somente em resumo. Resultados: foram selecionados 26 estudos com melhor abordagem dos desfechos selecionados para rastreamento e vigilância do câncer (CCR). O número global de pacientes submetidos às variáveis foi de 397.342 indivíduos. Os valores das variáveis de sensibilidade e especificidade para detecção de pólipos maior ou igual a 10mm e câncer colorretal apresentam percentagens semelhantes, sendo a taxa de sensibilidade da CTC diretamente proporcional ao tamanho do pólipo. A taxa de pacientes submetidos à CO após a CTC variou de 12% a 36,4%; destes, 3,8% apresentaram lesões significativas. A análise da taxa de CO incompleta obteve um padrão de variações entre 11% e 64,8%. A aceitação dos pacientes, tanto para o preparo intestinal como para o procedimento, foi maior para a CTC. Os achados extracólicos nos pacientes submetidos à CTC foram analisados e variaram de 58 a 69%. As complicações dos dois métodos foram baixas, maior na CO. Conclusão: as diferenças na sensibilidade e especificidade entre a CO e a CTC no rastreamento e vigilância do CCR não são relevantes. A indicação de CO após CTC deve seguir critérios consensuais para evitar aumento de custos e de riscos ao paciente. Pacientes com CO incompleta têm indicação de realizar CTC por se enquadrar no grupo de alto risco para desenvolver CCR. A aceitação dos pacientes na realização dos dois métodos é boa e não representa impedimento ao rastreamento e vigilância do CCR. Os achados extracólicos na CTC é um benefício adicional para o paciente. As complicações inerentes aos dois métodos não superam o impacto positivo dos mesmos na prevenção do CCR.

Objective: to compare in a systematic review the computed tomographic Colonography (CTC) and the optical Colonoscopy (OC) methods for the screening and monitoring of colorectal cancer (CRC). Method: english and portuguese studies on CTC and OC that were carried out on adult humans of both genders that had been published in MedLine/PubMed (National Library of Medicine) and SciELO (Scientific Electronic Library Online) between 1990 and 2013 were analyzed. The search included combinations of keywords (Colonoscopy, Cólonoscopic surgery, virtual Colonoscopy, CT Colonography, etc.) with the AND and OR Boolean operators. The inclusion criteria were as follows: controlled and randomized clinical trials, review studies, systematic reviews with or without meta-analysis, consensus, adult patients, and asymptomatic or symptomatic patients. The exclusion criteria were as follows: unsuitable patients and manuscripts only containing abstracts. Results: twenty-six studies that included the selected outcomes for screening for and monitoring CRC were selected. The overall number of patients analyzed was 397, 342 individuals. The sensitivity and specificity percentages for the detection of polyps greater than or equal to 10 mm and for colorectal cancer were similar between the two methods, and the CTC sensitivity rate was directly proportional to the size of the polyp. The rate of patients undergoing OC after CTC ranged from 12% to 36.4%, and of these patients, 3.8% had significant lesions. The analysis of the incomplete OC rate found variation ranging from 11 to 64.8%. The acceptance rates of the patients for both intestinal preparation and for the procedure were greater for CTC. The extracolic findings in patients undergoing CTC were analyzed and ranged from 58 to 69%. Complications were minimal for the patients undergoing both methods and higher for those in the OC group. Conclusion: the differences in the sensitivity and specificity of OC and CTC in screening and monitoring CRC are not significant. The indication of OC after CTC must follow agreed-upon criteria to avoid increased costs and risks to the patient. Patients with an incomplete OC should undergo CTC, as they fall within the high risk group for developing CRC. The acceptance of patients undergoing the two methods is good and does not represent an impediment to screening for and monitoring CRC. The extracolic findings, in the CTC group, is an additional benefit to the patient. The complications inherent in the two methods do not outweigh their positive impacts in the prevention of CRC.

Preferência do paciente no rastreamento do câncer colorretal: uma comparação entre colonografia por tomografia computadorizada e colonoscopia / Patient preferences toward colon cancer screening: a comparison between computed tomography colonography and conventional colonoscopy

OBJETIVO: Avaliar o grau de aceitação do paciente submetido a colonografia por tomografia computadorizada (CTC) em comparação com a colonoscopia, quando realizadas para rastreamento de doença colorretal. MATERIAIS E MÉTODOS: Cinquenta pacientes com suspeita de doença colorretal foram submetidos a CTC e colonoscopia. Questionários foram aplicados antes e após a realização da CTC e após a colonoscopia. Graduou-se o desconforto esperado e experimentado antes e após a realização da CTC e da colonoscopia, bem como a preferência do paciente por exame. RESULTADOS: Em relação à CTC, antes de iniciar o exame 18 por cento dos pacientes afirmaram esperar pouco desconforto, 78 por cento, desconforto moderado e 4 por cento, muito desconforto. Após a realização do exame, 72 por cento dos pacientes relataram pouco desconforto, 26 por cento, desconforto moderado e apenas um (2 por cento) dos pacientes referiu muito desconforto. Após a realização da colonoscopia, 86 por cento dos pacientes relataram preferência pela CTC. O grau de distensão colônica e a quantidade de fluido residual não influenciaram na preferência dos pacientes. CONCLUSÃO: Os pacientes preferiram a CTC à colonoscopia, não havendo relação estatística com o grau de distensão colônica na CTC e a eficiência do preparo intestinal.

OBJECTIVE: To assess the degree of acceptance of patients undergoing computed tomography colonography (CTC) in comparison with colonoscopy in the screening of colorectal disease. MATERIALS AND METHODS: Fifty patients with suspected colorectal disease underwent CTC and colonoscopy. Questionnaires were administered before and after the performance of the CTC and after the colonoscopy. The discomfort expected and experienced before and after the performance of both procedures as well as the patients' preference for each method were evaluated. RESULTS: As regards CTC, before the procedure, 18 percent of the patients reported expecting little discomfort, 78 percent, mild discomfort, and 4 percent, a lot of discomfort. After the procedure, 72 percent of the patients reported little discomfort, 26 percent, mild discomfort, and only one (2 percent) of the patients reported a lot of discomfort. Upon completion of the colonoscopy, 86 percent of the patients reported their preference for CTC. The degree of colonic distention and residual amount of fluid had no influence on the patients' preference. CONCLUSION: CTC was preferred to colonoscopy, with no statistical relationship with the degree of colonic distention at CTC and efficiency of bowel preparation.

Distensión colónica con bomba de CO2: Impacto en el disconfort del paciente en los estudios de colonoscopía virtual / Colonic distention with CO2 insufflation: Impact on the patient's discomfort in virtual colonoscopy studies

Objetivos. Analizar el rol de la distensión colónica con CO2 y su influencia en el disconfort del paciente y en el tiempo de duración de la colonoscopía virtual en nuestra práctica diaria. Materiales y Métodos. Se estudiaron 200 pacientes, 50 insuflados con aire ambiental y 150 con CO2. Los estudios se realizaron con un equipo multidetector de 64 filas con cortes de 2 mm de espesor, 120 kV y 50 mAs. En todos los pacientes se efectuó una adquisición en decúbito supino y otra en prono. Se calculó el tiempo total del procedimiento en cada grupo y se utilizó una prueba "t de Student" para calcular las diferencias. Los pacientes completaron un cuestionario en referencia al grado de disconfort percibido. Se utilizó una escala de 0 a 3: 0- sin disconfort, 1- disconfort leve, 2- moderado y 3- severo. Se utilizó un test de proporciones para calcular las diferencias del grado de disconfort entre ambos grupos. Resultados. El tiempo total de los procedimientos fue de 30,5 minutos para los realizados con CO2 y 35,4 minutos para los efectuados con aire ambiental, con una diferencia de -4,9 min (p=0,0003). En la valoración del disconfort, en el grupo con insuflado con aire ambiental, el 44% de los pacientes manifestó un grado de disconfort moderado, mientras que en el grupo con CO2 el 76% manifestó ausencia de disconfort. Conclusiones. La colonoscopía virtual realizada con insuflación de CO2 permitió disminuir en forma parcial el tiempo total del examen y, de modo significativo, el disconfort durante y después del examen.

Objectives. To analyze the role of colonic distention with CO2 and its influence on patients' discomfort and the duration of the virtual colonoscopy procedure in our daily practice. Materials and Methods. Two hundred patients were evaluated, 50 were insufflated using room air and 150 with CO2. The studies were performed with a 64-row CT scanner using 2-mm slice thickness, 120 kV and 50 mAs. In all patients, scans were acquired both in prone and supine positions. We calculated the total procedure time in each group; a Student's t-test was used to calculate the differences. Patients completed a questionnaire about the degree of discomfort perceived. We used a scale of 0 to 3: 0- no discomfort, 1- mild, 2- moderate and 3- severe discomfort. We used a test of proportions to calculate the differences in the degree of discomfort between the two groups. Results. The total procedure time was 30.5 minutes for studies performed with CO2 and 35.4 minutes for those performed with room air, with a difference of -4.9 min (p =0.0003). As regards the assessment of discomfort, in the group insufflated with room air, 44% of patients reported a moderate degree of discomfort, while in the group insufflated with CO2, 76% of the patients expressed no discomfort. Conclusions. Virtual colonoscopy performed with CO2 insufflation partially reduced the total procedure time, and significantly reduced discomfort during and after the procedure.

Hallazgos extracolónicos en estudios de colonoscopía virtual / Extracolonic findings in virtual colonoscopy studies

Objetivo. Analizar la presencia y tipo de hallazgos extracolónicos (HEC) en estudios de colonoscopía virtual (CV) y evaluar la conducta a seguir tras su diagnóstico. Materiales y Métodos. Se analizaron retrospectivamente 100 exámenes de CV en busca de HEC sin tener en cuenta el resultado de la C V. La población estudiada estuvo compuesta por 62 mujeres y 38 hombres con una edad promedio de 63 años. El motivo del examen fue variado, incluyendo tanto pacientes asintomáticos para screening como pacientes con diagnóstico presuntivo de patología neoplásica y casos que venían por colonosocopías ópticas incompletas. Los estudios fueron realizados con un equipo Philips Brilliance de 64 filas de detectores con protocolo específico para C V. Todos los pacientes recibieron preparación para limpieza intestinal y marcación de los residuos con bario. A los HEC se los clasificó como de importancia baja, moderada o alta. Los hallazgos de baja o nula importancia son aquellas alteraciones consideradas benignas y que difícilmente requieren nuevos exámenes. A los de importancia moderada se los define como alteraciones que no requieren un tratamiento inmediato, pero que probablemente necesitarán de mayor investigación o tratamiento más adelante. Los de importancia alta implican alteraciones que requieren tratamiento quirúrgico, intervención médica o nuevos exámenes en el corto plazo. Resultados. De los 100 pacientes, 66 presentaron HEC. En total hubo 122 HEC que se distribuyeron de la siguiente manera: 61% de baja importancia, 26% de moderada importancia y 13% de alta importancia. Conclusiones. Independientemente de que la evaluación extracolónica sea vista como un beneficio neto o una "debilidad" del método, en base a los puntos a favor y en contra, es una responsabilidad inevitable que debe ser manejada con extremo cuidado y criterio por el médico que interpreta el estudio y también por el médico que lo recibe. Es elemental siempre poner a los HEC en el contexto general del paciente.

Purpose. Analize the presence and type of extra-colonic findings (ECF) in virtual colonoscopy (VC) exams and evaluate the behavior after the diagnosis. Materials and Methods. 100 VC exams were retrospectively analyzed in search of ECF regardless of the outcome of the VC. The study population consisted of 62 women and 38 men with an average age of 63. The purpose of the exam included asymptomatic patients for screening as well as patients with apparent diagnosis of neoplasm pathology and cases which came with incomplete optical colonoscopies. The studies were carried out with a Philips Brilliance of 64 detector rows with specific protocol for VC. All patients received bowel cleansing and barium-based fecal tagging. The ECF were categorized as being of low, moderate or high importance. The findings of low or no importance are those benign alterations or those alterations that are unlikely to require further examination. Moderate importance ECF are defined as alterations that do not require immediate treatment but that will probably need investigation or treatment later. High importance ECF involve significant alterations that require surgical treatment, medical intervention or new tests in short term. Results. Out of 100 patients, 66 presented ECF. In total there were 122 ECF that were distributed as follows, 61% of low importance, 26% of moderate importance and 13% of high importance. Conclusions. Extracolonic evaluation needs to be handled with extreme care and judgement by the physician who interprets the study and also by the one who receives it. It is crucial to place ECF in the general context of the patient.

Colonoscopía virtual: realidad en un hospital público / Virtual colonoscopy: reality in a public hospital

Colon cancer is the third cause of death by cancer in Chile. Virtual CT colonoscopy (VC) is a non-invasive imaging technique in development. The most common indications of VC are screening of colonic polyp, incomplete conventional colonoscopy and staging of colorectal tumors. The objective of our study is to show our experience with this method in the Radiology Unit of Hospital Padre Hurtado. We reviewed 15 VC, corresponding to 15 patients (10 female and 5 male), with ages between 18 and 75. Six exams showed no significant findings (40%), 4 diverticular diseases (26,6%), 3 colon cancers (20%), and 2 familial polyposis (13,3%). VC proved to be an accesible method, well tolerated by the patients, less invasive than conventional colonoscopy and with no complications in our series. It also constitutes for us an excellent study method in patients where conventional colonoscopy is incomplete. We obtained an adecuate correlation with conventional colonosocopy, when this method was performed. Evaluation of the data obtained from VC requires a trained radiologist and, in some occasions, prolonged time for analysis and interpretation of the results.

El cáncer de colon es la tercera causa de muerte por cáncer en Chile. La colonoscopía virtual (CV) es una técnica de imagen no invasiva en desarrollo. Sus indicaciones habituales son: screening y detección de pólipos en el colon, colonoscopía convencional fallida o incompleta y, etapificación de tumores colorrectales. El objetivo de nuestro trabajo fue mostrar nuestra experiencia con este método diagnóstico en el Servicio de Imagenología del Hospital Padre Hurtado. Se revisaron 15 exámenes de CV que correspondieron a 15 pacientes (10 mujeres y 5 hombres), con edades entre 18 y 75 años. Los estudios mostraron 6 casos sin hallazgos patológicos significativos (40%), 4 enfermedades diverticulares (26,6%), 3 neoplasias de colon (20%) y 2 poliposis familiares (13,3%). La colonoscopía por TC resultó ser una técnica accesible, bien tolerada por los pacientes, menos invasiva que la fibrocolonoscopía y sin complicaciones. Además, para nosotros constituye un excelente método de estudio, sobretodo en aquellos pacientes en los cuales la fibrocolonoscopía resultó fallida o incompleta. Se obtuvo una buena correlación con colonoscopía convencional, cuando ésta se pudo realizar. El post-proceso de los datos requiere de entrenamiento del radiólogo y, algunas veces, tiempo prolongado para el análisis e interpretación de los resultados.

La radiología del colon por enema en el siglo XXI / Radiology of barium enema in the XXI century

Antecedentes: En los últimos años se ha introducido nuevos métodos para el estudio del colon. Objetivo: Analizar las distintas alternativas actuales para el diagnóstico de la patología colónica y el rol que el colon por enema (CxE) tiene en la actualidad, comparado con la videocolonoscopía (VCC), la colonoscopía virtual (CV) y la tomografía computada (TC). Material y métodos: Análisis de distintas series de la literatura que evalúan el papel de los diferentes métodos de estudio del colon. Resultados: Como estudio de catastro, la VCC y la CV fueron superiores en el diagnóstico de adenomas comparados con el CxE, que demostró una sensibilidad de alrededor del 50 por ciento según el tamaño de las lesiones con respecto a la VCC. Para pacientes sintomáticos, los resultados fueron similares. En pacientes ancianos, la TC mostró una sensibilidad comparable al CxE, no mostró el 2 por ciento de las lesiones radiológicas, sin las limitaciones de la preparación y la posibilidad de diagnóstico extracolónico. El CxE tiene utilidad en la colonoscopía incompleta pero compitiendo con la CV que tiene superior sensibilidad (50 contra 89 por ciento). Tiene mejor sensibilidad que la VCC en enfermedad diverticular (42 contra 18 casos), pero en patología asociada en colon sigmoideo, la sensibilidad es del 32 al 49 por ciento según el tamaño de las lesiones. La radiología aventaja a la VCC y CV en costo, siendo un 75 por ciento más económica. En series consultadas la indicación de CxE se ha reducido un 30 por ciento en los últimos 5 años. Conclusiones: El CxE tiene limitadas sus indicaciones en la actualidad y su utilización ha disminuido, siendo su futuro de indicación más restringida por el desarrollo y difusión de la VCC, el mejoramiento de la TC y el desarrollo de nuevos procedimientos como la CV.

Background: New methods to study the colon have been introduced in recent years. Objective: To assess current different alternatives to study colonic diseases, and the barium enema (BE) role compared to videocolonoscopy (VCO), virtual colonoscopy (VC), and computed tomography (CT). Material and methods: Analysis of different series of the bibliography that evaluate the various methods of colon study. Results: In the screening studies, the VCO and the VC were superior for the diagnosis of adenomas compared with BE which demostrated a sensitivity of around 50 per cent, according to polyp size, with respect to the VCO. For symptomatic patients, the results were similar. In elderly patients, the CT showed a comparable sensitivity with BE, did not show 2 per cent of the radiological injuries, but without the limitations of the preparation and the possibility of extracolonic diagnosis. BE is useful in incomplete colonoscopy, however, compete with VC, which has superior sensitivity (50 vs. 89 per cent). BE has better sensitivity than VCO in diverticular disease (42 vs. 18 cases), but in associated in sigmoid colon pathology, sensitivity is 32 to 49 per cent according to the size of the polyps. Radiology surpasses VCO and VC in cost, being 75 per cent less expensive. According to reviewed series, the indication of BE has been reduced by 30 per cent in the last 5 years. Conclusions: currently, BE has limited indications, which will be more restricted in the future due to the development and diffusion of VCO, the improvement of the CT and the development of new procedures, such as the VC.

Papel de la colonoscopia virtual en la evaluación de la enfermedad no polipoidea en pediatría / Virtual colonoscopy in pediatrics. Its role in the evaluation of non-polypoid lesions

Virtual colonoscopy is a new non-invasive method useful in the evaluation of elevated lesions. Due to the fact that the method has only been used for that purpose in the adult and pediatric population, the aim of this paper is to determine its utility in pediatric pathologies other than elevated lesions. Twenty patients with abdominal pain, chronic constipation and defecation problems were evaluated. The studies were performed with a 4-row CT scanner, using 1 mm slice thickness collimation. The acquisition time was 7-12 seconds. Neither sedation nor anesthesia was necessary. CT colonography can generate images similar to those from barium enema studies, without the use of barium contrast, avoiding related complications. The CT exam also provides information about the rest of the abdominal organs. All studies were performed without complications. Patients with Hirschprung disease, colorectal malformations, post-surgical complications and psichogenic megacolon were detected.

La colonoscopia virtual es una modalidad diagnóstica no invasiva para la valoración de enfermedad colorrectal sobre elevada. Dada su escasa aplicación en la población pediátrica, el objetivo de este trabajo es determinar su utilidad en otras patologías pediátricas. Se evaluaron 20 pacientes con síntomas como dolor abdominal, constipación crónica y dificultad en la defecación. Los estudios se realizaron con un tomógrafo de 4 filas de detectores, con cortes de 1 mm de espesor. La adquisición de las imágenes se realizó en decúbito supino, sin necesidad de apnea ni de anestesia. El tiempo de adquisición fue de aproximadamente 7 a 12 segundos. La colonoscopia virtual permite obtener imágenes similares a las de un colon por enema sin utilizar ningún tipo de contraste, por lo que evita posibles complicaciones. A ello se agrega la extrema rapidez del estudio, sin necesidad de movilizar al paciente. Además, brinda información adicional sobre el resto de los órganos abdominales, lo que determina un estudio más completo del paciente. No se observaron complicaciones. Se detectaron diversas patologías pediátricas como enfermedad de Hirschprung, megacolon psicógeno, malformaciones anorrectales y complicaciones posquirúrgicas

Colonoscopia virtual / Virtual colonoscopy

Since the first report in 1994 virtual colonoscopy or CT colonography has had an explosive development due to the improvement in hardware and software. The multidetector CT has allowed faster studies with better images due to better multiplanar reconstructions and its speed avoiding the artifact of the breathing or bowel peristalsis. The new software has allowed to obtain better 3D images and faster reconstruction with shorter interpretation. This development, the use of standarized protocol plus the experience of trained radiologists have obtained sensitivity and specificity over 85% and 95% in polyps smaller and larger than 10 mm respectively. These results and the lower price of virtual colonoscopy in the United States compared with fibrocolonoscopy has done this technique a real alternative for the screening of colorectal cancer side by side with fibrocolonoscopy.

Desde la primera publicación sobre colonoscopía virtual o colonografía por tomografía computada (TC) esta técnica ha tenido un explosivo crecimiento especialmente dado por el desarrollo en el hardware, específicamente por la introducción de la TC multicorte que ha permitido obtener mejores imágenes gracias a la mayor velocidad que ha obviado los artefactos dados por el movimiento respiratorio y el peristaltismo intestinal. Otro factor importante en su desarrollo ha sido el gran avance en los programas computacionales (software) que han automatizado la técnica obteniendo recons-trucciones 3D de mejor calidad y en menor tiempo. El notable desarrollo tecnológico sumado a la estandarización de la técnica y la mayor experiencia lograda en diferentes centros ha hecho que en la actualidad la sensibilidad y especificidad de la colonografía sobrepasen el 85 y 95% para los pólipos menores y mayores de 1 cm, respectivamente. Todo esto, sumado a la estandarización de la técnica ha llevado a posicionarla como una alternativa válida y en estrecha competencia con la fibrocolonoscopía en la pesquisa de los pólipos de colon.