CT Colography Research Articles

Signature Celebration of Gastroenterology, Colorectal Cancer

Abstract Gastroenterology has published many seminal articles that have transformed our understanding of colorectal cancer (CRC) as well as being influential in promoting colorectal cancer screening which has saved many people from developing the disease. CRC has a hereditary component most notably highlighted in Lynch syndrome. A key paper reported that the majority of mutations in patients with hereditary nonpolyposis colorectal cancer harbored mutations in the MLH 1 or MSH 2 mismatch repair proteins. Continuing on the gene mutation theme, another paper. highlighted that serrated polyps accounted for approximately 9% of all colon polyps and the majority of these harbored BRAF mutations, a mutation rarely seen in the traditional adenoma to carcinoma sequence. The journal also published key work outlining the role of COX-2 in the development of CRC and this led to the concept that CRC may be prevented by COX-2 inhibition. Gastroenterology has published many influential guidelines to promote screening for colorectal cancer. Initially Gastroenterology guidelines emphasized the need for offering any screening modality either alone or in combination such as fecal occult blood test, flexible sigmoidoscopy, CT colography or colonoscopy. These guidelines were very influential in persuading governments around the world of the importance of CRC and now many countries in the developed world offer national CRC screening programs. More recently guidelines have emphasized the need to offer screening programs that prevent CRC as well as early detection and colonoscopy would be the gold standard approach. Gastroenterology has also led the way in developing the concept of developing quality measures. The journal has published evidence as to which measures lead to improvement in adenoma detection and reduced interval CRC rates. These papers have been instrumental in current recommendations on quality colonoscopy practice.

The influence of rifaximin on diverticulitis rate and quality of life in patients with diverticulosis.

Diverticulosis, its associated symptoms and complications are one of the most common pathologies of the gastrointestinal tract in more economically developed countries. Presence of diverticuli and their clinical consequences can be divided into four categories: 1) diverticulosis, i.e. an asymptomatic presence of diverticuli that are usually found by accident 2) symptomatic uncomplicated diverticulosis 3) diverticulitis (acute uncomplicated diverticulitis) 4) complications of diverticulitis (conditions requiring hospital stay). The aim of this study was to retrospectively analyze the efficacy of rifaximin in preventing diverticulitis in patients visiting proctology clinics. The diagnostic criterium for diverticulosis was confirmation by colonoscopy, barium enema or CT colography (virtual colonoscopy) as well as history of at least one documented episode of diverticulosis. History of diverticulosis was evaluated based on medical records, clinical symptoms, elevated level of CRP (>5.0) and/or diagnostic imaging (ultrasound, CT). After setting strict exclusion criteria, 248 patients were qualified for the study out of 686, and they were later divided into two groups: control group (group I - 145 patients) and studied group (group II - 103 patients receiving rifaximin prophylaxis). Diverticulitis rate was comparable in both groups over a period of 6 months before study (p = 0.1306) and 6 months of treatment (p=0.3044). Between the 6th and 12th month of treatment, a significantly lower rate of diverticulitis was noted in the group receiving rifaximin compared to control group (p<0.0001). Patients receiving rifaximin reported higher quality of life (which was assessed using the VAS scale) compared to control group after 12 months. The results confirmed the efficacy of riaximin in prevention of diverticulitis, even in the scheme of repeated courses every 3 months. Not only did application of rifaximin lower the rate of diverticulitis and its complications in patients after an episode of diverticulitis, but also it improved the patients' quality of life. It seems that diverticulitis prophylaxis based on rifaximin can be economically efficient, however, it requires further research.

Microencapsulated sodium butyrate administered to patients with diverticulosis decreases incidence of diverticulitis—a prospective randomized study

BackgroundMicroencapsulated sodium butyrate (MSB) has been previously associated with anti-inflammatory and regenerative properties regarding large bowel mucosa. We aimed to examine a role of MSB in patients with diverticulosis, hypothesizing its potential for reduction of diverticulitis episodes and diverticulitis prevention.MethodsSeventy-three patients with diverticulosis (diagnosed in colonoscopy or/and barium enema or/and CT colography) were recruited for the study and randomized. The investigated group was administered MSB 300 mg daily; the control group was administered placebo. After 12 months, a total of 52 patients completed the study and were subject to analysis (30 subjects and 22 controls). During the study, the number of episodes of diverticulitis (symptomatic diagnosis with acute pain, fever, and leukocytosis), hospitalizations, and surgery performed for diverticulitis were recorded. Additionally, a question regarding subjective improvement of symptoms reflected changes in quality of life during the analysis.ResultsAfter 12 months, the study group noted a significantly decreased number of diverticulitis episodes in comparison to the control group. The subjective quality of life in the study group was higher than in the control group. There were no side effects of the MSB during the therapy.ConclusionsMSB reduces the frequency of diverticulitis episodes, is safe, and improves the quality of life. It can play a role in the prevention of diverticulitis.

AN AUDIT OF THE LAST 500 BOWEL CANCER SCREENING PROCEDURES WITHIN THE NORTHERN TRUST

IntroductionThe Bowel Cancer Screening Programme (BCS) in Northern Ireland offers screening every two years to all men and women aged 60 to 71. An FOB (faecal occult blood) kit is...

BOWEL CANCER SCREENING–ARE THE PATIENTS TRULY ASYMPTOMATIC?

IntroductionBowel Cancer Screening (BCS) was launched in 2010 in Northern Ireland, with screening colonoscopy lists starting in the Northern Trust in May 2010. Screening is offered every two years to...

Increasing colorectal cancer screening adherence: comment on "A randomized comparison of print and web communication on colorectal cancer screening".

Increasing colorectal cancer screening adherence: comment on "A randomized comparison of print and web communication on colorectal cancer screening".

Investigation of colorectal cancer by minimal preparation CT in the frail and elderly patient

IntroductionFrail & elderly patients frequently struggle with invasive colonic investigations and cathartic bowel preparation, commonly resulting in incomplete studies of uncertain significance. It is important there is a pragmatic method...

A New Technology to Visualize What the Endoscopist Does Not See During Colonoscopy

Background: Colonoscopy is currently the gold standard method for detection and prevention of colorectal cancer. However, the protective effect depends on the amount of colon mucosa that is actually seen by the endoscopist. Aim: To develop a new technique that estimates percent of mucosa inspected based on reconstruction of 3D shape from a 2D image. Methods: We use the angle between the plane defined by circular colon folds and the longitudinal colon axis and the amount of reflected light to reverse project the circular folds of a 2D image into 3D space. Next, we electronically create the colon mucosa between the folds using Cubic Bezier Curve interpolation. The estimated percent of mucosa inspected is the surface area of the mucosa seen and projected into 3D space divided by the total amount of mucosa interpolated by the computer to connect the folds. Results: From a 2D image (Fig A) we are able to recreate a 3D shape. Similar to CT colography, we can recreate a fly through experience (Fig B). We measured that about 65 percent of colon mucosa can be seen (Fig C) when looking into a 3D space model of a straight and well distended segment of colon using a 140o angle lens, and that 93 percent of colon mucosa can be seen when moving along the central axis of the 3D shape without any endoscope tip deflection (Fig D). Conclusions: We have successfully re-created 3D shape out of 2D images which allows estimation of percent of colon mucosa seen and not seen by the endoscopist. Preliminary results of a virtual fly through of a straight and well distended segment of recreated 3D colon show that about 7 percent of the colon mucosa is not seen without active scope deflections by the endoscopist. Comparison with CT colography derived surface area information, application to angular colon segments and testing on video are needed to determine the accuracy of our 2D image to 3D shape-based surface area estimation.

Colorectal Cancer Risk

Colorectal Cancer Risk

Radiation Protection in Diagnostic Radiology: More Intense Communication is Required

The article on radiation protection in diagnostic radiology constitutes an important scientific contribution. Details of individual dosimetric terms are explained in an exemplary fashion. All reported estimates are based primarily – as mentioned in the article – on the experiences of the nuclear bombs dropped on Japan in World War II. These calculations are bound to be rough estimates as the radiation doses and types at the time were different to those used in diagnostic radiology today. The reported tables are for orientation purposes, and it should be mentioned that a substantial variation in range exists which is mainly user dependent. The factor 400 for a thoracic computed tomography scan seems high, whereas in abdominal CT, more than 10 mSv can occur, depending on the number of the examined phases (1). Data are missing on catheter investigations (cardiac catheter, percutaneous transluminal coronary angioplasty), image guided treatments (vertebroplasty and kyphoplasty, intraoperative radiology), and modern methods (CT colography, cardiac CT, high resolution CT of the lung). The doses of all these investigations are often not known to referring doctors (2). Many unpredictable factors exist with regard to the attributable mortality risk (3). The absolute numbers may be correct under the given circumstances, but they are suitable merely for comparing exposure practices in the different countries. With regard to potential deaths or malignancies due to radiography, it needs to be kept in mind that investigations using ionizing radiation are usually done on severely ill patients who are often of advanced age. The authors emphasized the need for intensive communication between referrers and specialists – this is of crucial relevance. Radiation protection should start earlier than in the radiography department! The correct indication with set requirements and radiation-sparing investigation techniques will result in a dose reduction in the individual as well as in the population. In radiation protection, 1 g of cerebral matter weighs more than 1 tonne of lead (Felix Wachsmann, 1965).

Coloscopy and Colography Are the Appropriate Terms To Use When Referring to the Endoscopic and Radiological Examination of the Lower Gastrointestinal Tract

Purpose: The endoscopic examination of the colon is commonly referred to as colonoscopy and is currently the dominant modality for colon cancer screening, a major public health concern. It also forms the bulk of the current gastrointestinal endoscopic practice. The endoscopic examination of the colon is also referred to as coloscopy, especially in Europe. Despite the evolution of endoscopy, a large proportion of the US population remains unscreened and attempts are being made to enhance compliance with colon cancer screening. Part of this effort is the development of the non-invasive, radiological study of the colon, which is interchangeably referred to as both colonography and colography. This shows that the rapid advent of new technology and procedures in the field of gastroenterology has resulted in the indiscriminate use of medical terminology. Medical terminology is based on word construction and uses the concept of the word root in the context of the source language. By applying the rules of grammar and linguistics, we demonstrate that the desirable word root is col- (from the Greek col-on, meaning the gut) and not colon- (from the Greek colon-os, meaning a hill). The correct compound terms col-oscopy, col-ography, col-itis, col-ectomy and col-ostomy should therefore prevail over the corresponding terms colon-oscopy, colon-ography, colon-itis, colon-ectomy and colon-ostomy which would otherwise refer nonsensically to the examination of the hill, inflammation of the hill, surgical excision of the hill, etc. With regard to the two aforementioned ways of examining the lower gastrointestinal tract, the only correct terms are therefore coloscopy and colography. Old habits die hard, and colonoscopy has already become the established term to describe the endoscopic examination of the gut. However, it would certainly be appropriate for the term colography to prevail over colonography when referring to the more recently developed radiological evaluation of the gut, e.g. in the form of CT colography, PET colography and virtual coloscopy.

Cost-Effectiveness of Colorectal Cancer Screening in Average Risk Individuals

Aim: To estimate the incremental cost-effectiveness of nine different approaches to population-based colorectal cancer screening of average risk individuals in Canada. Methods: We constructed a life-time Markov model to compare 9 competing methods of colorectal cancer screening: no screening, annual fecal occult blood testing (aFOBT), biennial FOBT (bFOBT), q5 year flexible sigmoidoscopy (FS 5 yr), q5 year double contrast barium enema (DCBE 5 yr), q5 year DCBE/FS (DCBE/FS 5 yr), aFOBT/q5 year FS (aFOBT/FS 5 yr), q10 year CT colography (CTCOL 10 yr) and q10 year endoscopic colonoscopy (COL 10 yr).

Test Performance of CT Colonography: A Systematic Review of the Literature and Meta-Analysis

Background: Computed Tomography Colonography (CTC) is being proposed as a colorectal cancer screening modality that may improve screening adherence rates. The purpose of this study was to systematically review the test performance of CTC. Methods: We searched PubMed, Medline, EMBASE and Cochrane Controlled Trials Register for articles published in English language between January 1975 and October 2004 with the following MeSH terms or text words: virtual colonoscopy, CT colonography, CT colography or CT pneumocolon. We included only prospective blinded studies of adults undergoing CT colonography after full bowel preparation, using colonoscopy or surgery as the gold standard. Further, these studies had to use state-of-the-art technology with at least a single-detector CT scanner, both supine and prone positioning, air or CO2 colon insufflation of the colon, CT collimation < 5 mm, and both 2D & 3D views during interpretation. The data extracted included the overall sensitivity and specificity, as well as sensitivity and specificity for polyps <6mm, 6-9 mm and > 9mm in size. When data was sufficiently homogenous, we calculated weighted (by sample size) sensitivities and specificities. Heterogeneity was examined using stratified analyses and meta-regression. Results: A total of 31 studies were included that provided data from 5731 patients. There was a wide range of CTC sensitivities on a per patient analysis (21%-96%) that prevented pooling, even for polyps > 9 mm (range: 48%-100%). This heterogeneity was not explained by year published, demographics or cancer risk, imaging software used or CT reconstruction interval. Of note, collimation intervals, type of scanner and mode of imaging used did have an impact on heterogeneity. Data for specificity was homogenous with CTC being 92% specific (95% CI: 0.91-0.94) for polyps 6-9mm and 96% (95% CI: 0.96-0.97) for polyps > 9 mm. Discussion: While CTC is highly specific, there is a broad range of sensitivities that is not clearly related to patient or scanner characteristics--though collimation, type of scanner and mode of imaging do explain some of the disparity. The substantial heterogeneity underlines the concerns that CTC is not yet ready for widespread application. Experts may have valuable insights into CTC technique, but this study defines some of the specific technical issues that have impacted optimal test performance and supports the assertion that further scrutiny of CT Colonography is required. Background: Computed Tomography Colonography (CTC) is being proposed as a colorectal cancer screening modality that may improve screening adherence rates. The purpose of this study was to systematically review the test performance of CTC. Methods: We searched PubMed, Medline, EMBASE and Cochrane Controlled Trials Register for articles published in English language between January 1975 and October 2004 with the following MeSH terms or text words: virtual colonoscopy, CT colonography, CT colography or CT pneumocolon. We included only prospective blinded studies of adults undergoing CT colonography after full bowel preparation, using colonoscopy or surgery as the gold standard. Further, these studies had to use state-of-the-art technology with at least a single-detector CT scanner, both supine and prone positioning, air or CO2 colon insufflation of the colon, CT collimation < 5 mm, and both 2D & 3D views during interpretation. The data extracted included the overall sensitivity and specificity, as well as sensitivity and specificity for polyps <6mm, 6-9 mm and > 9mm in size. When data was sufficiently homogenous, we calculated weighted (by sample size) sensitivities and specificities. Heterogeneity was examined using stratified analyses and meta-regression. Results: A total of 31 studies were included that provided data from 5731 patients. There was a wide range of CTC sensitivities on a per patient analysis (21%-96%) that prevented pooling, even for polyps > 9 mm (range: 48%-100%). This heterogeneity was not explained by year published, demographics or cancer risk, imaging software used or CT reconstruction interval. Of note, collimation intervals, type of scanner and mode of imaging used did have an impact on heterogeneity. Data for specificity was homogenous with CTC being 92% specific (95% CI: 0.91-0.94) for polyps 6-9mm and 96% (95% CI: 0.96-0.97) for polyps > 9 mm. Discussion: While CTC is highly specific, there is a broad range of sensitivities that is not clearly related to patient or scanner characteristics--though collimation, type of scanner and mode of imaging do explain some of the disparity. The substantial heterogeneity underlines the concerns that CTC is not yet ready for widespread application. Experts may have valuable insights into CTC technique, but this study defines some of the specific technical issues that have impacted optimal test performance and supports the assertion that further scrutiny of CT Colonography is required.

Endoscopic colorectal cancer screening—can supply meet demand?

Endoscopic colorectal cancer screening—can supply meet demand?

Computed tomography colonography (virtual colonoscopy): review.

Computed tomography examination of the colon performed after bowel cleansing and distension of the lumen with gas goes by several different names--CT colonography (CTC) and CT colography perhaps being the most common. Strictly, the term 'virtual colonoscopy' (VC), should be reserved for the process of examining 3-D, simulated endoluminal images with a capability to navigate through the bowel using appropriate software. Computed tomography colonography appears to be the name that has gained favour among radiologists, although it is suspected that 'virtual colonoscopy' will persist as a generic term due to its attractive 'high-tech' connotations for non-radiological medical and lay persons. Whatever the name, the technique has been made possible through the advent of fast helical CT scanners which allow acquisition of a volume of data, and of proprietary software which enables multiplanar reformatting and 3-D endoluminal reconstructions. It is evident that if CTC/VC can be shown to be acceptable to patients, safe, affordable and accurate, it has enormous potential as a diagnostic and screening tool for colorectal neoplasia.

CT and MR colography (virtual colonoscopy): status report.

Computed tomography (CT) and magnetic resonance (MR) colography (virtual colonoscopy) are new techniques being developed for the purpose of imaging colorectal polyps and cancer. Limited data are available regarding the performance characteristics of either technique, particularly MR. Initial reports suggest that the sensitivity of CT and MR colography for patients with adenomas > or = 1 cm ranges from 75-90%, and decreases precipitously for smaller polyps. Very early data suggest that the specificity for patient with large adenomas is around 90%, but for patients with adenomas in the 5-9 mm range has been as low as 65%. This review discusses currently available published and abstracted data on CT and MR colography and discusses the real and potential advantages and disadvantages of CT and MR colography compared to current colonic imaging methods. The review discusses problems that must be overcome in order for CT or MR colography to be demonstrated as practical tests, and suggests guidelines for the performance of clinical trials testing the performance characteristics of these methods.

Colorectal polyp detection with 3D spiral CT colography: Technical evaluation of CT imaging protocol—work in progress

Colorectal polyp detection with 3D spiral CT colography: Technical evaluation of CT imaging protocol—work in progress

Three-dimensional CT colography: Is it detectable for flat tumors?

Three-dimensional CT colography: Is it detectable for flat tumors?

Computed Tomographic Colography and Virtual Colonoscopy

CT colography (CTC) is a powerful new approach to imaging the colorectum and a promising screening tool for the detection of colorectal neoplasia. From data generated by a helical CT scan, CTC uses virtual reality technology to produce highly discriminant two- and three-dimensional images that permit a thorough and minimally invasive evaluation of the entire colorectum. A dynamic CTC display technique from the endoluminal perspective, called cf2virtual colonoscopy,cf1 simulates colonoscopy by "flying" through the three-dimensional colon image. CTC offers potential advantages in diagnostic performance, safety, and patient acceptance over current screening approaches. Although early data suggest excellent colorectal polyp detection rates, this nascent technology will require rigorous clinical investigation and further refinements to assess adequately its place in the endoscopist's armamentarium.

A patient satisfaction study of cT colography (Virtual colonoscopy) and colonoscopy

A patient satisfaction study of cT colography (Virtual colonoscopy) and colonoscopy