Standards for gastroenterologists for performing and interpreting diagnostic computed tomographic colonography

Efficacy of 18-fluoro deoxy glucose-positron emission tomography computed tomography for the detection of colonic neoplasia proximal to obstructing colorectal cancer

Identification of secondary colonic neoplasia proximal to obstructing colorectal cancer is essential for determining the range of colorectal resection.We examined the accuracy of 18-fluoro deoxy glucose-positron emission tomography (FDG-PET) for detection of colonic neoplasia.We recruited patients with obstructing colorectal cancer from our registry. Preoperative FDG-PET was performed, and the detection rate for colonic neoplasia was estimated. Preoperative colonoscopy or postoperative colonoscopy within a year after operation was employed as the indexed standard.Ninety-three patients were included in this study. Colonic neoplasia proximal to obstruction was confirmed in 83 cases. The sensitivity and positive predictive value of FDG-PET were 25.3% and 77.8%, respectively. The sensitivity was higher in larger lesions (3.2% for <5 mm, 29.4% for 6-10 mm, 45.5% for 11-20 mm, and 71.4% for >21 mm) and in higher pathological grade lesions (14.6% for low-grade adenoma, 38.5% for high-grade adenoma, 66.7% for carcinoma in situ, and 100% for invasive carcinoma). The round shape in PET images was a predictor for neoplasia, with an area under the curve of 0.75293 at an aspect ratio of 1.70.FDG-PET should be used as a screening modality for invasive colorectal cancer (CRC) proximal to obstructing colorectal cancer.

Medicare cost of colorectal cancer screening: CT colonography vs. optical colonoscopy

PURPOSE

To compare the Medicare population cost of colorectal cancer (CRC) screening of average risk individuals by CT colonography (CTC) vs. optical colonoscopy (OC).

METHODS

The authors used Medicare claims data, fee schedules, established protocols, and other sources to estimate CTC and OC per-screen costs, including the costs of OC referrals for a subset of CTC patients. They then modeled and compared the Medicare costs of patients who complied with CTC and OC screening recommendations and tested alternative scenarios.

RESULTS

CTC is 29% less expensive than OC for the Medicare population in the base scenario. Although the CTC cost advantage is increased or reduced under alternative scenarios, it is always positive.

CONCLUSION

CTC is a cost-effective CRC screening option for the Medicare population and will likely reduce Medicare expenditures for CRC screening.

Reassessing medicare trends in diagnostic CT colonography after achieving CPT code category I status

PURPOSE

Compare national trends in utilization and coverage of diagnostic (non-screening) computed tomography colonography (CTC) in the Medicare population before and after achieving Current Procedural Terminology(®) (CPT) Category I code status in 2010.

METHODS

Claims by provider type and location for diagnostic CTC were identified between 2005 and 2013 using Medicare Physician Supplier Procedure Summary Master Files. Frequencies of billed and denied services were used to calculate denial rates for CTC and abdominal computed tomography (CT). PubMed search for articles with "CT colonography" in abstract or title during 1997-2013 was performed. Publications were recorded yearly and matched to CTC denial rates.

RESULTS

Annual Medicare claims for diagnostic CTC increased 212% during 2005-2009 in Category III status and increased 27.4% during 2009-2013 after implementation of Category I codes. Claims for abdominal CT rose 13.4% over the same overall period. Denial rates decreased from 70% to 32.8% between 2005 and 2009, and fluctuated between 24.7 and 30.6% thereafter. Denial rates for abdominal CT remained constant (4.1%-4.6%). From 2005 to 2013, services grew most in the private office (1678-7293) and hospital outpatient (1644-6449) settings with radiologists performing 93.3% of CTC. 1037 CTC publications were identified which increased 3567% between 1997 (3) and 2008 (107), plateaued until 2010 (114) and declined thereafter (75 in 2013).

CONCLUSIONS

Diagnostic CTC grew dramatically from 2005 to 2009, but slowed thereafter; even after achieving CPT Category I code status in 2010. Medicare denial rates declined during early years but later stabilized which paralleled a slowing in new peer-reviewed research. CTC continues to be performed predominately by radiologists in the outpatient setting.

Cancer Screening 2016

The primary goal of cancer screening is to reduce cancer-related mortality without incurring significant harm. Screening efforts for solid tumors, therefore, have targeted the precursors of the most common and the most deadly cancers-breast, cervical, colorectal, lung and prostate cancer. Balancing risk and benefit has led to controversy regarding the timing of cancer screening-when to begin, how often to screen and when to stop-and the nature of the modality of cancer screening-invasive or noninvasive, laboratory-centered or imaging-centered. Evidence-based guidelines published by general medical societies, subspecialty societies and publicly funded task forces on population-based screening aid healthcare providers in making individualized decisions with their patients.

Alternatives to Incomplete Colonoscopy

A thorough and complete colonoscopy is critically important in preventing colorectal cancer. Factors associated with difficult and incomplete colonoscopy include a poor bowel preparation, severe diverticulosis, redundant colon, looping, adhesions, young and female patients, patient discomfort, and the expertise of the endoscopist. For difficult colonoscopy, focusing on bowel preparation techniques, appropriate sedation and adjunct techniques such as water immersion, abdominal pressure techniques, and patient positioning can overcome many of these challenges. Occasionally, these fail and other alternatives to incomplete colonoscopy have to be considered. If patients have low risk of polyps, then noninvasive imaging options such as computed tomography (CT) or magnetic resonance (MR) colonography can be considered. Novel applications such as Colon Capsule™ and Check-Cap are also emerging. In patients in whom a clinically significant lesion is noted on a noninvasive imaging test or if they are at a higher risk of having polyps, balloon-assisted colonoscopy can be performed with either a single- or double-balloon enteroscope or colonoscope. The application of these techniques enables complete colonoscopic examination in the vast majority of patients.

Frequency and efficacy of additional investigations following incomplete colonoscopies: A population-based analysis

BACKGROUND

Limited data are available on the follow-up of patients with incomplete colonoscopy following positive faecal occult blood testing. Our study aimed to determine the proportion of and reasons for incomplete colonoscopies, the proportion of patients who completed colonic evaluations, the methods used and the subsequent findings.

METHODS

A total of 9483 colonoscopies performed after positive testing in a colorectal cancer screening programme setting were included. The study was prospective for index colonoscopy findings and partly retrospective for follow-up.

RESULTS

Overall 297 colonoscopies were incomplete (3.2%). A secondary colonic evaluation was deemed necessary in 245 patients, of which 126 underwent an additional examination (51.4%). Radiology was the primary method used for complete colonic evaluation, whereas a repeat colonoscopy was performed in only 6.4%; the examination was normal in 119 patients (94.4%). A mucosal high-grade neoplasia was removed in 1, and multiple (≥3) adenomas were removed in 2 patients.

CONCLUSIONS

The present screening programme with biennial faecal occult blood testing revealed a high colonoscopy completion rate, a low rate of secondary colonic evaluation, infrequent use of colonoscopy for completion, and a low detection rate of significant neoplasia.

Role of CT Colonography in Colonic Lesions and Its Correlation with Conventional Colonoscopic Findings

BACKGROUND

Preoperative evaluation in patients with colorectal carcinoma is essential for a correct therapeutic plan. Conventional colonoscopy has certain limitations including its inability to detect synchronous lesions in case of distal obstructive mass and inaccurate tumour localization. CT colonography combines cross sectional imaging with virtual colonoscopic images and offers a comprehensive preoperative evaluation in patients with colorectal carcinoma including detection of synchronous lesions with accurate segmental localization and loco regional staging.

AIM

The objective was to determine the role of CT colonography in various colonic lesions and to correlate the findings with conventional colonoscopy and histopathological findings.

SETTINGS AND DESIGN

This prospective study included 50 patients with clinical symptoms suspicious of colonic pathology.

MATERIALS AND METHODS

All the patients underwent both CT colonography and conventional colonoscopy on the same day. CT colonography was performed in supine and prone position. Considering histopathological and/or surgical findings as gold standard, sensitivity and specificity of both the modalities were calculated.

RESULTS

Conventional colonoscopy missed two synchronous lesions proximal to occlusive mass and one lesion proximal to the anastomotic site; all were detected with CT colonography. One carpet lesion in rectum and one case of mild ulcerative colitis were missed by CT colonography. Sensitivity and specificity for detection of colorectal cancer were 97.56% and 100%, resp. with PPV and NPV of 100% and 93.75%, for CT colonography and 92.68% and 100%, respectively with PPV and NPV of 100% and 83.3% for conventional colonoscopy. Sensitivity for correct detection of acute and chronic ulcerative colitis of CT colonography was 66.6 % and 100 %, resp.

CONCLUSION

CT colonography has higher sensitivity than conventional colonoscopy for detection of colorectal carcinoma, including its ability to detect abnormalities proximal to obstructing lesion, accurate segmental localization of lesions and staging. However, some limitations of CT colonography were difficulty in detection of flat lesions and lack of information about hyperemia and superficial mucosal erosion, where conventional colonoscopy scored over CT colonography.

Does training and experience influence the accuracy of computed tomography colonography interpretation?

AIM: To evaluate the effect of experience on the accuracy rate of computed tomography colonography (CTC) interpretation and patient preferences/satisfaction for CTC and colonoscopy.

METHODS: A prospective, non-randomized, observational study performed in a single, tertiary care center involving 90 adults who underwent CTC followed by colonoscopy on the same day. CTC was interpreted by an abdominal imaging radiologist and then a colonoscopy was performed utilizing segmental un-blinding and re-examination as required. A radiology resident and two gastroenterology (GI) fellows blinded to the results also interpreted the CTC datasets independently. Accuracy rates and trend changes were determined for each reader to assess for a learning curve.

RESULTS: Among 90 patients (57% male) aged 55 ± 8.9 years, 39 polyps ≥ 6 mm were detected in 20 patients and 13 polyps > 9 mm in 10 patients. Accuracy rates were 88.9% (≥ 6 mm) and 93.3% (> 9 mm) for the GI Radiologist, 89.8% (≥ 6 mm) and 98.9% (> 9 mm) for the Radiology Resident and 86.7% and 95.6% (≥ 6 mm) and 87.8% and 94.4% (> 9 mm) for each of the GI fellows respectively. The reader’s accuracy rate did not change significantly with the percentage change rate ranging between -1.7 to 0.9 (P = 0.12 to 0.56). Patients considered colonoscopy more satisfactory than CTC (30% vs 4%, P < 0.0001), they felt less anxiety during colonoscopy (36% vs 7%, P < 0.0001), they experienced less pain or discomfort during colonoscopy compared to CTC (69% vs 4%, P < 0.0001) and colonoscopy was preferred by 77% of the participants as a repeat screening test for the future.

CONCLUSION: No statistically significant learning curve was identified in CTC interpretation suggesting that further study is required to identify the necessary training to adequately interpret CTC scans.

Colon capsule endoscopy is feasible to perform after incomplete colonoscopy and guides further workup in clinical practice

BACKGROUND

Colon capsule endoscopy (CCE) could be an option to examine the colon after incomplete colonoscopy.

OBJECTIVE

To investigate the extent that CCE complements incomplete colonoscopy and guides further workup.

DESIGN

Prospective, follow-up study.

SETTING

Three tertiary-care centers.

PATIENTS

Consecutive outpatients after colonoscopy failure; 1-year study period.

INTERVENTION

Patients underwent CCE either immediately after colonoscopy or were rescheduled. Further investigations were guided by the results of CCE. Patients were followed as long as 2 years.

RESULTS

We studied 75 outpatients; 39 had a screening colonoscopy. One third of the patients underwent CCE immediately after colonoscopy. Overall, CCE reached or went beyond the colon segment at which colonoscopy stopped in 68 patients (91%). CCE technically complemented difficult colonoscopy independently of whether same-day CCE was performed (24 [96%]) or was not performed (44 [88%]). CCE detected additional significant findings in 36% of the same-day CCE cases and in 48% of the rescheduled ones. Two patients in the same-day group and 13 in the rescheduled CCE group underwent further colon examination that revealed additional significant findings in 3 of them. Ten percent of the patients reported mild adverse events (AE). If needed, 63 participants (84%) were willing to repeat CCE. Follow-up has not identified symptomatic missed colon cancers.

LIMITATIONS

Selected patient population, first-generation colon capsule, old preparation scheme.

CONCLUSION

CCE performed immediately or at a scheduled date after colonoscopy failure is feasible and safe. CCE after incomplete colonoscopy appears to yield significant findings, guide further workup, and has high patient acceptance.

Adverse events of computed tomography colonography: an Italian National Survey

AIM

To retrospectively study the frequency and magnitude of complications associated with computed tomography (CT) colonography in clinical practice.

METHODS

A questionnaire on complications of CT colonography was sent to Italian public radiology departments identified as practicing CT colonography with a reasonable level of training. The frequency of complications and possible risk factors were retrospectively determined. Responses were collated and row frequencies determined. A multivariate analysis of the factors causing adverse events was also performed.

RESULTS

40,121 examinations were performed in13 centers during the study period. No deaths were reported. Bowel perforations occurred in 0.02% (7 exams). All perforations were asymptomatic and occurred in patients undergoing manual insufflation. Five perforations (71%) occurred in procedures performed following a recent colonoscopy. There was no significant difference between perforations associated with rectal balloon (0.017%) and those that were not (0.02%). Complications related to vasovagal reaction (either with or without spasmolytic) occurred in 0.16% (63 exams). All vasovagal reactions resolved in less than 3h, without any sequelae.

CONCLUSIONS

Perforation rate at CT colonography in Italy is comparable with elsewhere in the world, occurring regardless of the experience of radiology centers. Although the risk is very small, it may not be negligible when compared with the risk of diagnostic colonoscopy.

[Colonoscopy quality control as a requirement of colorectal cancer screening]

The strategies used in population-based colorectal screening strategies culminate in colonoscopy and consequently the success of these programs largely depends on the quality of this diagnostic test. The main factors to consider when evaluating quality are scientific-technical quality, safety, patient satisfaction, and accessibility. Quality indicators allow variability among hospitals, endoscopy units and endoscopists to be determined and can identify those not achieving recommended standards. In Spain, the working group for colonoscopy quality of the Spanish Society of Gastroenterology and the Spanish Society of Gastrointestinal Endoscopy have recently drawn up a Clinical Practice Guideline that contains the available evidence on the quality of screening colonoscopy, as well as the basic requirements that must be met by endoscopy units and endoscopists carrying out this procedure. The implementation of training programs and screening colonoscopy quality controls are strongly recommended to guarantee the success of population-based colorectal cancer screening.

Preoperative colonoscopy for detection of synchronous neoplasms after insertion of self-expandable metal stents in occlusive colorectal cancer: comparison of covered and uncovered stents

Background/Aims

In patients with occlusive colorectal cancers, a complete preoperative evaluation of the colon proximal to the obstruction is often impossible. We aimed to evaluate the feasibility of preoperative colonoscopy after stent placement and to determine whether the success rate of colonoscopy differs between covered and uncovered stents.

Methods

Seventy-three patients with malignant colorectal obstruction were enrolled prospectively. In patients with a resectable cancer, a preoperative colonoscopy was performed after insertion of a self-expandable metal stent (SEMS). The success rate of complete preoperative colonoscopy was compared between covered and uncovered stents.

Results

Forty-five of 73 patients who underwent stent placement had a resectable cancer (61.6%). A complete preoperative colonoscopy was possible in 40 of 45 patients (88.9%). The success rate of complete preoperative colonoscopy was significantly lower in the covered-stent group when the obstructing mass lesion was located in the sigmoid colon (p=0.024). Synchronous cancer was detected in one patient (2.2%). Stent migration was observed in four patients with a covered stent.

Conclusions

A preoperative complete colonoscopy after SEMS placement was feasible and safe in most patients with malignant colorectal obstruction. Uncovered stents seem to have more advantages than covered stents in preoperative colonoscopy proximal to the obstruction.

Incomplete colonoscopy: maximizing completion rates of gastroenterologists

BACKGROUND

Cecal intubation is one of the goals of a quality colonoscopy; however, many factors increasing the risk of incomplete colonoscopy have been implicated. The implications of missed pathology and the demand on health care resources for return colonoscopies pose a conundrum to many physicians. The optimal course of action after incomplete colonoscopy is unclear.

OBJECTIVES

To assess endoscopic completion rates of previously incomplete colonoscopies, the methods used to complete them and the factors that led to the previous incomplete procedure.

METHODS

All patients who previously underwent incomplete colonoscopy (2005 to 2010) and were referred to St Paul's Hospital (Vancouver, British Columbia) were evaluated. Colonoscopies were re-attempted by a single endoscopist. Patient charts were reviewed retrospectively.

RESULTS

A total of 90 patients (29 males) with a mean (± SD) age of 58 ± 13.2 years were included in the analysis. Thirty patients (33%) had their initial colonoscopy performed by a gastroenterologist. Indications for initial colonoscopy included surveillance or screening (23%), abdominal pain (15%), gastrointestinal bleeding (29%), change in bowel habits or constitutional symptoms (18%), anemia (7%) and chronic diarrhea (8%). Reasons for incomplete colonoscopy included poor preparation (11%), pain or inadequate sedation (16%), tortuous colon (30%), diverticular disease (6%), obstructing mass (6%) and stricturing disease (10%). Reasons for incomplete procedures in the remaining 21% of patients were not reported by the referring physician. Eighty-seven (97%) colonoscopies were subsequently completed in a single attempt at the institution. Seventy-six (84%) colonoscopies were performed using routine manoeuvres, patient positioning and a variable-stiffness colonoscope (either standard or pediatric). A standard 160 or 180 series Olympus gastroscope (Olympus, Japan) was used in five patients (6%) to navigate through sigmoid diverticular disease; a pediatric colonoscope was used in six patients (7%) for similar reasons. Repeat colonoscopy on the remaining three patients (3%) failed: all three required surgery for strictures (two had obstructing malignant masses and one had a severe benign obstructing sigmoid diverticular stricture).

CONCLUSION

Most patients with previous incomplete colonoscopy can undergo a successful repeat colonoscopy at a tertiary care centre with instruments that are readily available to most gastroenterologists. Other modalities for evaluation of the colon should be deferred until a second attempt is made at an expert centre.

[Korean guidelines for colorectal cancer screening and polyp detection]

Colorectal cancer is the second most common cancer in males and the fourth most common in females in Korea. Since the most of colorectal cancer occur through the prolonged transformation of adenomas into carcinomas, early detection and removal of colorectal adenomas are one of the most effective methods to prevent colorectal cancer. Considering the increasing incidence of colorectal cancer and polyps in Korea, it is very important to establish Korean guideline for colorectal cancer screening and polyp detection. Korean Multi-Society Take Force developed the guidelines with evidence-based methods. Parts of the statements drawn by systematic reviews and meta-analyses. Herein we discussed the epidemiology of colorectal cancers and adenomas in Korea, optimal screening methods for colorectal cancer, and detection for adenomas including fecal occult blood tests, radiologic tests, and endoscopic examinations.

Korean guidelines for colorectal cancer screening and polyp detection

Now colorectal cancer is the second most common cancer in males and the fourth most common cancer in females in Korea. Since most of colorectal cancers occur after the prolonged transformation of adenomas into carcinomas, early detection and removal of colorectal adenomas are one of the most effective methods to prevent colorectal cancer. Considering the increasing incidence of colorectal cancer and polyps in Korea, it is very important to establish Korean guideline for colorectal cancer screening and polyp detection. The guideline was developed by the Korean Multi-Society Take Force and we tried to establish the guideline by evidence-based methods. Parts of the statements were draw by systematic reviews and meta-analyses. Herein we discussed epidemiology of colorectal cancers and adenomas in Korea and optimal methods for screening of colorectal cancer and detection of adenomas including fecal occult blood tests, radiologic tests, and endoscopic examinations.

Physician knowledge and appropriate utilization of computed tomographic colonography in colorectal cancer screening

GOALS

To assess physician understanding of computed tomographic colonography (CTC) in colorectal cancer (CRC) screening guidelines in a pilot study.

BACKGROUND

CTC is a sensitive and specific method of detecting colorectal polyps and cancer. However, several factors have limited its clinical availability, and CRC screening guidelines have issued conflicting recommendations.

STUDY

A web-based survey was administered to physicians at two institutions with and without routine CTC availability.

RESULTS

398 of 1655 (24%) participants completed the survey, 59% was from the institution with routine CTC availability, 52% self-identified as trainees, and 15% as gastroenterologists. 78% had no personal experience with CTC. Only 12% was aware of any current CRC screening guidelines that included CTC. In a multiple regression model, gastroenterologists had greater odds of being aware of guidelines (OR 3.49, CI 1.67-7.26), as did physicians with prior CTC experience (OR 4.81, CI 2.39-9.68), controlling for institution, level of training, sex, and practice type. Based on guidelines that recommend CTC, when given a clinical scenario, 96% of physicians was unable to select the appropriate follow-up after a CTC, which was unaffected by institution.

CONCLUSIONS

Most physicians have limited experience with CTC and are unaware of recent recommendations concerning CTC in CRC screening.

Expanding utilization and regional coverage of diagnostic CT colonography: early Medicare claims experience

PURPOSE

The aim of this study was to assess national and regional trends in utilization and Medicare coverage of diagnostic CT colonography (CTC).

METHODS

Medicare claims for diagnostic CTC were identified for the first 4 complete years for which Current Procedural Terminology® tracking codes existed (2005-2008). The frequencies of billed and denied services were extracted on a national and regional basis, along with physician provider specialty and site of service.

RESULTS

Total annual claims for diagnostic CTC for Medicare fee-for-service beneficiaries increased from 3,660 to 10,802 (+195%) between 2005 and 2008. Overall, 50.1% (14,051 of 28,048) of all claims were denied, with annual national denial rate decreasing from 70.0% to 43.4% (2,562 of 3,660 to 4,692 of 10,802, P < .001). Annual regional denial rates ranged from 16.5% to 98.3%. Of all 28,048 CTC claims, 25,893 (92.3%) were submitted by radiologists, 286 (1.0%) by gastroenterologists, and 369 (1.3%) by other specialists (specialties were indeterminate for 1,550). Most services were performed in office (n = 13,764 [49.1%]) and outpatient hospital (n = 12,110 [43.2%]) settings, with only a small number in the inpatient hospital (n = 1,768 [6.3%]) and other miscellaneous (n = 406 [1.4%]) settings.

CONCLUSIONS

Diagnostic CTC is performed predominantly by radiologists in private office and outpatient hospital settings. Since the advent of Current Procedural Terminology tracking codes, the utilization of diagnostic CTC by Medicare fee-for-service beneficiaries has tripled. Despite perceptions that new technology tracking codes are not payable, more than half of all examinations are now reimbursed by Medicare. Coverage varies regionally but overall is improving annually, setting the stage for expanded patient access.

Incremental benefit of computer-aided detection when used as a second and concurrent reader of CT colonographic data: multiobserver study

PURPOSE

To quantify the changes in reader performance levels, if any, during interpretation of computed tomographic (CT) colonographic data when a computer-aided detection (CAD) system is used as a second or concurrent reader.

MATERIALS AND METHODS

After institutional review board approval was obtained, 16 experienced radiologists searched for polyps in 112 patients, 56 of whom had 132 polyps. Each case was interpreted on three separate occasions by using an unassisted (without CAD), second-read CAD, or concurrent CAD reading paradigm. The reading paradigm and case order were randomized, with a minimal interval of 1 month between consecutive interpretations. The readers' findings were compared with the reference-truth interpretation. The mean per-patient sensitivity and mean per-patient specificity with CAD were compared with those achieved with unassisted reading. An increase in per-patient sensitivity was considered to be clinically more important than an equivalent decrease in specificity.

RESULTS

The mean per-patient sensitivity for identification of patients with polyps of any size increased significantly with use of second-read CAD (mean increase, 7.0%; 95% confidence interval [CI]: 4.0%, 9.8%) and concurrent CAD (mean increase, 4.5%; 95% CI: 0.8%, 8.2%). The mean per-patient specificity did not decrease significantly with use of second-read CAD (mean decrease, -2.5%; 95% CI: -5.2%, 0.1%) or concurrent CAD (mean decrease, -2.2%; 95% CI: -4.6%, 0.2%). With analysis restricted to patients with polyps 6 mm or larger, the benefit in sensitivity with second-read CAD remained (mean increase, 7.1%; 95% CI: 3.0%, 11.1%), whereas the increase with concurrent CAD was not significant (mean increase, 4.2%; 95% CI: -0.5%, 8.9%). Use of second-read CAD significantly increased the per-polyp sensitivity for polyps 6 mm or larger (mean increase, 9.0%; 98.3% CI: 4.9%, 12.8%) and polyps 5 mm or smaller (mean increase, 5.9%; 98.3% CI: 3.2%, 9.1%), but use of concurrent CAD increased the per-polyp sensitivity for only those polyps 5 mm or smaller (mean increase, 4.8%; 98.3% CI: 2.2%, 7.9%).

CONCLUSION

Use of second-read CAD significantly improves readers' per-patient and per-polyp detection. Concurrent CAD is less effective.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.10100354/-/DC1.

Evaluation of a standardized CT colonography training program for novice readers

PURPOSE

To determine how many computed tomographic (CT) colonography training studies have to be evaluated by novice readers to obtain an adequate level of competence in polyp detection.

MATERIALS AND METHODS

The study was approved by the Institutional Review Board. Informed consent was obtained from all participants. Six physicians (one radiologist, three radiology residents, two researchers) and three technicians completed a CT colonography training program. Two hundred CT colonographic examinations with colonoscopic verification were selected from a research database, with 100 CT colonographic examinations with at least one polyp 6 mm or larger. After a lecture session and short individual hands-on training, CT colonography training was done individually with immediate feedback of colonoscopy outcome. Per-polyp sensitivity was calculated for four sets of 50 CT colonographic examinations for lesions 6 mm or larger. By using logistic regression analyses, the number of CT colonographic examinations to reach 90% sensitivity for lesions 6 mm or larger was estimated. Reading times were registered.

RESULTS

The average per-polyp sensitivity for lesions 6 mm or larger was 76% (207 of 270) in the first set of 50 CT colonographic examinations, 77% (262 of 342) in the second (P = .96 vs first set), 80% (310 of 387) in the third (P = .67 vs first set), and 91% (261 of 288) in the fourth (P = .018). The estimated number of CT colonographic examinations for a sufficient sensitivity was 164. Six of nine readers reached this level of competence within 175 CT colonographic examinations. Reading times decreased significantly from the first to the second set of 50 CT colonographic examinations for six readers.

CONCLUSION

Novice CT colonography readers obtained sensitivity equal to that of experienced readers after practicing on average 164 CT colonographic studies.

Computed tomographic colonography: ready for prime time?

Computed tomographic (CT) colonography is a noninvasive method to evaluate the colon and has received considerable attention in the last decade as a colon-imaging tool. The technique has also been proposed as a potential primary colon cancer-screening method in the United States. The accuracy of the technique for the detection of large lesions seems to be high, perhaps in the range of colonoscopy. Overall, the field is rapidly evolving. Available data suggest that CT colonography, although a viable colon cancer screening modality in the United States, is not ready for widespread implementation, largely because of the lack of standards for training and reading and the limited number of skilled readers.

Radiologists should read CT colonography

This article defines the necessary skill set and knowledge base required for accurate computed tomography colonography (CTC) interpretation. The components of the interpretative process as well as the various strategies currently employed are discussed. The role of extracolonic evaluation as an integral part of this examination is also covered. Within this context, the question of whether a radiologist or gastroenterologist is better suited to interpret this examination is explored.

Performance of CT colonography for detecting small, diminutive, and flat polyps

The primary goal of colorectal cancer screening and prevention is the detection and removal of advanced neoplasia. Computerized tomography (CT) colonography is now well established as an effective screening test. Areas of greater uncertainty include the performance characteristics of CT colonography for detecting small (6-9 mm), diminutive (< or =5 mm), and flat (nonpolypoid) lesions. However, the actual clinical relevance of small, diminutive, and flat polyps has also been the source of debate. This article addresses these controversial and often misunderstood issues.

Gastroenterologists should read CT colonography

Screening for colorectal neoplasms has become the standard of care in advanced medical settings worldwide. Identifying asymptomatic colorectal neoplastic lesions has been shown to reduce colorectal cancer incidence and the overall cost of medical care. Clinicians have several alternatives at their disposal as they consider screening for their respective patient population. Two important methods to consider are optical colonoscopy and computed tomographic colonography (CTC). The purpose of this article is to make the case that gastroenterologists should read CTC. Central to the argument that gastroenterologists read CTC is the benefit of experience with video-assisted colonic imaging and the physician-patient relationship.

Establishing a CT colonography service

This article describes the steps involved in establishing a screening computed tomographic colonography (CTC) practice and integrating that practice within a gastroenterology practice. The standard operating procedures followed at the National Naval Medical Center's Colon Health Initiative are presented and are followed by a discussion of practical aspects of establishing a CTC practice, such as equipment specifications, CTC performance, and interpretation training requirements for radiologists and nonradiologists. Regulatory considerations involved in establishing a screening CTC program are examined along with the salient features of a CTC business plan. Finally, reimbursement issues, quality control, and the potential impact of screening CTC on colonoscopy practice are discussed.

ACR Colon Cancer Committee white paper: status of CT colonography 2009

PURPOSE

To review the current status and rationale of the updated ACR practice guidelines for CT colonography (CTC).

METHODS

Clinical validation trials in both the United States and Europe are reviewed. Key technical aspects of the CTC examination are emphasized, including low-dose protocols, proper insufflation, and bowel preparation. Important issues of implementation are discussed, including training and certification, definition of the target lesion, reporting of colonic and extracolonic findings, quality metrics, reimbursement, and cost-effectiveness.

RESULTS

Successful validation trials in screening cohorts both in the United States with ACRIN and in Germany demonstrated sensitivity > or = 90% for patients with polyps >10 mm. Proper technique is critical, including low-dose techniques in screening cohorts, with an upper limit of the CT dose index by volume of 12.5 mGy per examination. Training new readers includes the requirement of interactive workstation training with 2-D and 3-D image display techniques. The target lesion is defined as a polyp > or = 6 mm, consistent with the American Cancer Society joint guidelines. Five quality metrics have been defined for CTC, with pilot data entered. Although the CMS national noncoverage decision in May 2009 was a disappointment, multiple third-party payers are reimbursing for screening CTC. Cost-effective modeling has shown CTC to be a dominant strategy, including in a Medicare cohort.

CONCLUSION

Supported by third-party payer reimbursement for screening, CTC will continue to further transition into community practice and can provide an important adjunctive examination for colorectal screening.

Targeting Chemoprevention of Colorectal Cancer to Those Who Are Likely to Respond

In the past four decades, chemoprevention of colorectal cancer (CRC) has been the subject of many epidemiologic and intervention trials of naturally occurring or pharmacologic agents. Recently, the positioning of cyclooxygenase 2 inhibitors as a viable option in this context was a major breakthrough; however, it was hampered by adverse cardiovascular events. This review questions whether chemopreventive measures for CRC are ready to be used in mass or individual applications, standing alone or in combination with other CRC-preventive measures. It also discusses steps that may be undertaken to explore this field further.

Gastroenterologists' interpretation of CTC: a pilot study demonstrating feasibility and similar accuracy compared with radiologists' interpretation

OBJECTIVES

Computed tomography colonography (CTC) is an emerging colon cancer screening modality that has the potential to increase adherence to current screening recommendations. Traditionally, the interpretation of CTC has been limited to radiologists. As the technology of CTC has developed, three-dimensional endoluminal fly-through images have largely replaced two-dimensional CT images as the primary reading modality. Such a display is a realistic corollary to the endoscopic view obtained during colonoscopy. Our study sought to determine whether gastroenterologists could interpret the colonic display of CTC with an accuracy similar to that of trained radiologists.

METHODS

Three board-certified gastroenterologists and four gastroenterology fellows in various stages of training interpreted a mean of 45 CTCs (range: 30-50) in which colonoscopy had also been performed. Before reading any cases, each reader underwent CTC interpretation training with an experienced CTC radiologist. After interpreting each CTC, the gastroenterologist had access to both the original radiology interpretation of the CTC and the corresponding colonoscopy results. Outcomes included accuracy of the gastroenterologists' interpretation, time required for CTC interpretation, evidence of learning, and the level of diagnostic agreement between gastroenterologists and radiologists.

RESULTS

Gastroenterologist readers identified polyps >or=6 mm on CTC with a mean sensitivity and specificity of 83.5% (67-100%) and 78.8% (69-100%), respectively. Corresponding values for polyps >or=8 mm were 83.8% (68-100%) and 74% (30-93%), respectively, and those for polyps >or=10 mm were 87.8% (67-100%) and 85.2% (60-94%), respectively. Overall, 83% (5 of 6) of gastroenterologists achieved kappa scores >or=0.60, suggesting good agreement with radiologists; 66% achieved kappa>or=0.75. There was a direct relationship between diagnostic accuracy and level of gastroenterology training, with third-year fellows being nearly as accurate as the attendings. The average gastroenterologist CTC reading time was 18.4 min (range: 11.2-25.6).

CONCLUSIONS

The gastroenterologists in this study were able to read CTCs with an accuracy that approaches that of radiologists. The level of training affected the accuracy of CTC interpretation by the gastroenterologist. Average gastroenterologist CTC interpretation times in this study were similar to recommended colonoscopy times. Further studies are warranted to determine whether gastroenterologists are able to interpret CTCs independently in clinical practice.

Performance of computed tomographic colonography for the screening of colorectal polyp in acromegalic patients: a prospective study

CONTEXT

Acromegalic patients have better chances to develop colorectal polyps and cancer and, considered a high-risk group, need to undergo frequent screening examinations. Moreover, in acromegalia, the increased bowel length and the intestinal loop complexity can lead to higher levels of technical difficulties and increase the risks of complications at conventional colonoscopy. Computed tomographic colonography, also known as virtual colonoscopy, is an innovative and secure technology which is revolutionizing the diagnosis of colon and rectum neoplasias.

OBJECTIVE

To analyze computed tomographic colonography performance for the screening of colorectal polyps in acromegalic patients.

METHODS

A prospective study of 21 asymptomatic acromegalic patients, 12 male and 9 female, average age 49, who underwent computed tomographic colonography and conventional colonoscopy. Computed tomographic colonography was performed with a GE Helical Multislice Computed Tomography Apparatus. Conventional colonoscopy was performed in the same day, without previous knowledge of the computed tomographic colonography diagnostics. The study evaluated the capacity of computed tomographic colonography to detect patients with colorectal polyps and identify each colorectal lesion described by the colonoscopy.

RESULTS

In two patients (2/21), conventional colonoscopy was incomplete. However, in all patients computed tomographic colonography was complete. In Phase I ('per patient'), computed tomographic colonography diagnosed eight of the nine patients with colorectal polyps and showed 88% sensitivity, 75% specificity and 81% accuracy. In Phase II ('per polyp'), out of the 21 acromegalic patients included in this study, 12 presented normal findings at conventional colonoscopy. A total of 19 polyps were identified in 9 patients. Ten of the 19 polyps were smaller than 10 mm, and 9 were equal to or larger than 10 mm. Computed tomographic colonography identified 7 of the 9 polyps >10 mm described by conventional colonoscopy and only 6 of the 10 small polyps identified at conventional colonoscopy were detected by computed tomographic colonography. The histological analysis of resected lesions revealed 12 tubular adenomas, 6 hyperplastic polyps and 1 colonic tubulo-villous adenoma with an adenocarcinoma focus.

CONCLUSION

The authors present the first reports of computed tomographic colonography in the screening of colorectal polyps in acromegalic patients. In this study, computed tomographic colonography was performed without complications and a complete and safe colorectal evaluation was possible in all acromegalic patients. Moreover, computed tomographic colonography presented good sensitivity, specificity and accuracy for the identification of acromegalic patients with polyps of any size and better results in the diagnosis of large polyps, when they were compared to small polypoid lesions.

CT colonography: Friend or foe of practicing endoscopists

AIM

To investigate the perceived impact of computed tomographic colonography (CTC) on endoscopists' current and future practice.

METHODS

A 21-question survey was mailed to 1570 randomly chosen American Society for Gastrointestinal Endoscopy (ASGE) members. Participants reported socio-demographics, colonoscopy volume, percentage of colonoscopies performed for screening, and likelihood of integration of CTC into their practice.

RESULTS

A total of 367 ASGE members (23%) returned the questionnaire. Respondents were predominantly male (> 90%) and white (83%) with an average age of 49 years. Most respondents (58%) had no plans to incorporate CTC into daily practice and only 7% had already incorporated CTC into daily practice. Private practice respondents were the least likely to incorporate this modality into their daily practice (P = 0.047). Forty-three percent of participants were willing to take courses on CTC reading, particularly those with the highest volume of colonoscopy (P = 0.049). Forty percent of participants were unsure of CTC's impact on future colonoscopy volume while 21% and 18% projected a decreased and increased volume, respectively. The estimated impact of CTC volume varied significantly by age (P = 0.002). Respondents > 60 years felt that CTC would increase colonoscopy, whereas those < 40 years thought CTC would ultimately decrease colonoscopy.

CONCLUSION

Practicing endoscopists are not enthusiastic about the incorporation of CTC into their daily practice and are unsure of its future impact on their practice.

Colorectal cancer screening with CT colonography: key concepts regarding polyp prevalence, size, histology, morphology, and natural history

OBJECTIVE

The purpose of this article is to provide a timely update on a variety of key polyp topics to construct a proper framework for physicians who are interested in providing CT colonography screening as a clinical service.

CONCLUSION

As the medical community considers the expansion of CT colonography for screening, we believe it is prudent to update and review several key concepts regarding colorectal polyps. In particular, it is important to replace the older literature derived from high-risk and symptomatic cohorts with the wealth of newer and more applicable data from average-risk and asymptomatic screening cohorts. Familiarity with current concepts regarding flat (nonpolypoid) lesions and the natural history of small colorectal polyps is also vital to the effective application of this technique.

Computed tomographic colonography: current perspectives and future directions

Computed tomographic (CT) colonography, also known as virtual colonoscopy or CT colography, is capable of detecting colon polyps and cancers. It is emerging rapidly and has gained great momentum over the past several years, to the point where it has been proposed to be a viable primary colon cancer screening option. Despite the current publicity, many issues concerning CT colonography remain. As of 2009, the following topics are of paramount importance: (1) accuracy, including both sensitivity and specificity, (2) bowel preparation, (3) safety, (4) extracolonic findings, (5) patient acceptability, (6) training and standardization, and (7) implementation of CT colonography. Although much about CT colonography has already been learned, more remains to be learned in the future.

Comprehensive proteome analysis of an Apc mouse model uncovers proteins associated with intestinal tumorigenesis

Tumor-derived proteins may occur in the circulation as a result of secretion, shedding from the cell surface, or cell turnover. We have applied an in-depth comprehensive proteomic strategy to plasma from intestinal tumor-bearing Apc mutant mice to identify proteins associated with tumor development. We used quantitative tandem mass spectrometry of fractionated mouse plasma to identify differentially expressed proteins in plasma from intestinal tumor-bearing Apc mutant mice relative to matched controls. Up-regulated proteins were assessed for the expression of corresponding genes in tumor tissue. A subset of proteins implicated in colorectal cancer were selected for further analysis at the tissue level using antibody microarrays, Western blotting, tumor immunohistochemistry, and novel fluorescent imaging. We identified 51 proteins that were elevated in plasma with concordant up-regulation at the RNA level in tumor tissue. The list included multiple proteins involved in colon cancer pathogenesis: cathepsin B and cathepsin D, cullin 1, Parkinson disease 7, muscle pyruvate kinase, and Ran. Of these, Parkinson disease 7, muscle pyruvate kinase, and Ran were also found to be up-regulated in human colon adenoma samples. We have identified proteins with direct relevance to colorectal carcinogenesis that are present both in plasma and in tumor tissue in intestinal tumor-bearing mice. Our results show that integrated analysis of the plasma proteome and tumor transcriptome of genetically engineered mouse models is a powerful approach for the identification of tumor-related plasma proteins.

Computed tomographic colonography

PURPOSE OF REVIEW

Computed tomographic colonography is a new and noninvasive method to evaluate the colon. The goal of this review is to discuss the latest data and define outstanding issues related to computed tomographic colonography.

RECENT FINDINGS

Computed tomographic colonography is gaining momentum as a potential primary colon cancer screening method in the USA. Although not as accurate as colonoscopy, the accuracy of computed tomographic colonography for detection of large lesions appears to be in the 80-90% range. The field is rapidly evolving, not only in terms of technology but also in a variety of other practical areas.

SUMMARY

Current data suggest that computed tomographic colonography is a viable colon cancer screening modality in the USA. However, it is not ready for widespread implementation, largely because of lack of standards for training and reading and the fact that the number of skilled readers is limited.

Formative evaluation of standardized training for CT colonographic image interpretation by novice readers

PURPOSE

To introduce an educational intervention-specifically, a specialized training course-and perform a formative evaluation of the effect of the intervention on novice reader interpretation of computed tomography (CT) colonographic data.

MATERIALS AND METHODS

The study was institutional review board approved. Ten normal and 50 abnormal cases, those of 60 patients with 93 polyps-61 polyps 6-9 mm in diameter and 32 polyps 10 mm or larger-were selected from a previously published trial. Seven novice readers underwent initial training that consisted of a 1-day course, reading assignments, a self-study computer module (with 61 limited data sets), observation of an expert interpreting three cases, and full interpretation of 10 cases with unblinding after each case. After training, the observers independently interpreted 60 cases by means of primary two-dimensional reading with unblinding after each case. For each case, the reading time and the location and maximal diameter of the polyp(s) were recorded. A t test was used to evaluate the observers' improvements, and empirical receiver operating characteristic (ROC) curves were constructed.

RESULTS

By-patient sensitivities and specificities were determined for each observer. The lowest by-patient sensitivity at the 6 mm or larger polyp threshold was 86%, with 90% specificity. Four observers had 100% by-patient sensitivity at the 10 mm or larger polyp threshold, with 82%-97% specificity. For polyps 10 mm or larger, mean sensitivity and specificity were 98% and 92%, respectively. For the last 20 cases, the average interpretation time per case was 25 minutes. The range of areas under the ROC curve across observers was low: 0.86-0.95.

CONCLUSION

In the described polyp-enriched cohort, novice CT colonographic data readers achieved high sensitivity and good specificity at formative evaluation of a comprehensive training program. Use of a similar comprehensive training method might reduce interreader variability in interpretation accuracy and be useful for reader certification.

Computed tomography colonography (virtual colonoscopy): climax of a new era of validation and transition into community practice

Colorectal cancer, which kills more than 50,000 patients every year in the United States and costs more than $6 billion in direct health costs, is a prime target for cancer prevention. Computed tomography colonography (CTC) has emerged as a minimally invasive, structural examination of the entire colon that can complement the current tools of cancer prevention and may improve patient compliance. Large trials have suggested a sensitivity of roughly 90% and specificity greater than 97% for CTC for patients with polyps >or= 10 mm. Bowel preparation by diet restriction, catharsis, and stool and fluid tagging are typically used. A prepless CTC protocol is an active area of research with a focus on improving patient compliance. Insurance coverage of CTC is a key factor affecting current dissemination and local and national coverage decisions are ongoing. CT examination of the abdomen allows visualization of extracolonic organs, where detection of additional disease must balance any unnecessary anxiety and testing. Estimates of CTC cost-effectiveness are generally favorable, but vary due to the high sensitivity of these models to costs, polyp sensitivity, compliance rates, and other parameters, which are difficult to accurately assess. Quality initiatives are being developed that will be key for implementation into community practice.

CT colonography after incomplete colonoscopy in subjects with positive faecal occult blood test

AIM: To report our experience with computed tomography colonography (CTC) systematically performed in subjects with positive faecal occult blood test (FOBT) and an incomplete colonoscopy in the setting of a population-based screening for colorectal cancer (CRC).

METHODS: From April 2006 to April 2007, 43 290 individuals (age range 50-70) who adhered to the regional screening program for the prevention of CRC underwent immunochemical FOBT. FOBT was positive in 1882 subjects (4.3%). 1463 (77.7%) of these subjects underwent colonoscopy, 903 performed in a single center. Of 903 colonoscopies 65 (7.2%) were incomplete. Forty-two of these subjects underwent CTC. CTC was performed with a 16-MDCT scanner after standard bowel prep (polyethylene glycole) in both supine and prone position. Subjects whose CTC showed polyps or masses were referred to the endoscopist for repeat colonoscopy under sedation or underwent surgery. Per-lesion and per-segment positive predictive values (PPV) were calculated.

RESULTS: Twenty-one (50%) of 42 CTCs showed polyps or masses. Fifty-five of these subjects underwent a repeat colonoscopy, whereas 2 subjects underwent surgery for colonic masses of indeterminate nature. Four subjects refused further examinations. CTC correctly identified 2 colonic masses and 20 polyps. PPV for masses or polyps greater than 9 mm was of 87.5%. Per-lesion and per-segment PPV were, respectively, 83.3% and 83.3% for polyps greater or equal to 10 mm, and 77.8% and 85.7% for polyps of 6-9 mm.

CONCLUSION: In the context of a screening program for CRC based on FOBT, CTC shows high per-segment and per-lesion PPV for colonic masses and polyps greater than 9 mm. Therefore, CTC has the potential to become a useful technique for evaluation of the non visualized part of the colon after incomplete colonoscopy.

Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: a joint guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology

In the United States, colorectal cancer (CRC) is the third most common cancer diagnosed among men and women and the second leading cause of death from cancer. CRC largely can be prevented by the detection and removal of adenomatous polyps, and survival is significantly better when CRC is diagnosed while still localized. In 2006 to 2007, the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology came together to develop consensus guidelines for the detection of adenomatous polyps and CRC in asymptomatic average-risk adults. In this update of each organization's guidelines, screening tests are grouped into those that primarily detect cancer early and those that can detect cancer early and also can detect adenomatous polyps, thus providing a greater potential for prevention through polypectomy. When possible, clinicians should make patients aware of the full range of screening options, but at a minimum they should be prepared to offer patients a choice between a screening test that primarily is effective at early cancer detection and a screening test that is effective at both early cancer detection and cancer prevention through the detection and removal of polyps. It is the strong opinion of these 3 organizations that colon cancer prevention should be the primary goal of screening.

The utility of flexible sigmoidoscopy after a computerized tomographic colonography revealing only rectosigmoid lesions

BACKGROUND

Identifying polyps by computerized tomographic colonography typically prompts colonoscopy, increasing its cost, risk and inconvenience. Many polyps are confined to the rectosigmoid and theoretically amenable to resection via flexible sigmoidoscopy.

AIM

To determine the prevalence of advanced proximal colonic neoplasia when computerized tomographic colonography reveals only rectosigmoid polyps, and characterize the yield of polypectomy via flexible sigmoidoscopy in such patients.

METHODS

Subjects underwent computerized tomographic colonography and colonoscopy with segmental unblinding. Patients with only rectosigmoid findings by computerized tomographic colonography were identified retrospectively. Flexible sigmoidoscopy findings were estimated by including lesions distal to the descending/sigmoid colon junction during colonoscopy. Proximal lesions were also reviewed. Advanced lesions were defined as: adenocarcinoma, tubular adenoma >1 cm, > or =3 tubular adenomas, tubulovillous histology or high-grade dysplasia.

RESULTS

By computerized tomographic colonography, 15% (203 of 1372) had only rectosigmoid polyps. Concomitant lesions in the proximal colon were seen in 32% (64 of 203) during colonoscopy. Advanced proximal neoplasia occurred in 2% (three of 203) with only rectosigmoid polyps on computerized tomographic colonography.

CONCLUSIONS

Using flexible sigmoidoscopy to follow-up computerized tomographic colonography demonstrating only rectosigmoid polyps would eliminate 15% of subsequent colonoscopies. This strategy carries a small risk of missed proximal advanced neoplasia. This miss rate appears comparable to that of colonoscopy alone. Further study on the cost-effectiveness of this approach is warranted.