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Endoscopy 07/2011; 43 Suppl 2 UCTN:E266-7. · 5.21 Impact Factor
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A Ignjatovic,
J E East,
T Guenther,
J Hoare,
J Morris,
K Ragunath,
A Shonde,
J Simmons,
N Suzuki,
S Thomas-Gibson, B P Saunders
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ABSTRACT: In vivo optical diagnosis of small colorectal polyps has potential clinical and cost advantages, but requires accuracy and high interobserver agreement for clinically acceptability. We aimed to assess interobserver variability and diagnostic performance of endoscopic imaging modalities in characterizing small colonic polyps.
High quality still images of 80 polyps < 1 cm were recorded using white-light endoscopy (WLE), autofluorescence imaging (AFI) and narrow-band imaging with and without magnification (NBI and NBImag). All images were assessed for quality, prediction of polyp histology, and vascular pattern intensity (with NBI) by nine experienced colonoscopists (four experts in advanced imaging) from five UK centers. Interobserver agreement (kappa statistic), sensitivity, specificity, and accuracy were calculated compared with histopathological findings.
Interobserver agreement for predicting polyp histology using NBImag was significantly better for experts (κ = 0.63, substantial) compared with nonexperts (κ = 0.30, fair; P < 0.001), and was moderate for all colonoscopists with WLE, AFI and NBI. Interobserver agreement for vascular pattern intensity using NBI was 0.69 (substantial) for experts and 0.57 (good) for nonexperts. NBImag had higher sensitivity than WLE (experts, 0.93 vs. 0.68, P < 0.001; nonexperts, 0.90 vs. 0.52, P < 0.001) and higher overall accuracy (experts, 0.76 vs. 0.64, P = 0.003; nonexperts 0.61 vs. 0.40, P < 0.001). AFI had worse accuracy than WLE for both expert colonoscopists (0.53 vs. 0.64, P = 0.02) and nonexperts (0.32 vs. 0.40, P = 0.04).
Of the imaging modalities tested, NBImag appeared to have the best overall accuracy and interobserver agreement, although not adequate for in vivo diagnosis. NBI and AFI did not have better sensitivity, specificity, or accuracy compared with WLE.
Endoscopy 02/2011; 43(2):94-9. · 5.21 Impact Factor
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ABSTRACT: St Mark's Bowel Cancer Screening Centre commenced screening in October 2006 as a contributor to the national programme. The first 35 months' experience is reported.
Individuals with a positive faecal occult blood test (FOBT) were offered colonoscopy or alternatives if they had significant comorbidity. All screening data were collected prospectively.
Of the 98 815 FOBT kits issued, 42 523 were returned (43% uptake; 20.79% men). In total, 1339/1488 (90%) FOBT-positive participants attended the nurse clinic (57% men). Of these, 1057 had an index colonoscopy, 115 had a computed tomography colonoscopy (CTC) and eight had a flexible sigmoidoscopy. Five hundred and seventeen (44%) procedures were 'normal' (no polyps/cancers). Eighty (6%) individuals had colorectal cancer. The polyp detection rate in index procedures, including colonoscopy, CTC and flexible sigmoidoscopy, was 50%. The adenoma detection rate of all colonoscopies was 62.8%. The median polyp size was 5 (1-80) mm. In total, 1200 colonoscopies were performed by five accredited colonoscopists (96% completion rate). There were 13 (1%) adverse events with < 1 in 500 patients undergoing polypectomy requiring a transfusion. There was one 30-day postsurgical mortality, one perforation and no colonoscopy-related mortality. Almost all 39/40 (97%) patients in the BCS programme felt that the findings were adequately explained compared with 21/32 (64%) elective patients (P < 0.001) within the same unit.
At this bowel cancer screening single centre, colonoscopy completion rates were high (unadjusted caecal intubation rate of 96%) and complication rates were low. In contrast to other published data, the uptake and cancer-detection rates were lower.
Colorectal Disease 01/2011; 14(2):166-73. · 2.93 Impact Factor
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ABSTRACT: With the recent publication of international computed tomography (CT) colonography standards, which aim to improve quality of examinations, this review informs radiologists about the significance of flat polyps (adenomas and hyperplastic polyps) in colorectal cancer pathways. We describe flat polyp classification systems and propose how flat polyps should be reported to ensure patient management strategies are based on polyp morphology as well as size. Indeed, consistency when describing flat polyps is of increasing importance given the strengthening links between CT colonography and endoscopy.
Clinical radiology 12/2010; 65(12):958-66. · 1.65 Impact Factor
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Gut 09/2009; 58(8):1170; author reply 1170-1. · 10.11 Impact Factor
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ABSTRACT: Narrow band imaging (NBI) can accurately characterize colonic polyps using microvascular appearances. We aimed to assess whether the Kudo pit pattern classification is accurate when used with NBI (without dye-spray), and if microvascular appearances or NBI pit patterns maintain accuracy for polyp characterization at sizes < 10 mm.
116 polyps < 10 mm in size were detected in 62 patients undergoing surveillance colonoscopy. The polyps were prospectively assessed using NBI and magnification for Kudo pit pattern (III-V neoplastic, I-II non-neoplastic) and vascular pattern intensity (VPI), a measure of microvascular density (strong VPI, neoplastic; normal or weak VPI, non-neoplastic). Sensitivity, specificity, and accuracy were calculated and compared with results from histopathology.
The mean polyp size was 3.4 mm (range 1 - 9 mm). Overall, NBI pit pattern sensitivity, specificity, and accuracy were 0.88, 0.91, and 89.6 %, respectively. Equivalent values for VPI were 0.94, 0.89, and 91.4 %. Results were similar when polyps were subdivided into diminutive polyps (size <or= 5 mm) and flat polyps. Combining both pit pattern and VPI improved the sensitivity (0.98, P = 0.06 versus NBI pit pattern alone). There was very good agreement between NBI pit pattern and VPI for prediction of dysplasia (kappa = 0.83). No evidence of a learning curve for VPI was found. The NBI pit pattern was better than the VPI at subclassifying hyperplastic from other non-neoplastic polyps (sensitivity 0.79 versus 0.56, respectively, P = 0.02), but accuracy was poor.
The NBI pit pattern and VPI are both highly accurate in characterizing neoplastic colonic polyps of < 10 mm, with VPI appearing to be simple to learn. NBI has the potential to replace conventional histology for small polyps.
Endoscopy 11/2008; 40(10):811-7. · 5.21 Impact Factor
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ABSTRACT: Narrow band imaging is a new endoscopic technology that highlights mucosal surface structures and microcapillaries, which may be indicative of neoplastic change.
To assess the diagnostic precision of narrow band imaging for the diagnosis of epithelial neoplasia compared to conventional histology both overall and in specific organs.
We performed a meta-analysis of studies which compared narow band imaging-based diagnosis of neoplasia with histopathology as the gold standard. Search terms: 'endoscopy' and 'narrow band imaging'.
Five hundred and eighty-two patients and 1108 lesions in 11 studies were included. Overall, sensitivity was 0.94 (95% confidence interval 0.92-0.95), specificity 0.83 (0.80-0.86); weighted area under the curve was 0.96 (standard error 0.02), diagnostic odds ratio (DOR) 72.74 (34.11-155.15). DORs were 66.65 (25.84-171.90), 61.19 (7.09-527.97), 69.74 (8.04-605.24) for colon, oesophagus and lung respectively. Studies with more than 50 patients had higher diagnostic precision, relative DOR 4.96 (1.28-19.27), P = 0.022. There was no difference in accuracy between microvessel and mucosal (pit) pattern based measures, relative DOR 1.29 (0.05-35.16), P = 0.87. There was significant heterogeneity overall between studies, Q = 31.2, P = 0.003.
Narrow band imaging is accurate with high diagnostic precision for in vivo diagnosis of neoplasia across a range of organs, using simple microvessel-based measures.
Alimentary Pharmacology & Therapeutics 10/2008; 28(7):854-67. · 3.77 Impact Factor
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ABSTRACT: Colonoscopy has a known miss rate for polyps and adenomas. High definition (HD) colonoscopes may allow detection of subtle mucosal change, potentially aiding detection of adenomas and hyperplastic polyps.
To compare detection rates between HD and standard definition (SD) colonoscopy.
Prospective, cohort study with optimized withdrawal technique (withdrawal time >6 min, antispasmodic, position changes, re-examining flexures and folds). One hundred and thirty patients attending for routine colonoscopy were examined with either SD (n = 72) or HD (n = 58) colonoscopes.
Groups were well matched. Sixty per cent of patients had at least one adenoma detected with SD vs. 71% with HD, P = 0.20, relative risk (benefit) 1.32 (95% CI 0.85-2.04). Eighty-eight adenomas (mean +/- standard deviation 1.2 +/- 1.4) were detected using SD vs. 93 (1.6 +/- 1.5) with HD, P = 0.12; however more nonflat, diminutive (<6 mm) adenomas were detected with HD, P = 0.03. Twenty-three proximal hyperplastic polyps (0.32 +/- 0.58) were detected with SD vs. 31 (0.53 +/- 0.86) with HD, P = 0.35. Overall prevalence of proximal large (>9 mm) hyperplastic polyps was 7% (0.09 +/- 0.36).
High definition did not lead to a significant increase in adenoma or hyperplastic polyp detection, but may help where comprehensive lesion detection is paramount. High detection rates appear possible with either SD or HD, when using an optimized withdrawal technique.
Alimentary Pharmacology & Therapeutics 10/2008; 28(6):768-76. · 3.77 Impact Factor
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ABSTRACT: Colonoscopic surveillance for hereditary non-polyposis colorectal cancer (HNPCC) reduces death rates, but early interval cancers still occur, probably due to missed small, aggressive adenomas. Narrow band imaging (NBI), a novel endoscopic technology, highlights superficial mucosal capillaries and improves contrast for adenomas. This study examined whether a second pass with NBI in the proximal colon helped detect additional adenomas in patients with HNPCC.
62 patients from HNPCC families (Amsterdam II or genetic criteria) attending for colonoscopic surveillance were examined twice from caecum to sigmoid-descending junction, first with high definition white light and then a second pass with NBI in a back-to-back fashion. All polyps detected were removed for histopathological analysis.
At least one adenoma in the proximal colon was detected during the initial white light pass in 17/62 (27%). NBI detected additional adenomas in 17/62 (27%). 26/62 (42%) patients had at least one adenoma detected after both white light and NBI; absolute difference 15% (95% CI 4-25%), p = 0.004 versus white light alone. The total number of adenomas increased from 25 before NBI to 46 after NBI examination, p<0.001. The proportion of flat adenomas detected in the NBI pass, 9/21 (45%), was higher than in the white light pass, 3/25 (12%), p = 0.03. Including white light examination of the sigmoid and rectum, overall 28/62 (45%) patients had at least one adenoma detected.
Use of NBI in the proximal colon for patients undergoing HNPCC surveillance appears to improve adenoma detection, particularly those with a flat morphology. NBI could help reduce interval cancer rates.
Gut 01/2008; 57(1):65-70. · 10.11 Impact Factor
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ABSTRACT: Poor standards in colonoscopy services and the introduction of a colorectal cancer screening program in the United Kingdom have highlighted the need to establish high-quality training and competency assessments in colonoscopy. The aims of this study were to evaluate the effectiveness of a 1-week hands-on colonoscopy course utilizing novel assessment tools.
Twenty-one doctors with varying colonoscopy experience who attended an accelerated colonoscopy training week (ACTW) were prospectively studied. They were trained and assessed in key aspects of colonoscopy. Knowledge was assessed with a multiple choice question (MCQ) paper. Practical hand skills were taught and evaluated using a computer simulator and live case teaching. Actual colonoscopy performance was assessed using Direct Observation of Procedural Skills scores (DOPS) and an objective tri-split video score of insertion technique. Two independent trainers taught and assessed the trainees at the start and end of the ACTW and at a median of 9 months' follow-up.
Following training there were significant improvements in the MCQ score (P < 0.001), the simulator test case times (P = 0.02, P = 0.003), and the global DOPS score (P < or = 0.02). All improvements following the accelerated training were sustained at a median follow-up of 9 months.
This study is the first in the literature to describe the positive, sustained impact of an intensive hands-on colonoscopy training course. Measurements of performance in key areas of skill acquisition improved following training.
Endoscopy 09/2007; 39(9):818-24. · 5.21 Impact Factor
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ABSTRACT: A 62 year old man with longstanding ulcerative colitis and previous endoscopic excision of two dysplasia associated lesions or masses (DALMs) was admitted to our endoscopy unit for evaluation and resection of other possible DALMs. He had previously been offered and refused colectomy because of comorbidity from Parkinson's disease. He had multiple polypoid and sessile lesions which were assessed using a third generation prototype narrow band imaging (NBI) colonoscope with magnification. Selected lesions were either biopsied or resected with a combination of endoscopic submucosal dissection and endoscopic mucosal resection techniques. We correlated the pit pattern and vascular pattern intensity seen with magnification NBI with histology of both inflammatory and dysplastic lesions. Dysplastic areas showed Kudo pit patterns II, IIIL, and IV and high vascular pattern intensity. Non-dysplastic and dysplastic areas of recurrence immediately adjacent to the scar from a previous endoscopic mucosal resection site were also assessed. This is the first case report where NBI has been shown to help in DALM detection and to distinguish dysplastic from non-dysplastic mucosa in ulcerative colitis.
Gut 11/2006; 55(10):1432-5. · 10.11 Impact Factor
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ABSTRACT: Variation in the adenoma detection rate (ADR) at flexible sigmoidoscopy screening has been shown to be due to variation in endoscopist performance. There are no objective methods for scoring an endoscopist's performance reliably, and the aim of this study was to develop a valid and reliable objective scoring method using video footage of screening flexible sigmoidoscopies.
In a series of five experiments, experienced endoscopists (the scorers) independently scored a sample (n = 43) of the 40 000 flexible sigmoidoscopy extubations recorded as part of the United Kingdom Flexible Sigmoidoscopy Screening Trial (UK FSST). The scoring system, the parameters scored, and their definitions evolved over the course of the five experiments. The initial visual analogue score (range 0-100) used in the first two experiments evolved into a five-point score that ranged from 1 (E, poor) to 5 (A, excellent) in the last three experiments. The final parameters scored were: time spent viewing the mucosa, re-examination of poorly viewed areas, suctioning of fluid pools, distension of the lumen, lower rectal examination, and overall quality of the examination. The first four experiments scored one individual case per endoscopist; in experiment 5, an overall score was awarded for five cases performed by each endoscopist being assessed.
Scoring five cases examined by an individual endoscopist using the A-E grading system was the most reliable method (interclass correlation coefficient 0.89). Cluster analysis demonstrated that the endoscopists in the high-scoring ADR group (ADR 14.7-15.9 %) could be differentiated from those in the intermediate- and low-scoring ADR groups (ADR 8.6-12.6 %).
An objective scoring system for assessing the accuracy of performance at screening flexible sigmoidoscopy, based on video footage, is described. Endoscopists who might benefit from further training can be identified using this method.
Endoscopy 04/2006; 38(3):218-25. · 5.21 Impact Factor
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B P Saunders
Endoscopy 12/2005; 37(11):1094-7. · 5.21 Impact Factor
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ABSTRACT: Factual knowledge underpins competence in all clinical skills. A multiple-choice question paper (MCQ) was designed as part of an accelerated colonoscopy training week (ACTW). In the United Kingdom, there are no validated methods of assessing core knowledge in colonoscopy. The aims of this study were to develop an MCQ paper, to demonstrate its construct validity, and to establish whether the ACTW improved core knowledge.
Two 30-question MCQ papers (A and B) were designed. Delegates attending the British Society of Gastroenterology (BSG) 2004 meeting responded either to MCQ paper A or B. Demographic data were collected on their experience in colonoscopy. Doctors attending the ACTW completed either MCQ paper A or B before the course, and the other paper after the course.
Seventy-eight delegates at the BSG meeting completed the MCQ. There was a significant difference in the scores between those who had carried out less than 200 colonoscopies (mean 32.5 %) and those who had performed more than 200 (mean 58.4 %; P < 0.0001). Seventeen doctors attending the ACTW completed the MCQ. The mean score for papers A and B increased significantly following the course--57.2 % before the ACTW, 67 % after it ( P = 0.003).
This MCQ is capable of differentiating between endoscopists with different levels of experience in colonoscopy. Doctors attending an ACTW significantly improve their knowledge in colonoscopy. A validated MCQ such as this could be used as part of the assessment process to ascertain competence in colonoscopy.
Endoscopy 10/2005; 37(9):821-6. · 5.21 Impact Factor
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ABSTRACT: The risk of colorectal cancer is increased in ulcerative colitis (UC). Patients with UC have diverse colonoscopic appearances. Determining colonoscopic markers for cancer risk could allow patient risk stratification.
Following on from an earlier study which demonstrated a correlation between inflammation severity and neoplasia risk, a case control study was performed to look for colonoscopic markers of colorectal neoplasia risk in UC. Each patient with neoplasia detected between 1988 and 2002 was matched with two non-dysplastic colitic controls. Data were collected on post-inflammatory polyps, scarring, strictures, backwash ileitis, a shortened, tubular, or featureless colon, severe inflammation, and normal looking surveillance colonoscopies.
Cases (n = 68) and controls (n = 136) were well matched. On univariate analysis, cases were significantly more likely to have post-inflammatory polyps (odds ratio (OR) 2.14 (95% confidence interval 1.24-3.70)), strictures (OR 4.22; 1.08-15.54), shortened colons (OR 10.0; 1.17-85.6), tubular colons (OR 2.03; 1.00-4.08), or segments of severe inflammation (OR 3.38; 1.41-10.13), and less likely to have had a macroscopically normal looking colonoscopy (OR 0.40; 0.21-0.74). After multivariate analysis, a macroscopically normal looking colonoscopy (OR 0.38; 0.19-0.73), post-inflammatory polyps (2.29; 1.28-4.11), and strictures (4.62; 1.03-20.8) remained significant. The five year risk of colorectal cancer following a normal looking colonoscopy was no different from that of matched general population controls.
Macroscopic colonoscopic features help predict neoplasia risk in UC. Features of previous/ongoing inflammation signify an increased risk. A macroscopically normal looking colonoscopy returns the cancer risk to that of the general population: it should be possible to reduce surveillance frequency to five years in this cohort.
Gut 01/2005; 53(12):1813-6. · 10.11 Impact Factor
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Endoscopy 12/2004; 36(11):1001-7. · 5.21 Impact Factor
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ABSTRACT: To investigate the feasibility of using multidetector-row computed tomography (CT) duodenography to stage duodenal polyposis in patients with familial adenomatous polyposis.
Six patients underwent multidetector-row CT duodenography before upper gastrointestinal endoscopy. A single-blinded radiologist used a surface shaded three-dimensional endoluminal fly though and two-dimensional axial and multiplanar reformats to assign a score for maximum polyp size and number based on the Spigelman classification. Comparison was made with the corresponding Spigelman scores obtained from subsequent endoscopy.
CT duodenography was technically successful in five of six patients. The CT derived Spigelman score based on maximum polyp size was accurate in all five patients. The CT derived Spigelman score based on polyp number was accurate in only two cases: Polyp number was overestimated in one patient and underestimated in a further two. In retrospect, fine carpeting of tiny duodenal polyps was poorly visualized with CT.
CT duodenography is technically feasible and accurately predicts maximum polyp size but CT estimates of polyp number are relatively inaccurate. CT duodenography potentially has a useful role for duodenal surveillance in those patients intolerant of conventional endoscopy.
Clinical Radiology 11/2004; 59(10):939-45. · 1.95 Impact Factor
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Endoscopy 10/2004; 36(9):835. · 5.21 Impact Factor
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ABSTRACT: Colonoscopic surveillance for cancer in longstanding extensive ulcerative colitis relies heavily on non-targeted mucosal biopsies. Chromoendoscopy can aid detection of subtle mucosal abnormalities. We hypothesised that routine pancolonic indigo carmine dye spraying would improve the macroscopic detection of dysplasia and reduce the dependence on non-targeted biopsies.
One hundred patients with longstanding extensive ulcerative colitis attending for colonoscopic surveillance underwent "back to back" colonoscopies. During the first examination, visible abnormalities were biopsied, and quadrantic non-targeted biopsies were taken every 10 cm. Pancolonic indigo carmine (0.1%) was used during the second colonoscopic examination, and any additional visible abnormalities were biopsied.
Median extubation times for the first and second colonoscopies were 11 and 10 minutes, respectively. The non-targeted biopsy protocol detected no dysplasia in 2904 biopsies. Forty three mucosal abnormalities (20 patients) were detected during the pre-dye spray colonoscopy of which two (two patients) were dysplastic: both were considered to be dysplasia associated lesions/masses. A total of 114 additional abnormalities (55 patients) were detected following dye spraying, of which seven (five patients) were dysplastic: all were considered to be adenomas. There was a strong trend towards statistically increased dysplasia detection following dye spraying (p = 0.06, paired exact test). The targeted biopsy protocol detected dysplasia in significantly more patients than the non-targeted protocol (p = 0.02, paired exact test).
No dysplasia was detected in 2904 non-targeted biopsies. In comparison, a targeted biopsy protocol with pancolonic chromoendoscopy required fewer biopsies (157) yet detected nine dysplastic lesions, seven of which were only visible after indigo carmine application. Careful mucosal examination aided by pancolonic chromoendoscopy and targeted biopsies of suspicious lesions may be a more effective surveillance methodology than taking multiple non-targeted biopsies.
Gut 03/2004; 53(2):256-60. · 10.11 Impact Factor
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ABSTRACT: Small, flat colorectal cancers have been widely reported in the Japanese literature but are thought to occur rarely outside Japan. The aim of this retrospective cohort study was to clarify the prevalence of flat colorectal cancer in a Western population.
One thousand and twenty-six consecutive colonoscopies performed by a single experienced endoscopist were retrospectively analysed over a two-year period. The morphology, site and histological appearance of all documented colorectal cancers (CRC) were recorded.
Forty-seven cases of CRC were detected, five of which (10%) demonstrated flat configuration. Flat cancers varied between 8 and 15 mm in diameter (mean 11 mm). Histologically, all flat lesions were moderately differentiated Dukes A adenocarcinomas. Two of these cancers contained no adenomatous component.
This study confirms that small, flat colorectal cancers are not an uncommon finding at colonoscopy in Western patients. Compared to polypoid neoplastic lesions, flat cancers appear to undergo malignant change at a smaller size.
Colorectal Disease 02/2004; 6(1):15-20. · 2.93 Impact Factor
