This paper provides a novel approach for real-time detection of polyps. Using a photometric stereo sensor for endoscopy imaging in a porcine model, the 3D surface geometry of a porcine gut is recovered. Shape features are extracted from the 3D surface data and analysed to detect and identify regions that are locally spherical, suggestive of polyps to aid polyp detection

Emrith, Khemraj

Groves, Chris

Poullis, Andy

Slabaugh, Greg

Smith, Melvyn

English

UWE Bristol Research Repository

Results A total of 135 lesions were identified, with 12 monthrecurrence identified in 8.1% of cases. Caecal location demon-strated a strongly significant association with recurrence com-pared with non-caecal location (27.8% vs 5.1%, p = 0.007)Abstract PTU-022 Table 112 month recurrence (%) Total (n)no yesCaecal location? no 94.9 5.1 117yes 72.2 27.8 18Total 91.9% 8.1% 135Conclusion Caecal location was associated with over a 5-foldincrease (28.7% vs 5.1%) in the incidence of 12 month recur-rence. The results from this series confirm the increased techni-cal demands associated with the endoscopic resection of caecalLNPCPs, especially considering our study involved experiencedBCSP endoscopists. In view of the increased risk of endoscopictreatment failure, in addition to the established increased risk ofadverse endoscopic events, we feel that caecal LNPCPs may ben-efit from multidisciplinary discussion and should only be man-aged by experienced clinicians.Disclosure of interest None Declared.REFERENCES1 Rutter MD, Nickerson C, Rees CJ, et al. Risk factors for adverse events related topolypectomy in the English Bowel Cancer Screening Programme. Endoscopy2014;46:90–72 Metz AJ, Bourke MJ, Moss A, et al. Factors that predict bleeding following endo-scopic mucosal resection of large colonic lesions. Endoscopy 2011;43:506–113 Moss A, Bourke MJ, Williams SJ, et al. Endoscopic mucosal resection outcomesand prediction of submucosal cancer from advanced colonic mucosal neoplasia.Gastroenterology 2011;140:1909–18PTU-023 THE USE OF ARGON PLASMA COAGULATION TOPREVENT COLORECTAL POLYP RECURRENCEFOLLOWING PIECEMEAL ENDOSCOPIC MUCOSALRESECTIONA Chattree*, MD Rutter. Endoscopy, North Tees and Hartlepool NHS Foundation Trust,Stockton on Tees, UK10.1136/gutjnl-2015-309861.138Introduction High levels of recurrence and residual tissue havebeen reported following piecemeal endoscopic resection (pEMR)of large colorectal polyps with figures approaching 30%described.1 The application of argon plasma coagulation (APC)has been advocated to reduce recurrence following pEMR, withearly data appearing to support the use of APC to treat tinypolyp fragments not amenable to endoscopic snare resection.2More recent data however, appears to oppose this view, suggest-ing no change in or even increased recurrence following adjunc-tive APC use.1 With a lack of standardised APC application inrelevant international case series, many of which include onlysmall sample sizes, the position regarding its benefit remainscontroversial.Method Retrospective analysis was conducted on 153 pEMRprocedures undertaken in the Bowel Cancer Screening Pro-gramme (BCSP) between 2011–12. Recurrence rates on firstendoscopic follow-up were compared between 2 groups (APCuse vs no APC use). Statistical analysis was performed using thechi-squared test.Results Recurrence was detected on first endoscopic follow-upin 25.5% of cases. A lower level of recurrence was seen in theAPC group compared with the non APC group (17.9% vs31.4%), with statistical significance seen on 1-sided but not 2-sided chi square analysis (p = 0.042 (1-sided), p = 0.064 (2-sided))Abstract PTU-023 Table 1Piecemeal recurrence on first f/up (%) Total (n)no yesAPC use? no 68.6 31.4 86yes 82.1 17.9 67Total 74.5 25.5 153Conclusion While statistical significance was only seen on 1-sided chi-square analysis, the level of recurrence was over 40%lower in the APC group (17.9% vs 31.4%). It can be arguedthat our study may be underpowered and that the result indi-cates likely clinical significance. Our data does not support thedata from other studies indicating a possible detrimental effectof APC. Whilst the use of APC is likely to be more standardisedwithin the BCSP, the exact circumstances of its use, such as theamount of residual tissue post snare resection remaining prior toAPC use in other studies, is unclear. We believe APC is appropri-ate therapy for tiny residual polyp fragments post snare resec-tion, but should not be used on larger tissue areas. A largerandomised controlled trial with a standardised protocol forAPC application would add further evidence.Disclosure of interest None Declared.REFERENCES1 Moss A, Bourke MJ, Williams SJ, et al. Endoscopic mucosal resection outcomesand prediction of submucosal cancer from advanced colonic mucosal neoplasia.Gastroenterology 2011;140:1909–182 Brooker JC, Saunders BP, Shah SG, et al. Treatment with argon plasma coagula-tion reduces recurrence after piecemeal resection of large sessile colonic polyps: arandomized trial and recommendations. Gastrointest Endosc. 2002;55:371–5PTU-024 PHOTOMETRIC STEREO RECONSTRUCTION FORSURFACE ANALYSIS OF MUCOSAL TISSUE1A Poullis*, 1C Groves, 2G Slabaugh, 3K Emrith, 3M Smith. 1Gastroenterology, St George’sHospital; 2Department of Computer Science, City University, London; 3Centre forMachine Vision, University of the West of England, Bristol, UK10.1136/gutjnl-2015-309861.139Introduction The American Society of Gastroenterology endos-copy led Preservation and Incorporation of Valuable endoscopicInnovations initiative has identified real time polyp detectiondiagnosis as one of the next major technology-driven changes inendoscopy.1 We have recently described a novel photometricstereo (PS) imaging sensor for endoscopy imaging in a porcinemodel.2 Following image acquisition, reconstruction of the sur-face data is necessary to calculate the shape index (SI) to identifyregions that are locally spherical, suggestive of polyps to aidpolyp detection.Method Using a porcine gut model, photometric images werecaptured using a six-light source PS setup as previouslydescribed.2 Surface analysis of the obtained surface data was per-formed: Derivatives of the height fields arranged on a square lat-tice were calculated using finite differences, and used tocharacterise the differential geometry using the principalAbstractsA68 Gut 2015;64(Suppl 1):A1–A584curvatures.3 Surface measures analysis: for each point on the sur-face, the shape index (SI) was computed and used to measurethe local shape:SI = 1/2 – 1/p tan1 ((K1+K2)/(K1-K2))ResultsAbstract PTU-024 Figure 1 Porcine colonic data captured using thephotometric stereo system. Left to right: Colour image, Normal map,Reconstructed height map, SI image top view, SI image side viewConclusion Using a novel PS image acquisition 3D reconstruc-tion was obtained on colonic mucosa. We observe that the recov-ered 3D surface retains the surface geometry in the capturedareas and important structural information at a fine level ofdetail, even in the presence of numerous specular reflections.This is highly significant for automated processing and analysisof surface abnormalities.Disclosure of interest None Declared.REFERENCES1 Rex, et alet al. Gastrointest Endosc 2011;73:419–222 Poullis, et alet al. Gut 2014;63(Suppl 1):A463 do Carmo M. Differential geometry of curves and surfaces. Prentice Hall, 1976,ISBN:0132125897PTU-025 HOW ACCURATELY IS ROCKALL SCORE CALCULATEDFOR PATIENTS WITH ACUTE UPPER GASTROINTESTINALBLEEDING (AUGIB)?S Gupta, V Lam, A Taranath*. Gastroenterology, Croydon University Hospital, Croydon,UK10.1136/gutjnl-2015-309861.140Introduction Documentation of Rockall score (RS) in patientswith AUGIB should be accurate in order to prioritise patients forgastroscopy. We conducted a pilot study in 2012 which showedthat RS was calculated incorrectly in 46% patients. We investi-gated this further with a larger cohort of patients.Method Information was collected retrospectively on patientswho presented with presented with AUGIB from February 2012to February 2013. Patients who had out-of-hours gastroscopyexcluded. Demographics, time to perform gastroscopy, RS docu-mented by the doctor requesting the gastroscopy, RS calculatedby analysing patient records (including A&E, paramedic records)were collected. We analysed patients whose RS was either under-scored or overscored by the requesting doctor (this was com-pared to the actual score calculated by us) and correlated thecalculated RS with the need for endoscopic intervention.Results There were 248 patients with 149 (60%) males, age 16to 98 years (mean 69). Presenting symptoms were melaena in129 (51%), haemetemesis 35 (14%), coffee ground vomiting 64(25%), rectal bleed 17 (7%), melaena and haematemesis 4.RS was calculated incorrectly in 194 (78%) patients with 110(44%) over scored (Group A), 84 (34%) underscored (Group B).Mean RS on request form for Group A patients was 3.64 ±1.97 while the calculated RS was 1.85 ± 1.61. In Group B,mean RS documented was 1.8 ± 0.96 while the calculated RSwas 3.9 ± 1.04. Mean time from electronic booking to gastro-scopy was 2.02 days – 1.67 days for Group A and 2.04 days inGroup B.FY1s calculated incorrect scores in 83 (43%) patients, FY2s in20 (10%), SHOs in 81 (42%), registrars in 7 (4%) and consul-tants 3 (2%). Of the 111 FY1s (45%) who calculated the RS, 46(41%) overscored, 37 (33%) underscored and 28 (25%) calcu-lated RS correctly. The numbers for 27 FY2 (11%) were 11(41%), 9 (33%) and 7 (26%) respectively. Of the 95 (38%)SHOs, 47 (50%) overscored, 34 (36%) underscored and 14(15%) calculated RS correctly. There were 11 specialist registrars(4 correct, 4 overscored and 3 underscored) and 4 Consultantrequest forms (3 incorrect).Of the 248 patients, 37 (15%) required endoscopic interven-tion. In Group A, 16 (15%) needed endoscopic intervention,compared to 11 (13%) in Group B. Ten (19%) of the 54 patientsscored correctly required endoscopic therapy.Conclusion This study shows that it is important to documentthe RS at the time of first presentation of AUGIB rather than atthe time when the patient is seen by the admitting doctor. Thisstudy however does not show a direct correlation between theRS and endoscopic intervention. It emphasises the fact that alldoctors should be educated about the importance of document-ing the correct RS as more than three quarter of the RS onrequest forms were found to be inaccurate.Disclosure of interest None Declared.PTU-026 CYTOLOGICAL YIELD OF BILIARY BRUSHINGS OBTAINEDDURING ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY (ERCP): A SINGLE CENTREEXPERIENCE1A Sugumaran*, 2I Thompson, 1A Yeoman, 1M Allison, 1M Czajkowski. 1Gastroenterology;2Royal Gwent Hospital, Newport, UK10.1136/gutjnl-2015-309861.141Introduction British Society of Gastroenterology (BSG) guide-lines recommend cytological analysis of brushings taken frombiliary strictures to support diagnosis of malignancy in suspectedindividuals. There is wide variation reported in literature on testsensitivities ranging between 16% and 65%. We set out to reporta single centre experience on the diagnostic yield of cytologyspecimens of biliary strictures obtained from ERCP.Method Retrospective analysis on all biliary brushings takenbetween 2008 and 2011 was performed. All ERCPs were per-formed by two experienced endoscopists. Routinely, the cytologybrush is sent to the lab immediately after the procedure, analysisundertaken by liquid-based methodology and results verified bya histopathologist with special interest in pancreato-biliary disor-ders. The brushing result was then correlated with the final diag-nosis (‘suspicious’ and ‘atypical cells’ in cytology report wereconsidered malignant for audit purposes).Results Cytological specimens taken from 89 patients supporteddiagnosis of benign or malignant pathology in 67 showing anoverall sensitivity of 75.3%.Abstract PTU-026 Table 1Cytology result Final diagnosis cancer Final diagnosis benignPositive 54 0Negative 22 13Total 76 13AbstractsGut 2015;64(Suppl 1):A1–A584 A69

Ptu-024 - photometric stereo reconstruction for surface analysis of mucosal tissue

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Ptu-024 - photometric stereo reconstruction for surface analysis of mucosal tissue

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