Contrast-enhanced ultrasound of polyp malignant transformation with multiple metastases in a patient with Peutz-Jeghers syndrome.

Multi-systemic metastasis in patients with Peutz-Jeghers syndrome (PJS) is very rare, and there are nearly no relevant imaging reports, especially in contrast-enhanced ultrasound (CEUS). We present here a 40-year-old male patient who underwent several partial small bowel resections and endoscopic polypectomy for intestinal polyps. After reviewing the patient's clinical diagnosis and treatment process, CEUS with sulfur hexafluoride microbubbles (SonoVue, Bracco, Milan, Italy) in the liver and gastrointestinal tract was performed. We imaged multiple abnormal masses with sonographic features consistent with malignancies. Combined with other imaging examinations and 18 gauge core-needle puncture biopsy of liver masses, multiple metastases outside the gastrointestinal tract were considered. This case report suggests CEUS may be an easy, effective, and supplementary method for evaluating PJS patients with suspected multi-systemic malignant lesions including the gastrointestinal tract.

PRAPNet: A Parallel Residual Atrous Pyramid Network for Polyp Segmentation.

In a colonoscopy, accurate computer-aided polyp detection and segmentation can help endoscopists to remove abnormal tissue. This reduces the chance of polyps developing into cancer, which is of great importance. In this paper, we propose a neural network (parallel residual atrous pyramid network or PRAPNet) based on a parallel residual atrous pyramid module for the segmentation of intestinal polyp detection. We made full use of the global contextual information of the different regions by the proposed parallel residual atrous pyramid module. The experimental results showed that our proposed global prior module could effectively achieve better segmentation results in the intestinal polyp segmentation task compared with the previously published results. The mean intersection over union and dice coefficient of the model in the Kvasir-SEG dataset were 90.4% and 94.2%, respectively. The experimental results outperformed the scores achieved by the seven classical segmentation network models (U-Net, U-Net++, ResUNet++, praNet, CaraNet, SFFormer-L, TransFuse-L).

The prevalence of small-bowel polyps on video capsule endoscopy in patients with sporadic duodenal or ampullary adenomas.

BACKGROUND AND AIMS: Although sporadic duodenal and/or ampullary adenomas (DAs) are uncommon, they are increasingly diagnosed during upper endoscopy. These patients have a 3- to 7-fold increased risk of colonic neoplasia compared with the normal population. It is unknown, however, whether they also have an increased risk of additional small-bowel (SB) polyps. Our aim was to establish the prevalence of SB polyps in patients with DA. METHODS: In a single-center, prospective study, we used video capsule endoscopy (VCE) to investigate the prevalence of SB polyps in patients with a DA compared with patients undergoing VCE for obscure GI bleeding or iron deficiency anemia. RESULTS: Over 25 months, 201 patients were enrolled in the study; the mean age was 65 years and 47% were male. There were 101 control patients and 100 cases of DA cases (mean size, 30 mm (range, 10-80 mm)). We did not identify any SB polyps in either group. Colonic polyps were found more frequently in the DA group compared with controls (61% versus 37%, respectively (P =.002)). Advanced colonic adenoma (high-grade dysplasia, >10 mm, villous histology) were found in 18% of the DA group and 5% of the control group (P =.018). CONCLUSION: Our data suggest that patients with a DA are not at risk for additional SB polyps and hence do not support screening with VCE. However, colonoscopy is mandatory due to the significantly higher risk of colonic polyps including advanced adenomas. (Clinical trial registration number: NCT02470416.).

Two Types of Polyp Shape Observed in the Stomach of Patients with Peutz-Jeghers Syndrome.

The characteristics of gastric polyps in patients with Peutz-Jeghers (PJ) syndrome (PJS) have not been fully investigated. The objective of this study was to reveal the endoscopic and pathologic findings of gastric polyps in patients with PJS. We reviewed 11 patients with PJS treated at 6 institutions, and summarized the endo-scopic and pathologic features of their gastric polyps. The polyps were mainly classified into 2 types: (i) soli-tary or sporadic polyps > 5 mm, reddish in color with a sessile or semi-pedunculated morphology (n = 9); and (ii) multiple sessile polyps ≤ 5 mm with the same color tone as the peripheral mucosa (n = 9). Patients who underwent endoscopic mucosal resection for polyps > 5 mm were diagnosed with PJ polyps (n = 2), whereas those who underwent biopsy were diagnosed with hyperplastic polyps. Polyps ≤ 5 mm were pathologically diagnosed as fundic gland polyps or hyperplastic polyps. This study revealed that patients with PJS present with 2 types of polyps in the stomach. Endoscopic mucosal resection of polyps > 5 mm seems necessary for the pathologic diagnosis of PJ polyps.

Comparison of Underwater vs Conventional Endoscopic Mucosal Resection of Intermediate-Size Colorectal Polyps.

BACKGROUND & AIMS: Endoscopic mucosal resection (EMR) with submucosal injection is an established method for removing colorectal polyps, although the en bloc resection rate decreases when polyp size exceeds 10 mm. Piecemeal resection increases local recurrence. Underwater EMR (UEMR) is an effective technique for removal of sessile colorectal polyps and we investigated whether it is superior to conventional EMR (CEMR). METHODS: We conducted a multicenter randomized controlled trial at 5 institutions in Japan. Patients with endoscopically diagnosed, intermediate-size (10-20 mm) sessile colorectal lesions were randomly assigned to undergo UEMR or CEMR. Only the most proximal lesion was registered. The UEMR procedure included immersion of the entire lumen in water and snare resection of the lesion without submucosal injection of normal saline. We analyzed outcomes of 108 colorectal lesions in the UEMR group and 102 lesions in the CEMR group. R0 resection was defined as en bloc resection with a histologically confirmed negative resection margin. The primary endpoint was the difference in the R0 resection rates between groups. RESULTS: The proportions of R0 resections were 69% (95% confidence interval [CI] 59%-77%) in the UEMR group vs 50% (95% CI 40%-60%) in the CEMR group (P = .011). The proportions of en bloc resections were 89% (95% CI 81%-94%) in the UEMR group vs 75% (95% CI 65%-83%) in the CEMR group (P = .007). There was no significant difference in median procedure time (165 vs 175 seconds) or proportions of patients with adverse events (2.8% in the UEMR group vs 2.0% in the CEMR group). CONCLUSIONS: In a multicenter randomized controlled trial, we found that UEMR significantly increased the proportions of R0 resections for 10- to 20-mm sessile colorectal lesions without increasing adverse events or procedure time. Use of this procedure should be encouraged. Trials registry number: UMIN000018989.

Quality of same-day CT colonography following incomplete optical colonoscopy.

OBJECTIVES: Same-day CT colonography (CTC) following incomplete optical colonoscopy allows patients to avoid both a delayed diagnosis and the need for repeat bowel preparation. The aim of our study is to establish the diagnostic quality of same-day CT colonography following an incomplete optical colonoscopy. METHODS: We performed a retrospective review of patients undergoing same-day CT colonography following an incomplete colonoscopy at our center between July 2015 and December 2017 (N = 245). We divided the large bowel into thirteen subsegments in each patient. Using a semiquantitative scoring system, the quality of bowel preparation, adequacy of fecal tagging, and luminal distension were assessed in each subsegment on all views performed. A combined score for each subsection was obtained. RESULTS: Ninety-nine percent of studies did not require a repeat CTC or optical colonoscopy. Median values for bowel preparation and fecal tagging were satisfactory across the bowel segments for the cohort and luminal distension was acceptable in all but three patients. CONCLUSIONS: Same-day CTC should be considered in centers with capacity, following an incomplete optical colonoscopy. Same-day completion CTCs are of high diagnostic quality and this approach allows patients to avoid repeat bowel cleansing or a delayed diagnosis. KEY POINTS: • Same-day CT colonography is a high-quality examination that can be performed following incomplete optical colonoscopy. • Same-day CT colonography should be considered for patients with incomplete optical colonoscopy in centers with the capacity to offer this service. • Same-day CTC can avoid a delay in diagnosis and avoids repeat bowel preparation.

Detection of polyps in the small bowel of patients with acromegaly via capsule endoscopy.

BACKGROUND: the prevalence of small bowel (SB) polyps is unknown in acromegaly patients. OBJECTIVE: to evaluate the prevalence of polyps/tumors in SB of acromegaly patients. MATERIAL: this was a prospective and observational study that compared the prevalence of polyps/tumors using capsule endoscopy with a standard protocol in asymptomatic acromegaly patients and non-acromegaly patients, with abdominal pain, diarrhea or anemia. RESULTS: one hundred and eighty-three cases were included (61 acromegaly and 122 non-acromegaly). Polyps were found in six (9.8%) and three (2.5%) patients, respectively (RR: 4 [95% CI, 1.03-15.45; p = 0.038]). There were no differences in the tumors (n = 4, 6.6% vs n = 7, 5.7%). CONCLUSIONS: acromegaly may be associated with more polyps in SB.

Advanced endoscopy technologies to improve the detection and characterisation of colorrectal polyps. / Tecnologías de endoscopia avanzada para mejorar la detección y caracterización de los pólipos colorrectales.

Colorectal cancer is a major health problem. An improvement to its survival has been demonstrated by performing colonoscopy screenings and removing its precursor lesions: polyps. However, colonoscopy is not infallible and multiple strategies have been proposed aimed at improving the quality thereof. This report describes the endoscopic systems available to improve the detection and characterization of polyps, the different classifications for histological prediction and the current indications of advanced endoscopic diagnostic techniques.

A case of ectopic pancreas in the ileum presenting as obscure gastrointestinal bleeding and abdominal pain.

BACKGROUND: Ectopic pancreas is an infrequent submucosal tumor in the gastrointestinal tract defined as a pancreatic tissue lacking vascular or anatomic continuity with the main body of the pancreas. Ectopic pancreas in the ileum is a rare and often an incidental finding. We report a case of ectopic pancreas in the ileum causing obscure gastrointestinal bleeding and episodes of abdominal pain. CASE PRESENTATION: 59-year-old man with 3 months history of intermittent melena, accompanied by the episodes of abdominal pain in the left upper quadrant and generalized fatigue was admitted to our department. The investigations showed that the patient had a low hemoglobin level, i.e. 10.9 g/dL with hypochromic microcytic anemia pattern seen in complete blood count (MCV 70.2 fl, MCH 21.4 pg). Esophagogastroduodenoscopy and colonoscopy did not reveal any abnormalities. Magnetic resonance enterography revealed a large (2.5 × 2.3 cm) pedunculated polyp in the ileum. Examination by single-balloon enteroscopy revealed a polyp with long pedicle located approximately 1.5 m distal to terminal ileum. Polypectomy was performed. Histopathologic examination stated, that the specimen contained ectopic pancreatic tissue which was involving muscular layer of the ileum. Ectopic pancreatic tissue included acinar cells and cystically dilated secretory ducts without islets of Langerhans. CONCLUSION: Our case report reveals a very rare cause of obscure gastrointestinal bleeding accompanied by the episodes of abdominal pain - an ectopic pancreas located in the ileum.

The MRI assessment of SPECC (significant polyps and early colorectal cancer) lesions.

The development of high-resolution magnetic resonance imaging (MRI) has resulted in the ability to clearly depict the finer details of rectal wall anatomy. Careful specialist assessment of images obtained in patients with significant polyps and early rectal cancer lesions enables the identification of lesions that are confined to the bowel wall and amenable to organ preserving local excision. Currently, one-third of screen detected rectal cancers are limited to the bowel wall without nodal spread yet more than 90% undergo major excision surgery resulting in significant loss of bowel function, quality of life and at high economic cost. The SPECC initiative has highlighted the need for specialist training and accreditation of radiology specialists in precision assessment of significant polyps and early rectal cancer. The detailed assessment will enable provision of detailed roadmaps for surgeons and gastroenterologists to facilitate definitive excision of more lesions using minimally invasive endoscopic technique. Finally, the use of high resolution MRI in surveillance will enable the close monitoring of such patients where the preservation of the rectum has been achieved.

Adjunctive use of chromoendoscopy may improve the diagnostic performance of narrow-band imaging for small sessile serrated adenoma/polyp.

BACKGROUND AND AIM: Endoscopic diagnosis of sessile serrated adenoma/polyp (SSA/P) is challenging because of their subtle appearance. Narrow-band imaging (NBI) is useful for diagnosis, but its utility with concurrent chromoendoscopy (CE), especially to detect small SSA/P, is unproven. METHODS: This prospective study enrolled 367 consecutive patients who underwent screening colonoscopy with the finding of serrated polyps. Patients were divided into derivation and validation cohorts: Diagnostic criteria using different endoscopic modalities were generated by regression analysis in the derivation cohort and were validated in the validation cohort for sensitivity, specificity, and accuracy. RESULTS: There were 180 patients with 119 SSA/P and 147 hyperplastic polyps (HP) in the derivation cohort and 187 patients with 177 SSA/P and 125 HP in the validation cohort. With white-light endoscopy plus NBI, mucus cap, surface grooves, and expanded crypt were most associated with SSA/P. With white-light endoscopy plus CE, II-O pit pattern, mucus cap, and superficial telangiectasia were most associated with SSA/P. With the combined use of these three modalities, II-O pit pattern, mucus cap, and surface grooves were most associated with SSA/P. For large serrated polyp, NBI in combination with CE had a better accuracy than NBI alone (91% vs 86%, P = 0.025) to distinguish SSA/P from HP. CE alone had a better accuracy than NBI alone for distinguishing small SSA/P from small HP (85% vs 72%, P < 0.0001). CONCLUSION: Compared with NBI alone, adjunctive use of CE can improve the diagnostic accuracy for distinguishing SSA/P from HP, especially for small SSA/P.

A comparison of computer-assisted detection (CAD) programs for the identification of colorectal polyps: performance and sensitivity analysis, current limitations and practical tips for radiologists.

AIM: To directly compare the accuracy and speed of analysis of two commercially available computer-assisted detection (CAD) programs in detecting colorectal polyps. MATERIALS AND METHOD: In this retrospective single-centre study, patients who had colorectal polyps identified on computed tomography colonography (CTC) and subsequent lower gastrointestinal endoscopy, were analysed using two commercially available CAD programs (CAD1 and CAD2). Results were compared against endoscopy to ascertain sensitivity and positive predictive value (PPV) for colorectal polyps. Time taken for CAD analysis was also calculated. RESULTS: CAD1 demonstrated a sensitivity of 89.8%, PPV of 17.6% and mean analysis time of 125.8 seconds. CAD2 demonstrated a sensitivity of 75.5%, PPV of 44.0% and mean analysis time of 84.6 seconds. CONCLUSION: The sensitivity and PPV for colorectal polyps and CAD analysis times can vary widely between current commercially available CAD programs. There is still room for improvement. Generally, there is a trade-off between sensitivity and PPV, and so further developments should aim to optimise both. Information on these factors should be made routinely available, so that an informed choice on their use can be made. This information could also potentially influence the radiologist's use of CAD results.

Negative video capsule enteroscopy - what's the next step?

Video capsule endoscopy (VCE) is a reliable noninvasive method for examination of small-bowel mucosa. However, it has some limitations. The aim of this article was to review the approach in patients with negative VCE. It is clear that a negative VCE should be interpreted based on the indication. In suspected small bowel bleeding (SSBB), patients with ongoing/recurrent overt bleeding, or occult bleeders who experience significant declines in hemoglobin after a negative VCE should proceed small bowel study; on the other hand, patients with occult SSBB and only mild-moderate anemia should be managed with supportive care. In inflammatory bowel disease, a normal VCE has a very high sensitivity and negative predictive value. In small bowel tumor suspicion there is a high risk of false negative results, so another imaging modality should be considered. In polyposis syndromes, if VCE is negative, patients should continue screening within 2-3 years.

Incomplete resection rate of cold snare polypectomy: a prospective single-arm observational study.

Background and study aims Cold snare polypectomy (CSP) is considered to be safe for the removal of subcentimeter colorectal polyps. This study aimed to determine the rate of incomplete CSP resection for subcentimeter neoplastic polyps at our center. Patients and methods Patients with small or diminutive adenomas (diameter 1 - 9 mm) were recruited to undergo CSP until no polyp was visible. After CSP, a 1 - 3 mm margin around the resection site was removed using endoscopic mucosal resection. The polyps and resection site marginal specimens were microscopically evaluated. Incomplete resection was defined as the presence of neoplastic tissue in the marginal specimen. We also calculated the frequency at which the polyp lateral margins could be assessed for completeness of resection. Results A total of 307 subcentimeter neoplastic polyps were removed from 120 patients. The incomplete resection rate was 3.9 % (95 % confidence interval [CI] 1.7 % - 6.1 %); incomplete resection was not associated with polyp size, location, morphology, or operator experience. The polyp lateral margins could not be assessed adequately for 206 polyps (67.1 %). Interobserver agreement between incomplete resection and lateral polyp margins that were inadequate for assessment was poor (κ = 0.029, 95 %CI 0 - 0.04). Female sex was an independent risk factor for incomplete resection (odds ratio 4.41, 95 %CI 1.26 - 15.48; P  = 0.02). Conclusions At our center, CSP resection was associated with a moderate rate of incomplete resection, which was not associated with polyp characteristics. However, adequate evaluation of resection may not be routinely possible using the lateral margin from subcentimeter polyps that were removed using CSP.Trial registered at University Hospital Medical Information Network (UMIN 000010879).

Colorectal polypectomy and endoscopic mucosal resection (EMR): European Society of Gastrointestinal Endoscopy (ESGE) Clinical Guideline.

1 ESGE recommends cold snare polypectomy (CSP) as the preferred technique for removal of diminutive polyps (size ≤ 5 mm). This technique has high rates of complete resection, adequate tissue sampling for histology, and low complication rates. (High quality evidence, strong recommendation.) 2 ESGE suggests CSP for sessile polyps 6 - 9 mm in size because of its superior safety profile, although evidence comparing efficacy with hot snare polypectomy (HSP) is lacking. (Moderate quality evidence, weak recommendation.) 3 ESGE suggests HSP (with or without submucosal injection) for removal of sessile polyps 10 - 19 mm in size. In most cases deep thermal injury is a potential risk and thus submucosal injection prior to HSP should be considered. (Low quality evidence, strong recommendation.) 4 ESGE recommends HSP for pedunculated polyps. To prevent bleeding in pedunculated colorectal polyps with head ≥ 20 mm or a stalk ≥ 10 mm in diameter, ESGE recommends pretreatment of the stalk with injection of dilute adrenaline and/or mechanical hemostasis. (Moderate quality evidence, strong recommendation.) 5 ESGE recommends that the goals of endoscopic mucosal resection (EMR) are to achieve a completely snare-resected lesion in the safest minimum number of pieces, with adequate margins and without need for adjunctive ablative techniques. (Low quality evidence; strong recommendation.) 6 ESGE recommends careful lesion assessment prior to EMR to identify features suggestive of poor outcome. Features associated with incomplete resection or recurrence include lesion size > 40 mm, ileocecal valve location, prior failed attempts at resection, and size, morphology, site, and access (SMSA) level 4. (Moderate quality evidence; strong recommendation.) 7 For intraprocedural bleeding, ESGE recommends endoscopic coagulation (snare-tip soft coagulation or coagulating forceps) or mechanical therapy, with or without the combined use of dilute adrenaline injection. (Low quality evidence, strong recommendation.)An algorithm of polypectomy recommendations according to shape and size of polyps is given (Fig. 1).

Small-bowel Surveillance in Patients With Peutz-Jeghers Syndrome: Comparing Magnetic Resonance Enteroclysis and Double Balloon Enteroscopy.

BACKGROUND AND STUDY AIMS: Small-bowel surveillance with polypectomy of polyps ≥15 mm prevents complications in patients with Peutz-Jeghers syndrome (PJS). We aimed to compare magnetic resonance enteroclysis (MRE) and double balloon enteroscopy (DBE) for diagnostic yield of these polyps and for patient preference. MATERIALS AND METHODS: PJS patients prospectively underwent MRE followed by proximal DBE within 20 weeks. Endoscopists were blinded to the MRE results. We compared number of polyps ≥15 mm detected by MRE and DBE. Patients' perceptions of both procedures were assessed using questionnaires. RESULTS: Fifteen PJS patients (67% males, median age 47 y) underwent both MRE and DBE. Polyps ≥15 mm were identified by MRE and/or DBE in 12/15 (80%) patients. There was no significant difference in the detection of polyps ≥15 mm (38 by MRE vs. 50 by DBE, P=0.37). Sensitivity for these polyps was 62% (38/61) for MRE and 82% (50/61) for DBE. Patients' perceived shame and burden did not differ significantly between MRE and DBE. Patients reported significantly more pain during preparation for MRE than for DBE (moderate vs. no pain, P=0.02), although perceived pain during the procedures was comparable (both mild, P=0.89). For future small-bowel surveillance 10/13 (77%) patients preferred DBE over MRE (P=0.09). CONCLUSIONS: Our results suggest that MRE and DBE have a comparable diagnostic yield of polyps ≥15 mm. However, DBE allows for direct intervention and was preferred over MRE by most patients in this series. Larger cohorts of PJS patients are needed to fully evaluate the diagnostic yield of DBE compared with other modalities.

Computer-Aided Detection of Colorectal Polyps at CT Colonography: Prospective Clinical Performance and Third-Party Reimbursement.

OBJECTIVE: We assessed the initial clinical performance and third-party reimbursement rates of supplementary computer-aided detection (CAD) at CT colonography (CTC) for detecting colorectal polyps 6 mm or larger in routine clinical practice. MATERIALS AND METHODS: We retrospectively assessed the prospective clinical performance of a U.S. Food and Drug Administration-approved CAD system in second-reader mode in 347 consecutive adults (mean age, 57.6 years; 205 women, 142 men) undergoing CTC evaluation over a 5-month period. The reference standard consisted of the prospective interpretation by experienced CTC radiologists combined with subsequent optical colonoscopy (OC), if performed. We also assessed third-party reimbursement for CAD for studies performed over an 18-month period. RESULTS: In all, 69 patients (mean [± SD] age, 59.0 ± 7.7 years; 32 men, 37 women) had 129 polyps ≥ 6 mm. Per-patient CAD sensitivity was 91.3% (63 of 69). Per-polyp CAD-alone sensitivity was 88.4% (114 of 129), including 88.3% (83 of 94) for 6- to 9-mm polyps and 88.6% (31 of 35) for polyps 10 mm or larger. On retrospective review, three additional polyps 6 mm or larger were seen at OC and marked by CAD but dismissed as CAD false-positives at CTC. The mean number of false-positive CAD marks was 4.4 ± 3.1 per series. Of 1225 CTC cases reviewed for reimbursement, 31.0% of the total charges for CAD interpretation had been recovered from a variety of third-party payers. CONCLUSION: In our routine clinical practice, CAD showed good sensitivity for detecting colorectal polyps 6 mm or larger, with an acceptable number of false-positive marks. Importantly, CAD is already being reimbursed by some third-party payers in our clinical CTC practice.

The Serrated Polyp Pathway: Is It Time to Alter Surveillance Guidelines?

PURPOSE OF REVIEW: In this manuscript, we review current surveillance guidelines for serrated polyps (SPs) and discuss how recent studies inform the selection of appropriate surveillance intervals for patients with SPs. RECENT FINDINGS: Large and/or proximal SPs, particularly sessile serrated polyps (SSPs), are associated with increased risk of both synchronous and metachronous neoplasia, including advanced adenomas and colorectal cancer (CRC). Persons harboring multiple SSPs or dysplastic SSPs are at the highest risk. Moreover, a high percentage of large and/or proximal SPs are reclassified as SSPs when read by trained gastrointestinal pathologists, even if they were originally reported as hyperplastic polyps. These findings support the adoption of surveillance guidelines that prescribe closer surveillance of large and/or proximal SPs, regardless of subtype. SSPs remain a challenge to reliably identify, resect, and diagnose via histology. The increased risk of future neoplasia in patients with SSPs is likely driven by a combination of underdetection, inadequate removal, misclassification, and biology. Until further evidence emerges, we support guidelines that recommend close surveillance of patients with a history of large and/or proximal SPs and SSPs specifically in order to mitigate the threat of interval CRC.

Assessment of colorectal polyp recognition skill: development and validation of an objective test.

BACKGROUND: The quality of colonoscopy is known to vary. The extent to which colonoscopists can recognize the presence of subtle colorectal lesions by visually distinguishing them from the surrounding mucosa (i.e., polyp recognition skill) may be one of several attributes that influence polyp detection rates. The aim of the present study was to develop and validate the first objective test of polyp recognition skill. METHODS: Validation study. Twenty-eight experienced colonoscopists and eighty novices took a preliminary 280-item computer-based polyp recognition test. Items were genuine endoscopic images which participants assessed for the presence of "likely polyps." Half included clinically identified polyps. Participants clicked on a suspected lesion or a button marked "no likely polyp", and the main outcome measures were accuracy and response latency. The best items were selected for the final 50-item test. RESULTS: In the preliminary test, experienced colonoscopists correctly identified more polyps than novices (P < .0001) and better discriminated between clinically identified polyps and non-polyp features (as measured by d', P < .0001). For polyp items, the experienced group also responded faster (P < .01). Effect sizes were large for accuracy (Cohen's d = 3.22) and d' (Cohen's d = 3.22). The 50 final test items produced comparable results for accuracy, d', and response latency. For both versions of the test, score scale reliability was high for both polyp and non-polyp items (α = .82 to .97). CONCLUSIONS: The observed experienced-novice differences support the construct validity of the performance measures derived from the tests, indicating that polyp recognition skill can be quantified objectively. The final test may potentially be used to assess trainees, but test sensitivity may be insufficient to make fine-grained distinctions between different skill levels among experienced colonoscopists. More sensitive future tests may provide a valuable supplement to clinical detection rates, allowing objective comparisons between skilled colonoscopists.