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PubMed2004

Colonic polyp segmentation in CT colonography-based on fuzzy clustering and deformable models.

An automatic method to segment colonic polyps in computed tomography (CT) colonography is presented in this paper. The method is based on a combination of knowledge-guided intensity adjustment, fuzzy c-mean clustering, and deformable models. The computer segmentations were compared with manual segmentations to validate the accuracy of our method. An average 76.3% volume overlap percentage among 105 polyp detections was reported in the validation, which was very good considering the small polyp size. Several experiments were performed to investigate the intraoperator and interoperator repeatability of manual colonic polyp segmentation. The investigation demonstrated that the computer-human repeatability was as good as the interoperator repeatability. The polyp segmentation was also applied in computer-aided detection (CAD) to reduce the number of false positive (FP) detections and provide volumetric features for polyp classification. Our segmentation method was able to eliminate 30% of FP detections. The volumetric features computed from the segmentation can further reduce FP detections by 50% at 80% sensitivity.

Algorithms↗
PubMed2004

Hamartin and tuberin immunohistochemical expression in cutaneous fibroepithelial polyps.

BACKGROUND: Hamartin and tuberin are inactivating tumor suppressor proteins implicated in the development of gastrointestinal polyps and sporadic and tuberous sclerosis-associated cutaneous angiofibromas. The pattern of expression of these peptides has not been studied in fibroepithelial polyps (FEPs). DESIGN: The specific aim of the study was to evaluate the immunohistochemical expression of tuberin and hamartin within the epithelium and dermal fibrocytes of 20 cutaneous FEPs compared with the epithelium and dermal fibrocytes of normal skin. The diagnoses were confirmed independently by a dermatopathologist, and the pattern of intensity was assessed by the mean labeling intensity (MLI) of cytoplasmic and/or nuclear staining for each antibody. RESULTS: Hamartin and tuberin antibodies showed moderate staining of the keratinocytes and fibrocytes of normal skin and the keratinocytes within FEPs. Both antibodies showed diminished staining within the fibrocytes of the FEPs. The MLI of hamartin was 44.3 +/- 4.4 for keratinocyte nuclei in normal skin and 51.2 +/- 3.7 within the polyps. The MLI of tuberin was 42.9 +/- 3.6 within the keratinocyte nuclei of the normal skin compared to 39.7 +/- 3.0 for the polyps. The MLI for hamartin within the fibrocytes of the normal skin was 78.9 +/- 7.1 compared to 21.6 +/- 4.2 within the polyps, p = 0.01. The MLI for tuberin within the fibrocytes of normal skin was 70.6 +/- 5.0 compared to 47.1 +/- 4.7 within the polyps. CONCLUSION: The data suggest that down regulation or loss of tuberin and/or hamartin expression may be permissive to fibrocyte proliferation or promote collagen production leading to FEP formation.

Case-Control Studies↗
PubMed1990

Colon cancer and polyps in acromegaly: increased risk associated with family history of colon cancer.

A cohort of 52 subjects diagnosed with acromegaly in southeastern Michigan and northern Ohio between 1935 and 1985 were followed to determine the incidence of colon cancer and polyps. Medical records were reviewed, subjects or their next-of-kin were interviewed, and screening examinations of the colon were offered to the living patients who were located. Data on demographics, personal histories of cancer and colon polyps, family history of colon cancer, and cure from acromegaly were obtained for both living and deceased subjects. The risk for colon cancer compared to the general population was estimated using standardized incidence ratios (SIRs). The expected number of cases was determined utilizing age, sex and race-specific rates provided by the cancer registry in southeastern Michigan. Among the 52 subjects, one could not be located and nine were deceased, none from colon cancer, with one known to have a history of colon polyps. Of 13 (31%) who declined the screening physical, one had a history of polyps and none reported a history of colon cancer. Two of 29 screened patients were found to have right-sided adenocarcinoma of the colon. Of the entire cohort, eight people (including one deceased) had a current or previous diagnosis of polyps, with five known to be histologically adenomatous. The SIR for colon cancer was 4.7 (95% confidence interval 0.6-17.1). Seven subjects, including the two with detected adenocarcinoma and four of the six living subjects with polyps only, reported a family history of colon cancer. The SIR for the subset of subjects with a family history of colon cancer was 29.1 (95% confidence interval of 3.5-104.6).(ABSTRACT TRUNCATED AT 250 WORDS)

Acromegaly↗
PubMed2005

Demographic and pathological characteristics of serrated polyps of colorectum.

AIMS: To characterize a series of colorectal polyps, focusing on the clinicopathological features of serrated adenoma (SA), mixed polyp (MP) and the recently recognized sessile serrated adenoma (SSA). METHODS AND RESULTS: Eight hundred and ninety-one conventional adenomas (AD), 298 hyperplastic polyps (HP), 27 SSA, 10 MP and 24 traditional SA were obtained from patients during colonoscopic examination. SSA were more likely to be proximally located than other polyps. All SA, MP and SSA and a randomly selected subset of HP (n = 61) and ADs (n = 93) were assessed for expression of mucin, MLH1, MGMT, and Ki67. SSA expressed more MUC5AC than either HP or SA. Loss of MLH1 was not observed in any serrated polyps and in only one AD. Loss of MGMT occurred in 13% of AD, and showed no correlation with histological type, size or location. Loss of MGMT occurred in 24% of SSA, MP and SA (combined), and was more frequent in proximal lesions and larger lesions. SSA had a higher proliferative index than HP. In MP, the proliferative index of the non-dysplastic component was closer to HP than SSA, while the dysplastic component was intermediate between SA and AD. CONCLUSIONS: SSA differ from other serrated polyps of colorectum in terms of location, morphology and immunophenotype.

Adenoma↗
PubMed1975

Large-bowel polypectomy via the colonoscope: experience with 80 polyps.

The experience of two colonoscopy units in managing 88 patients referred with 114 suspected colonic polyps are presented. Almost a quarter of the suspected polyps were artefacts, while some actual polyps were not visualized at the initial colonoscopy. All but 10 of the confirmed polyps were successfully snared. Morbidity was low. Five of the polyps were malignant. The technical aspect of snaring and of setting up colonoscopy units are discussed. It is considered that colonoscopic polypectomy is the optimum management of colonic polyps.

Adult↗
PubMed1985

An assessment of an immunochemical test for human haemoglobin in the detection of colonic polyps.

It is now widely accepted that malignant tumours of the colon and rectum almost invariably arise from pre-existing adenomatous polyps. If such polyps could be detected and removed colonoscopically before they become malignant, theoretically the incidence of invasive colorectal cancer could be dramatically reduced. The purpose of this study was to determine whether an immunochemical test for faecal occult blood would identify patients with benign colonic polyps. The faecal samples from 121 patients scheduled to undergo colonoscopy were tested by our immunochemical method and the Hemoccult II test. There were nine patients who had malignant colorectal tumours. These were excluded from this study. Twenty-nine were found to have colonic polyps. Fifteen of these had one or more faecal samples which were positive by the immunochemical test. In contrast, there was only one patient who had a positive Hemoccult II test. Fourteen of the remaining 83 patients had positive immunochemical tests. The findings on colonoscopy provided satisfactory explanations in all these cases. Polyps of all sizes and histological type were associated with positive immunochemical tests. It is concluded that the immunochemical test has sufficiently high sensitivity for colonic polyps to make feasible the screening of patients at high risk of developing colonic cancer.

Colonic Polyps↗
PubMed1999

Cancer and adenomatous polyp distribution in the colorectum.

OBJECTIVE: To examine the possible role of adenomatous polyps in colorectal cancer development, this study focused on the relationship of the distribution between adenomatous polyps and cancer in the colorectum. METHODS: The distribution of 753 adenomatous polyps was compared with that of 35 colorectal cancer lesions in 510 male patients ranging from 45 to 55 yr of age who underwent a total colonoscopy. RESULTS: The incidence of cancer significantly increased with a distal shift in the colorectal sites in comparison with that of adenomatous polyps (p < 0.02). CONCLUSION: The different distribution between adenomatous polyps and cancer thus suggested that adenomatous polyps at various colorectal sites appear to have a different malignant potential for cancer development.

Adenocarcinoma↗
PubMed2000

Approach to colon polyps in the elderly.

Colorectal cancer is a common but potentially preventable disease. Nearly all colorectal cancers are thought to arise from adenomatous polyps. The conclusions from the National Polyp Study strongly support the concept that the removal of polyps may prevent the future development of colorectal cancer. With the growing acceptance of screening for colorectal cancer, many elderly patients with adenomatous polyps will be discovered. Because increasing age is a powerful determinant of a higher prevalence of colonic neoplasia in asymptomatic individuals, physicians will need to be prepared to make informed decisions regarding the treatment of elderly patients with colonic polyps. The literature is reviewed and guidelines are formed regarding the optimal surveillance interval for patients with colonic polyps. The age at which surveillance and screening for colorectal neoplasia should stop is also reviewed. Conclusions are based on the currently available data.

Aged↗
PubMed2004

Relationship of visceral adipose tissue to recurrence of adenomatous polyps.

OBJECTIVES: Insulin is a growth factor for colorectal cancer. Visceral adipose tissue (VAT) is strongly associated with insulin levels, and insulin and visceral obesity have been associated in cohort studies with colorectal cancer. The aim of this investigation was to determine whether VAT is associated with recurrence of adenomatous polyps, the precursor to colorectal cancer. METHODS: As an ancillary study to the Polyp Prevention Trial, a randomized clinical trial that evaluated the effect of a low-fat, high-fiber, high vegetable and fruit diet on adenomatous polyp recurrence, subjects at one clinical center underwent measurement of VAT with a single-slice CT scan through the L4-L5 interspace. The scan was performed around the time of the subject's year 4 colonoscopy that determined adenoma recurrence. RESULTS: Of 119 subjects, 44 of 84 men (52%) and 16 of 35 women (46%) had a recurrent adenoma (p= 0.51). Body mass index (BMI) and weight at baseline and at year 4 colonoscopy were unrelated to adenoma recurrence. In a multivariate model including visceral fat quartile, remote history of polyps, gender, age, and randomization group, only remote history of polyps was statistically significantly associated with recurrent adenoma with a relative risk of 4.6 (95% CI 1.7, 12.4, p= 0.001). There was no consistent monotonic trend of increased or decreased risk of recurrence as one ascended quartiles of adipose tissue for visceral, subcutaneous, or total abdominal fat. CONCLUSION: In this study, no association between visceral adipose tissue and adenomatous polyp recurrence was observed. Further study and exploration of the role of VAT in adenoma progression is required.

Adenomatous Polyps↗
PubMed2006

Diagnostic quality of: polyps resected by snare polypectomy: does the type of electrosurgical current used matter?

BACKGROUND: Traditionally, snare polypectomy is performed using blended, coagulation, or pure cutting electrical current (EC). The aim of this study was to assess and compare the diagnostic quality of polyps obtained by snare polypectomy using two different electrosurgical currents. METHODS: Consecutive patients undergoing colonoscopy underwent polypectomy using either blended EC with a conventional electrosurgical generator (ESG) or using an ESG with a microprocessor that automatically controls cutting and coagulation (Endocut). An experienced blinded gastrointestinal (GI) pathologist evaluated the specimens for diameter, cautery damage (amount and degree), margin evaluability, architecture, and general histologic diagnostic quality. RESULTS: One hundred sixteen patients (69% men, mean age 63.8 +/- 15 yr) underwent 148 polypectomies (78 using blended current and 70 using Endocut). We found that the cautery degree was less with the Endocut than with the blended current (p < 0.02). Cautery amount was also higher in polyps resected using blended current (56%) than Endocut (51%) but this difference did not reach statistical significance (p= 0.1). Polyps resected using Endocut had better margin evaluability (75.7% to 60.3%, p= 0.046). The overall tissue architecture was similar in both groups. Polyps removed with blended current had less overall quality as compared to polyps removed by Endocut (p= 0.024). CONCLUSIONS: More extensive tissue damage occurred using blended EC with the conventional ESG than when using Endocut. The quality of the polypectomy specimens was overall better using Endocut. Finally, the ability to evaluate resected polyp margins and overall tissue histology was better with the microprocessor-controlled ESG than with the conventional ESG.

Aged↗
PubMed2005

Reduction of false positives by internal features for polyp detection in CT-based virtual colonoscopy.

In this paper, we present a computer-aided detection (CAD) method to extract and use internal features to reduce false positive (FP) rate generated by surface-based measures on the inner colon wall in computed tomographic (CT) colonography. Firstly, a new shape description global curvature, which can provide an overall shape description of the colon wall, is introduced to improve the detection of suspicious patches on the colon wall whose geometrical features are similar to that of the colonic polyps. By a ray-driven edge finder, the volume of each detected patch is extracted as a fitted ellipsoid model. Within the ellipsoid model, CT image density distribution is analyzed. Three types of (geometrical, morphological, and textural) internal features are extracted and applied to eliminate the FPs from the detected patches. The presented CAD method was tested by a total of 153 patient datasets in which 45 patients were found with 61 polyps of sizes 4-30 mm by optical colonoscopy. For a 100% detection sensitivity (on polyps), the presented CAD method had an average FPs of 2.68 per patient dataset and eliminated 93.1% of FPs generated by the surface-based measures. The presented CAD method was also evaluated by different polyp sizes. For polyp sizes of 10-30 mm, the method achieved mean number of FPs per dataset of 2.0 with 100% sensitivity. For polyp sizes of 4-10 mm, the method achieved 3.44 FP per dataset with 100% sensitivity.

Biophysical Phenomena↗
PubMed2004

My approach to serrated polyps of the colorectum.

Hyperplastic polyps of the colorectum are heterogeneous lesions, a subset of which is now regarded as the precursor of colorectal cancer with DNA microsatellite instability. Some authors have distinguished this subset from classic hyperplastic polyps and have introduced the term "sessile serrated adenoma". These lesions frequently show BRAF mutation and DNA methylation. This personal perspective reviews recent insights into serrated polyps and highlights the importance of inhibition of apoptosis as a unifying mechanism. It is estimated that around 25 hyperplastic polyps of the proximal colon exist for every colorectal cancer with DNA microsatellite instability. Further research is required to identify additional risk factors for hyperplastic polyps other than anatomical location. These may be demographic, clinical, morphological, or molecular. It is not recommended that the term sessile serrated adenoma be used in routine reporting, but it is desirable that potentially aggressive hyperplastic polyps should be identified for the purposes of both clinical practice and research.

Colorectal Neoplasms↗
PubMed1992

Expression of HLA-DR antigen in different histological types of gastric polyp.

AIMS: To study the expression of HLA-DR antigen in the different histological types of gastric polyps. METHODS: Ninety five cases of gastric polyps were histologically classified and examined for the presence of Helicobacter pylori, and for degree and type of inflammation. Further sections were stained immunohistochemically for HLA-DR antigen expression in the epithelium using a monoclonal antibody that was reactive to formalin-fixed paraffin wax embedded tissue. RESULTS: HLA-DR antigen was expressed in all of the inflammatory polyps studied (20/20), and in most hyperplastic (12/16) and adenomatous (4/6) polyps. Only a few fundic gland polyps (8/51) stained positively for HLA-DR antigen. Gastric polyps seem to have a greater tendency to express HLA-DR antigens than non-polypoid gastric mucosa, even after considering the factors that may affect HLA-DR antigen expression, such as inflammation and the presence of H pylori. CONCLUSIONS: Growth disturbances/polyp formation may be associated with increased HLA-DR antigen expression.

Adolescent↗
PubMed2006

Polyp detection with CT colonography: primary 3D endoluminal analysis versus primary 2D transverse analysis with computer-assisted reader software.

PURPOSE: To retrospectively compare primary three-dimensional (3D) endoluminal analysis with primary two-dimensional (2D) transverse analysis supplemented by computer-assisted reader (CAR) software for computed tomographic (CT) polyp detection and reader reporting times. MATERIALS AND METHODS: Ethical permission and patient consent were obtained from all donor institutions for use of CT colonography data sets. Twenty CT colonography data sets from 14 men (median age, 61 years; age range, 52-78 years) with 48 endoscopically proved polyps were selected. Polyp coordinates were documented in consensus by three unblinded radiologists to create a reference standard. Two radiologists read the data sets, which were randomized between primary 3D endoluminal views with 2D problem solving and 2D views supplemented by CAR software. Reading times and diagnostic confidence were documented. The CAR software highlighted possible polyps by superimposing circles on the 2D transverse images. Data sets were reread after 1 month by using the opposing analysis method. Detection rates were compared by using the McNemar test. Reporting times and diagnostic confidence were compared by using the paired t test and Mann-Whitney U test, respectively. RESULTS: Mean sensitivity values for polyps measuring 1-5, 6-9, and 10 mm or larger were 14%, 53%, and 83%, respectively, for 2D CAR analysis and 16%, 53%, and 67%, respectively, for primary 3D analysis. Overall sensitivity values were 41% for 2D CAR analysis and 39% for primary 3D analysis (P=.77). Reader 1 detected more polyps than reader 2, particularly when using the 3D fly-through method (P=.002). Mean reading times were significantly longer with the 3D method (P=.001). Mean false-positive findings were 1.5 for 2D analysis and 5.5 for 3D analysis. Reader confidence was not significantly different between analysis methods (P=.42). CONCLUSION: Two-dimensional CAR analysis is quicker and at least matches the sensitivity of primary 3D endoluminal analysis, with fewer false-positive findings.

Aged↗
PubMed2006

Colonic polyps: effect of attenuation of tagged fluid and viewing window on conspicuity and measurement--in vitro experiment with porcine colonic specimen.

PURPOSE: To investigate effect of attenuation of tagged fluid and viewing window on polyp conspicuity and measurement with porcine colonic specimen. MATERIALS AND METHODS: Eleven (3-10-mm-diameter) polyps were created in porcine colon and the specimen submerged in saline. Four-detector row CT was performed after gas distension and after filling with six barium sulfate suspensions (attenuation, 100-1000 HU). Two readers independently measured maximal two-dimensional polyp diameter on each data set with the following four viewing windows and window levels and window widths, respectively: colon (-150 HU, 1500 HU), lung (-500 HU, 1500 HU), bone (500 HU, 2500 HU), and abdomen (40 HU, 400 HU). In consensus, polyp conspicuity (compared with air data set) was assigned a grade of 1-4 for each viewing window (grade 1, not seen or barely visible; grade 4, optimally seen). For statistical analysis, conspicuity grades were collapsed to a two-point scale. Data were analyzed with Mann-Whitney, Kruskal-Wallis, and chi2 tests. RESULTS: Accuracy of polyp measurement was independent of viewing window for attenuation of tagged fluid of 100-300 HU but differed significantly for 500-1000 HU (P < .001); that for colonic and bone viewing windows was superior (median size difference, 1.0 mm; interquartile range, 0.5-1.5). Conspicuity differed significantly according to viewing window at all attenuation values (P < .001). For 100-300 HU with abdominal viewing window, 83% (24 of 29) of observations were assigned grade 3 or 4 (best). For 500-1000 HU with bone viewing window, 94% (30 of 32) of observations were assigned grade 3 or 4 (superior). Overall conspicuity was best with bone viewing windows at 700 HU. CONCLUSION: Polyp conspicuity and measurement in tagged data sets were optimized at 700 HU with bone viewing windows. At less than 300 HU, conspicuity improved with abdominal viewing windows.

Animals↗
PubMed1987

Detection of colonic polyps on single-contrast barium enema study: emphasis on the elderly.

A systems approach was employed to improve results of the single-contrast barium enema examination for detection of colonic polyps. Improvements were made in each of the following areas: radiographic-fluoroscopic equipment, fluoroscopic-television images, screen-film combinations, barium suspensions, examination techniques, imaging sequences, and quality controls. Radiologic-endoscopic correlation was undertaken for 137 colonic polyps seen endoscopically in 91 patients. The average age of the patients was 69 years. The sensitivity of the single-contrast examination for detection of all polyps was 80%. Polyps 5-9 mm in size were detected with 66% sensitivity, while 94% of polyps 10 mm or larger were detected. The results indicate that the sensitivity of a suitably performed single-contrast barium enema examination may approach that of the double-contrast study for the detection of colonic polyps, even in an elderly and infirm patient population.

Adult↗
PubMed2000

Endometrial polyps: MR imaging features and distinction from endometrial carcinoma.

PURPOSE: To determine the magnetic resonance (MR) imaging characteristics of endometrial polyps and the accuracy of MR imaging in distinguishing endometrial polyps from endometrial carcinomas in a case-control study. MATERIALS AND METHODS: Cross-referencing pathology records with MR studies from two institutions disclosed 35 patients with surgically proved endometrial polyp or carcinoma after controlling for tumor size. All MR examinations were performed at 1.5 T with T2-weighted fast spin-echo sequences in multiple planes. Three independent readers blinded to histologic diagnoses and clinical data scored each image for the presence of several defined findings. RESULTS: A central fibrous core (low signal intensity on T2-weighted images) and intratumoral cysts (high signal intensity on T2-weighted images) were seen more frequently in endometrial polyps than in carcinomas; myometrial invasion and necrosis showed high predictive value for carcinomas. The readers' responses showed a mean sensitivity of 79%, specificity of 89%, accuracy of 86%, positive predictive value of 82%, and negative predictive value of 88% for diagnosis of carcinoma. The mean area under the receiver operating characteristic curve for the three readers was 0.87 for the diagnosis of carcinoma. CONCLUSION: MR images can help to distinguish most polyps from endometrial carcinomas on the basis of morphologic features. Accuracy does not appear to be sufficient to obviate biopsy, partly because carcinomas and polyps frequently coexist.

Adult↗
PubMed2005

Decreased intestinal polyp multiplicity is related to exercise mode and gender in ApcMin/+ mice.

Moderate-intensity treadmill running can alter male Apc(Min/+) mouse polyp formation. This purpose of this study was to examine whether exercise mode differentially affects Apc(Min/+) mouse intestinal polyp development in male and female mice. Male and female Apc(Min/+) mice were randomly assigned to control, treadmill (18 m/min; 60 min/day; 6 days/wk), or voluntary wheel running (24-h access) groups. Nine weeks of training decreased total intestinal polyps by 29% in male treadmill runners (66 +/- 9; P = 0.038) compared with male controls (93 +/- 7). The number of large polyps (>/=1-mm diameter) were also reduced by 38% in male treadmill runners (49 +/- 6; P = 0.005) compared with male controls (79 +/- 6). Treadmill running in female Apc(Min/+) mice and wheel running in both genders did not affect polyp number or size. Spleen weight decreased in male treadmill runners (91 +/- 9 mg; P = 0.011) and wheel runners (75 +/- 6 mg; P = 0.004) compared with controls (141 +/- 13 mg). Plasma IL-6 was reduced by 96% in male treadmill runners (1.2 +/- 0.6 pg/ml) and 78% in male wheel runners (6.6 +/- 3.3 pg/ml) compared with control mice (27.9 +/- 2.8 pg/ml; P < 0.05). Female mice responded similarly with an 86% decrease in plasma IL-6 with treadmill running (3.2 +/- 1.2 pg/ml) and 90% decrease with wheel running (2.9 +/- 2.0 pg/ml) compared with control mice (21.1 +/- 5.3 pg/ml; P < 0.05). The crypt depth-to-villus height ratio in the intestine, an indirect marker of intestinal inflammation, decreased by 21 (P = 0.024) and 24% (P = 0.029), respectively, in male and female treadmill runners but not wheel runners. Physical activity-induced attenuation of intestinal polyp number and size is dependent on exercise mode and differs between genders. The modulation of systemic and intestinal inflammation may also depend on exercise mode.

Adenomatous Polyposis Coli Protein↗