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At least 289 records · Page 16Linked to original sources
PubMed2004

Positional change in colon polyps at CT colonography.

PURPOSE: To determine the frequency with which polyps change positions with respect to the bowel surface and the cause of this movement. MATERIALS AND METHODS: From December 2001 to March 2003, 113 patients underwent computed tomographic (CT) colonography prior to colonoscopy. For all confirmed polyps that were 5 mm and larger, images obtained with CT colonography were retrospectively analyzed by one author to determine if the polyp was present on both data sets or on only one data set. Retrospective evaluation of these polyps for ventral or dorsal location within the colonic lumen was performed for data sets obtained with patients in the prone and the supine position. The data sets were further reviewed by another author to determine the cause of positional change, when present. RESULTS: Twenty-six patients had a total of 49 histologically proved colorectal polyps that were 5 mm and larger. Eight of 49 colorectal polyps were depicted only on images obtained with the patient in the supine or prone position. Of the remaining 41 polyps that were depicted on images obtained with the patient in the supine and the prone position, 11 moved from a dorsal to a ventral location or vice versa relative to the colonic surface when the patient changed position. Five of these polyps were pedunculated on a stalk. Six were sessile; two were located in the sigmoid colon, two in the transverse colon, one in the ascending colon, and one in the cecum. In these cases, polyp mobility was related to positional changes of the colon in the mesentery, as opposed to true mobility of the polyp. CONCLUSION: In this series, 27% of polyps moved from a ventral location to a dorsal location relative to the colonic surface when the patient was turned from the supine to the prone position; thus, polyps appeared to be mobile. Thus, a mobile filling defect cannot be assumed to be residual fecal material at CT colonography.

Aged↗
PubMed2006

Polyps: linear and volumetric measurement at CT colonography.

PURPOSE: To retrospectively determine which of several computed tomographic (CT) colonography-based polyp measurements is most compatible with the linear measurement at optical colonoscopy and which is best for assessing change in polyp size. MATERIALS AND METHODS: This HIPAA-compliant study had institutional review board approval; informed consent was obtained. Prone and supine CT colonography with same-day optical colonoscopy was performed in 216 patients (147 men and 69 women; age range, 46-79 years; mean age, 59.2 years) with 338 polyps detected at CT colonography. Polyp size was measured with three linear measurements and two volume measurements. One linear measurement and one volume measurement were performed by using automated segmentation; remaining measurements were performed manually. Compatibility with linear size at optical colonoscopy and measurement reproducibility were assessed three ways: variation from size measurement at optical colonoscopy, change between prone and supine scans, and variability between observers. Confidence analysis assessed the ability of each measurement to identify polyps with an optical colonoscopy measurement of 1 cm or greater. RESULTS: Two hundred fifty-one segmentable polyps were present on both supine and prone scans. Linear polyp diameter manually measured on a three-dimensional endoluminally viewed surface (L(M3D)) indicated with 95% confidence that a polyp measured as 0.8 cm or smaller was less than 1.0 cm at optical colonoscopy. Prone and supine polyp size difference was smallest for L(M3D) and the linear diameter computed from manual and automated volume measurements, with interquartile ranges smaller than or equal to 0.3, 0.2, and 0.5 cm, respectively. Interobserver and intraobserver variability was smallest for linear polyp diameter measurements on a two-dimensional display, with a mean percentage difference of 2.8% (95% Bland-Altman limits of agreement: -17.8%, 23.4%) and 5.0% (95% Bland-Altman limits of agreement: -28.3%, 38.3%), respectively. CONCLUSION: L(M3D) best approximated polyp size measurements at optical colonoscopy. Linear diameter calculated from automated volume measurements showed the smallest variation between supine and prone scans while avoiding observer variability and may be best for assessing polyp size changes with serial examinations.

Adult↗
PubMed2003

Changes in the expression of the peroxisome proliferator-activated receptor gamma gene in the colonic polyps and colonic mucosa of acromegalic patients.

Acromegalic patients have an increased prevalence of colonic neoplasms and lower peroxisome proliferator-activated receptor gamma (PPARgamma) levels, the latter acting as a tumor suppressor gene. In this study we evaluated the expression of PPARgamma in the biopsy samples of the polyps and outside polyps colonic mucosa from seven patients with active, untreated acromegaly, 11 with cured disease, and 15 controls. Serum GH and IGF-I levels were higher in patients with untreated acromegaly than in those with acromegaly in remission or controls (P = 0.003 and P = 0.002, respectively) The expression of PPARgamma mRNA (mean +/- SE) was 1) mucosa outside polyps, 24,188 +/- 3,254 transcripts in the controls, 22,432 +/- 2,006 transcripts in acromegaly in remission, and 1,952 +/- 342 transcripts in untreated acromegaly (P < 0.0001 vs. controls and acromegaly in remission); and 2) polyps mucosa, 1,554 +/- 236 transcripts in the controls, 1,112 +/- 143 in acromegaly in remission, and 1,570 +/- 251 in untreated acromegaly (P = NS among polyps groups and mucosa outside polyps of untreated acromegaly; P < 0.0001 vs. mucosa outside polyps of controls and acromegaly in remission). Eighty-five percent of the cells in the mucosa outside polyps from controls or acromegaly in remission were positive at immunohistochemistry, at variance with 45% of the cells from polyps mucosa from each group and from those of mucosa outside polyps of untreated acromegaly (P = 0.0002). In conclusion, patients with untreated acromegaly have reduced expression of PPARgamma in the mucosa outside polyps, which might be reversed by curing the disease; conversely, patients with acromegaly in remission have the same low levels of expression of PPARgamma in the polyps mucosa as untreated acromegaly or controls, supporting the concept that reduced expression of PPARgamma might be an early event in colonic tumorigenesis.

Acromegaly↗
PubMed2006

[Gallbladder polyps: correlation between ultrasonographic and histopathological findings].

BACKGROUND: Gallbladder polyps are becoming a common finding. The management of these polyps is complicated considering that they can bear malignant lesions. AIM: To analyze the ultrasonographic and histopathologic findings of patients operated due to gallbladder polyps. PATIENTS AND METHODS: The records of patients with ultrasonographic diagnosis of gallbladder polyp and that underwent cholecystectomy in a thirteen years period were reviewed, collecting their demographic, ultrasonographic and histopathological data. RESULTS: One hundred and twenty three patients were operated. The mean age was 44+/-13 years, and 69% were women. The mean size of polyps in ultrasonography was 7.3+/-5 mm. Histopathology confirmed the presence of polyps in 79% of patients, with a mean size and number of lesions of 5.1+/-3.8 mm and 2.1+/-2, respectively. Nine percent of polyps were greater than 10 mm, and single polyps were significantly larger than the multiple ones (p =0.003). Four cases of adenoma (3.2%) were diagnosed; one of them had in situ carcinoma. All were single and larger than 10 mm. We found a significant correlation between ultrasonographic and histopathological polyp size determination (r =0.47; p =0.002). Polyp size was also a predictor of the presence of adenoma (p =0.043; confidence intervals: 1.006-1.424). CONCLUSIONS: There is a good correlation between the size of the gallbladder polyp in ultrasonography and the size in the histopathology report. Gallbladder adenoma is uncommon and it correlates with the size of the polyp. In this series, size was the only predictor of the presence of adenoma.

Abdomen↗
PubMed1999

Detection of activated eosinophils in nasal polyps of an aspirin-induced asthma patient.

Aspirin-induced asthma (AIA) is frequently accompanied by nasal polyps. Eosinophil infiltration is a characteristic feature of nasal polyps associated with AIA. Even though steroids are well known to be effective on managing AIA and its nasal polyps, histochemical examinations after steroid therapy and at recurrence, involving eosinophil infiltration of nasal polyps, have been less studied. To know the histochemical effects of steroid treatment on eosinophil accumulation in nasal polyps of AIA and the histochemical feature of a recurring polyp and to detect distributional differences between storage and secreted forms of eosinophil cationic proteins, we carried out immunocytochemical labelling with antibodies against EGI (recognizing resting and activated eosinophils) and EG2 (recognizing only activated eosinophils), and determined eosinophil infiltration in nasal polyps that were obtained before and after steroid treatment, and at recurrence of polyps. A large number of eosinophils in AIA polyps were found before steroid treatment and at recurrence, and they were predominantly composed of activated eosinophils (EG2-positive). In contrast, eosinophil infiltration was rare in polyps obtained immediately after steroid treatment. This finding suggests that eosinophil infiltration may be associated with nasal polyp formation in AIA, and that activation of eosinophils plays an important role in accumulation of eosinophils and polyp formation beginning with the initial stage.

Adrenal Cortex Hormones↗
PubMed1999

[Risk of malignant degeneration of preoperatively-classified benign large sessile rectal polyps. A comparison with adenoma size].

From January 1986 to December 1995 307 patients with preoperatively as benign classified rectal polyps underwent transanal endoscopic microsurgery or transanal excision at the Hospital of General and Abdominal Surgery, Johannes Gutenberg-University Mainz. Mean polyp size was 3.9 cm in diameter. Postoperatively in 233 patients (75.9%) a benign rectal adenoma was found. In 69 patients (22.5%) with the preoperative diagnosis "benign rectal adenoma" the postoperative histologic result was a carcinoma. No residual polyps were encountered on snare excision in 5 patients (1.6%) with inconclusive evidence of surgical margin involvement. The mean size of malignant polyps was 3.4 cm and significantly below the mean size of benign polyps (4.1 cm, p = 0.009). Especially in polyps with a size to 1 cm and from 1 to 2 cm in diameter the part of malignant rectal polyps was unexpected high (8/15 polyps, 53.3%, respectively 16/37 polyps, 43.3%. Patients with preoperatively as benign classified large sessile rectal polyps had a high risk of malignancy even when polyp's size was small. Therefore in toto excision has to be done also in small polyps.

Adenocarcinoma↗
PubMed1975

Endoscopic assessment of gastric polyps.

The results of fibre gastroscopy in 100 patients with gastric polyp are reported. The polyps were removed in 38 patients. All cases were followed up. No malignant transformation of the polyp was demonstrable in any of the cases. The polypous growth proved to be early gastric carcinoma in two cases, neurogenic sarcoma in one case. The polyp was associated with gastric carcinoma in 11 cases, with gastric sarcoma in one case, and with tumours of other digestive organs in five cases. It has been concluded that 1. diagnosis and correct assessment of gastric polyps rest on the evidence of endoscopy. 2. In the majority of cases polypoid lesions of the stomach are either benign or malignant from the very outset. Endoscopy coupled with biopsy directed at the representative sites of the polyp permits differentiation between benigh and malignant cases with a fair degree of accuracy. 3. Removal of polyps should be selective. 4. Association of gastric polyps with gastric carcinoma is far more frequent than malignant transformation of the polyp. 5. Endoscopic follow-up of polyps is imperative even in polypectomized cases. 6. Detection of a gastric polyp necessitates a search for tumours of other organs.

Adult↗
PubMed2003

[The expression and relevent study of NO and TNF-alpha in nasal polyp tissue].

OBJECTIVE: To study the expression of NO and TNF-alpha in nasal polyp tissue and explore the effect and relevance of them in the formation of nasal polyp. METHOD: The level of NO and TNF-alpha were measured by RIA and chemical method (Griess Reaction) in nasal polyp tissue, inflammatory mucosa and serum of 33 nasal polyp patients and normal mucosa and serum of 10 deviated septum patients who hospitalized in our hospital from Nov. 1999 to Mar. 2001. RESULT: The level of NO and TNF-alpha in nasal polyp and inflammatory mucosa are higher than that in normal mucosa (P < 0.01). There is significant difference of NO between nasal polyp and inflammatory mucosa (P < 0.01) but not of TNF-alpha (P > 0.05). The level of NO and TNF-alpha in serum of two groups are similar (P > 0.05). There are negative relevance tendency between NO and TNF-alpha in nasal polyp of inflammatory mucosa (r = -0.411, P < 0.02 and r = -0.476, P < 0.01). There is a positive relevance tendency of TNF-alpha between nasal polyp and inflammatory mucosa (r = 0.808, P < 0.01). CONCLUSION: 1. NO and TNF-alpha play important roles in the formation of nasal polyp. 2. There is a negative relevance tendency of NO and TNF-alpha in nasal polyp tissue which reveals the possible negative feedback of NO in the inflammation. 3. The study confirms the theory of microenvironment of nasal polyp and reveals that nasal polyp is separated relatively from and associated closely with the inflammation of nasal cavity.

Adolescent↗
PubMed2005

Site of origin of nasal polyps: relevance to pathogenesis and management.

The site of origin of sino-nasal polyps was documented in 113 consecutive patients undergoing functional endoscopic sinus surgery (FESS). These patients were assigned pre-operatively to 4 clinical groups according to the out-patient recorded endoscopic appearance of their nasal cavities; chronic rhinosinusitis without polyps (CRSS) n=35, grade 1 polyps n=28, grade 2 polyps n=30 and grade 3 polyps n=20. In the group of patients diagnosed with polyps pre-operatively, 97.4% had polyps originating in the anterior ethmoid complex, of which 89.7% had polyps originating in the anterior ethmoidal cells and over 60% had polyps specifically originating from each of the following sites: the uncinate or infundibulum, the posterior ethmoid sinus, the frontal recess and the face of the bulla ethmoidalis. In the group diagnosed pre-operatively as CRSS without polyps, polyps were found in 60% of patients within the sinuses during surgery. In summary, our findings suggest that polyps originate from the middle meatus, and may be found at surgery when undetectable at pre-operative endoscopy.

Adult↗
PubMed2006

[The concentration and expression of IL-4, IL-5, IL-6, IL-8 in human nasal polyps tissues].

OBJECTIVE: To study the concentration and expression of IL-4, IL-5, IL-6, IL-8 in human nasal polyps tissues, and to explore the relationship between cytokines and the formative mechanism of nasal polyps. METHOD: The concentration and expression of IL-4, IL-5, IL-6, IL-8 in 54 cases with nasal polyps were determined by enzyme linked immunosorbent assay (ELISA) and immunohistochemistry, and the middle turbinate mucosa from 22 patients with the deviation of nasal septum were used as the control. RESULT: The concentration of IL-5, IL-8 in nasal polyps tissues were significantly higher than that in normal middle turbinate mucosa (P < 0.01). There was no significant difference between the concentration of IL-6 in nasal polyps and that in normal control group (P > 0.05). No significant difference was found between the concentration of IL-4 in nasal polyps tissues with negative allergic skin test and that in control group, but the concentration of IL-4 was significantly higher in nasal polyps tissues with positive allergic skin test than in control group (P < 0.05). IL-4 was mostly found in lymphocytes and plasma cells in nasal polyps and IL-5 in eosinophils and lymphocytes. IL-6 and IL-8 were mostly found in nasal polyps epithelium and inflammatory cells, as was no difference between positive allergic skin test and negative one. CONCLUSION: IL-5 and IL-8 are the key cytokines in the formation of nasal polyps, and IL-4 is a key cytokine in nasal polyps with positive allergic skin test. IL-6 isn't an important cytokine in the formative mechanism of nasal polyps.

Adolescent↗
PubMed1990

[Epithelial gastric polyps in a series of 13000 gastroscopies].

The frequency and characteristics of epithelial gastric polyps were studied over a 4-years periods. In a series of 13,000 gastric fibroscopies, 191 patients (1.3 per cent) were fund to have a "polypous lesion". Among these, 48 had hyperplastic polyps, 19 had fundic gland polyps and 6 had adenomatous polyps. The remaining patients had either lesions of interstitial gastritis (118) or normal histology (34). Hyperplastic polyps were 5 mm large in 87 per cent of the cases, and 7 out of 10 were solitary. They were equally distributed between fundus and antrum and associated with atrophic gastritis in 9 out of 22 cases. In 2 cases, they were accompanied with gastric cancer. Fundic gland polyps were less than 5 mm large in 84 per cent of the cases and solitary in 5 out of 19 cases. Adenomatous polyps were associated with hyperplastic polyps in 4 patients, including 1 mixed polyp (hyperplastic containing adenomatous areas). Follow-up with regular endoscopic examinations is accepted for adenomatous polyps; it seems to be justified in patients with hyperplastic polyps, and lesions bigger than 10 mm should be removed in view of the as yet imperfectly evaluated risk of malignant degeneration.

Adult↗
PubMed1984

Upper gastrointestinal polyps in Gardner's syndrome.

Upper gastrointestinal polyps have been considered an uncommon finding in patients with Gardner's syndrome and familial polyposis coli. Investigators from Japan, however, have recently reported finding gastric and duodenal polyps in a high percentage of Japanese patients with these conditions. We endoscopically examined 11 affected members of the originally described Gardner's syndrome kindred to determine if upper gastrointestinal polyps also occurred in patients with Gardner's syndrome living in the United States. Six of the patients were found to have numerous small polyps of the gastric fundus and body. Polyp histology in 5 of the 6 patients was consistent with fundic gland hyperplasia. Biopsy specimens from the remaining patient demonstrated normal mucosa only. Another patient with no fundic polyps had a single antral polyp that was an adenoma. Eight patients exhibited small polyps of the duodenum. Biopsy specimens were obtained in 7 of the 8. All polyps biopsied were adenomas. The terminal ileum was examined by endoscopy in 9 of the 11 study patients. All 9 had ileal polyps, but the polyps were adenomas in 6 patients and lymphoid aggregates in 3 patients. The results indicate that upper gastrointestinal polyps are a common pleiotropic manifestation of the genetic defect responsible for Gardner's syndrome.

Adenoma↗
PubMed1980

Nasal polyps in children.

The inflammatory nasal polyp is the most common benign or malignant nasal mass seen in children. Nasal polyps in the pediatric population appear to occur as inflammatory responses to bacterial infections. In 33% of the patients with polyps whom we studied, antral choanal polyps were noted, and in 20% of the patients the polyps were unilateral but not antral choanal. In 18% of the patients the polyps were bilateral and in an additional 29% they occurred bilaterally in association with cystic fibrosis. History of an allergy is infrequently associated with nasal polyps; allergies are potentially major contributing factors to nasal polyps only in patients without cystic fibrosis whose nasal polyps are bilateral. Patients with antral choanal polyps are most successfully managed by simultaneous Caldwell-Luc antrostomy and polypectomy. Sixty percent of patients with nasal polyps and cystic fibrosis are adequately managed with a single intranasal polypectomy. Simultaneous sinus surgery and polypectomy should be considered for all patients with recurrent polyps and for all patients with clinical or radiographic evidence of significant sinusitis. Complications, including epistaxis and intranasal synechia, occurred in 3% of the 170 surgical procedures performed.

Adolescent↗
PubMed1994

[Ureteral polyps: three case reports].

We observed recently three cases of ureteral polyps including a case of multiple polyps. The first patient was a 33-year-old man with multiple polyps at the left upper ureter. The second patient was a 51-year-old man and the third 49-year-old man, and both cases were complicated with ureteral stones. We divided 88 ureteral polyps reported in Japan from 1970 to 1990 into polyps in children and those in adults. We further divided the individual polyps into single and multiple polyps and examined them clinically. Characteristic findings were obtained in polyps in children; namely, multiple polyps were dominant, almost all of them occurred at the left upper ureter and no cases were complicated with ureteral stones. Furthermore, many of the multiple polyps in adults occurred at the left upper ureter and few were complicated with stones as in the children. In conclusion, the ureteral polyps in children and multiple ureteral polyps in adults were similar in character and we presumed that some congenital factors might be involved in their occurrence.

Adult↗
PubMed1996

Gastric polyps: relationship of size and histology to cancer risk.

OBJECTIVES: Management of gastric polyps based on polyp size (< or > 2 cm), and histology obtained from forceps biopsy sampling is controversial. To illuminate this subject, the 4-yr experience with endoscopic management of gastric epithelial polyps at a university hospital and a Veterans Administration medical center was reviewed with histopathologic correlation. METHODS: A computer data-base was used to recall the endoscopic diagnosis of "gastric polyp." Endoscopy reports, video, and still photography were reviewed for data on polyp appearance, size, location, and management. These data had been entered prospectively as required by the Computer-Based Management System. Histopathology was reviewed by a second, blinded, pathologist. Gastric polyps of epithelial origin, at least 0.5 cm in diameter, and not associated with polyposis syndromes, were included. RESULTS: Thirty-five gastric polyps in 23 patients met inclusion criteria. Snare polypectomy was ultimately performed on 26, and complete resection with forceps biopsy alone on 9. On histopathology 31 polyps were hyperplastic and 4 were adenomas. Six hyperplastic polyps contained focal dysplasia. Among these, carcinoma in situ was identified in three, all <2.0 cm. Furthermore, forceps biopsy in two of these did not reveal the dysplastic components. One adenomatous polyp also contained carcinoma, also <2.0 cm. CONCLUSIONS: These data emphasize that management based on polyp size or histology obtained from forceps biopsy sampling may be faulty. We recommend that gastric polyps >0.5 cm be removed in toto.

Adenocarcinoma↗
PubMed2006

Video capsule endoscopy compared with standard endoscopy for the evaluation of small-bowel polyps in persons with familial adenomatous polyposis (with video).

BACKGROUND: Video capsule endoscopy (VCE) may be useful for surveillance of small-bowel polyps in patients with familial adenomatous polyposis (FAP). OBJECTIVE: To compare VCE to standard endoscopy for diagnosing small-bowel polyps in a defined segment of small bowel (proximal to a tattoo) and the entire examined small bowel. DESIGN: Prospective. SETTING: Single tertiary referral center. PATIENTS: Participants with FAP (n = 32). The majority were selected for their high number of proximal small-bowel polyps and prior endoscopic tattoo placement in the proximal small bowel. INTERVENTIONS: VCE (interpreted by 2 readers), push enteroscopy (PE), and lower endoscopy (LE) to count and measure small-bowel polyps. RESULTS: In the defined segment, VCE detected a median of 10.0 (interquartile range [IQR], 5.0-19.0) and 9.0 (IQR, 6.0-16.0) polyps for each reader compared with a median of 41.0 (IQR, 19.0-64.0) polyps on PE (P = .002). Agreement between the 2 methods was fair (kappa = 0.34, 0.36). Agreement between VCE and PE was poor to fair (kappa = 0.10, 0.22) for estimating the size of the largest polyp and poor (kappa = -0.20, -0.27) for detecting large polyps (> or =1 cm). In the entire examined small bowel, VCE diagnosed a median of 38.0 (IQR, 10.5-71.5) and 54.0 (IQR, 13.0-100.0) polyps for each reader compared with a median of 123.0 (IQR, 38.5-183.0) for combination endoscopy (PE and LE) (P < .001). Agreement between the 2 methods was fair to moderate (kappa = 0.21, 0.56). LIMITATIONS: Participants selected for high polyp burden, and results may not be applicable to all patients with FAP. CONCLUSIONS: VCE underestimates the number of small-bowel polyps in persons with FAP and does not reliably detect large polyps.

Adenomatous Polyposis Coli↗
PubMed2004

Polyp oriented modelling of coral growth.

The morphogenesis of colonial stony corals is the result of the collective behaviour of many coral polyps depositing coral skeleton on top of the old skeleton on which they live. Yet, models of coral growth often consider the polyps as a single continuous surface. In the present work, the polyps are modelled individually. Each polyp takes up resources, deposits skeleton, buds off new polyps and dies. In this polyp oriented model, spontaneous branching occurs. We argue that branching is caused by a so called "polyp fanning effect" by which polyps on a convex surface have a competitive advantage relative to polyps on a flat or concave surface. The fanning effect generates a more potent branching mechanism than the Laplacian growth mechanism that we have studied previously. We discuss the application of the polyp oriented model to the study of environmentally driven morphological plasticity in stony corals. In a few examples we show how the properties of the individual polyps influence the whole colony morphology. In our model, the spacing of polyps influences the thickness of coral branches and the overall compactness of the colony. Density variations in the coral skeleton may also be important for the whole colony morphology, which we address by studying two variants of the model. Finally, we discuss the importance of small scale resource translocation in the coral colony and its effects on the morphology of the colony.

Animals↗
PubMed2003

CT colonography: does improved z resolution help computer-aided polyp detection?

Multislice helical CT offers several retrospective choices of longitudinal (z) resolution at a given detector collimation setting. We sought to determine the effect of z resolution on the performance of a computer-aided colonic polyp detector, since a human reader and a computer-aided polyp detector may have optimal performances at different z resolutions. We ran a computer-aided polyp detection algorithm on phantom data sets as well as data obtained from a single patient. All data were reconstructed at various slice thicknesses ranging from 1.25 to 10 mm. We studied the performance of the detector at various ranges of polyp sizes using free-response receiver-operating characteristic analyses. We also studied contrast-to-noise ratios (CNR) as a function of slice thickness and polyp size. For the phantom data, reducing the slice thickness from 5 to 1.25 mm improves sensitivity from 84.5% to 98.3% (all polyps), from 61.4% to 95.5% (polyps in the range [0, 5) mm) and from 97.7% to 100% (polyps in the range [5, 10) mm) at a false positive rate of 20 per data set. For polyps larger than 10 mm, there is no significant improvement in detection sensitivity when slice thickness is reduced. CNRs showed expected behavior with slice thickness and polyp size, but in all cases remained high (> 4). The results for the patient data followed similar patterns to that of the phantom case. Thus we conclude that for this detector, the optimal slice thickness is dependent upon the size of the smallest polyps to be detected. For detection of polyps 10 mm and larger, reconstruction of 5 mm sections may be sufficient. Further study is required to generalize these results to a broader population of patients scanned on different scanners.

Colon↗