Colonic polyp patterns in familial polyposis

The diagnosis of familial polyposis depends on there being more than 100 adenomatous polyps in the large bowel. The polyps are the result of intramucosal microadenomatous growth. The age at which this occurs varies, and in the early stages of polyp development relatively few larger polyps may be seen. The numbers and size of the polyps as seen on double-contrast barium enema were compared with the macroscopic findings on the resected specimens in 27 patients with proven polyposis. Of these patients, 23 (83%) were diagnosed when polyps were first found at sigmoidoscopy. Radiologically the predominant polyp size was more than 5 mm in only four cases, 2-5 mm in 22 (81%), and less than 2 mm in one. Of the 22 with predominately 2-5 mm polyps, eight had significant numbers of nodules smaller than 2 mm and three had considerable numbers of polyps larger than 5 mm. Eleven (41%) were thought to have fewer than 70 polyps. Pathologically the nodular pattern (less than 2 mm) predominated in 11 (41%) and 14 had polyps of 2-5 mm. More than 100 polyps were present in each case, with fewer than 500 polyps in eight. In the 11 patients thought radiologically to have fewer than 70 polyps, the nodular pattern predominated in nine. In the initial stages of polyp growth, the larger polyps are less numerous, and the background nodular pattern is a useful diagnostic feature of familial polyposis.     

Colonic muco-submucosal elongated polyp: diagnosis with endoscopic ultrasound

Colonic muco-submucosal elongated polyp is a new clinical entity first reported in 1998. The purpose of this report is to determine the value of endoscopic ultrasound in the diagnosis of this condition. We reviewed the endosonographic and histological findings of seven colonic muco-submucosal elongated polyps that were removed completely by endoscopic resection or surgery. The lesions appeared as pedunculated submucosal tumours, measuring 1-4 cm in maximal diameter. Endosonographically, all lesions consisted of mucosal and submucosal layers, and microcystic components were found in the submucosal layer. There were no echogenic masses or muscularis propria within the polyps. These endosonographic features corresponded to histological findings of this type of polyp which was covered with normal mucosa and composed of submucosal layer alone. The submucosal layer consisted of oedematous, loose, connective tissue and/or fibrous tissue, accompanied by dilated blood vessels and lymphatics. Endoscopic ultrasound enabled differentiation of colonic muco-submucosal elongated polyp from other submucosal lesions.     

Colonic polyps: complementary role of computer-aided detection in CT colonography

PURPOSE: To apply a computer-aided detection (CAD) algorithm to supine and prone multisection helical computed tomographic (CT) colonographic images to confirm if there is any added benefit provided by CAD over that of standard clinical interpretation. MATERIALS AND METHODS: CT colonography (with patients in both supine and prone positions) was performed with a multisection helical CT scanner in 40 asymptomatic high-risk patients. There were two consecutive series of patients, 20 of whom had at least one polyp 1.0 cm in size or larger and 20 of whom had normal colons at conventional colonoscopy performed the same day. The CT colonographic images were interpreted with an automated CAD algorithm and by two radiologists who were blinded to colonoscopy findings. RESULTS: For 25 polyps at least 1.0 cm in size ("large" polyps), sensitivity for detection by at least one radiologist was 48% (12 of 25). The sensitivity of CAD for detecting large polyps was also 48% (12 of 25), but the CAD algorithm detected four of 13 large polyps that were not detected by either radiologist (31%, 95% two-sided CI: 9, 61), increasing the potential sensitivity to 64% (16 of 25). For polyps identifiable retrospectively, sensitivity of CAD was 67% (12 of 18), and sensitivity of the combination of detection with the CAD algorithm or by at least one radiologist was 89% (16 of 18). There were an average of 11 false-positive detections per patient for CAD. CONCLUSION: In this series of patients in whom radiologists had difficulties detecting polyps (compared with sensitivities of 75%-90% reported in the literature), this CAD algorithm played a complementary role to conventional interpretation of CT colonographic images by detecting a number of large polyps missed by trained observers.     

Manual and automated polyp measurement comparison of CT colonography with optical colonoscopy

RATIONALE AND OBJECTIVES: The purpose of this study was to assess (1) the agreement of two-dimensional (2D) and three-dimensional (3D) manual and automated polyp linear diameter measurements at CT colonography (CTC), with optical colonoscopic equivalents and (2) intraobserver and interobserver agreement of the CTC measurements. MATERIALS AND METHODS: Using the same CTC system, two radiologists independently measured the maximum linear diameter of 44 polyps (reference size 3-15 mm) matched on CTC and optical colonoscopy: manual 2D optimized multiplanar reformatted planes with standard window settings (level 1500 HU, width -200 HU), manual 3D measurement with software calipers and automated 3D measurement with software. After 2 weeks, polyps were measured again. Compatibility of CTC measurement with that of optical colonoscopy and measurement reproducibility was assessed statistically. RESULTS: In the manual measurement, 44 polyps were analyzed and 41 in automated measurement; three polyps could not be extracted. Although the measurement difference was noted for automated, manual 3D, and manual 2D measurements, statistically supported agreement with optical colonoscopic measurement was noted only with manual 2D measurement for both observers. However, 95% limits of agreement were wide for all the measurement methods. When categorized according to the optical colonoscopic measurement, manual 2D, 3D, and automated measurements showed "good" agreement. Although intraobserver and interobserver agreement was good with manual measurement, intraobserver and interobserver agreement was excellent with automated measurement. CONCLUSION: Manual 2D measurements demonstrated trends of better approximation to optical colonoscopy measurements than manual 3D or automated measurements. And automated measurement eliminated intraobserver and interobserver variability. For noninvasive CTC surveillance, manual 2D measurements are expected to measure medium-sized polyps with sufficient agreement with optical colonoscopic measurements and excellent intraobserver and interobserver variability, especially if combined with automated measurement.     

Colonic masses: detection with MR colonography

PURPOSE: To assess magnetic resonance (MR) colonography as a method for detection of colorectal masses, with conventional colonoscopy as the reference standard. MATERIALS AND METHODS: MR colonography was performed in 132 patients referred for colonoscopy because of the possible presence of a mass. After rectal filling with a gadopentetate dimeglumine and water enema, T1-weighted three-dimensional gradient-echo MR studies were acquired with the patient in the prone and supine positions. Water-sensitive single-shot fast spin-echo MR images were also obtained. Surface-rendered virtual endoscopic endoluminal views, orthogonal sections in three planes, and water-sensitive MR images were interactively assessed for presence of colorectal masses by two radiologists. RESULTS: MR colonography was well tolerated without sedation or analgesia. MR image quality was sufficient for diagnosis in 127 (96%) patients. Most small (10-mm) lesions were correctly identified. For these large masses, MR colonography had a sensitivity of 93%, specificity of 99%, positive predictive value of 92%, and negative predictive value of 98% for detection of masses. CONCLUSION: MR colonography is a promising modality for help in detecting colorectal mass lesions larger than 10 mm in diameter.     

Effect of visualization display colour on polyp conspicuity at virtual colonoscopy

AIM: To investigate the effect of different colour three-dimensional (3D) displays on polyp detection at virtual colonoscopy (VC). METHODS: Five VC trained observers were shown "brief flashes" (lasting 0.2s) of 125 3D endoluminal image snap-shots, repeated for each of six display colours (750 images total). One hundred images contained a single polyp (diameter range 5-42mm) and 25 contained no polyp ("normal"). Images were reviewed in random order over five reading sessions, readers recording either normality or presence and location of a polyp. Multilevel logistic regression was used to examine any influence of colour on polyp detection stratified according to polyp size (medium 5-9mm/large >/=10mm). The kappa statistic was used to assess effect of colour on observer agreement. RESULTS: Individual reader polyp detection rates ranged between 75-94%. Compared to the default pink "soft tissue" display, the odds of polyp detection were 0.65 (CI 0.41,1.01) for green, 0.82 (0.53,1.30) for blue, 1 (0.63,1.59) for red, 1.12 (0.7,1.79) for monochrome, and 1.15 for yellow (0.72,1.84). Overall, there was no significant difference between the displays (p=0.11). Including normal cases, there was no overall difference in correct case classification between the six colours (p=0.44). The odds of detecting large versus medium polyps was significantly greater for 3/5 observers; odds ratio (OR) 2.84-10.1, although unaffected by display colour (p=0.3). CONCLUSION: The background colour display generally has a minimal effect on polyp detection at VC, although green should be avoided.     

腹腔镜联合结肠镜微创技术在结直肠息肉治疗中应用价值

目的探讨腹腔镜联合结肠镜微创技术在结直肠息肉治疗中的临床应用价值。方法选取上海市宝山区仁和医院自2014年1月至2016年1月收治的结直肠息肉患者86例,根据随机数表法分为A组和B组,每组各43例患者。A组采用结肠镜切除术进行治疗,B组采用腹腔镜联合结肠镜进行治疗。记录两组患者的总有效率、术中指标、术后恢复情况,并严密观察患者并发症的发生情况。术后6个月随访,观察患者的息肉残留率及复发率。结果 B组患者的总有效率为88.4%(38/43),明显高于A组的60.5%(26/43),两组间比较,差异有统计学意义(P<0.01);B组患者术中出血量及手术时间均显著低于A组,且差异均有统计学意义(P<0.01);与A组相比,B组患者术后恢复情况明显改善(P<0.01);A组患者的并发症发生率、息肉残留率及复发率均显著高于B组,且差异均有统计学意义(P<0.05)。结论腹腔镜联合结肠镜微创技术可以有效地治疗结直肠息肉,改善患者的围术期及术后相关指标,并降低患者并发症的发生率、息肉残留率及复发率,为临床治疗结直肠息肉提供了新的思路。     

Impact of different window settings on colon polyp measurements with CT virtual colonoscopy: a phantom study

The aim of this study was to evaluate the impact of window settings on measurement of colon polyps with CT virtual colonoscopy with experiment. Twenty-four artificial polyps' diameter were measured and scanned 10 times with identical scan parameters using a 64-multidetector computed tomographic scanner. The diameter of each polyp was measured using lung window and abdominal soft tissue window settings and compared with the actual diameter. The lung window setting offers accurate measurement of colon polyps.     

Colorectal polyps: detection with dark-lumen MR colonography versus conventional colonoscopy

PURPOSE: To prospectively compare dark-lumen magnetic resonance (MR) colonography with conventional colonoscopy in the detection of colorectal polyps. MATERIALS AND METHODS: Local ethical committee approval and informed consent were obtained. One hundred consecutive patients (56 men, 44 women; mean age +/- standard deviation, 67.7 years +/- 14.7; range, 25-82 years) who were referred for conventional colonoscopy from January 2003 to January 2004 underwent MR colonography and conventional colonoscopy after standard precolonoscopic bowel cleansing. Colonoscopy was performed immediately after MR colonography. For MR colonography, the colon was filled with approximately 2000 mL of tap water. Imaging was performed with a 1.5-T MR unit with patients in the prone position. A T1-weighted three-dimensional volumetric interpolated breath-hold sequence was performed before and 75 seconds after intravenous administration of 0.2 mmol gadobenate dimeglumine per kilogram of body weight. Results of MR colonography were analyzed on a per-polyp and per-patient basis. Findings at colonoscopy were used as the reference for determining accuracy, sensitivity, specificity, and positive and negative predictive values of MR colonography. RESULTS: Of 100 patients recruited for study, 92 (52 men, 40 women; mean age, 61.5 years +/- 14.5; range, 25-82 years) underwent complete MR and conventional colonoscopy examinations. Forty-three of the 92 patients (47%) had normal findings at conventional colonoscopy. In the other 49 patients (53%), conventional colonoscopy depicted 107 polyps (82 adenomas, 25 hyperplastic polyps) and seven carcinomas. At per-polyp analysis, sensitivity of MR colonography in the detection of adenomatous polyps was 100% for polyps at least 10 mm in diameter and 84.2% for polyps 6-9 mm in diameter. At per-patient analysis, the accuracy of MR colonography was 93.1% (sensitivity, 89%; specificity, 96%) if detection of adenomatous polyps of all sizes was considered. CONCLUSION: Dark-lumen MR colonography is a promising modality with high accuracy for detecting colorectal polyps larger than 5 mm in diameter.     

Virtual colonoscopy: effect of computer-assisted detection (CAD) on radiographer performance

AIM: To investigate the effect of a virtual colonoscopy (VC) computed-assisted detection (CAD) system on polyp detection by trained radiographers. MATERIALS AND METHODS: Four radiographers trained in VC interpretation and utilization of CAD systems read a total of 62 endoscopically validated VC examinations containing 150 polyps (size range 5-50mm) in four sessions, recording any polyps found and the examination interpretation time, first without and then with the addition of CAD as a "second reader". After a temporal separation of 6 weeks to reduce recall bias, VC examinations were re-read using "concurrent reader" CAD. Interpretation times, polyp detection, and number of false-positives were compared between the different reader paradigms using paired t and paired exact tests. RESULTS: Overall, use of "second reader" CAD significantly improved polyp detection by 12% (p<0.001, CI 6%,17%)) from 48 to 60%. There was no significant improvement using CAD as a concurrent reader (p=0.20; difference of 7%, CI -3%, 16%) and no significant overall difference in recorded false-positives with second reader or concurrent CAD paradigms compared with unassisted reading (p=0.25 and 0.65, respectively). The mean interpretation time was 21.7 min for unassisted reading, 29.6 (p<0.001) min for second reader and 19.1 min (p=0.12) for concurrent reading paradigms. CONCLUSION: CAD, when used as a second reader, can significantly improve radiographer reading performance with only a moderate increase in interpretation times.     

Automated polyp detection at CT colonography: feasibility assessment in a human population

PURPOSE: To test the feasibility of and improve a computer algorithm to automatically detect colonic polyps in real human computed tomographic (CT) colonographic data sets. MATERIALS AND METHODS: Twenty patients with known polyps underwent CT colonography in the supine position. CT colonographic data were processed by using a shape-based algorithm that depicts masses that protrude into the lumen. We studied nine shape criteria and three isosurface threshold settings. Results were compared with those of conventional colonoscopy performed the same day. RESULTS: There were 50 polyps (28 were > or =10 mm in size; 12, 5-9 mm; 10, <5 mm). The sensitivity with optimal settings for detecting polyps 10 mm or greater was 64% (18 of 28). Sensitivity improved to 71% (10 of 14) for polyps 10 mm or greater in well-distended colonic segments. Performance decreased for polyps less than 10 mm, poorly distended colonic segments, and other shape algorithms. There was a mean of six false-positive lesion sites per colon. These sites were reduced 39% to 3.5 per colon by sampling CT attenuation at the lesion site and discarding sites having attenuation less than a threshold. CONCLUSION: Automated detection of colonic polyps, especially clinically important large polyps, is feasible. Colonic distention is an important determinant of sensitivity. Further increases in sensitivity may be achieved by adding prone CT colonography.     

Colorectal cancer: role of CT colonography in preoperative evaluation after incomplete colonoscopy

PURPOSE: To evaluate computed tomographic (CT) colonography in patients with clinical suspicion of colorectal cancer and in whom colonoscopy was incomplete. MATERIALS AND METHODS: After incomplete colonoscopy, 34 patients underwent CT colonography before and after intravenous injection of iodinated contrast agent, in supine and prone positions. Twenty patients with no evidence of colon cancer after complete colonoscopy were included as a control group. Sensitivity and specificity of CT colonography were determined for detection of cancers, polyps, and metastases to liver. RESULTS: In 29 patients, surgery revealed 30 colorectal cancers (three synchronous cancers) and two ischemic lesions of the descending colon. Colonoscopy missed 10 colorectal cancers and three synchronous cancers; all were detected with CT colonography. Sensitivity and specificity for detection of colorectal cancer were 56% and 92%, respectively, for incomplete colonoscopy and 100% and 96%, respectively, for CT colonography (P <.01). Sensitivity and specificity of CT colonography in detection of polyps were 86% and 70%, respectively, for diameters of 5 mm or less; 100% and 80%, respectively, for 5-10-mm diameters; and 100% for diameters greater than 10 mm. Spiral CT of the liver revealed four metastases (2-5 cm); sensitivity and specificity were 100% and 43% for nonenhanced scans and 100% for contrast-enhanced scans (P <.01). CONCLUSION: In this selected group of patients, CT colonography provided complete information to properly address surgery of colorectal cancer and treatment of liver metastases.     

Sinochoanal polyp and its variant, the angiomatous polyp: MRI findings

The angiomatous polyp corresponds to the vascular compromised nasochoanal part of a sinochoanal polyp. We describe the MRI characteristics of such lesions in four patients. All patients had an angiomatous polyp, in three cases as part of an antrochoanal polyp, and in one case as part of a sphenochoanal polyp. The unenhanced MR images depicted the typical appearance of a sinochoanal polyp, hypointense on T1-weighted and hyperintense on T2-weighted images. On gadolinium-enhanced MR images, the sinusal part showed little or no peripheral enhancement; however, the nasochoanal part, corresponding to the angiomatous polyp, showed strong enhancement. An angiomatous polyp mimics a hypervascular mass lesion on enhanced MR studies. The anatomic location and association with a sinusal polyp allows the correct diagnosis. Received: 7 September 1999 Revised: 8 June 2000 Accepted: 9 June 2000