human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Barium enema and colonoscopy are commonly used for the investigation of suspected colonic cancer . These techniques are relatively invasive and both the investigation and the preceding bowel preparation are dem and ing , particularly in the elderly . A prospect i ve , blinded trial was conducted to compare ultrasound ( US ) and CT with colonoscopy . CT and colonoscopy were performed on 50 patients with symptoms suggesting colonic cancer . Both radiological investigations were performed prior to the bowel preparation for colonoscopy . US was performed without any preparation and oral contrast medium was the only preparation used for CT . Colonoscopy detected six cancers , all of which were diagnosed by both US and CT . In addition , US and CT diagnosed a further cancer not seen on colonoscopy due to an incomplete study . US had a sensitivity and specificity of 100 % and CT a sensitivity of 100 % and a specificity of 84 % . US and CT were poor at diagnosing polyps . If the detection of polyps greater than 2 cm is included then US sensitivity falls to 67 % and CT sensitivity falls to 89 % and specificity rises to 88 % . In conclusion , both US and CT are possible alternatives to colonoscopy in the investigation of symptomatic patients with suspected colonic cancer . The use of these techniques could markedly reduce the need for colonoscopy  in this patient population with attendant cost savings . Non-invasive imaging has particular advantages in the elderly who cope poorly with both the bowel preparation and the procedure Colorectal cancer is the second-leading cause of cancer death . New noninvasive options for screening capable of diagnosing cancer at an early stage are needed to improve compliance and reduce mortality . This study was design ed to provide an estimate of the sensitivity and specificity of a multitarget assay panel ( MTAP ) of stool DNA changes .  Eighty patients with advanced colorectal neoplasia and 212 control subjects provided stool sample s before colonoscopy . Patients with hereditary colorectal cancer syndromes were excluded . The MTAP included 21 specific mutations in the adenomatous polyposis coli ( APC ) , p53 , and K-ras genes , a microsatellite instability marker ( BAT-26 ) , and a marker of abnormal apoptosis ( DNA Integrity Assay ) . All sample s were analyzed in the clinical laboratory at EXACT Sciences . Multitarget assay panel detected 33 of 52 patients ( 63.5 % , 95 % confidence interval [ CI ] , 49.0%-76.4 % ) with invasive colorectal cancer , including 26 of 36 ( 72.2 % ) with node-negative disease ( American Joint Committee on Cancer [ AJCC ] stage I/II ) and 7 of 16 ( 43.7 % ) with advanced disease ( AJCC stage III/IV ) . Sixteen of 28 patients ( 57.1 % ; 95 % CI , 37.2%-75.5 % ) with advanced adenomas ( lesions containing high- grade dysplasia , villous adenomas , or tubular adenomas > 1 cm in size ) were detected , including 6 of 7 ( 85.7 % ) with high- grade dysplasia and 10 of 21 ( 47.6 % ) with other advanced adenomas . Specificity was 96.2 % ( 95 % CI , 92.7%-98.4 % ) in patients with either no colorectal lesions or diminutive polyps . Multitarget assay panel has better sensitivity than that reported with use of Hemoccult(R ) II in fecal occult blood testing , with similar specificity . Sensitivity appeared to be equally high for patients with node-negative and advanced disease , as well as for advanced adenomas . This study contained a disproportionately high number of distal cancers and , as such , may not be representative of results in proximal lesions . Although a prospect i ve study in an average-risk population is needed to vali date these findings , MTAP may offer an important noninvasive option for population -based screening BACKGROUND Virtual colonoscopy is a new method of imaging the colon in which thin-section , helical computed tomography ( CT ) is used to generate high-resolution , two-dimensional axial images . Three-dimensional images of the colon simulating those obtained with conventional colonoscopy are then reconstructed off-line . We compared the performance of virtual and conventional colonoscopy for the detection of colorectal polyps . METHODS We prospect ively studied 100 patients at high risk for colorectal neoplasia ( 60 men and 40 women ; mean age , 62 years ) . We performed virtual colonoscopy immediately before conventional colonoscopy . We inserted a rectal tube and insufflated the colon with air to the maximal level that the patient could tolerate . We administered 1 mg of glucagon intravenously immediately before CT scanning to minimize the degree of smooth-muscle spasm and peristalsis and to reduce the patient 's discomfort . RESULTS The entire colon was clearly seen by virtual colonoscopy in 87 patients and by conventional colonoscopy in 89 . Fifty-one patients had normal findings on conventional colonoscopy .  In the other 49 , we identified a total of 115 polyps and 3 carcinomas . Virtual colonoscopy identified all 3 cancers , 20 of 22 polyps that were 10 mm or more in diameter ( 91 percent ) , 33 of 40 that were 6 to 9 mm ( 82 percent ) , and 29 of 53 that were 5 mm or smaller ( 55 percent ) . There were 19 false positive findings of polyps and no false positive findings of cancer . Of the 69 adenomatous polyps , 46 of the 51 that were 6 mm or more in diameter ( 90 percent ) and 12 of the 18 that were 5 mm or smaller ( 67 percent ) were correctly identified by virtual colonoscopy . Although discomfort was not specifically recorded , none of the patients requested that virtual colonoscopy be stopped because of discomfort or pain . CONCLUSIONS In a group of patients at high risk for colorectal neoplasia , virtual and conventional colonoscopy had similar efficacy for the detection of polyps that were 6 mm or more in diameter AIM To evaluate prospect ively the usefulness of ultrasound in determining the site and cause of distal small bowel and colonic obstruction . MATERIAL S AND METHODS Ultrasound findings in 60 consecutive patients with suspected distal ileal or colonic obstruction were correlated with final surgical and radiological diagnoses . The diagnostic value of ultrasound was compared with plain abdominal radiography ( AXR ) for the presence and level of obstruction . RESULTS Forty-five patients were confirmed to be obstructed .  Ultrasound  correctly identified obstruction in 44/45 and the cause in 36/45 ( 80 % ) . Overall sensitivity of US for obstruction was 98 % and specificity 80 % , compared with 79 % and 53 % respectively for the AXR . CONCLUSION Ultrasound is useful in determining the presence and cause of distal ileal and colonic obstruction BACKGROUND Although fecal occult-blood testing is the only available noninvasive screening method that reduces the risk of death from colorectal cancer , it has limited sensitivity . We compared an approach that identifies abnormal DNA in stool sample s with the Hemoccult II fecal occult-blood test in average-risk , asymptomatic persons 50 years of age or older . METHODS Eligible subjects su bmi tted one stool specimen for DNA analysis  , underwent st and ard Hemoccult II testing , and then underwent colonoscopy . Of 5486 subjects enrolled , 4404 completed all aspects of the study . A subgroup of 2507 subjects was analyzed , including all those with a diagnosis of invasive adenocarcinoma or advanced adenoma plus r and omly chosen subjects with no polyps or minor polyps . The fecal DNA panel consisted of 21 mutations . RESULTS The fecal DNA panel detected 16 of 31 invasive cancers , whereas Hemoccult II identified 4 of 31 ( 51.6 percent vs. 12.9 percent , P=0.003 ) . The DNA panel detected 29 of 71 invasive cancers plus adenomas with high- grade dysplasia , whereas Hemoccult II identified 10 of 71 ( 40.8 percent vs. 14.1 percent , P<0.001 ) . Among 418 subjects with advanced neoplasia ( defined as a tubular adenoma at least 1 cm in diameter , a polyp with a villous histologic appearance , a polyp with high- grade dysplasia , or cancer ) , the DNA panel was positive in 76 ( 18.2 percent ) , whereas Hemoccult II was positive in 45 ( 10.8 percent ) . Specificity in subjects with negative findings on colonoscopy was 94.4 percent for the fecal DNA panel and 95.2 percent for Hemoccult II . CONCLUSIONS Although the majority of neoplastic lesions identified by colonoscopy were not detected by either noninvasive test , the multitarget analysis of fecal DNA detected a greater proportion of important colorectal neoplasia than did Hemoccult II without compromising specificity BACKGROUND Ultrasonic examination has become increasingly important in the diagnosis of diseases of the gastrointestinal tract . In neoplastic diseases of the large intestine , however , the diagnostic value of conventional transabdominal sonography is limited . The purpose of this investigation was to determine whether the evaluation and staging of colonic tumors would be improved by the retro grade instillation of water into the colon in a procedure called hydrocolonic sonography . METHODS Three hundred patients were examined in a prospect i ve study in which both conventional transabdominal sonography and transabdominal hydrocolonic sonography were performed before the diagnosis was verified by colonoscopy . The indication for the examinations was abdominal pain , diarrhea , weight loss , or the presence of occult blood in a stool specimen . RESULTS With the instillation of water into the colon , it was possible to display the colon sonographically from the rectosigmoid transition to the cecum in 97 percent of the patients examined . In addition to permitting the evaluation of the colonic lumen , the procedure allowed the five layers of the colonic wall and the connective tissue surrounding the colon to be examined in detail . Only 9 of 29 carcinomas were diagnosed by conventional abdominal sonography ( 31 percent ) , whereas hydrocolonic sonography permitted the diagnosis of 28 ( 97 percent ) . No polyps could be detected by conventional abdominal sonography , whereas hydrocolonic sonography permitted the diagnosis of 38 of 42 polyps greater than or equal to 7 mm ( 91 percent ) and 3 of 12 polyps less than 7 mm ( 25 percent ) . In addition , detailed evaluation of the structure of the bowel wall with hydrocolonic sonography permitted a more precise staging of colonic tumors . CONCLUSIONS Hydrocolonic sonography , a new diagnostic procedure , can facilitate the diagnosis and staging of colonic tumors 
    Output:
    
agent
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Barium enema and colonoscopy are commonly used for the investigation of suspected colonic cancer . These techniques are relatively invasive and both the investigation and the preceding bowel preparation are dem and ing , particularly in the elderly . A prospect i ve , blinded trial was conducted to compare ultrasound ( US ) and CT with colonoscopy . CT and colonoscopy were performed on 50 patients with symptoms suggesting colonic cancer . Both radiological investigations were performed prior to the bowel preparation for colonoscopy . US was performed without any preparation and oral contrast medium was the only preparation used for CT . Colonoscopy detected six cancers , all of which were diagnosed by both US and CT . In addition , US and CT diagnosed a further cancer not seen on colonoscopy due to an incomplete study . US had a sensitivity and specificity of 100 % and CT a sensitivity of 100 % and a specificity of 84 % . US and CT were poor at diagnosing polyps . If the detection of polyps greater than 2 cm is included then US sensitivity falls to 67 % and CT sensitivity falls to 89 % and specificity rises to 88 % . In conclusion , both US and CT are possible alternatives to colonoscopy in the investigation of symptomatic patients with suspected colonic cancer . The use of these techniques could markedly reduce the need for colonoscopy  in this patient population with attendant cost savings . Non-invasive imaging has particular advantages in the elderly who cope poorly with both the bowel preparation and the procedure Colorectal cancer is the second-leading cause of cancer death . New noninvasive options for screening capable of diagnosing cancer at an early stage are needed to improve compliance and reduce mortality . This study was design ed to provide an estimate of the sensitivity and specificity of a multitarget assay panel ( MTAP ) of stool DNA changes .  Eighty patients with advanced colorectal neoplasia and 212 control subjects provided stool sample s before colonoscopy . Patients with hereditary colorectal cancer syndromes were excluded . The MTAP included 21 specific mutations in the adenomatous polyposis coli ( APC ) , p53 , and K-ras genes , a microsatellite instability marker ( BAT-26 ) , and a marker of abnormal apoptosis ( DNA Integrity Assay ) . All sample s were analyzed in the clinical laboratory at EXACT Sciences . Multitarget assay panel detected 33 of 52 patients ( 63.5 % , 95 % confidence interval [ CI ] , 49.0%-76.4 % ) with invasive colorectal cancer , including 26 of 36 ( 72.2 % ) with node-negative disease ( American Joint Committee on Cancer [ AJCC ] stage I/II ) and 7 of 16 ( 43.7 % ) with advanced disease ( AJCC stage III/IV ) . Sixteen of 28 patients ( 57.1 % ; 95 % CI , 37.2%-75.5 % ) with advanced adenomas ( lesions containing high- grade dysplasia , villous adenomas , or tubular adenomas > 1 cm in size ) were detected , including 6 of 7 ( 85.7 % ) with high- grade dysplasia and 10 of 21 ( 47.6 % ) with other advanced adenomas . Specificity was 96.2 % ( 95 % CI , 92.7%-98.4 % ) in patients with either no colorectal lesions or diminutive polyps . Multitarget assay panel has better sensitivity than that reported with use of Hemoccult(R ) II in fecal occult blood testing , with similar specificity . Sensitivity appeared to be equally high for patients with node-negative and advanced disease , as well as for advanced adenomas . This study contained a disproportionately high number of distal cancers and , as such , may not be representative of results in proximal lesions . Although a prospect i ve study in an average-risk population is needed to vali date these findings , MTAP may offer an important noninvasive option for population -based screening BACKGROUND Virtual colonoscopy is a new method of imaging the colon in which thin-section , helical computed tomography ( CT ) is used to generate high-resolution , two-dimensional axial images . Three-dimensional images of the colon simulating those obtained with conventional colonoscopy are then reconstructed off-line . We compared the performance of virtual and conventional colonoscopy for the detection of colorectal polyps . METHODS We prospect ively studied 100 patients at high risk for colorectal neoplasia ( 60 men and 40 women ; mean age , 62 years ) . We performed virtual colonoscopy immediately before conventional colonoscopy . We inserted a rectal tube and insufflated the colon with air to the maximal level that the patient could tolerate . We administered 1 mg of glucagon intravenously immediately before CT scanning to minimize the degree of smooth-muscle spasm and peristalsis and to reduce the patient 's discomfort . RESULTS The entire colon was clearly seen by virtual colonoscopy in 87 patients and by conventional colonoscopy in 89 . Fifty-one patients had normal findings on conventional colonoscopy .  In the other 49 , we identified a total of 115 polyps and 3 carcinomas . Virtual colonoscopy identified all 3 cancers , 20 of 22 polyps that were 10 mm or more in diameter ( 91 percent ) , 33 of 40 that were 6 to 9 mm ( 82 percent ) , and 29 of 53 that were 5 mm or smaller ( 55 percent ) . There were 19 false positive findings of polyps and no false positive findings of cancer . Of the 69 adenomatous polyps , 46 of the 51 that were 6 mm or more in diameter ( 90 percent ) and 12 of the 18 that were 5 mm or smaller ( 67 percent ) were correctly identified by virtual colonoscopy . Although discomfort was not specifically recorded , none of the patients requested that virtual colonoscopy be stopped because of discomfort or pain . CONCLUSIONS In a group of patients at high risk for colorectal neoplasia , virtual and conventional colonoscopy had similar efficacy for the detection of polyps that were 6 mm or more in diameter AIM To evaluate prospect ively the usefulness of ultrasound in determining the site and cause of distal small bowel and colonic obstruction . MATERIAL S AND METHODS Ultrasound findings in 60 consecutive patients with suspected distal ileal or colonic obstruction were correlated with final surgical and radiological diagnoses . The diagnostic value of ultrasound was compared with plain abdominal radiography ( AXR ) for the presence and level of obstruction . RESULTS Forty-five patients were confirmed to be obstructed .  Ultrasound  correctly identified obstruction in 44/45 and the cause in 36/45 ( 80 % ) . Overall sensitivity of US for obstruction was 98 % and specificity 80 % , compared with 79 % and 53 % respectively for the AXR . CONCLUSION Ultrasound is useful in determining the presence and cause of distal ileal and colonic obstruction BACKGROUND Although fecal occult-blood testing is the only available noninvasive screening method that reduces the risk of death from colorectal cancer , it has limited sensitivity . We compared an approach that identifies abnormal DNA in stool sample s with the Hemoccult II fecal occult-blood test in average-risk , asymptomatic persons 50 years of age or older . METHODS Eligible subjects su bmi tted one stool specimen for DNA analysis  , underwent st and ard Hemoccult II testing , and then underwent colonoscopy . Of 5486 subjects enrolled , 4404 completed all aspects of the study . A subgroup of 2507 subjects was analyzed , including all those with a diagnosis of invasive adenocarcinoma or advanced adenoma plus r and omly chosen subjects with no polyps or minor polyps . The fecal DNA panel consisted of 21 mutations . RESULTS The fecal DNA panel detected 16 of 31 invasive cancers , whereas Hemoccult II identified 4 of 31 ( 51.6 percent vs. 12.9 percent , P=0.003 ) . The DNA panel detected 29 of 71 invasive cancers plus adenomas with high- grade dysplasia , whereas Hemoccult II identified 10 of 71 ( 40.8 percent vs. 14.1 percent , P<0.001 ) . Among 418 subjects with advanced neoplasia ( defined as a tubular adenoma at least 1 cm in diameter , a polyp with a villous histologic appearance , a polyp with high- grade dysplasia , or cancer ) , the DNA panel was positive in 76 ( 18.2 percent ) , whereas Hemoccult II was positive in 45 ( 10.8 percent ) . Specificity in subjects with negative findings on colonoscopy was 94.4 percent for the fecal DNA panel and 95.2 percent for Hemoccult II . CONCLUSIONS Although the majority of neoplastic lesions identified by colonoscopy were not detected by either noninvasive test , the multitarget analysis of fecal DNA detected a greater proportion of important colorectal neoplasia than did Hemoccult II without compromising specificity BACKGROUND Ultrasonic examination has become increasingly important in the diagnosis of diseases of the gastrointestinal tract . In neoplastic diseases of the large intestine , however , the diagnostic value of conventional transabdominal sonography is limited . The purpose of this investigation was to determine whether the evaluation and staging of colonic tumors would be improved by the retro grade instillation of water into the colon in a procedure called hydrocolonic sonography . METHODS Three hundred patients were examined in a prospect i ve study in which both conventional transabdominal sonography and transabdominal hydrocolonic sonography were performed before the diagnosis was verified by colonoscopy . The indication for the examinations was abdominal pain , diarrhea , weight loss , or the presence of occult blood in a stool specimen . RESULTS With the instillation of water into the colon , it was possible to display the colon sonographically from the rectosigmoid transition to the cecum in 97 percent of the patients examined . In addition to permitting the evaluation of the colonic lumen , the procedure allowed the five layers of the colonic wall and the connective tissue surrounding the colon to be examined in detail . Only 9 of 29 carcinomas were diagnosed by conventional abdominal sonography ( 31 percent ) , whereas hydrocolonic sonography permitted the diagnosis of 28 ( 97 percent ) . No polyps could be detected by conventional abdominal sonography , whereas hydrocolonic sonography permitted the diagnosis of 38 of 42 polyps greater than or equal to 7 mm ( 91 percent ) and 3 of 12 polyps less than 7 mm ( 25 percent ) . In addition , detailed evaluation of the structure of the bowel wall with hydrocolonic sonography permitted a more precise staging of colonic tumors . CONCLUSIONS Hydrocolonic sonography , a new diagnostic procedure , can facilitate the diagnosis and staging of colonic tumors 
    Output:
    