***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 
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    Input: BACKGROUND It is unclear whether the administration of oral contrast followed by immediate computerised tomographic ( CT ) scanning presents a significant risk of aspiration and whether it is useful in the diagnosis of hollow viscus injury . OBJECTIVE Determine the number of intestinal perforations diagnosed by oral contrast enhanced CT scans for blunt trauma and identify those who developed aspiration pneumonitis causally related to oral contrast administration . METHODS We analysed a data base of consecutive blunt trauma admissions over a 2-year period . The majority received oral contrast immediately prior to CT scanning . We determined the number of intestinal perforations identified by abdominal CT confirmed at laparatomy and the number of cases of aspiration pneumonia . RESULTS Nine ( 1 % ) of the 1173 CT scans  identified enteric perforations .  Oral contrast enhanced CT scans demonstrated pneumoperitoneum ( 3 ) , extraluminal contrast extravasation ( 2 ) , and the presence of free fluid with small bowel wall thickening ( 8) . In this same cohort , eight ( 0.7 % ) cases of aspiration pneumonia were diagnosed within 48 h of admission in patients with a mean GCS of 4.25 ; only one ( 0.1 % ) was temporally related to oral contrast administration . In a prospect i ve study , none of the 65 consecutive patients who received oral contrast had witnessed aspiration . CONCLUSIONS Oral contrast administration given immediately prior to CT scanning does not increase the risk of clinical ly significant aspiration and assists in the detection of enteric perforation HYPOTHESIS Oral contrast solution ( OC ) is unnecessary in the acute computed tomographic ( CT ) evaluation of the patient with blunt abdominal trauma . DESIGN R and omized controlled clinical trial . SETTING Level I trauma center at a university-affiliated teaching hospital . PATIENTS Five hundred adult patients sustaining blunt abdominal trauma and requiring urgent resuscitation and CT evaluation of the abdomen were eligible for the study . Those patients who were younger than 18 years , pregnant , or in police custody were excluded . One hundred six patients were excluded from the analysis ( 15 for inappropriate enrollment , 9 because a CT scan had not been performed , 1 owing to inability to accept a nasogastric tube , and 81 owing to missing or incomplete records ) . Three hundred ninety-four patients with an average age of 36 years , an average Revised Trauma Score of 10 , and an average Glasgow Coma Scale score of 12 are included in the analysis . INTERVENTIONS Patients were r and omized via computer-generated assignment to 1 of 2 groups either receiving OC or not receiving OC ( no OC ) after placement of a nasogastric tube . All patients received intravenous contrast solution and then underwent helical CT scan of the abdomen and pelvis using the GE HiSpeed Advantage CT scanner ( GE Medical Systems , Milwaukee , Wis ) . MAIN OUTCOME MEASURES Abnormal CT results , need for laparotomy , missed gastrointestinal tract and solid organ injuries , nausea , and vomiting . RESULTS There were 199 patients in the OC group and 195 patients in the no OC group .  Vomiting occurred in 12.9 % of patients and the incidence was not different between groups . One hundred five abnormal scans ( 50 OC and 55 no OC ) were obtained and 33 patients with abnormal scans ( 19 OC and 14 no OC ) underwent laparotomy . There was 1 nontherapeutic laparotomy in each group . There was 1 missed small-bowel injury in the OC group ( sensitivity , 86 % ) and no missed small-bowel injuries in the no OC group ( sensitivity , 100 % ) . Six bowel injuries were identified at laparotomy in the OC group . Two of the injuries were perforations without contrast extravasation but with pneumoperitoneum in 1 . Three bowel injuries were identified in the no OC group , none of which were perforations . Seven of the 9 patients with bowel injury at laparotomy had associated intra-abdominal injury . Specificity for solid organ injury was 94 % in the OC group and 57.1 % in the no OC group . Sensitivity for solid organ injury was 84.2 % in the OC group and 88.9 % in the no OC group . The average time to abdominal CT scanning after placement of a nasogastric tube was 39.02+/-18.73 minutes in the no OC group and 45.92+/-24.17 minutes in the OC group ( P= .008 ) . CONCLUSION The addition of OC to the acute CT protocol for the evaluation of the patient with blunt abdominal trauma is unnecessary and delays time to CT scanning Appendicitis is a common pediatric emergency and one of the most common causes for surgical exploration in the pediatric patient .  Imaging has become an essential tool in the evaluation of the child with suspected appendicitis , aim ing to avoid misdiagnosis and to facilitate early surgery , thus decreasing potential morbidity from ruptured appendicitis . The objective of this paper is to compare the luminal diameter of the normal appendix by computed tomography ( CT ) when utilizing the traditionally used high-attenuation oral contrast material ( OCM ) , Gastrografin , and the relatively new neutral agent VoLumen , with the goal of establishing normal appendiceal size parameters for this neutral OCM . Twenty-six cases of VoLumen-enhanced CT studies of the abdomen and pelvis were identified , of which 13 met the inclusion criteria . These were r and omly matched to age control Gastrografin CT examinations .  Appendiceal diameters ( from wall to wall ) were measured in three orthogonal planes and the average of these was recorded . We show that there is no statistical difference between normal appendiceal diameters in patients with a VoLumen-opacified CT versus a Gastrografin-enhanced CT ( p = 0.8 ) being 5.0 ± 1.3 and 5.1 ± 1.5 mm , respectively . Chart review revealed no clinical suspicion of appendicitis prior to imaging or on discharge diagnosis in the patients included in this study . The rate of nonvisualization of the appendix with VoLumen in our study was 31 % , which equals previously published estimates in children . In summary , as VoLumen use increases in the evaluation of abdominal pathology in the ailing child , we provide guidelines to identify the normal appendix when utilizing this oral contrast agent PURPOSE To prospect ively evaluate the performance of an orally administered 0.1 % barium suspension , Volumen , as a bowel-marking agent for multi-detector row computed tomography ( CT ) . MATERIAL S AND METHODS This HIPAA-compliant study was approved by the Institutional Review Board and conformed to the institutional st and ards for research funded by a commercial sponsor . A total of 60 patients ( 33 women , 27 men ; average age , 58.2 years ) who were referred for multi-detector row CT of the pancreas were r and omized into two groups . Prior to examination , group 1 consumed 1200 mL of Volumen over a 30-minute period and group 2 consumed 1200 mL of a solution containing three parts water and one part methylcellulose over a 30-minute period . Results were independently review ed by two radiologists who were unaware of the contrast agent used . The degree of distention and the visualization of mural detail were qualitatively scored on a five-point scale . Differences were evaluated by using the Mann-Whitney test at a confidence level of 95 % . RESULTS There was significantly better distention in the stomach ( P = .013 ) , duodenum ( P = .006 ) , jejunum ( P = .029 ) , and ileum ( P = .014 ) [ corrected ] in group 1 compared with group 2 . Significant distention was also evident by comparing the products of the widest cross-sectional diameters in duodenum ( P = .143 ) , jejunum ( P < .001 ) , and ileum ( P < .001 ) . Group 1 also demonstrated significantly better visualization of mural features in the duodenum ( P = .003 ) , jejunum ( P = .024 ) , and ileum ( P = .01 ) and a trend toward better visualization of mural features in the stomach ( P = .092 ) . CONCLUSION Oral administration of Volumen provided excellent distention and excellent visualization of mural features in the gastrointestinal tract RATIONALE AND OBJECTIVES Because of the increased clinical use of computed tomography ( CT ) for imaging the abdominal vasculature and urinary tract , there is a need for negative contrast agents . The authors undertook this study to assess the suitability of simethicone-coated cellulose ( SCC ) , which is approved for use as an oral contrast agent in sonography , for use as a negative oral contrast agent in abdominal CT . MATERIAL S AND METHODS This prospect i ve study involved 40 adult patients scheduled to undergo abdominal CT for the evaluation of hematuria . Prior to scanning , 20 subjects received 800 mL of SCC and 20 received 800 mL of water as an oral contrast agent . Imaging was performed with a multi-detector row helical scanner in two phases , according to the abdominal CT protocol used for hematuria evaluation at the authors ' institution . The first , " early " phase began an average of 15 minutes after the ingestion of contrast material ; the second , " late " phase began an average of 45 minutes after the ingestion of contrast material . Blinded analysis was performed by three abdominal radiologists separately , using a three-point scale ( 0 = poor , 1 = acceptable , 2 = excellent ) to assess the effectiveness of SCC for marking the proximal , middle , and distal small bowel . Average scores for enhancement with SCC and with water were obtained and compared . Statistical analysis was performed with a Wilcoxon signed-rank test . RESULTS SCC was assigned higher mean scores than water for enhancement in each segment of the bowel , both on early-phase images ( 0.8 - 1.35 for SCC vs 0.6 - 1.1 for water ) and on late-phase images ( 1.1 - 1.4 vs 0.81 - 0.96 ) . Bowel marking with SCC , particularly in the jejunum and ileum , also was rated better than that with water in a high percentage of patients . The differences between the scores for water and for SCC , however , were not statistically significant ( P > .05 ) . CONCLUSION SCC is effective as a negative oral contrast agent for small bowel marking at CT STUDY OBJECTIVE To determine how frequently oral contrast medium ( OC ) is essential for computed tomography ( CT ) diagnosis of blunt intraabdominal injury and to quantify the delay associated with OC administration and the incidence of adverse effects . METHODS This retrospective chart review , with prospect i ve reevaluation of CT scans for diagnostic value of OC , took place in a university teaching hospital and Level l trauma center . Participants were blunt-trauma victims admitted between June 1 , 1988 , and November 1 , 1993 , who had abdominal CT as part of their initial evaluation . Trauma registry records were used to identify study patients . Available charts and CTs were review ed for all patients with intestinal/mesenteric and pancreatic injuries . R and omly selected cases of liver injury , spleen injury , and no intraabdominal injury were also review ed . Blinded CT scans were reevaluated for quality of bowel opacification and value of OC to diagnostic impression . RESULTS During the study period , 2,162 blunt-trauma patients had an abdominal CT ; 297 intraabdominal injuries were diagnosed in 248 patients . Full review was done on 124 charts , and 70 CT scans were reevaluated . Thirty-one ( 100 % ) of 31 liver and spleen injuries were diagnosed on CT , and OC was considered essential in none of these studies . One ( 4.5 % ) of 22 intestinal and mesenteric injuries was seen on CT , but this was the only such injury treated nonoperatively . None of 21 surgically confirmed intestinal/mesenteric injuries was seen on CT . Free air or free OC was seen in none of 7 cases of intestinal perforation . OC was judged essential in none of 20 scans in patients without intraabdominal injury . On 2 scans . OC was considered essential for the radiographic diagnosis . One of these was a normal pancreas at exploration ( radiographic false-positive result ) . The only pancreatic injury requiring specific surgical treatment was missed on CT . Twenty-one percent of patients required placement of nasogastric tube for contrast administration after failing oral administration , and 23 % vomited OC . One of 124 had documented aspiration of OC . Average additional time incurred in the ED for administration of OC was 144 minutes . CONCLUSION OC is rarely essential for CT diagnosis of intraabdominal injury . It may improve sensitivity for pancreatic injury , but it does not help identify injuries requiring surgical treatment . Even with OC , CT is insensitive for intestinal injury . Vomiting and aspiration are significant risks . Use of OC adds a significant amount of time to ED evaluation . Adverse effects of OC administration , in this setting , may outweigh its benefits OBJECTIVE The purpose of our study was to prospect ively compare the cost , effectiveness , and patient tolerance of milk and VoLumen , a 0.1 % barium suspension , in patients undergoing abdominal and pelvic CT with oral and i.v . contrast media . SUBJECTS AND METHODS Two hundred fifteen consecutive out patients were r and omly assigned to receive either whole milk ( n = 115 ) or VoLumen ( n = 
    Output:
    
Conclusions There is no difference in accuracy between CT performed with positive oral contrast agents or with no , neutral or negative oral contrast agent .
Key Points• There is no difference in the accuracy of CT with or without oral contrast agent . •
There is no difference in the accuracy of CT with Gastrografin or water .
•Omission of oral contrast , utilising neutral or negative oral contrast agent saves time , costs and decreases risk of aspiration