Uniformity of Oral Contrast Material in the Bowel

Study Overview
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Brief Summary
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Although positive oral contrast agents are used for the majority of abdominopelvic CT scans in the United States, the quality of bowel opacification has not been compared between the three major classes of positive oral contrast material (barium sulfate, ionic iodinated contrast material, and non-ionic iodinate contrast material). This is a retrospective single institution study of clinical records to show whether the uniformity of bowel opacification is different between the three main types of positive CT oral contrast material used in the United States (Barium sulfate, Diatrizoate, and Iohexol). The investigators will retrospectively identify 250 patients each who received oral barium sulfate, diatrizoate, and iohexol for CT scanning of the abdomen and pelvis (total 750 patients) and assess the quality of bowel lumen opacification by the positive oral contrast agents.

Detailed Description
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Although positive oral contrast agents are used for the majority of abdominopelvic CT scans in the United States, the quality of bowel opacification has not been compared between the three major classes of positive oral contrast material (barium sulfate, ionic iodinated contrast material, and non-ionic iodinate contrast material). The investigators will retrospectively identify 250 patients each who received oral barium sulfate, diatrizoate, and iohexol for CT scanning of the abdomen and pelvis (total 750 patients) and assess the quality of bowel lumen opacification by the positive oral contrast agents. Primary objective: To show the uniformity of bowel opacification is different between the three main types of CT oral contrast material used in the United States (Barium sulfate, Diatrizoate, and Iohexol). Secondary objectives: To show whether or not one of the oral contrast agents provides more uniform opacification than the others in the proximal or distal bowel To assess the relative opacification of the distal small bowel (ileum) by the three contrast agents.

Official Title
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Uniformity of Oral Contrast Material in the Bowel

Conditions
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Known or Suspected Abdominal Disease

Intervention / Treatment
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* Drug: Barium
* Drug: Diatrizoate
* Drug: Iohexol


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: CT scans in which oral contrast material was given Exclusion Criteria: CT scans in which an obvious paucity of oral contrast material is seen, CT scans of patients who had studies within 1 week prior where enteric contrast may have been given, including fluoroscopic, endoscopic, or interventional studies

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Barium<br>Patients who received barium sulfate oral contrast for abdominopelvic CT | Drug: Barium<br>* Administration of barium oral contrast agent prior to CT scan<br>* Other names: Barium sulfate;|
| diatrizoate<br>Patients who received diatrizoate oral contrast for abdominopelvic CT | Drug: Diatrizoate<br>* Administration of diatrizoate oral contrast agent prior to CT scan<br>* Other names: ionic iodinated contrast agent;|
| iohexol<br>Patients who received iohexol oral contrast for abdominopelvic CT | Drug: Iohexol<br>* Administration of iohexol oral contrast agent prior to CT scan<br>* Other names: nonionic iodinated contrast agent;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Participants With Non-uniform Bowel Lumen Opacification at CT Imaging | Nonuniform contrast enhancement of the bowel lumen is a potential diagnostic pitfall at CT imaging since non-uniform enhancement may be distracting to the reader and interfere with accurate diagnosis. Conversely, homogeneously enhancing bowel lumen makes it easier to assess the bowel for potential disease. For each patient's CT scan, the bowel that is seen to be visibly opacified by oral contrast at CT imaging will be assessed as a whole as showing the presence or absence of nonuniform contrast enhancement of the lumen. | within 1 day from administration of oral contrast. The CT scan generally occurs within 3 hours after oral contrast administration, and the CT scan images will be evaluated for the imaging appearance of oral contrast uniformity for this outcome. | 
| Severity of CT Imaging Artifacts Caused by the Oral Contrast Agent | For the segments of bowel visibly opacified by oral contrast, the severity of CT imaging artifacts caused by the oral contrast agent was recorded on the following 3 point scale: 0 = no artifact; 1 = mild artifact without impairment of anatomic delineation; 2 = severe artifact with impairment of anatomic delineation. Lower scores are preferred | within 1 day from administration of oral contrast. The CT scan generally occurs within 3 hours after oral contrast administration, and the CT scan images will be evaluated for the imaging appearance of oral contrast uniformity for this outcome. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Extent of Bowel Opacification of Bowel at CT Imaging | The most distal segment of bowel (stomach, jejunum, ileum, and /or colon) that was opacified by contrast material at the time of CT imaging was recorded | within 1 day from administration of oral contrast. The CT scan generally occurs within 3 hours after oral contrast administration, and the CT scan images will be evaluated for imaging appearance of oral contrast seen in bowel for this outcome. |