Development of a Noninvasive Metric to Measure Small Bowel Sensation - The Small Intestine Stress Test

Healthy adult volunteers will receive all three mannitol solution osmolarities-76 milliosmol (mOsm/L), 189 mOsm/L, and 325 mOsm/L-on three separate testing occasions spaced at least 5 days apart. Each solution will be administered orally as 500 mL radiolabeled with Pentetate Indium Disodium In-111 (111Indium-DTPA).

Participants will ingest 500 mL of mannitol solution at 76 mOsm/L radiolabeled with 111Indium-DTPA during one testing visit.

Participants will ingest 500 mL of mannitol solution at 189 mOsm/L radiolabeled with 111Indium-DTPA during one testing visit.

Participants will ingest 500 mL of mannitol solution at 325 mOsm/L radiolabeled with 111Indium-DTPA during one testing visit.

Scintigraphy will be used to track gastric emptying, small bowel transit, and colonic filling of the radiolabeled mannitol solution during each testing visit.

Peak gastrointestinal symptom severity will be assessed using a 7-point Likert symptom scale after ingestion of radiolabeled mannitol solution. Symptoms assessed include abdominal pain or discomfort, nausea, bloating, distension, borborygmi, diarrhea, urgency, and related gastrointestinal symptoms. The peak symptom score observed during the small bowel phase will be identified. The small bowel phase is defined as the period during which scintigraphy confirms radiolabeled solution in the small bowel and before more than 25% of tracer has reached the ascending colon. Scores range from 1 to 7, with higher scores indicating greater symptom severity.

Peak gastrointestinal symptom severity will be assessed using a 7-point Likert symptom scale after ingestion of radiolabeled mannitol solution. Symptoms assessed include abdominal pain or discomfort, nausea, bloating, distension, borborygmi, diarrhea, urgency, and related gastrointestinal symptoms. The peak symptom score observed during the small bowel phase will be identified. The small bowel phase is defined as the period during which scintigraphy confirms radiolabeled solution in the small bowel and before more than 25% of tracer has reached the ascending colon. Scores range from 1 to 7, with higher scores indicating greater symptom severity.

Peak gastrointestinal symptom severity will be assessed using a 7-point Likert symptom scale after ingestion of radiolabeled mannitol solution. Symptoms assessed include abdominal pain or discomfort, nausea, bloating, distension, borborygmi, diarrhea, urgency, and related gastrointestinal symptoms. The peak symptom score observed during the small bowel phase will be identified. The small bowel phase is defined as the period during which scintigraphy confirms radiolabeled solution in the small bowel and before more than 25% of tracer has reached the ascending colon. Scores range from 1 to 7, with higher scores indicating greater symptom severity.

Peak abdominal pain intensity will be assessed after ingestion of 500 mL radiolabeled 76 mOsm/L mannitol solution using the Kohn Reactivity Scale. The peak pain intensity score observed during the small bowel phase will be identified. The small bowel phase is defined as the period during which scintigraphy confirms radiolabeled solution in the small bowel and before more than 25% of tracer has reached the ascending colon. The total score ranges from 24 to 120. Higher scores indicate greater pain intensity

Peak abdominal pain intensity will be assessed after ingestion of 500 mL radiolabeled 189 mOsm/L mannitol solution using the Kohn Reactivity Scale. The peak pain intensity score observed during the small bowel phase will be identified. The small bowel phase is defined as the period during which scintigraphy confirms radiolabeled solution in the small bowel and before more than 25% of tracer has reached the ascending colon. The total score ranges from 24 to 120. Higher scores indicate greater pain intensity

Peak abdominal pain intensity will be assessed after ingestion of 500 mL radiolabeled 325 mOsm/L mannitol solution using the Kohn Reactivity Scale. The peak pain intensity score observed during the small bowel phase will be identified. The small bowel phase is defined as the period during which scintigraphy confirms radiolabeled solution in the small bowel and before more than 25% of tracer has reached the ascending colon. The total score ranges from 24 to 120. Higher scores indicate greater pain intensity

Peak abdominal pain unpleasantness will be assessed after ingestion of 500 mL radiolabeled 76 mOsm/L mannitol solution using the Kohn Reactivity Scale. The peak pain unpleasantness score observed during the small bowel phase will be identified. The small bowel phase is defined as the period during which scintigraphy confirms radiolabeled solution in the small bowel and before more than 25% of tracer has reached the ascending colon. The total score ranges from 24 to 120. Higher scores indicate greater levels of pain unpleasantness.

Peak abdominal pain unpleasantness will be assessed after ingestion of 500 mL radiolabeled 189 mOsm/L mannitol solution using the Kohn Reactivity Scale. The peak pain unpleasantness score observed during the small bowel phase will be identified. The small bowel phase is defined as the period during which scintigraphy confirms radiolabeled solution in the small bowel and before more than 25% of tracer has reached the ascending colon. The total score ranges from 24 to 120. Higher scores indicate greater levels of pain unpleasantness.

Peak abdominal pain unpleasantness will be assessed after ingestion of 500 mL radiolabeled 325 mOsm/L mannitol solution using the Kohn Reactivity Scale. The peak pain unpleasantness score observed during the small bowel phase will be identified. The small bowel phase is defined as the period during which scintigraphy confirms radiolabeled solution in the small bowel and before more than 25% of tracer has reached the ascending colon. The total score ranges from 24 to 120. Higher scores indicate greater levels of pain unpleasantness.

Gastrointestinal symptom severity will be assessed after ingestion of 500 mL radiolabeled 76 mOsm/L mannitol solution using a modified Gastric Symptom Severity Scale. Symptoms assessed include abdominal pain or discomfort, nausea, bloating, distension, borborygmi, diarrhea, loose stools, urgency, and related gastrointestinal symptoms. Scores range from 1 to 7, with higher scores indicating greater symptom severity.

Gastrointestinal symptom severity will be assessed after ingestion of 500 mL radiolabeled 189 mOsm/L mannitol solution using a modified Gastric Symptom Severity Scale. Symptoms assessed include abdominal pain or discomfort, nausea, bloating, distension, borborygmi, diarrhea, loose stools, urgency, and related gastrointestinal symptoms. Scores range from 1 to 7, with higher scores indicating greater symptom severity.

Gastrointestinal symptom severity will be assessed after ingestion of 500 mL radiolabeled 325 mOsm/L mannitol solution using a modified Gastric Symptom Severity Scale. Symptoms assessed include abdominal pain or discomfort, nausea, bloating, distension, borborygmi, diarrhea, loose stools, urgency, and related gastrointestinal symptoms. Scores range from 1 to 7, with higher scores indicating greater symptom severity.