Iso-osmotic PEG Contrast Agent for CT Bowel Distension

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Solution Overview

Problem

Current contrast agents for CT scans, particularly for abdominal and pelvic imaging, face challenges in adequately distending the small bowel and consistently opacifying the terminal ileum and cecum, leading to limitations in diagnostic quality and increased preparation time, especially in cases of suspected appendicitis.

Innovation Solution

The use of an iso-osmotic contrast agent, such as a polyethylene glycol (PEG) solution with electrolytes, which is administered orally and can be used with or without a positive contrast agent, effectively distends the small bowel and rapidly moves through the gastrointestinal tract, even in the absence of peristalsis, allowing for improved visualization and reduced preparation time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If high-density contrast agents are used to opacify the gastrointestinal tract, then bowel loop delineation is improved, but diagnostic quality deteriorates due to interference with CT angiographic techniques and reduced resolution

Engineering Contradiction:

Improvebowel loop delineationVSAvoiddiagnostic quality

Core Design Contradiction:

Illumination intensityVSMeasurement precision

Solution Approach 1:

The patent changes the density parameter of the contrast agent from high-density (barium sulfate) to low-density (water-based), which eliminates interference with CT angiographic techniques while maintaining bowel loop visualization capability through alternative mechanisms

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite formulations combining water with carbon dioxide gas and/or foam agents to create a contrast medium that provides both low density for CT compatibility and sufficient opacity for bowel delineation through the combined effects of gas bubbles and foam structures

Inventive Principle:

Principle #40Composite materials

2Measurement precision

If water is used as oral contrast agent, then low attenuation is achieved, but small bowel distension is insufficient due to rapid absorption

Engineering Contradiction:

ImproveattenuationVSAvoidsmall bowel distension

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent introduces carbon dioxide gas and/or foam as an intermediary substance that is not rapidly absorbed like water, allowing the small bowel to remain distended for the duration of the examination while maintaining low attenuation properties

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the physical state parameter by incorporating gas bubbles and foam structures into the oral contrast solution, transforming it from a purely liquid rapidly-absorbed substance to a multi-phase formulation that provides sustained distension

Inventive Principle:

Principle #35Parameter changes

3Volume of moving object

If large volumes of contrast agent are administered, then adequate small bowel distension is achieved, but patient comfort deteriorates and preparation time increases

Engineering Contradiction:

Improvesmall bowel distensionVSAvoidpatient comfort

Core Design Contradiction:

Volume of moving objectVSEase of operation

Solution Approach 1:

The patent changes the physical properties of the contrast agent by incorporating carbon dioxide gas and foam, which increase the volumetric expansion capability per unit of administered liquid, allowing adequate distension with smaller total volumes

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent utilizes phase transition from liquid to gas (carbon dioxide) and liquid-to-aerosol (foam formation) to achieve significant volume expansion within the bowel lumen, providing adequate distension with minimal administered fluid volume

Inventive Principle:

Principle #36Phase transitions

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The iso-osmotic PEG solution provides better distension and visualization of the gastrointestinal tract, including the small bowel and colon, reduces preparation time, and consistently opacifies the terminal ileum and cecum, enhancing diagnostic efficiency and patient satisfaction.

Implementation Method 1

the iso-osmotic PEG solution...rapidly moves through the gastrointestinal tract, even in the absence of peristalsis

Methodology Applied

Scientific EffectOsmotic pressure: Osmotic Pressure

Data Source

PatentUS7582283B2Contrast agents to improve gastrointestinal tract opacification during abdominal and pelvic CT scans

Publication Date: 2009.09.01 WISCONSIN ALUMNI RES FOUND

AI summary

Methods of imaging a portion of a body of a patient are provided. In the methods, a contrast agent including an iso-osmotic contrast agent is administered to the patient. In a preferred embodiment, the iso-osmotic contrast agent comprises polyethylene glycol (PEG) and electrolytes, which make the PEG iso-osmotic. In a preferred embodiment, a positive contrast agent, such as an iodine-based contrast agent, is added to the PEG. The iso-osmotic contrast agent can be administered in volumes that are lower than previous contrast agents. The iso-osmotic contrast agent can be administered in combination with a positive intravenous contrast agent. At least one image of the portion of the patient's body is obtained, such as by computed tomography, after the contrast agent is administered. The methods can be used to image a pelvis, GI tract, and/or appendix of the patient. Iso-osmotic contrast agents are also provided.