Ingestible Contrast Agents for Gastrointestinal Imaging

Abstract

Gastrointestinal (GI) ailments cover a wide variety of diseases involving the esophagus, stomach, small intestine, large intestine, and rectum. They bring about many inconveniences in daily life in chronic diseases and can even be life threatening in acute cases. Rapid and safe detection approaches are essential for early diagnosis and timely management. Contrast agents for GI imaging can enhance contrast to distinguish abnormal lesions from normal structures. Computed tomography and magnetic resonance imaging are two important diagnostic tools for the evaluation of GI conditions. This review mainly involves several common GI diseases, including inflammatory diseases, intestinal tumors, diarrhea, constipation, and gastroesophageal reflux diseases. Selected contrast agents, such as barium sulfate, iodine‐based agents, gadolinium‐based agents, and others, are summarized. Going forward, continued endeavors are being made to develop more emerging contrast agents for other imaging modalities.

Selection of dilution material for non-iodinated iodine as an oral contrast agent for esophageal cancer: a preliminary clinical trial

“…Filling the esophagus with a contrast agent is conducive to the correct T staging and can provide more valuable imaging signs [ 16 ]. The currently used esophageal contrast agents, including positive contrast agents and negative contrast agents, must meet the following conditions: (1) can fill the esophagus; (2) have good contrast; (3) not easy to produce artifacts caused by excessive density differences; (4) low price and convenient source; and (5) good taste, harmless to the human body, and good tolerance [ 19 , 20 ].…”

Hitchhiking probiotic vectors to deliver ultra-small hafnia nanoparticles for ‘Color’ gastrointestinal tract photon counting X-ray imaging

“…1,2 Intravenously administered positive contrast agents have an X-ray attenuation greater than that of water. 3 Although these agents are generally well-tolerated and effective in producing good…”

“…31 For instance, in the omnipresent clinical method known as barium meal, the patient must ingest 100 ml of barium sulphate after 6-8 h of fasting while there are reports about unknown median lethal dose for this compound and potential false positive results. 3,32 Spectral CT is an emerging technique where information is derived from photon-counting detectors that distinguish photon energies of individual photons. [33][34][35] The detected X-rays are divided into several energy windows to discriminate multiple materials based on their unique k-edge energies (Fig.…”

“…1,2 Intravenously administered positive contrast agents have an X-ray attenuation greater than that of water. 3 Although these agents are generally well-tolerated and effective in producing good gastric distention, the delineation of the GI tract and stomach is not optimal. Contrast agents administered by the oral route is the most convenient due to high patient compliance, less sterility limitations and the ease of scale up.…”

“…31 For instance, in the omnipresent clinical method known as barium meal, the patient must ingest 100 ml of barium sulphate after 6–8 h of fasting while there are reports about unknown median lethal dose for this compound and potential false positive results. 3,32…”