Common Procedures and Imaging Studies

Gastroenterologists utilize multiple and distinct imaging techniques and procedures to aid in the diagnosis and management of pediatric gastrointestinal (GI) diseases. Detailed below are several of the most commonly used imaging techniques and procedures employed in pediatric gastroenterology.

Imaging Studies

Modified barium swallow (MBS) or video fluoroscopic swallowing exam (VFSE) is a fluorographic study that aids in the evaluation of deglutition, the act of swallowing. Pediatric patients with a history of coughing or choking with feeds, recurrent aspiration pneumonias, questionable aspiration, progressive swallowing discoordination, dysphagia (difficulty swallowing), or those with a condition strongly associated with swallowing dysfunction are candidates for MBS. During an MBS, the patient is fed liquids and/or solids mixed with barium sulfate, a powdered radiopaque compound. Via fluoroscopy, a speech and language pathologist along with a radiologist can then view a patient’s swallowing in real time. Multiple repeated swallows are typically evaluated from a lateral view. MBS may uncover laryngeal penetration, whereby food or liquid (including saliva) enters the laryngeal vestibule above the true vocal cords, or true aspiration, whereby food or liquid travels below the level of the true vocal cords into the trachea. The child’s response to liquids of different viscosity can also be evaluated to determine if some viscosities are safer for oral feeding in a patient with aspiration.

View an example of a normal MBS performed on an adult patient swallowing a liquid mixed with barium.

Esophagram is a fluorographic study that evaluates the contour and shape of a patient’s esophagus. Esophagrams may be helpful in evaluating patients with dysphagia or odynophagia (painful swallowing) and may be used to confirm esophageal impaction in patients with suspected foreign-body ingestion. During an esophagram, a patient swallows liquid contrast while images are taken of the esophagus as the contrast moves distally, revealing areas of stenosis, stricture, ulceration, perforation, fistula, or obstruction/impaction. Peristaltic contractions of the esophagus may also be seen.

View an example of a fluoroscopic image from an abnormal esophagram revealing achalasia in an adult patient.

Upper gastrointestinal (UGI) series is a fluorographic study used primarily to characterize the anatomy of the esophagus, stomach, and duodenum. A UGI series may be useful in the evaluation of structural or functional abnormalities including hiatal hernia, intestinal malrotation, gastric outlet obstruction, superior mesenteric artery (SMA) syndrome, ulcers, masses, or bezoars. For this study, a patient drinks a liquid contrast solution containing barium while the radiologist tracks the movement of the contrast through the use of fluoroscopy typically to the ligament of Treitz. If the contrast is followed further into the small intestine, to the jejunum and ileum, the study is considered a UGI series with small-bowel follow-through. A follow-through study may be helpful in identifying patulous regions of the small intestine and those regions affected by inflammation from conditions such as Crohn disease.

Rectal contrast study or barium enema is a fluoroscopic study that provides structural imaging information of colonic, rectal, and terminal ileal conditions such as Hirschsprung disease, meconium ileus, and neonatal small-left-colon syndrome. During the study, a barium or similar contrast-containing solution is introduced into the rectum using a thin tube, and sequential images are obtained as the rectum and colon are filled with contrast. The contrast may be followed to the terminal ileum to assist in the diagnosis of small-intestinal disorders such as distal intestinal obstruction syndrome (DIOS) seen in patients with cystic fibrosis. Rectal contrast studies may be therapeutic as well as diagnostic, such as when air is introduced into the colon instead of barium contrast in the treatment of intussusception.

View an example of a water-soluble rectal contrast study in a full-term infant with cystic fibrosis, showing microcolon and multiple filling defects throughout the colon and distal ileum (panel B), radiographic findings in line with a diagnosis of meconium ileus.

Gastric emptying study is a nuclear-medicine-based evaluation of the stomach’s gastric motor function and ability to empty after consumption of either a liquid or a solid meal. Gastric emptying studies are primarily used in the evaluation of pediatric patients with suspected gastroparesis. After a period of fasting, patients are fed a standardized volume of either a liquid or solid meal (usually toast with scrambled eggs) labeled with a technetium-99m sulfur colloid that can be detected and quantified using gamma camera imaging. After the labeled food is ingested, images of the stomach are then taken at regular intervals, and the technetium-99m detected at each interval is quantified and compared to established standards. Though no established standards exist for gastric emptying times in pediatric patients, adult-based standards have been achieved through consensus and have gained acceptance in the evaluation of gastric emptying time in children.

Gastrointestinal Procedures

The two most common GI procedures performed in pediatric patients are upper endoscopy and colonoscopy, which may be performed for both diagnostic and therapeutic purposes.

Upper endoscopy involves a thin, flexible endoscope used to visualize portions of the upper GI tract. The endoscope has at its tip a camera and light source, allowing a gastroenterologist to view, photograph, and biopsy the esophagus, stomach, and duodenum. Upper endoscopy is useful in the diagnosis and monitoring of mucosal disorders such as eosinophilic esophagitis, gastritis, ulcerative disease, esophageal/gastric/duodenal varices, inflammatory bowel disease, Helicobacter pylori infection, and celiac disease, among others. Upper endoscopy can also be performed for a number of therapeutic purposes. Ingested foreign bodies such as coins, magnets, sharp objects and button batteries or food boluses impacted in the esophagus can be removed with graspers or baskets introduced through the endoscope. A number of hemostatic techniques are available to treat upper intestinal bleeding, and multiple endoscopic techniques are available to treat upper intestinal strictures, polyps, and varices. Patients typically must have nothing by mouth (NPO) for several hours prior to an upper endoscopy.

(Images courtesy of Dr. Peter Ngo.)

Colonoscopy involves a thin, flexible colonoscope that is introduced into the anus, then advanced into the rectum, sigmoid colon, descending colon, transverse colon, ascending colon, and cecum, then ultimately into the terminal ileum in a retrograde fashion through the ileocecal valve, allowing a clinician to view, photograph, and biopsy these regions of the lower gastrointestinal tract. A colonoscopy may be performed to identify possible causes of abdominal pain, weight loss, stool pattern changes, melena, and hematochezia. In the pediatric population, colonoscopy is particularly useful in the diagnosis and monitoring of conditions such as inflammatory bowel disease and has a central role in the identification and treatment (via polypectomy) of polyp disorders such as familial adenomatous polyposis or juvenile polyposis syndrome. Patients typically undergo a laxative-based “cleanout” prior to a colonoscopy.

Advanced Procedures

Video capsule endoscopy, endoscopic retrograde cholangiopancreatography (ERCP), endoscopic ultrasonography, computed tomography, ultrasonography, and magnetic resonance imaging (usually MR enterography) are modalities used by pediatric gastroenterologists. The indications are similar to indications in adult practice.