Gastric emptying in infants: epigastric impedance versus scintigraphy

Pediatric Gastrointestinal Nuclear Medicine

General localization of gastrointestinal bleeding through the use of labeled red blood cells may be performed in children, or (99m)Tc-pertechnetate may be used if a Meckel's diverticulum is suspected. As in adults, cholecystitis and biliary leak may be assessed in children via (99m)Tc-IDA derivatives. Gastroesophageal reflux can be evaluated by oral consumption of the child's usual diet labeled with (99m)Tc sulfur colloid. For the scintigraphic determination of pulmonary aspiration, a relatively high concentration of tracer within a drop of liquid is placed beneath the child's tongue followed by dynamic imaging of the respiratory tract. Colonic transit scintigraphy can aid in the identification and therapeutic decision-making in patients with functional fecal retention, the most common cause of chronic constipation in children. (18)F-DOPA positron emission tomography is useful for classifying pancreatic involvement in infantile hyperinsulinism as focal or diffuse, thereby differentiating between patients who should receive curative focal pancreatic resection versus those who should receive medical management. Assessment of protein-losing enteropathy can be conducted scintigraphically and, compared with fecal alpha-1 antitrypsin collection, the scintigraphic method can detect esophageal and gastric protein loss. Also, scintigraphic quantification of protein loss can be performed without the requirement for fecal collection. Intestinal inflammation in children with inflammatory bowel disease can be evaluated using (99m)Tc white blood cells. The scintigraphic method is safe, accurate, well-tolerated by children and complementary to endoscopy in most patients.

Update on gastrointestinal scintigraphy

Nuclear medicine offers a variety of studies for evaluating motility throughout the gastrointestinal tract. Gastric emptying remains the "gold standard" for studying gastric motor function, but its application in most centers remains limited to measuring only total gastric emptying in spite of data that show assessment of both fundal and antal function is of clinical value for evaluating patients with dyspepsia. Similarly, newer methods to study small bowel and colon transit have not gained widespread use. This review summarizes the state-of-the-art of prior established and newer scintigraphic studies with an emphasis on their clinical applications.

Relationship between gastro-oesophageal reflux and gastric activity in newborns assessed by combined intraluminal impedance, pH metry and epigastric impedance

The pathogenesis of gastro-oesophageal reflux disease (GORD) is complex and multifactorial. A motility disorder resulting from immaturity of the gastro-oesophageal tract may be involved. We have combined multichannel intraluminal impedance (MII) and pH monitoring with epigastric impedance (EGI) to evaluate the activity of this tract in neonates with suspected GORD. Multichannel intraluminal impedance, pH and EGI were followed for 3 h in 30 newborns displaying apparent life-threatening events and signs of GORD. Simultaneous application of MII and pH monitoring identifies reflux episodes and illustrates their duration, height and pH. Episodes detected by MII were placed on the EGI curve and the contemporaneous gastric filling state and emptying velocity were calculated. During the total measuring time, 248 reflux episodes were revealed. An inverse correlation was evident for reflux frequency and gastric emptying velocity (r2 = 0.94; P < 0.001), and between acid refluxes and the gastric filling state (r2 = 0.95; P < 0.001), whereas a positive correlation was found between the reflux level and the gastric filling state (r2 = 0.52; P < 0.05). Simultaneous MII, pH and EGI monitoring provided new information on the relationship between refluxes and gastric activity. Data suggest that gastric emptying patterns influence the frequency, level and pH of reflux episodes.