Gastric Esophageal Reflux

1. Disease
   1. Gastroesophageal reflux disease (GERD)
      1. Results from episodes of gastroesophageal reflux (GER)
      2. Reflux esophagitis can cause mucosal changes and result in inflammation, hyperplasia, and erosion. This is the secondary effect caused by GER
      3. GER
         1. When reflux is in the esophagus it usually clears quickly
         2. However, in the presence of acid (from the stomach), reflux clearing will take several minutes
         3. It is saliva that neutralizes the acid in which reflux will then pass back into the stomach
      4. GER is not usually caused by one single factor, and reflux may be due to
         1. Increased acid and/or pepsin will cause GER
         2. Inappropriate peristalsis of the esophagus
         3. Delayed gastric emptying
         4. Esophageal epithelial resistance
         5. Hiatal hernia
      5. Reduced or relaxed lower esophageal sphincter (LES) pressure will also cause reflux into the esophagus, however, this will not occur if LES baseline pressure is above 10 mmHg
   2. Symptoms include heartburn, chest pain, regurgitation, and sour breath
2. Gastroesophageal Reflux Procedure
   1. Patient should be NPO 12M, prior to the exam
   2. Preparation of the "atomic cocktail"
      
      1. 150 mL of orange juice
      2. 150 mL 0.1 N HCl
      3. 300 μCi of Tc99mSulfur Colloid
   3. Acquisition parameters
      1. 64 x 64 matrix
      2. Nine 30 second images are required
      3. Collimation – LEHS or LE GAP
   4. Acquisition
      1. The patient is then instructed to drink the acidified orange juice and should then be placed in a supine on the imaging table
      2. An abdominal binder is then placed around the patient’s abdomen (large blood pressure cuff)
      3. Camera is placed with the stomach at the lower end of the imaging field
      4. The following images are then taken at 30 second intervals: Pre-Valsalva, Valsalva, (and then each image requires an increase of pressure applied via the abdominal binder) 0 mmHg, 20 mmHg, 40 mmHg, 60 mmHg, 80 mmHg, 100 mmHg, 120 mmHg
      5. If reflux is seen before the end of the procedure, the remaining images do not need to be acquired
   5. Analysis of acquired data
      1. Visual interpretation will identify activity in the esophagus indicating a positive study
      2. Using the above formula, ROIs can be drawn around the stomach at 0 mmHg and the esophagus (in all images)
      3. If the activity is ≥ 5%, then quantitatively the study is considered positive
3. Case presentation

The above case shows some of the images collected in a gastroesophageal procedure. Activity in the esophagus appears on the 40 mmHg image indicating a positive study. No quantification analysis was completed in this exam.

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