GASTROINTESTINAL TRACT_2

• Beginning with the mouth and terminating with the anus “28 – 34 ft.” in length (840-1020 cm).

• Radiologically important accessory organs of the digestive system are:

  • Salivary glands, Liver, Pancreas & GB

ACCESORY ORGANS

• SALIVARY GLAND– secrete fluid for insalivation

• LIVER – production of bile

• PANCREAS – produces specialized digestive juices into the small intestine.

  • chyme – during gastric digestion

  • chyle – during intestinal digestion

    • milky fluid taken from the food during digestion

• GALLBLADDER– storage for bile

ALIMENTARY CANAL

• ORAL CAVITY

• PHARYNX

• ESOPHAGUS

• STOMACH

• DUODENUM & SMALL INTESTINE

• LARGE INTESTINE

• ANUS

Esophagus

• A muscular, collapsible tube located posterior of the larynx & trachea.

• Serves as the connection between the pharynx and stomach and is approximately 22.5 – 27.5 cm in length. 2cm in diameter

• 25cm> Bontrager

Esophagram

• Radiographic study of esophagus from pharynx down to the junction of the stomach with the used of positive and negative contrast media.

• Contrast to be used

  • Single contrast

    • 30 – 50 % weight / volume suspension

  • Double contrast (for w/ UGIS)

    • low-viscosity, high density barium

  • Note: whatever the weight/volume concentration of barium, the most important, it must flow sufficiently to coat the walls of esophagus.

4 normal esophageal constriction

• AORTIC ARCH

• LEFT MAIN BRONCHUS

• HEART (LEFT VENTRICLE)

• DIAPHRAGM

CLINICAL INDICATIONS

• ACHALASIA(CARDIOSPASM)

• ANATOMIC ANOMALIES

• BARRETT'S ESOPHAGUS

• CARCINOMA

• DYSPHAGIA

• ESOPHAGEAL VARICES

• FOREIGN BODIES

• GERD (Gastroesophageal Reflux disease)

Treacheoesophageal (TE) fistula

• A congenital or ulcerative opening (fistual tract) between the esophagus and trachea.

• Radiographic examinations of fistulas are fistulagrams, or sinograms (sinus tract).

• Barium in the bronchial tree may result from a TE fistula, or aspiration of barium.

Foreign bodies in esophagus

• Radiolucent FBs, such as chicken or fish bones, may require a swallow of barium to demonstrate.

Rotary blades from an electric razor. One stuck in the proximal esophagus, and one in the pyloric canal.

DIVERTICULUM

Examination procedure positions:

• upright position whenever possible.

• AP/PA projection, Oblique and lateral positions

Examinations of the esophagus

• Two procedures are done, one for the throat and one for the esophagus

• Barium Swallow (Esophagram) or modified barium swallow (MBS). For both the pharynx and esophagus the exam begins under fluoroscopy, in the upright position. Filming is typically done using a spot film camera or digital fluoroscopy

Examinations of the esophagus

Contrast Media

• Like the other examinations of the alimentary track, barium sulfate is used unless there are contraindications to barium.

• Both thin and thick barium are used.

  • Thin barium is useful to outline the esophagus quickly. When administered in the upright position is empties into the stomach in seconds.

  • Thick barium (barium paste) is mixed with one part water to 3-4 parts barium powder. Commercial products are often packaged in a tube.

    • Thick barium coats and adheres to the mucosa. It may be mixed with cotton balls, marshmallows, or other foods.

• No patient preparation is need for an esophagram, unless it is to be followed by an UGI

• Esophagrams begin under fluoroscopy, in the upright position. The patient holds a cup of barium, with a straw, in the right hand. The radiologist instructs the patient to patient to drink, and films in the AP, RPO, and LPO positions.

• The patient is often put into an RAO before the table to lowered to horizontal. The examination continues in the recumbent position.

• Overhead films are taken per the radiologist’s routine.

• A large diameter straw is needed, and care must be taken that the end of the straw does not become vacuum sealed to the bottom of the cup.

Positioning for Esophagram:

• AP and PA of esophagus RAO and LAO esophagus Right lateral esophagus Film Critique

Routine Esophagus Positioning

Preparation

1. Evaluate the order

2. Greet the patient

3. Take History

   1. What is pertinent Hx?

      • chest pain, heartburn, dysphagia (difficulty swallowing), odynophagia (pain on swallowing)

4. Remove jewelry, check attire, snaps, pins, NG tubes, etc.

5. Explain the exam in layman’s terms

6. Questions?

7. Set technique before positioning

Routine AP, PA Positioning

Steps

• Pathology demonstrated: Strictures, foreign bodies, anatomic anomalies and neoplasm

1. 14” x 17” lengthwise (7” x 17” are also used)

• Shielding: place lead shield over pelvic region (gonadal)

• Central Ray:

  • CR perpendicular to IR

  • CR MSP, 1inch inferior to sternal angle (T5-T6)

  • 40 SID> Table

  • 72SID> Upright

• Part Position:

  • Align MSP to Midline of IR

  • Right arm up to hold cup

  • IR 2 inches above the houlder to place CR Center to IR

• Use of thick barium, 1 part and 3 spoon fools

• Structure shown:

  • Entire esophagus filled with barium

Critique criteria for frontal projections of the esophagus

Entire esophagus filled with barium, in an unrotated frontal projection.

When there is inadequate filling of the esophagus, under -penetration, and/or insufficient density, the esophagus is difficult to visualize against the mediastinum.

Good filling, contrast, and density, demonstrating a condition called presbyesophagus

Routine RAO or LAO Positioning

Steps

1. 14” x 17” lengthwise (7” x 17” are also used)

2. 50 -450 RAO position. (Spine must be as straight as possible, especially with tight collimation.)

3. CR to T5-6 (Top of film 2” above shoulders), several inches left of the spinous processes.

Critique criteria for RAO & LAO esophagus

• Like the RAO stomach, which is the single best projection, the RAO is also best for the esophagus.

• The heart provides a homogeneous background to contrast it against, and the distal esophagus, traversing the esophageal hiatus, is laid out in profile.

• The RAO should demonstrate the entire barium filled esophagus.

• The abdominal portion is more important than the pharyngeal portion, which may be evaluated by direct inspection.

Critique criteria for LAO esophagus

• The LAO may provide valuable diagnostic information, but contrasts the esophagus against the hilar area of the right lung and foreshortens the abdominal esophagus at the gastroesophageal junction.

• The RAO & LAO should both demonstrate the entire barium filled esophagus.

• The abdominal portion is more important than the pharyngeal portion, which may be evaluated by direct inspection.

Routine Right lateral Positioning

Steps

1. 14” x 17” lengthwise (7” x 17” are also used)

2. Right lateral. C-spine “coextensive” to T-spine.

3. CR to T5-T6 (Top of film 2”above shoulders) in the midcoronal plane.

4. The arms may be raised and superimposed (like a lateral chest position), or the left shoulder may be rotated posteriorly for a “swimmers lateral.”

Critique criteria for lateral esophagus

• Entire barium filled esophagus projected posterior to heart, and anterior to the T -spine