Radiography Of The GI System

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Radiography Of The GI System

• Kyle Thornton
• DMI 63

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Pertinent Anatomy Of The Digestive System

• Accessory glands
• Salivary glands
• Liver
• Gallbladder
• Pancreas

• Alimentary Canal
• Mouth
• Pharynx
• Esophagus
• Stomach
• Small / Large Intestine

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Esophagus

• Long muscular tube that carries food and saliva
  from laryngopharynx to stomach
• Approximately 10 in. long in adult
• Lies in the midsagittal plane
• Originates around C-6
• In the thorax, it is anterior to the spine,
  posterior to trachea and heart
• Passes through diaphragm through esophageal hiatus

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Esophagus

• Inferior to diaphragm curves sharply left
• Increases in diameter
• Joins stomach at esophagogastric junction
• Cardiac antrum
• At level of xyphoid tip
• 4 layers of the esophagus
• Outermost - fibrous
• Muscular
• Submucosal
• Innermost - Mucosal

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Stomach

• Dilated saclike portion of digestive tract
• Composed of same 4 layers as esophagus
• Divided into 4 parts
• Cardia
• Fundus
• Body
• Pyloric portion

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Stomach

• Cardia
• Immediately surrounding esophageal opening
• Fundus
• Superior portion
• Fills dome of left hemidiaphragm
• Generally contains gas
• Body
• Begins at cardiac notch
• Contains rugae
• Terminates at angular notch
• Pyloric portion
• Consists of pyloric antrum and canal

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Stomach

• Anterior and posterior surface
• Right border marked by lesser curvature
• Left border marked by greater curvature
• Begins at esophogogastric junction, terminates at
  pylorus
• 4-5 times longer than lesser curvature
• Entrance to stomach is the cardiac orifice
• Controlled by cardiac sphincter
• Exit is the pyloric orifice
• Controlled by pyloric sphincter

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Body Habitus And Its Effect On Positioning

• Hypersthenic
• Horizontal and superior
• Dependent portion above umbilicus
• Asthenic
• Vertical and inferior
• Sthenic
• Generally found between xyphoid process and iliac
  crest

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Functions Of The Stomach

• Storage area for further digestion
• Food is chemically broken down
• This broken down material is called chyme

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Small Intestine

• Extends from pyloric sphincter to ileocecal valve
• Joins large intestine at right angle
• Digestion and absorption of food occur in small
  intestine
• Approximately 22 feet in length in adult
• Contains same four layers as stomach and
  esophagus
• The mucosa contains projections called villi to
  facilitate digestion and absorption
• Divided into three parts
• Duodenum
• Jejunum
• Ileum

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Duodenum

• 8 - 10 inches in length
• Widest portion of small intestine
• Follows a C-shaped course
• Contains 4 regions
• Superior, descending, horizontal, ascending
• The first region is known as the duodenal bulb
• The fourth portion joins the jejunum and is
  supported by the ligament of Trietz
• The head of the pancreas is contained in the
  duodenal loop - second portion

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Jejunum And Ileum

• Jejunum
• Upper remaining two-fifths of small bowel
• Ileum
• Terminates at ileocecal valve
• Both are gathered into freely movable loops
  (gyri)
• Attached to posterior abdominal wall by mesentary
• Generally found in central and lower part of abd.
  cavity within arch of large intestine

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Large Intestine

• Begins at right iliac region
• Joins ileum of small intestine
• Forms an arch around the small intestine
• Four main parts
• Cecum
• Colon
• Rectum
• Anal canal

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Large Intestine

• About 5 feet in length in adult
• Greater in diameter than small intestine
• Contains same four layers as esophagus, small
  intestine, and stomach
• The muscular portion contains external bands of
  muscle known as taeniae coli
• These bands create a series of pouches known as
  haustra
• The large intestine functions to reabsorb fluids
  and eliminate waste products

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Portions Of The Large Intestine

• Cecum
• Ascending
• Joins transverse colon at right colic flexure
• Transverse
• Descending
• Joins transverse colon at left colic flexure
• Sigmoid
• Rectum
• Anal canal

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Variations In Body Habitus

• Hypersthenic
• The colon generally lies in the periphery of the
  abdomen
• May require more films to adequately display the
  anatomy
• Asthenic
• Intestines are bunched together
• Lie low in the abdomen

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Contrast Media

• Barium sulfate
• Water insoluble
• Iodinated contrast media
• Water soluble
• Horrible taste
• Does not adhere to wall of alimentary tract
• Indicated in case of perforation
• Air
• Considered a negative contrast
• Generally administered by carbon dioxide crystal
  ingestion
• Barium and Air are often used as a double
  contrast agent

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Imaging Notes/Preparation

• Have contrast agents mixed and ready
• Explain examination to patient
• Ensure that patient has followed preparation
  instructions
• Ensure that footboard is securely on table
• Use short exposure times
• Use high kVp to penetrate barium
• Take exposures at the end of full expiration

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Radiography Of The Esophagus

• Can use double or single contrast
• The barium should flow to sufficiently coat the
  esophagus
• Examinations can be done in the upright or
  recumbent position
• The exam will usually be started with fluoroscopy

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AP or PA Projection

• Place patient supine or prone
• Center the midsagittal plane to the film
• Bottom of film should be placed just below tip of
  xyphoid
• Patient should commence drinking contrast before
  exposure and continue drinking during exposure
• Use shielding for every exposure

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RAO or LAO Positions

• Patient should be rotated 35 - 40 degrees
• Center about two inches lateral to MSP
• Bottom of film below xyphoid
• Patient must drink before and during the exposure
• Use shielding

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Lateral Projection

• Place patient in lateral position
• Center the midcoronal plane to the film
• Bottom of film below xyphoid process
• Patient must drink continuously before and during
  exposure
• Use shielding

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Structures Shown/Film Evaluation

• Entire barium filled esophagus from lower neck to
  stomach
• Barium should be sufficiently penetrated
• Surrounding structures should be visible, not
  overpenetrated
• No rotation on AP, PA, or lateral projections
• Esophagus should be displayed between heart and
  spine on oblique projections

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Valsalva Maneuver

• Useful in demonstrating esophageal varices
• Have patient first deeply inspire
• Swallow contrast
• Bear down
• This should be done in the recumbent position

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Radiography Of The Stomach

• Referred to as the Upper GI Series
• Generally consists of fluoroscopy and serial
  radiographs
• Single or double contrast is used
• Patient should follow a low residue diet for 2
  days prior to the examination
• Patient must be NPO after midnight
• AP scout generally obtained prior to exam

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Single v. Double Contrast

• Single Contrast
• Shows size, shape, and position of the stomach
• Examines changing contour of stomach during
  peristalsis
• Observe filling and emptying of duodenal bulb

• Double Contrast
• Mucosal lining is well visualized
• Small lesions are less easily obscured

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UGI Positioning - PA Projection

• Position
• Prone
• Center between MSP and Mid-Axillary line if using
  small film
• Center at MSP if using 14 X 17
• CR
• Perpendicular to plane of film at level of L1-L2
• Structures
• Size, shape, and relative position of stomach
• Pyloric canal and duodenal loop in hypo or
  asthenic patients
• Evaluation
• All pertinent anatomy
• No rotation
• Exposure sufficient to penetrate barium
• Surrounding structures visible

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UGI Positioning - PA Oblique Projection

• Position
• Recumbent
• Body rotated 40 - 70 degrees
• Hypersthenic patients require more rotation
• CR
• Perpendicular to L1-L2
• Between vertebral column and elevated lateral
  border of the abdomen
• Structures
• Entire duodenal loop
• Best image of pyloric canal and duodenal bulb
• Evaluation
• All pertinent anatomy
• No superimposition of pylorus and duodenal bulb
• Duodenal bulb and loop in profile

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UGI Positioning - AP Oblique Projection

• Position
• Supine
• Right side elevated 30 - 60 degrees
• Average about 45 degrees
• CR
• Between vertebral column and left lateral border
  at L1-L2
• Structures
• Fundic portion of stomach filled with barium
• Evaluation
• All pertinent anatomy
• No superimposition of pylorus and duodenal bulb
• Barium filled fundus

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Lateral Projection

• Position
• Lateral recumbent - right side
• CR
• Level of L1-L2
• Between midcoronal and anterior of abdomen
• Structures
• Anterior/posterior portions of stomach
• Pyloric canal and duodenal bulb in hypersthenic
  patients
• Evaluation
• No rotation
• All pertinent anatomy

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UGI Positioning - AP Projection

• Position
• Supine
• CR
• MSP at L1-L2
• Between MSP and left side if using small film
• At MSP if using 14 X 17
• Structures
• Barium filled fundic portion
• Hiatal hernias, if present

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Wolf Method - Hiatal Hernia

• Patient rotated 40-45 degrees
• Patient lies on compression sponge
• CR angled about 20 degrees caudal
• Patient must drink during exposure
• Very useful in diagnosing hiatal hernia

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Radiography Of Small Intestine

• Contrast administration
• Orally
• Retrograde
• Reflux filling via barium enema
• Direct injection of contrast through NG tube
• Enteroclysis

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Small Intestine

• Preparation
• Low residue diet for 2 days prior when possible
• NPO after midnight before the exam
• Examination Procedure
• Scout film obtained
• Patient drinks barium
• Films obtained in prone or supine position
• Films begin at 15 minutes after barium
• Barium usually reaches ileocecal valve in about 2
  -3 hours

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Small Bowel - AP/PA Projection

• Patient supine or prone
• CR centered to level of L2 for early films
• Iliac crest for later films
• Continue taking radiographs until barium reaches
  terminal ileum
• Fluoroscopic spot films may be taken of terminal
  ileum

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Radiography Of The Colon

• Single or double contrast
• Single demonstrates the anatomy and tonus of the
  colon, along with most abnormalities
• Double allows visualization of the intestinal
  lumen along with any polyps or lesions

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Preparation Of The Colon

• Patient must take a laxative on the day prior to
  the examination
• Patient may have a clear liquid on the day prior
  to the exam
• NPO after midnight
• Cleansing enemas may also be indicated

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Patient Preparation

• Explain the examination fully to the patient
• Use care when inserting the enema tip
• Retention-type balloon tips should only be
  inflated under fluoroscopic control
• Barium should only be administered under
  fluoroscopic control

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PA Projection - Barium Enema

• Pt. prone
• MSP centered to film
• CR at iliac crest
• Entire colon must be visualized
• The barium should be sufficiently penetrated with
  surrounding structures visible

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PA Axial Projection - BE

• Pt. prone
• MSP centered to film
• CR directed 30 - 40 degrees caudal to ASIS
• Demonstrates rectosigmoid area of colon
• This area must be centered to film

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PA Oblique Projection (RAO)- Barium Enema

• Pt. prone
• Left side elevated 35 - 45 degrees
• CR at iliac crest, 1 -2 inches lateral to midline
  of body
• Best demonstrates right colic flexure
• Ascending and sigmoid portion
• Entire colon must be visualized

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PA Oblique (LAO) - BE

• Pt. prone
• Right side elevated 35 - 45 degrees
• CR to iliac crest, 1 - 2 inches lateral to
  midline
• Best demonstrates left colic flexure
• Descending portion of colon
• Entire colon must be visualized

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Lateral Projection - Barium Enema

• Lt. or Rt. lateral recumbent position
• Center midcoronal plane to film
• CR enters midcoronal plane at level of ASIS
• Best demonstrates rectum and distal sigmoid
  portions of colon
• There should be no rotation
• Rectosigmoid area should be centered

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AP Projection - Barium Enema

• Supine position
• MSP centered to cassette
• CR at iliac crest
• Demonstrates entire colon
• Entire colon must be included
• Two cassettes are sometimes necessary

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AP Axial Projection - BE

• Pt. supine
• MSP centered to film
• CR to 2 in. above iliac crest
• 30 - 40 degrees cephalic
• Demonstrates rectosigmoid area of colon
• Rectosigmoid area should be free of
  superimposition
• Rectosigmoid area centered to film

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AP Oblique Projection - BE

• Pt. supine
• Body rotated 35 - 45 degrees
• CR 1 - 2 in. lateral to midline at iliac crest
• LPO - Right colic flexure, ascending and sigmoid
  portions of colon
• RPO - Left colic flexure, descending colon
• Must demonstrate entire colon

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Lateral Decubitus Positions - BE

• Lateral recumbent position
• Horizontal CR to MSP at level of iliac crest
• Demonstrates AP or PA projection
• Dependent side is barium filled
• Up side is air-filled
• Must include entire colon
• Air-filled portion must not be overpenetrated

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Upright Positions - Barium Enema

• Cassette must be lowered to compensate for the
  drop of the bowel in this position
• Demonstrates air-filled flexures and transverse
  colon