Radiography of the GI System Chapter 17 Radiography of the GI System

Anatomy Of Digestive System Alimentary Canal Mouth Pharynx Esophagus Stomach Small / Large Intestine

Anatomy Of Digestive System Accessory glands Liver Gallbladder Salivary glands Pancreas

Esophagus Long muscular tube carries food and saliva from laryngopharynx to stomach Approximately 10 in. long in adult Lies in midsagittal plane

Esophagus Originates around C-6 In thorax, it is anterior to spine, posterior to trachea and heart Passes through diaphragm through esophageal hiatus

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

Stomach Dilated saclike portion of digestive tract Composed of same 4 layers as esophagus Outermost - fibrous Muscular Submucosal Innermost - Mucosal

Stomach (cont’d) Divided into 4 parts Cardia Fundus Body Pyloric portion Entrance to stomach is cardiac orifice Controlled by cardiac sphincter Exit is the pyloric orifice Controlled by pyloric sphincter

Stomach (cont’d) Body Begins at cardiac notch Contains rugae Terminates at angular notch Pyloric portion Consists of pyloric antrum and canal (antrum: cavity or chamber)

Body Habitus - Effect On Positioning Hypersthenic Horizontal and superior Dependent portion above umbilicus Asthenic Vertical and inferior Sthenic Generally found between xyphoid process and iliac crest

Functions Of Stomach Breaks down food chemically Broken down material is called? chyme A storage area for further digestion

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 __ feet in length in adult 22

Small Intestine Contains same four layers as stomach and esophagus Mucosa contains projections called villi to facilitate digestion and absorption Divided into 3 parts: Duodenum Jejunum Ileum

Duodenum Contains 4 regions 8 - 10 inches in length Widest portion of small intestine Follows a C-shaped course Contains 4 regions Superior, descending, horizontal, ascending

Jejunum And Ileum Jejunum Ileum Upper remaining 2/5 of small bowel Ileum Terminates at ileocecal valve Both are gathered into freely movable loops (gyri) Attached to posterior abdominal wall by mesentary (the double layer of peritoneum)

Valvulae conniventes Muscular bands encircling small bowel usually seen to traverse bowel wall at right angles to long axis of the bowel

Large Intestine What is the main purpose? Reabsorbs fluids and eliminate waste products About _____ feet in length in adult 5 Greater in diameter than small intestine Contains same four layers as esophagus, small intestine, and stomach Which are?

Portions Of Large Intestine Cecum Ascending Joins transverse colon at right colic flexure Transverse Descending Joins transverse colon at left colic flexure Sigmoid Rectum Anal canal

Large Intestine The muscular portion contains external bands of muscle known as taeniae coli These bands create a series of pouches known as? haustra

Compare Valvulae conniventes Small bowel Haustra Large bowel

Variations In Body Habitus Hypersthenic Colon lies in periphery of abdomen May need double films! Asthenic Intestines are bunched together in lower abdomen

Radiographic Exams

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

Contrast Media Air Considered a negative contrast Generally administered by carbon dioxide crystal ingestion Barium and Air are often used as a double contrast agent

Preparing pt. for GI study Have contrast agents mixed and ready to go Explain exam to pt. Ensure pt. has followed preparation instructions!

Preparation cont’d Ensure that footboard is securely on table! Use short exposure times Use high kVp to penetrate barium Take exposures end of full expiration!

Radiography Of Esophagus Can use double or single contrast Barium should flow to sufficiently coat esophagus Can be done upright or recumbent Exam will usually be started with fluoroscopy

AP or PA Projection Pt. supine or prone Center midsagittal plane to cassette Bottom of cassette should be placed just below tip of xyphoid Pt. drinks contrast before exposure and continues drinking during exposure Shield!

RAO or LAO Positions Pt should be rotated 35 - 40 degrees Center about 2 inches lateral to MSP Bottom of cassette below xyphoid

RAO or LAO Positions Pt must drink before and during exposure Use shielding!

Lateral Projection Place pt in lateral position Center midcoronal plane to cassette Bottom of cassette below xyphoid process Pt must drink continuously before and during exposure Use shielding!

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

What is the Valsalva Maneuver? Useful in demonstrating esophageal varices Have pt. first deeply inspire Swallow contrast Bear down Recumbent position

Esophageal varices Extremely dilated sub-mucosal veins in the lower esophagus Most often a consequence of portal hypertension, commonly due to cirrhosis Pts with esophageal varices have a strong tendency to develop bleeding

Radiography Of The Stomach Upper GI Series Generally consists of fluoroscopy and serial radiographs Single or double contrast Pt. should follow a low residue diet for 2 days prior to exam Pt. must be NPO after midnight AP scout generally obtained prior to exam

UGI Positioning - AP Projection 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

Single v. Double Contrast Single Contrast Shows size, shape, and position of 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

Compare Single and Double Contrast

Which is taken AP and which is taken PA?

UGI Study - PA Projection Prone Position Center at MSP if using 14 X 17 CR Perpendicular to plane of film at level of L1-L2

UGI study - PA Projection Structures shown? Size, shape, and relative position of stomach Evaluation: All pertinent anatomy No rotation Exposure sufficient to penetrate barium Surrounding structures visible

UGI Positioning - PA Oblique Projection 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

UGI Positioning - PA Oblique Projection 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

UGI Positioning - AP Oblique Projection 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

Lateral Projection Position Lateral recumbent - right side CR Level of L1-L2 Between midcoronal and anterior of abdomen

Lateral Projection Structures Pyloric canal and duodenal bulb in hypersthenic patients Evaluation No rotation All pertinent anatomy

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

Radiography Of Small Intestine Contrast administration 3 Ways Orally Retrograde Reflux filling via barium enema Direct injection of contrast through NG tube Enteroclysis (Radiocontrast is infused through tube inserted through nose to duodenum, and images are taken in real time as contrast moves through)

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

Small Intestine Follow Through 15 minutes Immediate

Small Intestine Follow Through 1 hour 30 minutes

T.I. Demonstrates Ileocecal Valve

Radiography Of Colon

Preparation of Colon Pt must take laxative on day prior to exam Pt may have clear liquid day prior to exam NPO after midnight Cleansing enemas may also be indicated

Pt. Preparation Explain exam fully to pt. Use care when inserting enema tip! Retention-type balloon tips should only be inflated under fluoroscopic control Barium should only be administered under fluoroscopic control by radiologist

Single or double contrast Single demonstrates anatomy and tonus (contraction) of colon, along with most abnormalities Feces

Double Contrast Double allows visualization of lumen along with any polyps or lesions

AP Projection - Barium Enema Supine MSP centered to cassette CR at iliac crest Entire colon must be included Two cassettes are sometimes necessary

PA Projection - Barium Enema Pt. prone MSP centered to film CR at iliac crest Entire colon must be visualized Barium should be sufficiently penetrated with surrounding structures visible

PA Axial Projection - BE Pt. prone MSP centered to IR CR directed 30 - 40 degrees caudal to ASIS Demonstrates rectosigmoid area of colon Area must be centered to IR

PA Axial Projection - BE

AP Oblique Projection - BE Pt. Supine Body rotated 35 - 45 degrees CR 1 - 2 in. lateral to midline at iliac crest

AP Oblique Projection - BE LPO - Right colic flexure, ascending and sigmoid portions of colon RPO - Left colic flexure, descending colon Must demonstrate entire colon Which oblique is this?

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

PA Oblique Projection (RAO)- Barium Enema Best demonstrates hepatic flexure Ascending and sigmoid portion Entire colon must be visualized What projection is this similar to?

PA Oblique (LAO) - BE Pt. prone Right side elevated 35 - 45 degrees CR to iliac crest, 1 - 2 inches lateral to midline

PA Oblique (LAO) - BE Demonstrates descending portion of colon Entire colon must be visualized What flexture doe this best demonstrate? (splenic) What projection is it comparable to?

Lateral Projection - Barium Enema Lt. or Rt. lateral recumbent position Center midcoronal plane to film CR enters midcoronal plane at level of ASIS

Lateral Projection - Barium Enema Best demonstrates rectum and distal sigmoid portions of colon Rectosigmoid area should be centered, no rotation

Lateral Decubitus Positions - BE AP or PA projection

Left Lateral Decubitus Positions - BE Up side is air-filled Must include entire colon Air-filled portion must not be overpenetrated

Upright Position - Barium Enema Demonstrates air-filled flexures and transverse colon

Chassard Lapine’ Demonstrates rectum, rectosigmoid juntion and sigmoid

What is a Defecography? (evacuation proctography) Radiographic exam of defecation process under fluoroscopy Used to evaluate disorders of lower bowel not evident by tests such as colonoscopy or sigmoidoscopy

Defecation (Having a bowel movement) is a complex action requiring coordination with relaxation and contraction of a large number of muscles Controlled by nervous system, but is also under voluntary control.

Defecation cont’d Process is initiated by arrival of stool into rectum This sensation leads to chain of events which ends in evacuation of stool from anus Defecation is voluntarily controlled in healthy, normally functioning people.

Defecography is used to Evaluate: Chronic Constipation Rectal prolapse (walls of rectum protrude through anus and become visible outside body) Rectocele (outpouching of rectum) Fecal incontinence Anismus (inappropriate spasm of anal sphincter)

Defecography A thickened barium contrast putty is injected into rectum then excreted by patient while radiologist watches and videotapes