RT 304 Midterm PDF

Gastrointestinal System The Digestive Tract of the body contains all the Organs, Ducts and components to start and complete the...

Gastrointestinal System The Digestive Tract of the body contains all the Organs, Ducts and components to start and complete the Digestive Process:  Mastication (Chewing): mechanical breakdown of food.  Deglutition: is a complex process that requires coordination of Head, Neck and the precise opening / closing of Esophageal Sphincters. Esophagus: is a vertical tube about 10 inches long.  It extends from C6, inferior of Pharynx to the Stomach at the level of T11. Stomach: is a large inflatable sac that is located in the Left Upper Quadrant of the Abdomen.  Most Dilated Portion of Digestive Tract; it can hold almost 1.5 quarts (qt) of food and liquid. Small Bowel (Intestines): extends from the Pyloric Sphincter to the Cecum.  Called Small Bowel because (measures 18 - 23 feet) its Lumen is smaller than large bowel.  3 Divisions: Duodenum, Jejunum, and Ileum. Large Bowel (Intestines): average 5 - 6 feet in length. It extends from Cecum to Anus.  Divisions: Ascending, Transverse, Descending, & Sigmoid Colon, Rectum, Anal Canal. Pathology: Esophagus – Congenital Anomaly 1. Atresia  Esophageal Atresia: refers to an Absence in the Continuity of the Esophagus.  Inappropriate division of the Primitive Foregut into the Trachea and Esophagus.  This is the Most Common Congenital Anomaly of the Esophagus. Clinical Manifestation:  Esophageal Atresia: may be suspected in the Neonate.  1. Inability to swallow saliva or milk.  2. Aspiration during early feedings.  3. Failure to pass a Nasogastric Tube into the stomach successfully. Digestive System  Digestive System: alters the Chemical and Physical Composition of food so that it can be Absorbed and Used by Body Cells. 2. Tracheoesophageal Fistula (Passageway) Pathology: Esophagus – Acquired Type  Failure of a satisfactory Esophageal Lumen to develop completely separate from Trachea. 1. Esophagitis Reflux (GERD – Gastroesophageal Reflux Disease)  Congenital Esophageal Atresia: the lack of the development of the Esophageal Lumen resulting in a Blind Pouch.  Is a spectrum of disease that occurs when Gastric Acid refluxes from the Stomach into the Lower end of the Esophagus across the Lower  Esophageal Atresia & TE fistulas: often associated with other Congenital Malformations Esophageal Sphincter. involving the Skeleton, Cardiovascular System, and GI Tract.  Alcohol, Chocolate, Caffeine, and Fatty Food: tend to decrease the pressure of the Esophageal Sphincter, allowing reflux to occur. Radiographic Features  The difficulty in the radiographic diagnosis of gastro-esophageal reflux disease lies in the presence of Spontaneous Reflux on Upper GI Examination in 20% of normal individuals.  While some patients with Pathologic Gastro-Esophageal Reflux Disease may present with Reflux only after provocative maneuvers such as Valsalva, Leg Raising, and Coughing. Appearance  They consist of Superficial Ulcerations or Erosion that appear as Streaks or Dots of Barium Superimposed on the Flat Mucosa of the Distal Esophagus. 2. Barrett’s Esophagus Types of Findings for Tracheoesophageal (TE) Fistula  Condition related to Severe Reflux Esophagitis. Normal Squamous Lining of the Lower Congenital TE Fistula Esophagus is destroyed & replaced by Columnar Epithelium similar to the Stomach. Type 1: 2nd most common.  Unusually high susceptibility in developing Malignancy in Columnar Cell-Lined Portion.  These tumors are almost always Adenocarcinoma which are otherwise very rare in the  Pure Esophageal Atresia – Upper and Lower Esophagus blind pouches. Esophagus (5% of Esophageal Cancer). Type 2  Upper Esophagus communicates with Trachea; Lower segment blind pouch. Type 3: Most common.  Upper Esophagus forms blind pouch (Esophageal Atresia) with a Distal Esophagus communicating with the Trachea. Type 4: 3rd most common.  Upper and Lower Esophageal segments blind pouches. Both connected to Bronchial Tree.  H Fistula: is a connection at the mid-Esophagus and Trachea. 3. Candida and Herpes Virus Acquired TE Fistula – Fistula caused by:  Candida (Fungal) & Herpes Virus: organisms most responsible for Infectious Esophagitis. 1. Mediastinal Malignancy 2. Infection Process 3. Trauma  Usually occurs in patients with Widespread Malignancy who are receiving Radiation Therapy, Chemotherapy, Corticosteroids, or Immunosuppressive Agents and Antibiotics (Tetracycline).  Candida Esophagitis Herpes Esophagitis Bleaches / Caustics Hypochlorous Acid Bleach – neutral pH commercially Peroxide Mildew Remover Appearance  Irregular Cobblestone Pattern with a Shaggy (Hairy) Marginal Contour of the esophagus caused by Deep Ulceration and Sloughing of the Mucosa.  Candida Infection: manifests as Plaques & Nodules; from Superficial Collection of Fungi. 5. Esophageal Cancer  Herpetic Esophagitis: include Small Mucosal Ulcers or Plaques.  Relatively Uncommon Tumor that occurs within the Esophagus of affected individuals. 4. Ingestion of Corrosive Agents  Symptoms: Increasing Dysphagia that progress from Solid Foods to Liquids.  Alkaline & Acidic Corrosive Agents: produce acute inflammatory changes in esophagus. Clinical Manifestation:  Strong Alkaline Agents: ingestion causes Deeper Lesions than ingestion of strong acids,  1. Increasing Dysphagia and only half of those who ingest an Acid suffer severe injury.  2. Worsening Reflux Appearance  3. Hoarseness and Cough  Alkaline: Deeper Ulceration and Stricture Formation. Radiographic Appearance  Acidic: Superficial Minimal Ulceration and Stricture Formation.  Barium Swallow Double Contrast: Flat Plaque like Lesion, Infiltrating Lesion, (Irregular Alkali Wall) and Polypoid Mass (Deep Ulceration). Sodium Hydroxide  CT Scan with Contrast: Wall Thickening Greater Than 3 – 5 mm. Potassium Hydroxide Oven Cleaners, Liquid Agents, Liquid Drain Cleaners, Disk Batteries Calcium Hydroxide Hair Relaxers Lithium Hydroxide Hair Relaxers Ammonia Household Cleaners Dishwater Detergents Acid Sulfuric Acid Hydrochloric Acid Toilet Bowl, and Swimming Pool Cleaners, Rust Removers Nitric Acid  Esophageal Diverticula are classified differently based on where they are Located along the Esophagus and include: Traction Diverticula or Mid-esophageal Diverticula  Pouches most commonly occur in the Middle Area of the Esophagus.  Traction Diverticulum: occurs when there is an external force on the wall of the Esophagus that creates the Pouch.  Formed in response to Pull from Fibrous Adhesions following Lymph Node Infection (TB)  True Diverticulum: contains all 3 Esophageal Layers.  May form from Increased Intraluminal Pressure and be Pulsion Diverticula. Pulsion Diverticula or Epiphrenic / Epiphanic Diverticula  Pouches occur at the Base or Lower Part of the Esophagus.  This happens when the esophagus is being Pushed due to Incoordination of the Sphincter Muscle in the Lower Esophagus. 6. Esophageal Diverticula (Outpouching)  Sphincter: is a Ring made of Muscle that helps connect the Esophagus with the Stomach.  Location is usually in Distal Esophagus on Lateral Esophageal Wall, right > left.  Traction or True Diverticula: Common Lesions that either contain all Layers of the wall.  Often associated with Hiatal Hernia.  Pulsion or False Diverticula: Mucosa & Submucosa herniating through the muscular layer.  Pulsion Diverticulum.  Small Diverticula: do not retain food or secretions and are Asymptomatic.  False Diverticulum.  When a diverticulum fills with food or secretions, Aspiration Pneumonia may result. Zenker's Diverticulum  Esophageal diverticula found in the Top Part or Area of the Esophagus.  Zenker's Diverticulum: caused by Abnormal Tightening of Upper Esophageal Sphincter between the Lower Pharynx (Throat) and the Upper Esophagus.  This causes a Bulge to form, and over time pressure will cause a Diverticulum to develop.  Most Common type of Esophageal Diverticulum.  Occurs in older women.  Posteriorly at Site of Killian’s Dehiscence: superior boundary is Thyropharyngeal Muscle and inferior boundary is Cricopharyngeal Muscle.  Pulsion Diverticulum  False Diverticulum: Herniation of Mucosa and Submucosa through Muscular Layer. Esophageal Diverticulum: 7. Esophageal Varices  Pouch or Sac that Protrudes Outwards from the wall of the Esophagus.  Dilated Veins in the wall of Esophagus. Most commonly the result of Increased Pressure in  Can appear anywhere on the Esophagus. Portal Venous System (Portal Hypertension), which is a result of Cirrhosis of the Liver.  Most commonly found in Middle-Aged or Older People.  Are infrequently demonstrated in the Absence of Portal hHypertension.  Develops in 3 Variations: Traction Diverticula, Pulsion Diverticula & Zenker’s Diverticulum.  Can occur when Muscles involved in Digestion stop working properly. 2 Types of Esophageal Varices:  Most people don’t receive Treatment but Surgery can happen in severe cases.  The Sacs found in Esophageal Diverticula can appear anywhere on the Esophagus.  Uphill Esophageal Varices: most common form, caused by Portal Hypertension, as a Collateral Pathway between the Portal Vein and the Superior Vena Cava.   Downhill Esophageal Varices: relatively rare, typically caused by Superior Vena Cava 9. Achalasia Obstruction, as part of Superior Vena Cava Syndrome, as a Collateral Pathway between the Superior Vena Cava into the Portal Circulation and/or the Inferior Vena Cava.  Refers to the combined Failure of Peristalsis to pass food down the esophagus and Failure of Relaxation of the Cardia. Appearance  Failure of organized Esophageal Peristalsis that causes Impaired Relaxation of the Lower Esophageal Sphincter, resulting in food stasis and marked dilatation of the Esophagus.  Serpiginous (Wavy Border) Thickening of Folds which appear as Round Oval Filling Defects resembling the Bead of Rosary. Radiographic Features  Achalasia: characteristically involves a Short Segment (less than 3.5 cm in length) of the Distal Esophagus. Appearance  Rat Tail or Bird Beak Sign. 8. Hiatal Hernia  It occurs in about half of the population over age 50 years.  Early Stages: a hiatal hernia is Reducible.  Chronic Herniation: may be associated with GERD.  Patients with Hiatus Hernia are Asymptomatic, and it is an Incidental Finding.  Symptoms: Epigastric or Chest Pain, Postprandial Fullness, Nausea and Vomiting. There are 2 Main Types of Hiatus Hernia (although they may co-exist): 10. Esophageal Perforation  1. Sliding Hiatal Hernia (90% most common).  Complication of esophagitis, peptic ulcer, neoplasm, external trauma, & instrumentation  2. Rolling Hiatal Hernia: (Paraesophageal) Hiatal Hernia.  Perforation of a previously healthy esophagus can result from Severe Vomiting (the most common cause) or Coughing, often from Dietary or Alcoholic Recklessness. Radiographic Appearance  Mallory-Weiss Syndrome: refers to a Tear or Laceration of the Mucous Membrane, most commonly at the point where the Esophagus and the Stomach meet.  Plain Radiograph: Retrocardiac Mass with or without an Air-Fluid Level.  Schatzki Ring: Sliding Hiatal Hernia (Trendelenburg Position).  Fluoroscopy: Numerous Coarse Thick Gastric Folds within the Suprahiatal Pouch Tortuous Esophagus with an Eccentric Gastro-Esophageal Junction. Radiographic Appearance Ingestion of Corrosive Agents  Perforation that extends throughout the Entire Esophageal Wall can lead to Free Air in the Location: Alkaline Ingestion. Mediastinum or Peri-Esophageal Soft Tissues. Imaging Appearance:  The administration of Radiopaque Contrast Material may demonstrate Extravasation through the Perforation or an Intramural Dissection Channel separated by an Intervening  Deeper Ulceration. Lucent Line from the Normal Esophageal Lumen.  Stricture Formation. Summary of Findings for the Esophagus Location: Acidic Ingestion. Congenital Tracheoesophageal Fistula Imaging Appearance: Location:  Superficial Minimal Ulceration.  Stricture Formation.  Blind Pouch Superiorly  Blind Pouch Distally or Tracheal Fistula Esophageal Cancer Imaging Appearance: Location:  Blind Pouch filled with Contrast Agent or NG Tube  Distal Esophagus.  Fistula Track (if one exists), NG Tube Injection  Esophagogastric Junction.  CT: demonstrates Fistula location and Size for Presurgical Planning Imaging Appearance: Tracheoesophageal Fistula – Acquired Double-contrast Barium Swallow Study: Location: Usually at level of the Carina or more Proximal.  Flat Plaque-Like Lesion. Imaging Appearance: Demonstration of connection between Esophagus and Tracheobronchial Tree  Infiltrating Lesion (Irregular Wall).  Polypoid Mass (Deep Ulceration). Reflux Esophagitis CT with Contrast Enhancement Location: Distal Esophagus.  Wall Thickening Greater Than 3-5 mm. Imaging Appearance: Streaks or Dots Superimposed on Flat Mucosa. Esophageal Diverticula Barrett’s Esophagus Location: Location: Middle to Lower Esophagus.  Traction: all Layers of the wall. Imaging Appearance: Smooth Tapered Strictures. Imaging Appearance: Candida (Fungal) and Herpesvirus Esophagitis  Esophagram: an Outpouching or Pocket Filling with Barium. Location: Entire Esophagus. Location: Imaging Appearance:  Epiphrenic: Distal Portion of the Esophagus.  Cobblestone Pattern.  Shaggy Marginal Contour. Imaging Appearance:  Small Mucosal Ulcers or Plaques.  CT: an Outpouching at the Pharyngoesophageal Junction. Esophageal Varices Stomach: Pathology Location: Distal Esophagus and Stomach. 1. Gastritis Imaging Appearance:  Inflammation of Stomach. Result of irritants like Alcohol, Corrosive Agents, & Infection.  Esophagram: Serpiginous Thickening of Folds – resembles Rosary Beads.  Gastritis: changes the Normal Surface Pattern of the Gastric Mucosa.  Endoscopic Ultrasound: Compressible Hypoechoic mass in Outer or Submucosal Layer.  3 Types: Alcoholic, Corrosive, Bacteria (Phlegmonous) Gastritis. Hiatal Hernia Radiographic Appearance Location: Esophagogastric Region.  1. Alcoholic Gastritis: Thickening of Gastric Folds and Multiple Superficial Gastric Erosions.  2. Corrosive Gastritis: Acute Inflammatory Reaction heals by Fibrosis and Scarring, which Imaging Appearance: result in Severe Narrowing of the Antrum and may cause Gastric Outlet Obstruction.  GI Series: Numerous Thicker Folds of the Stomach above the Diaphragm.  3. Bacterial (Phlegmonous) Gastritis: Inflammatory Thickening of the Gastric Wall causes Narrowing of the Stomach that may mimic Gastric Cancer. Achalasia: Functional Obstruction  Infectious Gastritis Diagnosis: can be made if there is evidence of Gas Bubbles (produced Location: Distal Esophagus with Proximal Dilation. by the Bacteria) in the Stomach Wall. Imaging Appearance: Gastritis Emphysematous Gastritis  Chest Radiograph: Dilated Esophagus.  GI Series: Narrowing of Distal Esophageal Segment. Foreign Bodies: Food Bolus or Non-Opaque Objects Location: Any region of the Esophagus. Imaging Appearance:  Barium Swallow: to demonstrate the level of Impaction causing the Obstruction. Foreign Bodies: Non-Food-Related (Coin) or Opaque Location: Any region of the Esophagus. Imaging Appearance: Intraluminal Filling Defect with an Irregular Surface. Esophageal Perforation: inflammatory, neoplastic, or traumatic. Location: Any region of the Esophagus. Imaging Appearance:  Perforation Through Entire Wall – Air in the Mediastinum. 2. Pyloric Stenosis  Extravasation of Contrast Material through Perforation.  Infantile Hypertrophic Pyloric Stenosis (IHPS).  Occurs when the 2 Muscular Layers of Pylorus become Hyperplastic and Hypertrophic.  Environmental and Hereditary Factors: are believed to cause this process in 2 - 4 per 1000 live births (0.02 – 0.04%). Radiographic Appearance Duodenal Ulcer: Most Common Manifestation of Peptic Ulcer Disease.  Ultrasound: modality of choice. High Sensitivity & Specificity. Accuracy approach 100%  More than 95% of Duodenal Ulcers occur in the 1st Portion of Duodenum (Duodenal Bulb).  Appears as a Thickened Pyloric Muscle (width >3 mm) and an Elongated Pyloric Canal  Well-defined collection of barium in ulcer crater “cloverleaf deformity” if healed with scarring (>1.2 cm) on the Longitudinal Sonogram.  Chronic Duodenal Ulcer Disease: typical Cloverleaf Deformity is visible.  Palpable Olive appears as a “Doughnut” or “Target” Sign in the Cross-Sectional Image.  Duodenal Ulcer: Ulcer Position appears as a Rounded Collection of Barium surrounded by Lucent Edema. Thickened, Hypoechoic Gastric Antral Muscle with an Elongated Canal nearly 2 cm in Length.  (B) Transverse Image demonstrates the typical Hypoechoic Doughnut. Gastric Ulcers: another form of Peptic Ulcer Disease, usually occur on Stomach’s Lesser Curvature  Duodenal Ulcers are virtually always Benign, up to 5% of Gastric Ulcers are Malignant.  Barium-Filled Ulcer Crater along the Lesser Curvature or Posterior Wall of the Stomach, with 3. Peptic Ulcer Disease surrounding Mucosal Edema “Radiating Folds” around Gastric Ulcers.  Group of Inflammatory Processes involving the Stomach and Duodenum.  (A) Small, slender folds extending to the edge of crater indicate the Benign nature of ulcer.  It is caused by the Action of Acid and the Enzyme Pepsin secreted by the Stomach and  (B) Malignant Gastric Ulcer: thick folds radiate to an irregular mound of tissue around ulcer. occurs most frequently on the Lesser Curvature.  Acute Upper GI Bleeding: most commonly caused by Peptic Ulcer Disease.  Pneumoperitoneum with Peritonitis: most commonly caused by Free Perforation of a Peptic Ulcer located in the Anterior Wall of the Stomach or Duodenum.  Gastric Outlet Obstruction: most commonly caused by Narrowing of the Lumen of the Distal Stomach or Duodenal Bulb caused by Peptic Ulcer Disease.  Peptic Ulcer Disease: involves Ulceration of the Stomach or Duodenal Lining caused by an imbalance between Digestive Fluids in the Stomach and the Protective Lining. 4 Types of Peptic Ulcer Disease:  1. Inflammation Process  2. Gastric Ulcer Benign Gastric Ulcer  3. Duodenal Ulcer  On en face projection, Prominent Radiating Folds extend directly to the Ulcer.  4. Superficial Gastric Erosion  Lucency around the Ulcer represents Inflammatory Mass Effect. Radiographic Appearance  Penetration of Contrast Material outside the Normal, Barium-Filled Gastric Lumen associated with a Thin, Sharply Demarcated, Lucent Line with Parallel Straight Margins, representing Edema at the Base of the Ulcer Crater. Superficial Gastric Erosions: are Ulcerations that are so Small and Summary of Findings for the Stomach Shallow that they are rarely demonstrated on conventional Single- Gastritis Contrast Upper GI Examinations. Location:  Double-Contrast Techniques: Superficial Gastric Erosion typically appears radiographically as a Tiny Fleck of Barium,  Alcohol: Gastric Folds. which represents the Erosion, surrounded by a Radiolucent Halo, which represents a Mound of Edematous Mucosa. Imaging Appearance: 4. Cancer of the Stomach  Thickened Gastric Folds.  Gastric Outlet Obstruction.  Malignant Growth of Cells in the Stomach Lining, which may present in various forms. Location: 2 Common Types of Stomach Cancer:  Corrosive: Narrowing of Antrum.  1. Gastric Wall Infiltration (Linitis Plastica): Diffuse Infiltration of the Stomach Wall by Cancer Cells, causing Thickening and Loss of Elasticity. Location:  2. Polypoid Mass: a Protruding Mass that can develop from the Inner Lining of the  Bacterial or Infectious: Gastric Wall. Stomach, which may be Malignant. Imaging Appearance: Thickened Gastric Wall causing narrowing of Stomach & Gas in Stomach Wall Radiographic Appearance Location:  Gastric Wall Infiltration (Linitis Plastica): a rigid, non-distensible stomach with Loss of Rugal Folds. “Leather Bottle Stomach” Appearance.  Chronic Atrophic: Mucosal Folds.  Polypoid Mass: a Large, Lobulated Filling Defect within the Stomach, sometimes with Imaging Appearance: Thinning and Absence of Mucosal Folds (Bald). Central Ulceration on a Barium study. Pyloric Stenosis Location: Two Muscular Layers of the Pylorus. Imaging Appearance:  US: Thickened Pyloric Muscle (> 3 mm width) and Elongated Pyloric Canal (> 1.2 cm) on Longitudinal Sonogram.  UGI: demonstrate Shouldering caused by Filling Defect at the Antrum. Peptic Ulcer Small Bowel (Intestine): Pathology Location: Inflammatory Process. Imaging Appearance: Small Shallow Erosions to Perforations – Bleeding Ulcer. Location: Duodenal Ulcer. Imaging Appearance:  CT: Irregular Collection of Contrast Material in the Gastric Wall.  Rounded or Linear Collection of Contrast Material surrounded by Lucent Folds that often Radiate toward the Crater. Location: Gastric Ulcer. 1. Crohn’s Disease (Regional Enteritis) Imaging Appearance:  Is a Chronic Inflammatory Disorder of Unknown Cause.  Benign: Mucosal Folds are Smooth and Slender and extend to the edge of the Crater.  Most often involves the Terminal Area of the Ileum but can affect any part of the GI tract.  Malignant: Irregular Folds merge to a Mound of Polypoid Tissue around the Crater.  Although it can occur at any age, Crohn’s disease is most common in Young Adults.  The underlying cause is Unknown, although there appears to be some growing element; Location: Superficial Gastric Erosions. Stress or Emotional Upsets are frequently related to the Onset or Relapse of the disease. Imaging Appearance: Fleck of Barium with Radiolucent Halo. Radiographic Appearance Cancer Irregular Thickening & Distortion of Mucosal Folds; by Submucosal Inflammation & Edema. Location: Gastric Wall Infiltration.  String Sign: Narrowing of the Terminal Ileum due to Chronic Inflammation and Fibrosis. Imaging Appearance: Diffuse Thickening, Narrowing, and Fixation of Stomach Wall.  Skip Lesions: Patchy Areas of Inflammation separated by Normal Bowel Segments, seen on Small Bowel Series. Location: Polypoid Mass.  Cobblestone Appearance: due to Ulcerations and Submucosal Edema. Imaging Appearance: Irregularity and Ulceration suggest Malignancy.  Fistulas: Abnormal Connections between Bowel Loops or to adjacent structures, visible on Contrast Studies.  CT: o Stage 1: Intraluminal Mass without Wall Thickening. Cobblestone Appearance: is produced by Transverse and Longitudinal Ulcerations separating o Stage 2: Wall Thickening < 1 cm without invasion outside the organ. islands of Thickened Mucosa and Submucosa. o Stage 3: Thickened Wall with Extension into adjacent organs.  Arrows point to widely separated areas of disease (Skip Lesions). o Stage 4: Wall Thickening and Obliteration of Perigastric Fat.  The Lesions are greatly narrowed segments of small bowel (String Sign).  Endoscopic Ultrasound: Increased Echogenicity of Gastric Mucosa with Vertical Invasion through the wall. 2. Small Bowel Obstruction There are 2 Major Variants of Adynamic Ileus: Imaging Appearance  Localized Ileus: refers to an Isolated Distended Loop of small and large bowel (the Sentinel Loop), which is often associated with an adjacent Acute Inflammatory Process.  Distended Loops of Small Bowel containing Gas and Fluid can usually be recognized  Colonic Ileus: refers to Selective or Disproportionate Gaseous Distention of the Large radiographically within 3 - 5 hours of the Onset of Complete Obstruction. Bowel without an Obstruction. Almost all Gas proximal to a Small Bowel Obstruction represents Swallowed Air.  Upright or Lateral Decubitus Projections: the interface between Gas and Fluid forms a Straight Horizontal Margin. Supine A & Upright B projections demonstrate large amounts of Gas in dilated loops of small bowel.  Image B: taken with patient in Upright Position & using a Horizontal Beam, demonstrates Multiple Prominent Air–Fluid Levels. A single, small collection of Gas remains in Colon. Small Bowel Obstruction 2. Mechanical Ileus  Dilated Loops of Small Bowel occupy the Central Portion of Abdomen, with the Nondilated  Blockage caused by a Physical Obstruction, such as Tumors, Adhesions, Hernias. Cecum and Ascending Colon positioned Laterally around the periphery of the Abdomen. Radiographic Appearance  Uniformly Dilated Loops of Bowel (both Small and Large Bowel).  No Air-Fluid Levels, as there is No Active Peristalsis.  Diffuse Gas Pattern throughout the Abdomen with No Point of Transition. 3. Intussusception  Is a condition where one segment of the intestine Telescopes into an adjacent segment, leading to Obstruction and Compromised Blood Flow.  Children: Intussusception is most common in the region of the Ileocecal Valve. 1. Adynamic Ileus Radiographic Appearance  Lack of Intestinal Peristalsis, results in Functional Obstruction without Physical Blockage.  Barium Enema or Ultrasound: "Coiled Spring" or "Target Sign", representing layers of  Adynamic Ileus: occurs in almost every patient who undergoes Abdominal Surgery. the Bowel Telescoping into itself.  Other causes of Adynamic Ileus: are Peritonitis, Medications that decrease Intestinal  Contrast Studies: a Cupped Filling Defect can be seen in the Intestine. Peristalsis (with an Atropine-like effect), Electrolyte & Metabolic Disorders, and Trauma.  Ultrasound: show a Doughnut or Target Sign, which is characteristic of Intussusception. Imaging Appearance  The Radiographic Hallmark of Adynamic Ileus is the Retention of Large Amounts of Gas and Fluid in loops of Dilated Small and Large Bowel.  The entire Small and Large Bowel in Adynamic Ileus, appears almost Uniformly Dilated with no demonstrable point of Obstruction. Imaging Appearance Appearance:  Radiographically: an Intussusception produces the Classic Coiled-Spring Appearance of  Small Bowel Series: Barium trapped between the Intussusceptum and the surrounding portions of Bowel. o Irregular Thickened Mucosal Folds.  Reduction of a Colonic Intussusception can sometimes be accomplished by a Barium o Cobblestone Appearance. Enema Examination, although great care must be exercised to prevent Excessive o String Sign and Skip Lesions. Intraluminal Pressure, which may lead to Perforation of the Colon.  CT: Thick Mucosal Walls and “Dirty Fat” Mesenteric Appearance.  CT Images: Intussusception appears as 3 Concentric Circles forming a Soft Tissue Mass.  CT Enterography: Subtle Wall Thickening and Mucosal Vascular Changes.  Ulcerations: Fistula Formation. 4. Malabsorption Disorder Small Bowel Obstruction  Large number of conditions in which there is Defective Absorption of Carbohydrates, Proteins, and Fats from the Small Bowel. Location: Mechanical  Regardless of the cause, Malabsorption results in Steatorrhea — the passage of Bulky, Foul-Smelling, High-Fat-Content Stools that Float. Appearance: Imaging Appearance – The 2 Major Radiographic Appearances:  Abdomen: o Caliber of Air-filled bowel appears as dilated proximal bowel & collapsed distal bowel.  Many of the diseases that cause Malabsorption produce radiographic abnormalities in the o Stepladder Appearance. Small Bowel, although Malabsorption can exist without detectable Small Bowel changes.  CT: Herniation illustrated as a “Target Sign” as a result of Slight Wall Thickening with  1. Small Bowel Dilation with Normal Folds. Mesenteric Engorgement.  2. Pattern of Generalized, Irregular, Distorted Small Bowel Folds. Adynamic Ileus Sprue: Diffuse Dilation of entire Small Bowel with Excessive Intraluminal Fluid in Patient with Location: Loss of Motility in Small Bowel. Malabsorption. Appearance: Large amounts of Gas and Fluid in Small and Large Bowel. Whipple’s Disease: Diffuse, Irregular Thickening of Small Bowel Folds in a Patient with Malabsorption. Intussusception Atrophy of Folds: Reversal of the Fold Pattern with more Prominent Folds in the Ileum and Location: Featureless Bald Appearance of the Jejunum.  Children: Ileocecal Valve. Appearance:  Radiograph: Coiled Spring Appearance on Contrast Enema.  CT: 3 Concentric Circles forming a Soft Tissue Mass.  Ultrasound: Doughnut-shaped Lesion. Malabsorption Disorders Location: Throughout Small Bowel. Summary of Findings for the Small Bowel Appearance: Crohn’s Disease (Regional Enteritis)  Dilation with Normal Folds.  Irregular Distorted Folds. Location: Most often in Terminal Ileum. Large Bowel (Intestine): Pathology  The Incidence of Colonic Diverticulosis increases with Age.  Rare in persons younger than 30 years. 1. Acute Appendicitis  Diverticula: can be demonstrated in up to half of persons older than 60 years.  Develops when the Neck of the Appendix becomes Blocked by a Fecalith or by Post  Diverticular Disease: is presumed to occur in individuals who frequently exert High Inflammatory Scarring that creates a Closed-Loop Obstruction within the organ. Pressures in the Lumen while straining to pass a large bulk of Stool.  Because of Inadequate Drainage, Fluid accumulates in the Obstructed Portion and serves as a Breeding Ground for Bacteria.  High Intraluminal Pressure: causes Distention and Thinning of the Appendix distal to the Obstruction, which interferes with Circulation and may lead to Gangrene and Perforation.  Appendicitis: occurs in all age groups but is more common in Children and Adolescents. Imaging Appearance  Plain Abdominal Radiographs: demonstrate Round or Oval, Laminated Calcified Fecalith in the Appendix (Appendicolith).  CT Scan: CT of Upper Pelvis. Shows an Appendix with an Enlarged Thickened Wall indicating Inflammation. An Appendicolith can be seen in the Appendix. Diverticulosis  The typical Sawtoothed Configuration is produced by Thickened Circular Muscle and is associated with Multiple Diverticula. Imaging Appearance  Colonic Diverticula: appear radiographically as Round or Oval Outpouchings of Barium projecting beyond the confines of the Lumen.  Vary in size from Barely Visible Dimples to Saclike Structures 2 cm or more in Diameter.  Giant Sigmoid Diverticula: up to 25 cm in Diameter, which probably represent slowly progressing Chronic Diverticular Abscesses.  May appear as: Large, Well-Circumscribed, Lucent Cystic Structures in Lower Abdomen 2. Colonic Diverticula  Are Outpouchings that represent Acquired Herniations of Mucosa and Submucosa through the Muscular Layers at points of Weakness in the Bowel Wall.   Aphthous Ulcers: in Crohn’s disease have a Patchy Distribution against a background of Normal Mucosa, unlike the blanket of Abnormal Granular Mucosa in Ulcerative Colitis. Diffuse Aphthous Ulcers in early Crohn’s Colitis. Long Intramural Fistula in the Transverse Colon. Diverticulitis  Complication of Diverticular Disease of the Colon (Necrosing Inflammation in the Diverticula), especially in the Sigmoid Region.  Perforation of a Diverticulum leads to the development of a Peridiverticular Abscess. Thin Projection of Contrast Material (arrow) implies Extravasation from colonic lumen. Summary of Findings for Inflammatory Disease – Colitis  Severe Spasm of the Sigmoid Colon caused by Intense Adjacent Inflammation. Ulcerative 3. Ulcerative Colitis  Location: Rectal Involvement in 95% of cases; moves Proximally.  An Idiopathic Inflammatory Condition of the Colon which results in Diffuse Friability and  Involvement: Continuous Superficial Erosions on the Colonic Wall and associated Bleeding.  Layers: Only in Mucosal Layer  Main Symptoms: Bloody Diarrhea, Abdominal Pain, Fever, and Weight Loss. Crohn’s  Irregular Mucosa with Loss of Normal Haustral Markings.  Location: Proximal Colon (Terminal Ileum in 80% of cases)  Involvement: Patchy  Layers: All Intestinal Wall Layers (Mucosal through Serosal Layer) 5. Ischemic Colitis  Characterized by the Abrupt Onset of Lower Abdominal Pain and Rectal Bleeding.  Physical Examination: Diarrhea is common, as is Abdominal Tenderness.  Most patients are older than 50 years, and have a history of prior Cardiovascular Disease. Imaging Appearance  The initial radiographic appearance of ischemic colitis is Fine Superficial 4. Crohn’s Colitis Ulceration caused by Inflammatory Edema of the Mucosa.  The earliest radiographic findings in Crohn’s Disease of the Colon are seen on Double-  As the disease progresses, Deep Penetrating Ulcers, Pseudopolyps, Contrast Examinations. and characteristic Thumbprinting can be demonstrated.  Isolated Tiny, Discrete Erosions (Aphthous Ulcers) appear as Punctate Collections of  Thumbprinting: refers to Sharply Defined, Finger-Like Indentations Barium with a Thin Halo of Edema around them. along the margins of the colon wall. Soft Tissue Polypoid Densities (arrow) protrude into the Lumen of the Descending Colon in a 8. Hemorrhoids patient with Acute Abdominal Pain and Rectal Bleeding.  Hemorrhoids: are Swollen Veins in the Lower Rectum or Anus 6. Colon Cancer that can cause Discomfort, Bleeding, and Itching.  Colon Cancer: Malignant Tumor of the Colon, often arising from Adenomatous Polyps, Radiographic Appearance which can cause Bowel Obstruction, Bleeding, or Perforation.  Imaging (rarely needed): Hemorrhoids are not usually diagnosed Radiographic Appearance via Radiology, but on Colonoscopy, they appear as Swollen, Dilated Veins in the Rectum or Anus.  Barium Enema: Apple-Core or Napkin-Ring Lesion, a Constricted Segment of the Bowel.  Ultrasound or Doppler: May show Dilated Venous Structures in  CT Scan: Irregular, Annular Narrowing of the Colon with Thickened Walls, possible severe cases. Lymph Node Enlargement, and Distant Metastases.  Colonoscopy: Direct visualization of Polypoid or Ulcerative Mass. 9. Hirschsprung Disease or Congenital Aganglionic Megacolon Annular Carcinoma (described as Apple-Core or Napkin-Ring Carcinoma) is one of the most  Hirschsprung Disease: is a Congenital Condition characterized by the Absence of typical forms of Primary Colonic Malignancy. Ganglion Cells in the Distal Colon, leading to a Functional Bowel Obstruction.  Aganglionic Segment: cannot relax properly, resulting in Severe Constipation or Intestinal Blockage. 7. Volvulus  Twisting of the bowel on itself that may lead to Intestinal Obstruction. Barium Enema Cecal Volvulus  Demonstrates a Reduced Caliber Rectum and Sigmoid (the Rectum is smaller than the  Distended Cecum tends to be displaced upward & to left. Descending Colon) with a Saw-Tooth Appearance to the Wall.  Although it can be found anywhere within the abdomen.  Transition Point is seen at the junction between Sigmoid and Descending Colon.  A Pathognomonic Sign of Cecal Volvulus is a Kidney-Shaped Mass (representing the Summary of Findings of the Colon Twisted Cecum) with the Twisted and Thickening Mesentery mimicking the Renal Pelvis. Appendicitis Sigmoid Volvulus Location: Appendix  Barium Enema Examination: demonstrates an Obstruction to the flow of Contrast Material at the site of Volvulus and considerable Distention of the Rectum. Appearance:  The Lumen of the Sigmoid tapers toward the site of Stenosis, and a pathognomonic Bird’s- Beak Appearance is produced.  KUB: Appendicolith  US: Noncompressible 7 mm or Larger Outer Diameter.   CT: Round or Oval Mass, possibly containing Gas; Dilated Lumen with Thickened, Irritable Bowel Syndrome Circumferentially Enhancing Wall. Location: Alteration of Intestinal Motility. Diverticulosis Appearance: Location: Most Common in Sigmoid.  No specific findings. Appearance: Round or Oval Outpouching projecting beyond Lumen; usually Multiple.  Rule out other disorders. Diverticulitis Cancer Location: Inflammation of Diverticula. Location: 50% in Rectum and Sigmoid Region. Appearance: Appearance:  Diverticular Perforation with possible Abscess.  Sessile Lesion: Irregular, Lobulated Surface.  US: Hypoechoic Projection surrounded by Inflamed Fat.  CT: Larger than 2 cm, "Apple-Core" or "Napkin-Ring” Appearance.  CT: Nonspecific Wall Thickening with a Narrowed Bowel Lumen. o Circumferential Bowel Wall Thickening, Metastasis, Lymphadenopathy. o Virtual Colonoscopy demonstrates 8 - to 10 - mm Lesions. Ulcerative Colitis  US: Transrectal; depth of Tumor Invasion into Bowel Wall. Location: Superficial and Acute; beginning in Rectosigmoid Area with continuous involvement  PET: detection of Distant Nodular Metastasis. throughout Colon.  Fusion (PET/CT) imaging: provides the most specific detail. Appearance: Large Bowel Obstruction  KUB: Deep Ulcers with Intraluminal Gas or Polypoid Changes, Loss of Haustral Markings. Location: Large Bowel.  BE (Double Contrast): Fine Granularity of Mucosa; Submucosa with broad-based Ulcers Appearance: having a Collar-Button Appearance.  Ileocecal Valve Competent: large dilated Colon, thin-walled Cecum, little small-bowel Gas. Crohn's Disease  Ileocecal Valve Incompetent: gas-filled loops of Colon and of Small bowel. Location: Terminal Ileum and Proximal Colon most often. Volvulus Appearance: Location: Cecal or Sigmoid Colon.  BE (Double Contrast): Patchy Distribution, Noncontiguous Segments (Skip Lesions). Appearance:  CT: Colonic Wall Thickening and Abscess Formation.  Distended Cecum, displaced Upward and to the Left. Ischemic Colitis  Distended Rectum, devoid of Haustral markings, and a Sausage or Balloon shape. Location: Entire Colon.  Bird's-Beak appearance. Appearance: Hemorrhoids  Fine Superficial Ulceration. Location: Distal Rectum.  Characteristic "Thumbprinting". Appearance:  Tubular Narrowing and a Smooth Stricture.  Single or Multiple Rectal Filling Defects simulating Polyps.