1. Abdominal Sonography I Lecture 8 Gastrointestinal Tract
HHoldorf

3. Outline Bowel Wall Gastro esophageal Junction Acute Appendicitis
Hypertrophic Pyloric Stenosis
Laboratory values
Diverticulitis
Bowel Obstruction
Duodenal Atresia
Intussusception

4. Bowel Wall
The normal intestinal wall is between 3 and 5 mm thick, depending on distention of the bowel. Five sonographic interfaces can be seen when imaging the intestinal wall.
Intestinal pathology creates a sonographic pattern known as the TARGET or PSEUDOKIDNEY sign. This appears as a hypoechoic external rim corresponding to thickened intestinal wall and a hyperechoic center relating to a residual gut lumen or mucosal ulceration. .
Be able to identify an image of the pseudokidney sign

6. Normal Bowel wall

7. The wall is divided into four layers as follows:
Mucosa : The innermost layer of the digestive tract
Submucosa
Muscularis externa
Serosa/mesentery
The outer layer of the gut is formed by fat and another layer of epithelial cells called mesothelium.

8. Causes of Wall Thickening of the Small Bowel
Wall edema Malignancy
Postoperative Lymphoma
Cirrhosis/ascites Peritoneal carcinomatosis
Hypoproteinemia

9. Causes of Wall Thickening of the Small Bowel
Inflammatory bowel disease
Crohn’s disease
Acute ileitis
Extraintestinal inflammatory conditions
Pancreatitis
Endometriosis
Homework: Define Crohn’s Disease

10. Causes of Wall Thickening of the Small Bowel
Mesenteric ischemia/infarction
Thrombosis of mesenteric veins
Thrombosis of mesenteric arteries
Small bowel disease/malabsorption
Celiac disease
Whipple’s disease : Define Whipple’s Disease for homework
Benign intestinal tumors
adenoma,
lipoma

11. Benign Gastric Wall Thickening
Benign Gastric Wall Thickening. The wall of the gastric antrum (arrow) as seen in short axis view is diffusely and symmetrically thickened by adjacent acute pancreatitis

12. Pseudokidney sign

13. Gastro esophageal junction
The segment of esophagus between the diaphragm and the stomach is called the gastroesophageal junction.
On a longitudinal midline view of the epigastrum, this is seen as a target sign posterior to the left lobe of the liver.
Be able to recognize an image of the Gastroesophageal Junction (GE junction)

15. Gastroesophageal Junction (GE junction)

16. Acute Appendicitis
Acute appendicitis is the most common cause of an acutely painful abdomen. Patients present with
Peri-umbilical pain shifting to RLQ
Leukocytosis (increased WBC count)
Nausea, vomiting, and low-grade fever
Rebound tenderness

17. McBurney’s point
The right lower quadrant location of the most tender area in the early stages of appendicitis.

18. Appendicitis is caused by the obstruction of the appendiceal lumen by a fecalith or hyperplasia of the submucosa.
Mucosal secretions increase the intraluminal pressure and compromise venous and lymphatic drainage.
Bacterial infection leads to gangrene and perforation. Perforation leads to peritonitis.

19. Graded –compression ultrasound is utilized to displace bowel gas and decrease the distance between the transducer and the appendix.
Sonographic criteria for diagnosing an inflammatory appendix includes
Non-compressible appendix
> 6 mm diameter
Appendicolith (fecalith)
NOTE: Do not be afraid to push the gas away.
In female patients of child-bearing age, right lower quadrant pain may be due to pathology of the appendix or gynecologic structures.

20. Color flow hyperemia can be observed with an inflamed appendix.
Be able to identify several images/examples of acute appendicitis.

22. Normal Appendix

23. Abnormal Appendix: Thickened appendix secondary to Crohns’s disease.

24. Hypertrophic Pyloric Stenosis
Hypertrophic pyloric stenosis (HPS or sometimes referred to as IHPS) has a 4 to 1 male to female ratio. Characterized by hypertrophy of the circular muscle resulting in elongation of the pylorus and constriction of the canal.

26. The neonatal (3-6 weeks of age) patient presents with
Projective vomiting
Palpable olive-shaped abdominal mass
Ultrasound is the method of choice for diagnosing HPS. The diagnostic criteria includes
Pyloric muscle thickness >3mm
Pyloric channel length >12 mm
Pyloric cross section >15 mm
With hypertrophic pyloric stenosis, there is an increase in the pyloric diameter and length.

27. Identify images of a hypertrophic pyloric stenosis with muscle thickness measured, channel length measured, and cross section measured.

28. IHPS

29. IHPS : Radiology string sign

30. IHPS

31. Laboratory values Carcinoembryoinic antigen (CEA)
Increased levels are found in patients with colon carcinoma. Although it is not specific for colon cancer, it is also associated with cirrhosis, ulcerative colitis, and other cancers.

32. Diverticulitis
Diverticulitis is the inflammation of diverticulum (Colonic outpouchings). Diverticulum commonly involve the sigmoid colon.
Symptoms of diverticulitis include
Fever
Leukocytosis
Left lower quadrant pain

34. Sonographic findings include:
Thickening of the bowel wall (> 4mm)
Abscess formation
Inflamed diverticula (round echogenic structures
Be able to identify an image of diverticulitis

35. Diverticulitis of the Sigmoid colon

36. Bowel Obstruction
Mechanical small-bowel obstruction (SBO) can be caused by
Intraluminal (food bolus)
Bowel wall lesion (tumor, Crohn disease)
Extrinsic (adhesions, hernia)-most common
Prolonged bowel obstruction can result in
Bowel ischemia
Bowel necrosis
Septicemia
Perforation
Peritonitis

38. Symptoms include
Abdominal distention
Paint
Vomiting
Hypotension (caused by fluid depletion)
Leukocytosis
Ultrasound is used to demonstrate loops of distended bowel, level of obstruction, and peristalsis
Identify images of Bowel obstruction in the small bowel and the large colon.

39. Bowel Obstruction

40. Duodenal Atresia
Duodenal atresia presents in newborns with the onset of vomiting within hours of birth. Once delivered, epigastric fullness form dilatation of the stomach and proximal duodenum is noted.
Duodenal atresia may be discovered during a prenatal ultrasound. The ultrasound evaluation will demonstrate:
Polyhydramnios
Fluid-filled stomach
Fluid-filled proximal duodenum
This is referred to as the double bubble sign
Identify an image of the double bubble sign

43. Duodenal Atresia

44. Intussusception
Intussusception is a process in which a segment of intestine invaginates into the adjoining intestinal lumen (telescoping), causing a bowel obstruction. This is the most common cause of obstruction in infants and typically occurs less than one year of age.

46. Classic symptoms of Intussusception include
Vomiting
Abdominal pain
Rectal bleeding
Although difficult to detect, a physical finding of a sausage-shaped mass in the right hypochondrium is a classic sign of an Intussusception.
Sonographically, Intussusception usually presents as an oval, pseudokidney-appearing mass. On a transverse view, concentric rings of folded bowel are typically seen.
Identify images of Intussusception on transverse views.

47. Intussusception: Target Sign

48. This one has a Think Tank
Next week
Think Tank Time!!!!!