Radiography and CT of Adult Large-Bowel Obstruction

A review of the imaging findings in multiple causes of large bowel obstruction and a comparison with acute colonic pseudo-obstruction.

Course ID: Q00469 Category:
Modalities: ,


Satisfaction Guarantee


Targeted CE per ARRT’s Discipline, Category, and Subcategory classification:
[Note: Discipline-specific Targeted CE credits may be less than the total Category A credits approved for this course.]

Computed Tomography: 1.50
Procedures: 1.50
Abdomen and Pelvis: 1.50

Radiography: 0.50
Procedures: 0.50
Head, Spine and Pelvis Procedures: 0.50

Registered Radiologist Assistant: 2.00
Procedures: 2.00
Abdominal Section: 2.00


  1. Introduction
  2. Clinical Findings and Pathophysology
  3. Abdominal Radiography Technique
    1. Merits of Abdominal Radiography
    2. Challenges of Abdominal Radiography in Patients with LBO
  4. Multidetector CT
    1. CT Technique
    2. Pitfalls of CT Imaging of LBO
  5. The Contrast Enema
  6. LBO: Major Causes
    1. Colon Carcinoma
    2. Volvulus
    3. Sigmoid Volvulus
    4. Cecal Volvulus
    5. Transverse Colon Volvulus
    6. Diverticulitis
    7. Adult Intussusception
    8. Intraluminal Contents Causing LBO
    9. Hernias
    10. Inflammatory Bowel Disease
    11. Adhesions
    12. External Compression
  7. ACPO or Ogilvie Syndrome: An Important Mimic of LBO


Upon completion of this course, students will:

  1. describe the anatomy and function of the colon
  2. understand the symptoms of LBO
  3. describe both common and less common causes of LBO
  4. know the frequency of LBO compared to SBO
  5. describe the key topographic anatomical landmarks of the abdomen
  6. know the main anatomical sites in the colon where LBO occurs
  7. describe a volvulus and where they occur
  8. understand how abdominal sounds relate to LBO
  9. describe the quadrants that make up the abdominal cavity
  10. describe the radiographic projections used in an abdominal radiographic series
  11. know which radiographic views are able to show air/fluid levels in the abdomen
  12. understand the sensitivity of abdominal radiography in diagnosing LBO
  13. describe pneumatosis intestinalis and the associated CT findings
  14. describe ACPO and its alternative names
  15. understand the role CT plays in diagnosing LBO
  16. understand the role a contrast enema plays in diagnosing LBO
  17. know the relationship between colon malignancy and LBO
  18. know the various radiographic signs related to a sigmoid volvulus
  19. describe a cecal volvulus
  20. know the abdominal radiography, CT and contrast enema findings of a cecal volvulus
  21. describe the CT findings of ischemia associated with cecal volvulus
  22. describe a volvulus of the transverse colon and its findings on a contrast enema
  23. know the relationship between diverticulitis and LBO
  24. know how diverticulitis is characterized with CT
  25. describe adult intussusception and its relationship to LBO
  26. know the classic appearance of adult intussusception on a contrast enema
  27. know how intraluminal contents relate to LBO
  28. know the various types of internal hernias and their relationships to LBO
  29. describe the relationship between Crohn disease and LBO
  30. understand how adhesions and external compression from masses relate to LBO