Plain abdominal X-ray

Normal plain abdominal X-ray

Structures Normally Seen Liver Spleen Kidneys Stomach Duodenum Small Intestine Cecum Colon Bladder Prostate Retroperitoneal fat

Structures Not Normally Seen Gall bladder Pancreas Adrenals Ovaries Uterus Ureters Lymph nodes Mesentery Vasculature

What to Examine Gas pattern Extra luminal air Soft tissue masses Calcifications Foreign body

1-calcification

1-calcification pancreas

kidney

Gall bladder

Suprarenal glands

Pancreatic mass

Fibroid uterus

Ureteric calculi

Calcified phicolith

- Gas pattern 2

Normal Gas Pattern *Stomach *Small Bowel *Large Bowel Always Two or three loops of non-distended bowel Normal diameter = 2.5 - 3.5 cm *Large Bowel In rectum or sigmoid – almost always Normal diameter=5.5 - 7.5cm

Gas in stomach Gas in a few loops of small bowel Gas in rectum or sigmoid Normal Gas Pattern

(Gas pattern) Intra-luminal gas can be normal. Extra-luminal gas is abnormal. However, intra-luminal gas can be abnormal if it is in the wrong place or if too much is seen.

Normal Fluid Levels *Stomach *Small Bowel *Large Bowel Always (except supine film) *Small Bowel Two or three levels possible *Large Bowel None normally

Always air/fluid level in stomach A few air/fluid levels in small bowel Erect Abdomen

Large vs. Small Bowel *Large Bowel Peripheral Haustral markings don't extend from wall to wall *Small Bowel -Central -Valvulae extend across lumen

Complete Abdomen Obstruction Series *Supine *Erect or left decubitus *Chest - erect or supine

Abnormal Gas Patterns *Functional Ileus *Mechanical Obstruction Localized (Sentinel Loops) Generalized dynamic ileus *Mechanical Obstruction SBO LBO

Localized Ileus Key Features One or two persistently dilated loops of large or small bowel Gas in rectum or sigmoid

Supine Prone Sentinel Loops

Generalized Ileus Key Features Gas in dilated small bowel and large bowel to rectum Long air-fluid levels Only post-op patients have generalized ileus

Generalized Adynamic Ileus Supine Erect Generalized Adynamic Ileus

Mechanical SBO Key Features Dilated small bowel Multiple fluid levels in small bowel Little gas in colon, especially rectum

SBO

Mechanical SBO Causes Adhesions Hernia Volvulus Gallstone ileus Intussusception *Cause may be visible on plain film

Mechanical LBO Key Features Dilated colon to point of obstruction Little or no air in rectum/sigmoid Little or no gas in small bowel, if… Ileocecal valve remains competent

Supine Prone LBO

Mechanical LBO Causes Tumor Volvulus Hernia Diverticulitis Intussusception

Extra luminal Air Free Intraperitoneal Air

Free Air Causes Rupture of a hollow viscus Post-op 5–7 days Perforated ulcer Perforated diverticulitis Perforated carcinoma Trauma or instrumentation Post-op 5–7 days NOT perforated appendix

3-Soft Tissue Masses

Soft Tissue Masses Hepatosplenomegaly Tumor or cyst Plain films poor for judging liver size Tumor or cyst Bowel displacement *decrease of gas *Extrinsic compression of bowel

Splenomegaly

hernia

Extrinsic compression of bowel Right Renal Cyst

Coin in esophagus