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-calcificationpancreas

kidney

Gall bladder

Suprarenal glands

Pancreatic mass

Fibroid uterus

Ureteric calculi

Calcified phicolith

- Gas pattern2

Normal Gas Pattern

*Stomach– Always

*Small Bowel– 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– Always (except supine

film)

*Small Bowel– Two or three levels

possible

*Large Bowel– None normally

Erect Abdomen

Always air/fluid level in stomach

A few air/fluid levels in small bowel

Large vs. Small Bowel

*Large Bowel– Peripheral– Haustral markings don't

extend from wall to wall

*Small Bowel-Central

-Valvulae extend across lumen

Complete AbdomenObstruction Series

*Supine

*Erect or left decubitus

*Chest - erect or supine

Abnormal Gas Patterns

*Functional Ileus– Localized (Sentinel

Loops)– Generalized dynamic

ileus

*Mechanical Obstruction– SBO– LBO

• One or two persistently dilated loops of large or small bowel

• Gas in rectum or sigmoid

Localized IleusKey Features

Sentinel Loops

Supine Prone

• Gas in dilated small bowel and large bowel to rectum

• Long air-fluid levels

• Only post-op patients have generalized ileus

Generalized IleusKey Features

Generalized Adynamic Ileus

Supine Erect

Mechanical SBOKey Features

• Dilated small bowel

• Multiple fluid levels in small bowel

• Little gas in colon, especially rectum

SBO

Mechanical SBOCauses

• Adhesions

• Hernia

• Volvulus

• Gallstone ileus

• Intussusception

*Cause may be visible on plain film

Mechanical LBOKey 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

LBO

Supine Prone

Mechanical LBOCauses

• Tumor

• Volvulus

• Hernia

• Diverticulitis

• Intussusception

Extra luminal AirFree Intraperitoneal Air

Free AirCauses

• Rupture of a hollow viscus– 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– Plain films poor for judging liver

size

• Tumor or cyst– Bowel displacement

*decrease of gas

*Extrinsic compression of bowel

Splenomegaly

hernia

Right Renal Cyst

Extrinsic compression of bowel

Coin in esophagus