BASIC GI RADIOLOGY
THE “FLAT” PLATE
Michael Maristany, MD
Janis Letourneau, MD
After: Robert S. Perret, MD
KUB/Abdominal plain film
Most common
abdominal
radiograph
 Patient supine
 Often combined
with upright (CXR)

KUB
Normal
KUB
KUB
K
kidney
 U ureter
 B bladder
 Term KUB indicates that the kidneys,
ureters, and bladder are on the film
 But these organs are not
necessarily seen on the image
K
K
u
u
u
u
B
KUB –
Backwards
KUB
Paradoxically, organ system of greatest
interest is often GI tract
 Small bowel situated centrally
 Large bowel located on periphery

colon
colon
small
bowel
rectum
Contrast filled
stomach and
small bowel
Contrast filled
Colon
Miller-Abbott
decompression tube
For intestinal
obstruction
KUB
KUB’s
Why order them, anyway?

> 85% (for pain, colic, nausea, etc)
 KUB will be non-contributory or normal
Why can KUB be useful?
Bowel gas pattern characterization
 Detection of free air
 Abnormal calcifications
 Detection of organomegaly
 Discovery of abdominal masses
 Evaluation of bony structures
 Surgical / other medically relevant history

Bowel Gas Pattern
Four major patterns
 Ileus
 Obstruction
 Gasless
 Normal
 “Free” air

Abnormal Bowel Gas Pattern:
Small Bowel Obstruction
Bowel Obstruction
 Dilated loops of bowel
 SBO – (small bowel obstruction)
 Adhesions
 Less likely inflammatory/neoplastic
 Colonic obstruction
 More often of malignant etiology

Small Bowel Obstruction
Dilated loops of small bowel (>3 cm) KUB
 With air/fluid levels on upright view
 Stair-step pattern to air/fluid levels
 Gasless colon

Normal
Abnormal
Dilated small bowel - KUB
Air/fluid levels on upright
PFs => SBO
CT ABDOMEN: SBO
Transition point – luminal caliber
Normal
KUB
What’s likely dx?
Common etiologies?
FREE (INTRAPERITONEAL) AIR
KUB is not the best exam; upright or LLQ views helpful
Think also of CT; not only good for detection, but for cause
KUB – Abnormal Ca++
Calcifications
 Gallstones
 Kidney stones
 Vascular
 Masses with calcifications (myoma, AAA)
 Gallstones
 20% < will be calcified
 Kidney stones
 >75% will be calcified

KUB - gallstones
KUB - Porcelain Gallbladder
(or very large calcified stones)
Gallstones?
ERCP
Most gallstones will not be seen on KUB
– not sufficiently calcified
KUB - kidney stones
Kidney stones will often be visualized
 Related to extent of calcification
 Detection limit 1-2 mm
 Overlying intestinal gas limiting
 Obesity limiting

Kidney Stones
Other Calcified Abnormalities






Uterine myomas
Pancreatic ductal calcifications
Vascular calcification
Appendicolith
Neoplasms
 sarcoma, testicular cancer, neuroblastoma
Old hematomas
Uterine Myoma
CHRONIC PANCREATITIS
Calcified
Uterine arteries
Appendicolith
Splenic hematoma
Injection granulomata
Patient
Detained
Miami International
Non-calcified mass
or mass effect
Major limitation of plain films
 Organomegaly (multifocal dz vs diffuse)
 Neoplasm, abscess, hematoma
 Free peritoneal fluid (distribution of SB)
 Difficult to differentiate
 Relatively homogeneous
 Soft tissue density
 Merit of CT and MRI

Non calcified mass effect
OTHER GI
IMAGING MODALITIES
Esophagram
 Upper GI Series
 Small Bowel Follow-Through
 Barium Enema (or Contrast Enema)
 CT and CT Colonography
 ERCP
 MRCP
 US

UGIS and SBFT
AC Barium Enema
UNKNOWN CASE
52 yo man from Boston
Bloody diarrhea
Following half-marathon
(CCC and poor training)
Thumb-printing: colonic wall edema
Inflammation, ischemia, diffuse mural infiltration
CONSIDERATIONS
UNKNOWN (REAL) CASES
Patient age and gender
 Clinical symptoms
 Underlying diseases
 Including psychiatric (case of gym sock)
 Need for additional views (one at least)
 Localize mass or foreign body
 Deductive reasoning……….

Not the usual “stacked” coin appearance
And not causing GOO
More typical “stacked” coins