Michael J. Callahan, M.D.
Department of Radiology
Boston Children’s Hospital
5 things I learned the
hard way : GI imaging
• Free air can be costly
• Not partial to small bowel
obstruction
• Read between the lines
• Bone to pick
• Contrast media, friend or foe?
5 things I learned the
hard way : GI imaging
• Free air can be costly
• Not partial to small bowel
obstruction
• Read between the lines
• Contrast media is my friend
• Contrast Media is my enemy
5 things I learned the
hard way : GI imaging
4-year-old girl with a cecal
perforation due to enteritis.
• Subphrenic air
• Falciform ligament sign
• Ligamentum teres sign
• Rigler’s sign
NEJM Radiologic Signs of Pneumoperitoneum
Ching-Hsing Lee, M.D.
N Engl J Med 2010
Signs
“Pseudo-pneumoperitoneum”
• Liver looks lucent
• Mimics free
intraperitoneal air
• Pt received 7 ml/kg
iodinated contrast in
cardiac cath lab
• peritoneal fluid is
dense due to third
space fluid loss with
contrast
Pseudo-pneumoperitoneum
• Peritoneum
looks lucent
relative to liver
• UVC misplaced,
eroded through
liver
• Fat-containing
TPN in peritoneal
cavity
• Respect the scout film
• Not partial to small bowel
obstruction
• Read between the lines
• Contrast media, friend
• Contrast Media, foe
5 things I learned the
hard way : GI imaging
Radiographic Findings
of SBO
• Air-fluid levels of differential
height in the same small
bowel loop
• Mean small bowel air-fluid
width greater than or equal to
25 mm
• Dilated proximal Small bowel
• Collapsed Colon
“Normal” Air - Fluid levels
• Stomach
– Almost always (upright or decub)
• Small Bowel
– A few are usually acceptable
• Large Bowel
– Normally none
Diff Dx Pediatric SBO
“AIM” X 2
– Appendicitis
– Adhesions
– Internal hernia
– Intussusception
– Meckel’s
– Malrotation
IBD
Ingested
Foreign
Body
Adynamic Ileus
– “paralytic”
– can simulate mechanical obstruction
– Generally causes BOTH small and
large intestine to dilate
– CAN have AFLs
Caffey Edition, 2010 Part VII Small Intestine, Parker BR, pp. 1616 -
What is a “PSBO”?
• Mechanical Obstruction – blocked
lumen
• Functional / Neurogenic Obstruction
– Abnormal or absent peristalsis
– Called “ileus” in reference to small
bowel
• Colon ?
• 10 y.o. male w
Scoliosis
• “There is a mild
broad-based
dextroscoliosis of
the thoracolumbar
spine”
• “There is a
gastrostomy tube
in place, and a
partially
obstructive bowel
gas pattern”.
9 yo male w autism and
abdominal pain
12/11/16 early AM,
GoLytely therapy
12/11/16 KUB: “ multiple air-fluid
levels, concerning for evolving
small bowel obstruction
Referring clinician was
called: “Patient is
asymptomatic”
• Respect the scout film
• Not partial to small bowel
obstruction
• Read between the lines
• Contrast media, friend
• Contrast Media, foe
5 things I learned the
hard way : GI imaging
Trainee prelim read, “feeding
tube in the stomach”
5 yo male, w
septo-optic dysplasia
Chest radiograph obtained
hours later confirmed the
feeding tube to be in the
segmental left lower lobe
bronchus
Radiograph shows
endotracheal tube tip
overlying carina,
underinflated lungs, and
air-distended esophagus,
stomach and small bowel
Preterm male infant
Trainee prelim read, “ETT
in the right mainstem
bronchus, pull back 1 cm”
Esophageal intubation
• Free air can be costly
• Not partial to small bowel
obstruction
• Read between the lines
• Bone to pick
• Contrast media, friend or foe?
5 things I learned the
hard way : GI imaging
• Respect the scout film
• Not partial to small bowel
obstruction
• Read between the lines
• Contrast media, friend or foe?
5 things I learned the
hard way : GI imaging
Contrast Medium
• Substance
used to
enhance the
“contrast” of
structures or
fluids within
the body for
medical
imaging
GE Cor 3-D MRCP sequence
Nature’s Place Organic
Blueberry Juice
True Blue Blueberry
Juice Walgreen’s Distilled Water
CT
• Variable opinions on need of
enteric contrast media for
pediatric CT abdominal imaging
• Can be helpful in children w
paucity of retroperitoneal and
intraperitoneal fat, and increased
image noise
• Diff. Diagnosis: Mesenteric cyst
vs. LM
• Drainage by IR
• Ruptured, resulting in hypotension
and ICU stay
• Discharged w tumor markers sent
• Back to ED 10 days later,
abdominal pain
CT: Is enteric contrast
necessary ?
• Not always
• Can be helpful, but certainly not
mandatory
• Trauma, Appendicitis
• Can be helpful in children w
paucity of retroperitoneal and
intraperitoneal fat, and increased
image noise
• Free air can be costly
• Not partial to small bowel
obstruction
• Read between the lines
• Bone to pick
• Contrast media, friend or foe?
5 things I learned the
hard way : GI imaging