The Scope of the Problem: Imaging of Complications ... · Intraperitoneal Colonic Perforation...
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Transcript of The Scope of the Problem: Imaging of Complications ... · Intraperitoneal Colonic Perforation...
The Scope of the Problem:
Imaging of Complications
Following Optical Colonoscopy
Aaron Harman, MD
Kevin J. Chang, MD, FSAR
Department of Diagnostic Imaging
Rhode Island Hospital
The Warren Alpert Medical School of
Brown University
Disclosures
We have no relationships with
commercial interests to disclose.
Goals and Target Audience
• Goals: To provide the learner with high-
yield information on imaging findings of
complications from optical colonoscopy.
• Target Audience: Radiology residents,
radiologists, and CT technologists.
Background
• Optical colonoscopy has traditionally been
considered the gold standard for colorectal
cancer screening.
• Serious complications are reportedly rare
(0.1-0.3%), however given the increasing
volume of patients undergoing the procedure,
a significant number of patients are affected.
Background
• The most common complications are
hemorrhage and large bowel perforation.
• Upright plain films of the chest and abdomen
can be helpful in identifying intraperitoneal
free air but are insensitive in detecting other
pathology.
• CT imaging plays a key role in the diagnosis
of complications as well as in treatment
planning.
Colonic Perforation Mechanism:
1) Barotrauma caused by pneumatic dilatation
2) Direct trauma from the endoscope
• increased risk with polypectomy, stricture dilatation,
and stenting
Imaging Appearance: Extraluminal air may be
intraperitoneal, extraperitoneal, or both depending on the
segment of colon which was perforated.
Clinical Significance: This usually requires surgical
treatment, though there is increasing interest in
endoscopic clipping for localized perforations.
Intraperitoneal Colonic Perforation
• Intraperitoneal portions of the colon include the
cecum, transverse colon, and the sigmoid
colon.
• The cecum, having the largest caliber of any
portion of the large bowel, is most susceptible
to barotrauma injury, as predicted by the law of
LaPlace.
Intraperitoneal Colonic Perforation
Barotrauma perforations
tend to have larger
volumes of free air than
perforations due to direct
endoscope trauma.
66-year-old woman presented with
right shoulder pain following
colonoscopy. A large cecal
perforation was confirmed at the
time of surgery.
Lateral topogram (above)
and axial CT (right)
demonstrate a large
amount of free
intraperitoneal air.
Right: Coronal CT
demonstrates an
unremarkable cecum.
Extraperitoneal Colonic Perforation
• Retroperitoneal portions of the colon include the
ascending colon, descending colon, and the rectum.
• Above: Large amount of retroperitoneal air predominantly
on the right, which was found to originate from an
ascending colonic perforation at the time of surgery.
Extraperitoneal Colonic Perforation with
Extraabdominal Free Air • Free air may dissect through the fascial planes to extent
beyond the retroperitoneum.
Left: 78-year-old woman
presented with abdominal
pain and distention following
colonoscopy, found to have
pneumoretroperitoneum
(arrow), pneumomediastinum
(arrow) and subcutaneous
emphysema (arrow). Found to
have a perforation of the
ascending colon at the time of
surgery.
Intraperitoneal and Extraperitoneal
Colonic Perforation
Above: Intraperitoneal and
extraperitoneal free air on CT.
Below: AP CXR demonstrates subdiaphragmatic
free air (arrow), pneumomediastinum (arrow), &
subcutaneous emphysema in the neck (arrow).
56-year-old woman presenting with swelling of face and neck
hours after colonoscopy with dilatation of a sigmoid stricture.
Pneumatosis Coli
Air in the colonic wall (arrows) following colonoscopy may
be associated with perforation, or occur as a result of
barotrauma or biopsy without transmural perforation.
Postpolypectomy Coagulation
Syndrome
Mechanism: Electrocautery injury following polypectomy
extends beyond the mucosa and submucosa to cause a
serositis.
Imaging Appearance: Localized colonic mural thickening at
the site of polypectomy with stranding of the pericolonic fat
but without frank free air
Clinical Significance: 1% or less of all polypectomies.
Usually self-limited; treated with bowel rest and antibiotics.
Postpolypectomy Coagulation
Syndrome 63-year-old woman presents with right-
sided abdominal pain and chills which
began minutes after colonoscopy with
cecal polypectomy.
Coronal CT demonstrates mural
thickening (arrow) of the cecum with
metallic hemostatic clip. No free air.
The patient was admitted for 2 days,
treated with pain management and
antibiotics, and was discharged in
good condition.
Splenic Laceration
Proposed mechanisms:
1) Direct trauma by endoscope
2) Traction on the splenocolic ligament or adhesions by
endoscope maneuvers
- increased risk with splenomegaly, adhesions, prior
pancreatitis, and inflammatory bowel disease
Imaging Appearance: Perisplenic hematoma with focal splenic
hypoattenuation
Clinical Significance: In hemodynamically unstable patients,
emergent endovascular embolization or splenectomy is
generally indicated. Stable patients may be observed.
Splenic Laceration: Subcapsular
80-year-old man with acute abdominal pain following
colonoscopy earlier the same day. Axial and coronal CT
reformats show a subcapsular splenic hematoma of
mixed attenuation. He was hemodynamically stable
and was managed conservatively without surgery or
embolization.
Splenic Laceration: Extracapsular Axial and coronal contrast-enhanced
CT images performed for abdominal
pain and hemodynamic instability
following colonoscopy demonstrate a
large perisplenic hematoma with
hyperdense active extravasation
(arrows), as well as hemoperitoneum
within the pelvis.
The patient was taken to
the OR where she
underwent a splenectomy.
Hemorrhage
Mechanism: Hemorrhage can be intraluminal or extraluminal.
Intraluminal hemorrhage is most often due to polypectomy.
Extraluminal hemorrhage may be due to injury of blood
vessels adjacent to bowel during post-polypectomy cautery or
traction on the bowel wall during manipulation of the
colonoscope.
Imaging Appearance: Intraluminal hemorrhage may be
diagnosed with nuclear tagged-RBC scan, angiography, or
colonoscopy. Extraluminal hemorrhage manifests as a high-
density intraperitoneal or extraperitoneal fluid on CT.
Clinical Significance: Bleeding can be treated by endoscopic
clipping, endovascular embolization, or surgery.
Hemoperitoneum
72-year-old man with left upper quadrant pain one week following
colonoscopy. Axial CT shows hyperdense free fluid in the pelvis
consistent with hemoperitoneum (arrow). No other abnormality
was noted on the remainder of the exam. The patient was
managed conservatively without surgery.
Acute Diverticulitis
Mechanism: Colonoscope can cause mechanical injury to preexisting colonic diverticuli, or displace stool into and thereby obstruct diverticuli, leading to inflammation.
Imaging Appearance: On CT there is colonic wall thickening, pericolonic fatty stranding, and in cases of perforation, free air and/or a peripherally-enhancing fluid collection representing an abscess.
Clinical Significance: Uncomplicated diverticulitis is treated with symptomatic relief and IV antibiotics. Diverticulitis complicated by perforation may require percutaneous abscess drainage and/or partial colectomy.
Acute Diverticulitis
73-year-old female with rectal bleeding following incomplete
colonoscopy. Axial and Coronal reformats from a CT colonography
show sigmoid wall thickening with pericolonic fatty stranding and an
adjacent fluid collection (arrows). Surgery confirmed acute on chronic
diverticulitis with an adherent left ovary.
Intrathoracic Colonic Herniation
Mechanism: Either creation of a new diaphragmatic hernia or
exacerbation of an existing diaphragmatic defect from blunt
trauma of the colonoscope or colonic insufflation of air.
Imaging Appearance: Loop of colon herniating into the chest
through a diaphragmatic defect, possibly resulting in a bowel
obstruction.
Clinical Significance: Rare. Often asymptomatic, but
symptoms may arise long after the injury. May cause
gastrointestinal symptoms such as nausea or abdominal pain
and may lead to obstruction. May also cause respiratory
symptoms. Both asymptomatic and symptomatic hernias are
repaired surgically.
Intrathoracic Colonic Herniation 67-year-old man with history of esophagectomy
and gastric pull-through for esophageal cancer 2
years earlier presented with abdominal pain and
dyspnea 1 day following colonoscopy.
Below: AP topogram demonstrates a dilated,
gas-filled structure in the left hemithorax (arrow)
with dilated proximal bowel.
Above: Sagittal CT demonstrates a
dilated, incarcerated loop of colon
herniating into the left hemithorax
(arrow) via a preexisting diaphragmatic
defect.
Conclusion
• Despite widespread acceptance of optical
colonoscopy as the preferred modality for
colorectal cancer screening, there are
multiple documented complications.
• It is important to be familiar with the CT
findings of these complications so
appropriate treatment can be instituted.
• Increasing use of CT colonography for
primary screening could potentially avoid
a large portion of these procedural
complications.
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Author Correspondence
Information
Aaron Harman, MD
Kevin J. Chang, MD, FSAR
Director of CT Colonography
Rhode Island Hospital, The Miriam Hospital, &
Rhode Island Medical Imaging