Inflammatory Bowel
Disease
Inflammatory Bowel Disease
Inflammatory bowel disease (IBD) is an idiopathic disease,
probably involving an immune reaction of the body to its
own intestinal tract.
The 2 major types of IBD are ulcerative colitis (UC) and
Crohn disease (CD).
Frequency:
In the US:
• Approximately 1 million people in the United States have UC or CD.
• The prevalence of IBD among Americans of African descent is estimated to be
the same as the prevalence among Americans of European descent.
• The prevalence is lower among Americans of Asian and Hispanic descent.
Internationally:
• The incidence of IBD is assumed to be highest in developed countries and
lowest in the developing regions of the world.
Inflammatory Bowel Disease
Crohn disease
• CD consists of segmental involvement by a nonspecific granulomatous
inflammatory process.
• The most important pathologic feature is involvement of all layers of the bowel,
not just the mucosa and the submucosa, as is characteristic of UC.
• CD is discontinuous, with skip areas interspersed between one or more involved
areas.
• Late in the disease, the mucosa develops a cobblestone appearance, which
results from deep longitudinal ulcerations interlaced with intervening normal
mucosa.
Inflammatory Bowel Disease
Crohn disease
The 3 major patterns of involvement in CD are:
1. disease in the ileum and cecum, occurring in 40% of patients
2. disease confined to the small intestine, occurring in 30% of patients
3. disease confined to the colon, occurring in 25% of patients.
• Rectal sparing is a typical but not constant feature of CD. However, anorectal
complications (eg, fistulas, abscesses) are common.
• Much less commonly, CD involves the more proximal parts of the GI tract,
including the mouth, tongue, esophagus, stomach, and duodenum.
CD causes 3 patterns of involvement:
1. inflammatory disease,
2. strictures
3. fistulas.
Inflammatory Bowel Disease
Ulcerative colitis
• Inflammation always begins in the
rectum, extends proximally a certain
distance, and then abruptly stops.
• A clear demarcation exists between
involved and uninvolved mucosa.
• The rectum is always involved in UC,
and no "skip areas" are present.
• UC primarily involves the mucosa
and the submucosa, with formation
of crypt abscesses and mucosal
ulceration.
Inflammatory Bowel Disease
Ulcerative colitis
• UC remains confined to the rectum in approximately
25% of cases. In the remainder of cases, UC spreads
proximally and contiguously.
• Pancolitis occurs in 10% of patients.
• The small intestine is never involved, except when the
distal terminal ileum is inflamed in a superficial manner,
referred to as backwash ileitis.
• As the disease becomes chronic, the colon becomes a
rigid foreshortened tube that lacks its usual haustral
markings, leading to the lead pipe („stove-pipe”)
appearance observed on barium enema.
• The skip areas (ie, normal areas of the bowel
interspersed with diseased areas) observed in CD of the
colon do not occur in UC.
Inflammatory Bowel Disease
• UC and CD are generally diagnosed using clinical, endoscopic, and histologic criteria.
• No single finding is absolutely diagnostic for one disease or the other.
• Approximately 20% of patients have a clinical picture that falls between CD and UC;
they are said to have indeterminate colitis.
Distinguishing Features of CD Versus UC
Features
Crohn Disease
Ulcerative Colitis
Skip areas
Common
Never
Cobblestone mucosa
Common
Rare
Transmural
involvement
Common
Occasional
Rectal sparing
Common
Never
Perianal involvement
Common
Never
Fistulas
Common
Never
Strictures
Common
Occasional
Granulomas
Common
Occasional
Inflammatory Bowel Disease
Distinguishing Features of CD Versus UC
CD
UC
Inflammatory Bowel Disease
Imaging Studies - plain radiography
The role of plain radiography is fairly limited.
The 2 major purposes that it serves are:
1. to assess the presence of intestinal obstruction and
2. to evaluate pneumoperitoneum prior to further radiological workup.
Inflammatory Bowel Disease
Toxic megacolon is a complication of inflammatory bowel disease. It is
due to transmural inflammation with loss of neuromuscular function.
There is loss of the normal mucosal outline to the large bowel,
with an irregular margin and no visible haustral markings,
indicating mucosal inflammation and oedema. There is
marked dilatation of the large bowel, from the caecum on the
right to a loop of sigmoid seen centrally in the pelvis.
The appearances and the extent indicate a pancolitis.
The transverse colon measures more than 5.5 cm
across, which in the presence of colitis indicates a
toxic megacolon, with the risk of imminent perforation It constitutes a surgical emergency.
Inflammatory Bowel Disease
There is a high congruence (95%) between the
radiological and endoscopic diagnosis.
Although generally safe and well tolerated, DCBE (Double
Contrast Barium Enema) is relatively contraindicated in
patients with severe colitis as it may precipitate toxic
megacolon or perforation.
Inflammatory Bowel Disease
Imaging Studies - DC barium enema
Normal barium enema findings virtually exclude active ulcerative
colitis, whereas abnormal findings can be diagnostic.
Several terms have been used to describe abnormalities found after barium
studies of the colon. These include:
1. a “stove-pipe” appearance, which suggests chronic colitis that has
resulted in a loss of colonic haustrae;
2. “rectal sparing”, which suggests Crohn colitis in the presence of
inflammatory changes in other portions of the colon;
3. “thumbprinting”, which indicates mucosal inflammation
4. “skip lesions” (discontinuous disease), which suggests areas of
inflammation alternating with normal-appearing areas, again suggesting
Crohn colitis
Inflammatory Bowel Disease
Imaging Studies - DC barium enema
a “stove-pipe” appearance ulcerative colitis
ulcerative colitis
Giant barrel sponge (Xestospongia muta)
Stove-pipe sponge (Aplysina archeri)
Inflammatory Bowel Disease
Imaging Studies - DC barium enema
“rectal sparing” - Crohn colitis
The film shows a narrowing of the
descending colon, as well as an
area of narrowing with
speculation in the splenic
flexure.
Crohn colitis
The areas of “skip lesions” are
typical of a diagnosis of
Crohn’s disease.
Inflammatory Bowel Disease
Imaging Studies - DC barium enema
Bowel wall "thumbprinting" is a radiological sign
of thickening of the colonic wall.
It occurs secondary to submucosal haemorrhage
and oedema from capillary leakage
Intestinal “thumbprinting”of the
transverse colon.
This sign can also be
seen frequently on the
abdominal flat plate
Inflammatory Bowel Disease
Imaging Studies - DC barium enema
Crohn colitis
The irregular involvement in the
colon, skip lesions, and the
string sign – Crohn disease.
Inflammatory Bowel Disease
Imaging Studies - DC barium enema
Crohn colitis
aphthous ulcers
„cobblestone”
appearance
fissures and string sign
Inflammatory Bowel Disease
Imaging Studies - DC barium enema
ulcerative colitis
normal
mucosa
superficial
ulcerations
extensive
ulcerations
granular mucosa
inflammatory
pseudopolyps
Inflammatory Bowel Disease
Barium Enema Findings In Inflammatory Bowel Disease
Inflammatory Bowel Disease
Small bowel series/small bowel follow-through
The small bowel series, with or without an upper gastrointestinal
tract series, provides invaluable information about Crohn disease.
The small bowel series is usually sufficient for the evaluation of
small intestine Crohn disease
This study can reveal if inflammation is present, can assist in the
assessment of stricture length and severity, and can help decide
the most appropriate surgical approach.
Fistulae are often demonstrated on films from a small bowel series,
even if they are not suggested based on the clinical evaluation.
Inflammatory Bowel Disease
Small bowel series/small bowel follow-through
Changes of early/intermediate
Crohn's disease, with thickened
folds, tending to asymmetry and
obliteration in places.
Inflammatory Bowel Disease
Small bowel enteroclysis
The enteroclysis differs from a small bowel series in that a nasoenteric
or oroenteric tube is placed and contrast is instilled directly into the
small intestine.
This is usually performed when fine detail of the intestinal mucosa is
required or the distal small intestine is not adequately seen on the
small bowel series because the contrast is diluted as it passes through
the (usually dilated) small bowel.
Inflammatory Bowel Disease
Small bowel enteroclysis
Conventional posteroanterior
enteroclysis image shows a
long high-grade stricture of a
jejunal loop (arrowheads) and a
jejunocolic fistula (arrows)
From: Radiology. 2000;215:717-725. Small-Bowel
Disease: Comparison of MR Enteroclysis Images with
Conventional Enteroclysis and Surgical Findings
H. W. Umschaden et al.
Inflammatory Bowel Disease
CT SCAN
• CT scanning of the abdomen and pelvis has limited use in the diagnosis of
IBD, but findings may be very suggestive of IBD.
• Wall thickening on CT scans is nonspecific and may occur from smooth
muscle contraction alone, especially in the absence of other
extraintestinal inflammatory changes; however, the presence of
inflammatory changes significantly increases the predictive value of the
CT scan.
• CT scanning is the ideal study to determine if the patient has abscesses,
and it can be used to guide percutaneous drainage of these abscesses.
Inflammatory Bowel Disease
CAT SCAN
Typical appearances of active Crohn disease.
Transverse CT images show segmental
luminal narrowing, mural thickening (arrows),
mucosal hyperenhancement (arrowhead), and
low-grade partial small bowel obstruction.
Small bowel follow-through image shows
eccentric narrowing and string sign
(arrows) in the same bowel loop.
From: Radiology 2003;229:275-281. Assessment of Small Bowel Crohn Disease: Noninvasive Peroral CT Enterography Compared
with Other Imaging Methods and Endoscopy Peter B. Wold, et al.
Inflammatory Bowel Disease
CAT SCAN
CT
enteroclysis
Inflammatory Bowel Disease
MRI
Traditionally, MRI has had a well-defined role in evaluation of anorectal
complications of Crohn disease.
Recently, the development of faster pulse sequences (eg, single-shot fast
spin-echo and gradient-echo sequences) and higher-gradient systems has
made T1- and T2-weighted breath-hold imaging possible. This breath-hold
imaging has been a major breakthrough in overcoming physiologic motion
artifacts in abdominal imaging. It has made routine abdominal MRI feasible.
Because of a decrease in cumulative radiation exposure and because of the
possibility of attaining high-quality coronal images correlating with barium
studies, MRI is currently being investigated for monitoring disease activity
in Crohn disease.
Inflammatory Bowel Disease
MRI
Active Crohn disease in the terminal ileum.
Narrowing of the involved bowel segment with
prestenotic dilatation is shown on conventional
enteroclysis (a), postgadolinium three-dimensional
FLASH (b), and true FISP (c) images.
From: Radiographics. 2001;21:S161-S172. MR Enteroclysis Imaging of Crohn Disease Panos Prassopoulos, MD et al.
Inflammatory Bowel Disease
Ultrasound
• US features are nonspecific and include bowel wall thickening,
which may involve both the hypoechoic muscular coat and the
echogenic mucosa.
• There is longitudinally extending wall thickening, with
decreased echogenicity and luminal narrowing.
• Localized perforation may lead to the formation of an abscess,
which may be clinically silent if the patient is receiving steroid
therapy.
Inflammatory Bowel Disease
Capsule enteroscopy:
This technique is performed by having the
patient swallow an encapsulated video
camera that transmits images to a receiver
outside the patient.
Most commonly used for finding obscure
sources of gastrointestinal blood loss, the
images can find ulcerations associated
with Crohn disease if upper endoscopy
and colonoscopy are unrevealing.
The major risk in patients with Crohn
disease is the potential for the camera to
become lodged at the point of a stricture,
which could require operative intervention
for removal.
Inflammatory Bowel Disease
Inflammatory Bowel Disease
A study published in the June issue of The American Journal of
Gastroenterology (Volume 98, Issue 6) concludes that capsule
endoscopy is better than enteroclysis in diagnosing small bowel
ulcers.
"The results of this study indicate that wireless capsule endoscopy is
better than enteroclysis in the diagnosis of small bowel ulcers. Wireless
capsule endoscopy is the new gold standard for detecting Crohn’s
disease in the small bowel."
said Douglas K. Rex, M.D., F.A.C.G., Professor of Medicine, Division of Gastroenterology
and Hepatology, Department of Medicine, Indiana University School of Medicine, and
President-elect of the American College of Gastroenterology (ACG).
„CONCLUSION: In patients without a small-bowel stricture at barium
study, more small-bowel disease was found at CE when findings were
retrospectively compared with barium examination and CT findings.”
Radiology 2004;230:260. Small Bowel: Preliminary Comparison of Capsule Endoscopy with Barium Study and
CT Amy K. Hara et al.
Inflammatory Bowel Disease
The FDA’s decision, together with peer reviewed
publications, confirm that Capsule Endoscopy
should be the first line diagnostic tool to evaluate
patients with persistent abdominal symptoms
following a negative upper and lower endoscopy.
Diverticular Disease
Diverticular Disease
Diverticular disease of the colon begins as diverticulosis
(colonic outpouchings), which may develop into
diverticulitis (diverticular inflammation and perforation).
Diverticular Disease
• Diverticular disease is the most common colon disease in
Western nations. In the West, colonic diverticula occur in 5% of
the population by the time individuals are aged 40 years.
• They affect 33-50% of the population older than 50 years and
more than 50% of the population older than 80 years.
• Diverticulitis is the most common complication of diverticulosis,
and it has been reported in 10-20% of patients with diverticulosis.
• Approximately 20% of patients with diverticulitis require surgical
treatment.
• In underdeveloped nations in Asia and Africa, diverticulosis
occurs in less than 0.2% of the population. This low rate is
probably the result of a high-fiber diet.
Diverticular Disease
• Diverticula can be either acquired or congenital, and it can affect
either the small intestine or the large intestine.
• Acquired diverticula are more common and consist of herniation
of the mucosa and submucosa through the muscularis, usually at
the site of a nutrient artery.
• Diverticula involve the sigmoid colon in as many as 95% of
patients with diverticulosis. The cecum is involved in 5% of
patients.
Diverticular Disease
Barium study
The appearance of diverticula
varies with the projection in which
they are viewed and with the
amount of air and barium they
contain.
• In profile, a diverticulum appears
as a protrusion outside of the
colon that is joined to the colonic
wall by a neck.
• En face, a diverticulum may
appear as a well-defined collection
of barium or as a ring shadow. It
may resemble a bowler hat.
Diverticular Disease
Barium study
The appearance of
diverticula varies with the
projection in which they are
viewed and with the amount
of air and barium they
contain.
• In profile, a diverticulum
appears as a protrusion
outside of the colon that is
joined to the colonic wall by
a neck.
• En face, a diverticulum
may appear as a welldefined collection of barium
or as a ring shadow. It may
resemble a bowler hat.
Diverticulitis
Barium study
A single-contrast
examination is the preferred
method in patients in whom
diverticulitis is suspected.
Diverticulitis
Barium study
Many features of diverticulitis
are depicted on barium enema
images.
Narrowing, deformity, or
displacement of the bowel lumen
is commonly seen.
Diverticulitis
On barium enema examination,
diverticulitis can be diagnosed by
recognizing a perforated
diverticulum.
Barium may track through a
perforated diverticulum into a
sinus tract, fistula, or abscess.
Less commonly, it may
extravasate freely into the
peritoneum.
Single-contrast barium enema study demonstrates sigmoid diverticulitis
with a colovesical fistula. Note the contrast material in the bladder.
Diverticulitis
On barium enema examination,
diverticulitis can be diagnosed by
recognizing a perforated
diverticulum.
Barium may track through a
perforated diverticulum into a
sinus tract, fistula, or abscess.
Less commonly, it may
extravasate freely into the
peritoneum.
Single-contrast barium enema study in a
patient with diverticulitis demonstrates an
intramural abscess filling with barium.
Diverticulitis
The preferred examination is CT scanning of the
abdomen and pelvis.
CT findings can help in confirming clinical suspicion of
diverticulitis and in excluding other abdominal or
pelvic disease.
Diverticulitis
The most common CT
finding is paracolic fat
stranding.
The fat stranding
characteristically is
disproportionately more
severe than the relatively
mild, focal colonic wall
thickening.
Diverticulitis. Axial CT image of a man with left-sided diverticulitis shows severe pericolonic
fat stranding that is greater than the degree of wall thickening of the descending colon.
A "normal" diverticulum (open arrow) and a ill-defined (fuzzy) diverticulum (solid straight arrow)
are also seen.
From: „Disproportionate Fat Stranding: A Helpful CT Sign in Patients with Acute Abdominal Pain” J. M. Pereira et al. RadioGraphics 2004;24:703-715
Diverticulitis
The inflammatory
process can result in
accumulation of fluid in
the root of the sigmoid
mesentery, which
appears on CT scans as
the "comma sign", and
engorgement of the
mesenteric vessels,
which appears as the
"centipede sign".
Diverticulitis and the comma sign. Axial nonenhanced CT image of a 47-year-old patient
with cecal diverticulitis shows thickening of the lateral conal fascia, a finding known as the
reverse comma sign (arrowhead). Note the mild wall thickening of the cecum (small arrow)
and a diverticulum (large arrow).
From: „Disproportionate Fat Stranding: A Helpful CT Sign in Patients with Acute Abdominal Pain” J. M. Pereira et al. RadioGraphics 2004;24:703-715
Diverticulitis
The inflammatory
process can result in
accumulation of fluid in
the root of the sigmoid
mesentery, which
appears on CT scans as
the "comma sign", and
engorgement of the
mesenteric vessels,
which appears as the
"centipede sign" .
Diverticulitis and the centipede sign. Axial contrast-enhanced CT image of a patient with
diverticulitis shows engorgement of the vasa recta that feeds the sigmoid colon, a finding
known as the centipede sign (open arrows). Note also the mild wall thickening of the colon
(long solid arrow), diverticula (arrowheads), and fluid at the root of the sigmoid mesentery (short
solid arrow).
From: „Disproportionate Fat Stranding: A Helpful CT Sign in Patients with Acute Abdominal Pain” J. M. Pereira et al. RadioGraphics 2004;24:703-715
Diverticulitis
The most important entity in the differential diagnosis to exclude
is colon adenocarcinoma.
Differentiating Features of Diverticulitis and Colon Adenocarcinoma on CT:
From: „Disproportionate Fat Stranding: A Helpful CT Sign in Patients with Acute Abdominal Pain” J. M. Pereira et al. RadioGraphics 2004;24:703-715
Diverticulitis
The most important entity in the differential diagnosis to exclude
is colon adenocarcinoma.
Colon adenocarcinoma. Axial contrast-enhanced
CT image shows severe wall thickening of the
ascending colon with no fat stranding. This
disproportionate degree of thickening suggests that
the patient’s disease originates in the bowel wall.
The most common CT finding
is paracolic fat stranding.
From: „Disproportionate Fat Stranding: A Helpful CT Sign in Patients with Acute Abdominal Pain” J. M. Pereira et al. RadioGraphics 2004;24:703-715