Mahan Mathur
Gillian Lieberman, MD
CT evaluation of
inflammatory conditions
of the colon
Mahan Mathur
McGill Medicine Class of 2007
Advanced Clerkship in Radiology
BIDMC, Harvard Medical School
Mahan Mathur
Gillian Lieberman, MD
Outline
1. Normal CT considerations of Bowel
2. Disease Spectrum
• IBD (Crohns, Ulcerative Colitis)
• Infectious ( Pseudomembranous Colitis,
typhlitis)
• Vascular (ischemic)
• Diverticulitis
• Appendicitis
• Epiploic Appendagitis
Mahan Mathur
Gillian Lieberman, MD
Outline
1. Normal CT considerations of Bowel
2. Disease Spectrum
• IBD (Crohns, Ulcerative Colitis)
• Infectious ( Pseudomembranous Colitis,
typhlitis)
• Vascular (ischemic)
• Diverticulitis
• Appendicitis
• Epiploic Appendagitis
Mahan Mathur
Gillian Lieberman, MD
Normal CT considerations of
Bowel
• Advantages:
– Ease of availability and performance
– Accurate delineation of anatomy – intestinal
and extraintestinal + complications
– Multidetector CT => short scan times, thin
slices, reformations
Normal Scout film PACS, BIDMC Normal Axial CT slice, PACS, BIDMC
Mahan Mathur
Gillian Lieberman, MD
Normal CT considerations of
Bowel
• Normal Colon:
– Small Bowel: 3 cm
– Large Bowel: 6 cm
– Cecum: 9 cm
• Bowel wall thickness:
– Normal: 3 mm
– Distended: 1-2 mm
Normal Coronal CT reformation, PACS, BIDMC
Normal Sagittal CT reformation PACS, BIDMC
Mahan Mathur
Gillian Lieberman, MD
Outline
1. Normal CT considerations of Bowel
2. Disease Spectrum
• IBD (Crohns, Ulcerative Colitis)
• Infectious ( Pseudomembranous Colitis,
typhlitis)
• Vascular (ischemic)
• Diverticulitis
• Appendicitis
• Epiploic Appendagitis
Mahan Mathur
Gillian Lieberman, MD
Patient #1: Scout and Axial Films
29 yo F with 3 wks of abdo pain, anemia and increased WBC
PACS, BIDMC PACS, BIDMC
Scout Film
Axial CT slice: Note the
Bowel Wall thickness
Mahan Mathur
Gillian Lieberman, MD
Patient #1: Coronal Reformation
PACS, BIDMC
Note the distal ileal distribution of
Bowel Wall thickness
Mahan Mathur
Gillian Lieberman, MD
Patient #1: Sagittal Reformations
Note the
difference
between small
and large bowel
wall (seen here
is Transverse
Colon)
thickness
PACS, BIDMC PACS, BIDMC
Mahan Mathur
Gillian Lieberman, MD
Patient #1: Coronal Reformation
Note the
difference
between
small and
large bowel
wall
thickness
PACS, BIDMC
Mahan Mathur
Gillian Lieberman, MD
IBD: Crohn’s
• Etiology: unknown
• Involvement: mouth to perianal
– 80%: small bowel (distal ileum = most common)
– 50%: ileocolitis
– 20%: limited to colon – sparing of rectum
• Clinical Manifestations:
– Diarrhea, Abdo pain, Weight Loss, Fever, bleeding
– SBO (fibrotic strictures)
– Fistula (entero-vaginal/vesical/cutaneous)
– Perforation: sinus tracts with serosal penetration
Related to
Pathophysiology
Of Transmural
Bowel Wall
inflammation
Mahan Mathur
Gillian Lieberman, MD
Crohn’s: Extraintestinal
Manifestations
Localized
Episcleritis
Anterior
uveitis/iritis.
Pyoderma
gangrenosum
Erythema
Nodosum
Apthous
Stomatitis
Mintz et all. Inflamm Bowel Dis. 2004
Trost et all. Postgrad Med J. 2005
Mahan Mathur
Gillian Lieberman, MD
ERCP showing Sclerosing
Cholangitis
GallBladder
Common Bile
Duct
Common
Hepatic
duct
Right/Left
Hepatic
ducts
Presti et all. Dig Dis Sci. 1997
Note: Narrow CBD
and stenotic CHD
with prestenotic
dilatation of Left
Hepatic Duct +
intraheptatic duct
pruning
Mahan Mathur
Gillian Lieberman, MD
Crohn’s: Imaging Options
– Colonoscopy
– Barium studies
– CT (sens: 94-100%, spec 95%); sens 70%
early stage disease
Disadvantage: Limited evaluation of
extramural extension +
extraintestinal complications
Colonoscopy showing Cobblestone Mucosa
Lee et all, Endoscopy 2006
Barium study demonstrating a crohns induced bowel Fistula
Maconi et all. Am J Gastroenterol. 2003
Mahan Mathur
Gillian Lieberman, MD
Crohns: Findings on CT
• Small bowel, terminal ileum; left sided colitis rare; rectal sparing
• Eccentric Wall thickening with contrast enhancement:
– 11mm +/- 5.1
• Homogenous or Stratified/segmental appearance (“skip” lesions)
– Psedodiverticula
• Luminal Narrowing with prestenotic dilatation (“string sign”)
• Fibrofatty proliferation adjacent to small bowel segments
(“Creeping fat”) -> separation of small bowel loops
• Mesenteric Lymphadenopathy (3-8mm): if>1cm -> consider
lymphoma
• Water Halo and Target Signs => acute bowel injury
• Engorged Mesenteric Vessel (“comb sign”) => acute bowel injury
• Abscess, Fistulas
Mahan Mathur
Gillian Lieberman, MD
Close-up Axial and Sagittal
views of Patient #1’s abdomen
Bowel Wall Thickening (>1cm) Comb Sign + Fibrofatty proliferation
PACS, BIDMC PACS, BIDMC
Mahan Mathur
Gillian Lieberman, MD
Close-up Axial view of patient
#1’s Abdomen
Mesenteric Lymphadenopathy: Note size<1cm
PACS, BIDMC PACS, BIDMC
Mahan Mathur
Gillian Lieberman, MD
Close-up Coronal View of Patient
#1’s Abdomen: Target Sign
Target Sign:
1. Outer later for
high
attenuation:
inflamed
muscularis
propria
2. Middle layer:
intermediate
(edema)/low
attenuation (fat)
3. Inner later:
inflamed
muscosaPACS, BIDMC
Mahan Mathur
Gillian Lieberman, MD
Follow-up + Summary for Patient
#1
• Combination of Clinical and Radiological
Findings point to diagnosis of Crohn’s Disease
in our patient
• Radiological Findings: Distal Ileal Bowel wall
thickening with Target sign, Comb sign, fibrofatty
proliferation and Mesenteric Lymphadenopathy
• Patient had subsequent follow-up with
Gastroenterology and a c-scope with biopsies
confirming the diagnosis of Crohns
Mahan Mathur
Gillian Lieberman, MD
Patient #2: Scout and Axial
images of Abdomen
57yo M with history of Ulcerative Colitis presents with 4 days of watery
diarrhea, afebrile, normal WBC. Previous allergic reaction to IV Iodine
(thus, no IV contrast given)
PACS, BIDMC PACS, BIDMC
Mahan Mathur
Gillian Lieberman, MD
Two Coronal Reformations in
different planes for Patient #2
PACS, BIDMC PACS, BIDMC
Note: Involvement
of Hepatic Flexure Note: Ahaustral, thickened bowel
transverse colon
Mahan Mathur
Gillian Lieberman, MD
Sagittal and Axial slices in
Patient #2
PACS, BIDMC PACS, BIDMC
Ahaustal rectosigmoid
colon => likely chronic UCTransverse Colon involvement
Mahan Mathur
Gillian Lieberman, MD
IBD: Ulcerative Colitis
• Etiology: unknown
• Involvement: Rectum -> Large Bowel
– Beware of “backwash Ilietis”
• Clinical Manifestations:
– Abdo pain, bloody diarrhea, weight loss, fever
– Increased risk of colon cancer (increased with duration
and extent of colonic involvement)
– Toxic megacolon with muscle layer infiltration
– Strictures, Abscess
• Extraintestinal Manifestations (see Crohn’s)
Mahan Mathur
Gillian Lieberman, MD
Ulcerative Colitis: Imaging Options
• Imaging
– Flexible Sigmoidoscopy
– Colonoscopy
– Barium enema – rare use : low sensitivity in mild
disease, risk of bowel perforation in severe disease
– CT
• Rectal involvement + Left sided/pancolitis – occasional
backwash ileitis
• Symmetric wall thickening: 7.8mm +/- 1.9
• Proliferation of perirectal fat
• Target sign, Comb Sign in large bowel
• Colon cancer, Toxic Megacolon
Tests of choice
Mahan Mathur
Gillian Lieberman, MD
Coronal Slice of Patient #2 and Axial
Slice of another patient (patient #3)
with UC
Ahaustral Transverse
colon
Sigmoid Colon involvement in a different
patient with known Ulcerative colitis and
possible rectal stricture
PACS, BIDMC PACS, BIDMC
Mahan Mathur
Gillian Lieberman, MD
Axial Slices for patient #3
Stricture: note the increase in
bowel wall thickness along the
horizontal plane versus the
vertical plane
Rectal Wall Thickening
PACS, BIDMC PACS, BIDMC
Mahan Mathur
Gillian Lieberman, MD
Coronal and Sagittal Views of
Patient #3
Target Sign + sparing of small
bowel at rectosigmoid junction
Rectosigmoid
involvement
PACS, BIDMC PACS, BIDMC
Mahan Mathur
Gillian Lieberman, MD
Follow-up + Summary for Patient #2
• Again, Combination of Clinical and Radiological
Findings point to the diagnosis of UC
exacerbation in our patient
• Radiological Findings: Rectal wall thickness +
exclusive large bowel involvement, perirectal
fatty proliferation, target sign in rectosigmoid
junction
• Subsequent Colonoscopy confirmed the
diagnosis in this patient
Mahan Mathur
Gillian Lieberman, MD
Patient #4: Scout and Axial
images of Abdomen
86 yo F with Fever, Abdo Pain, watery diarrhea x 2days.
Multiple recent hospitalizations. Last June 2006 for pneumonia
PACS, BIDMC
PACS, BIDMC
Note the
irregular looking
Bowel wall
appearance
Mahan Mathur
Gillian Lieberman, MD
Sagittal and Coronal Reformation of
Patient #4’s Abdomen
PACS, BIDMC PACS, BIDMC
Reformations indicate pancolitisSigmoid Wall thickness
Mahan Mathur
Gillian Lieberman, MD
Pseudomembranous Colitis
• Etiology: C. Difficile
– Nosocomial, s/p antibiotics
• Involvement: Pancolitis/isolated colitis
• Clinical Manifestations
– Asymptomatic carrier, watery diarrhea, abdo
pain, fever, high WBC: 5-10d s/p Antibiotics
(penicillin, clindamycin, cephalosporins)
– Toxic Megacolon: colonic dilatation>7cm
Mahan Mathur
Gillian Lieberman, MD
Pseudomembranous Colitis:
Imaging
• Imaging:
– Sigmoidoscopy/Colonoscopy:
• Pseudomembrane plaques
– CT
Often not
necessary:
Clinical
Diagnosis
Kawamoto et all, Radiographics. 1999 Kawamoto et all, Radiographics. 1999
Pathology
specimen
showcasing
plaques
(straight
arrows) +
erythema/
edema
(curved
arrow)
Mahan Mathur
Gillian Lieberman, MD
Pseudomembranous Colitis: CT
Findings
– Bowel Wall thickening: 3-32mm (mean 14.7mm)
• Irregular, “shaggy”
– Target Sign
– Accordion Sign: alternating bands of high and low
attenuation (contrast trapped between thickened
folds): non-specific (also found in other infectious
colitis, ischemic colitis)
– Ascites: Important in differentiating from IBD (but
again, non-specific)
Mahan Mathur
Gillian Lieberman, MD
Close up Axial and normal Axial
images of abdomen in Patient #4
Accordion Sign
PACS, BIDMC PACS, BIDMC
Mahan Mathur
Gillian Lieberman, MD
Follow-up + Summary for Patient #4
• Clinical history particularly important in this case
although, as demonstrated by the radiographic
findings, P. Colitis demonstrates an irregular
(“shaggy”) wall appearance with an accordion
sign +/- ascites that allow for a reasonably
distinct appearance
• Stool for C. Diff confirmed the diagnosis of P.
Colitis. Antibiotic treatment was started for this
patient.
Mahan Mathur
Gillian Lieberman, MD
Complication of P. colitis + UC
• Toxic Megacolon : bowel wall> 7cm
Thoeni et all. Radiology. 2006
Mahan Mathur
Gillian Lieberman, MD
Outline
1. Normal CT considerations of Bowel
2. Disease Spectrum
• IBD (Crohns, Ulcerative Colitis)
• Infectious ( Pseudomembranous Colitis,
typhlitis)
• Appendicitis
• Diverticulitis
• Vascular (ischemic)
• Epiploic Appendagitis
Mahan Mathur
Gillian Lieberman, MD
Typhlitis
– Terminal ileum/ Cecal / Asc. colon involvement
– Neutropenic patients
– Fever, watery/bloody diarrhea
– Unknown etiology
– Txt: conservative – resolution with return of functioning
neutrophils
Axial image of abdomen
showing circumferential
thickening of the cecal
wall + pericecal
inflammation
Horton et all. Radiographics. 2000
Mahan Mathur
Gillian Lieberman, MD
Appendicitis
– Luminal occlusion with
venous congestion,
ischemia, inflammation
– RLQ pain
– CT: thickened wall with
dilated appendix (>6mm)
+ pericecal inflammation
– Txt: Surgery (risk of
perforation)
Axial Image of Abdomen
showing inflamed appendix
and periappendiceal fat
stranding
Horton et all. Radiographics. 2000
Mahan Mathur
Gillian Lieberman, MD
Diverticulitis
– Outpouchings of colonic
musoca/submucosa at site
where vessels exit
– Etiology: Obstruction by
stool/food/inflammation
– CT: descending/sigmoid
colon wall thickening with
pericolic inflammation in
patient with diverticulae
PACS, BIDMC
Diverticulae
Axial Image of Abdomen
demonstrating mild fat
stranding and fascial
thickening in 60 yo M with
LLQ pain
Mahan Mathur
Gillian Lieberman, MD
Ischemic Colitis
– Older population
– Ischemia (MI, Arrhythmia, embolus)
– Colonic mucosal changes due to restoration
of blood flow (free radical damage)
– “Watershed” area: distal transverse colon
(splenic flexure) + distal descending colon
(rectosigmoid junction)
Mahan Mathur
Gillian Lieberman, MD
Epiploic Appendagitis
– 1–4-cm, oval, fatty pericolic lesion with surrounding
mesenteric inflammation
– Associated with torsion/thrombosis
– Can be confused clinically with appendicitis
– Conservative management
Axial image of Abdomen showing
peripheral enhancement of fatty
epiploic appendage with
surrounding mesenteric
inflammation. Note the sparing of
the large bowel
Thoeni et all. Radiology. 2006
Mahan Mathur
Gillian Lieberman, MD
Summary: clinical history is
paramount
Thoeni et all. Radiology. 2006
• Crohns: Right sided, distal ileum, left sided (rare) with rectal sparing
• UC: Rectal involvement +/- large bowel involvement, occasional ileitis
• P. colitis: pancolitis, accordion sign, ascites, Hx of antibiotic use
Mahan Mathur
Gillian Lieberman, MD
References
1. Trost LB, McDonnell JK. Important cutaneous manifestations of inflammatory bowel disease.
Postgrad Med J. 2005 Sep;81(959):580-5. Review.
2. Mintz R, Feller ER, Bahr RL, Shah SA. Ocular manifestations of inflammatory bowel disease.
Inflamm Bowel Dis. 2004 Mar;10(2):135-9. Review
3. Presti ME, Neuschwander-Tetri BA, Vogler CA, Janney CG, Roche JK. Sclerosing cholangitis,
inflammatory bowel disease, and glomerulonephritis: a case report of a rare triad. Dig Dis Sci.
1997 Apr;42(4):813-6. Review
4. Furukawa A, Saotome T, Yamasaki M, Maeda K, Nitta N, Takahashi M, Tsujikawa T, Fujiyama
Y, Murata K, Sakamoto T. Cross-sectional imaging in Crohn disease.
Radiographics. 2004 May-Jun;24(3):689-702. Review.
5. Lee YJ, Yang SK, Byeon JS, Myung SJ, Chang HS, Hong SS, Kim KJ, Lee GH, Jung HY,
Hong WS, Kim JH, Min YI, Chang SJ, Yu CS. Analysis of colonoscopic findings in the
differential diagnosis between intestinal tuberculosis and Crohn's disease.
Endoscopy. 2006 Jun;38(6):592-7. Epub 2006 Apr 27.
6. Maconi G, Sampietro GM, Parente F, Pompili G, Russo A, Cristaldi M, Arborio G, Ardizzone S,
Matacena G, Taschieri AM, Bianchi Porro G. Contrast radiology, computed tomography and
ultrasonography in detecting internal fistulas and intra-abdominal abscesses in Crohn's
disease: a prospective comparative study.
Am J Gastroenterol. 2003 Jul;98(7):1545-55.
7. Kawamoto S, Horton KM, Fishman EK. Pseudomembranous colitis: spectrum of imaging
findings with clinical and pathologic correlation.
Radiographics. 1999 Jul-Aug;19(4):887-97. Review.
8. Thoeni RF, Cello JP. CT imaging of colitis.
Radiology. 2006 Sep;240(3):623-38. Review.
9. Horton KM, Corl FM, Fishman EK. CT evaluation of the colon: inflammatory disease.
Radiographics. 2000 Mar-Apr;20(2):399-418.
Mahan Mathur
Gillian Lieberman, MD
• Acknowledgements
– Dr. V. Raptopoulos
– Dr. J. Kruskal
– Dr. A. Hochberg
– Dr. K. Mani
– Dr. G. Lieberman
– George Lynskey
– Pamela Lepkowski
– Larry Barbaras Chisasibi, Northern Quebec,
summer 2003
CT evaluation of inflammatory conditions of the colon
Outline
Outline
Normal CT considerations of Bowel
Normal CT considerations of Bowel
Outline
Patient #1: Scout and Axial Films
Patient #1: Coronal Reformation
Patient #1: Sagittal Reformations
Patient #1: Coronal Reformation
IBD: Crohn’s
Crohn’s: Extraintestinal Manifestations
ERCP showing Sclerosing Cholangitis
Crohn’s: Imaging Options
Crohns: Findings on CT
Close-up Axial and Sagittal views of Patient #1’s abdomen
Close-up Axial view of patient #1’s Abdomen
Close-up Coronal View of Patient #1’s Abdomen: Target Sign
Follow-up + Summary for Patient #1
Patient #2: Scout and Axial images of Abdomen
Two Coronal Reformations in different planes for Patient #2
Sagittal and Axial slices in Patient #2
IBD: Ulcerative Colitis
Ulcerative Colitis: Imaging Options
Coronal Slice of Patient #2 and Axial Slice of another patient (patient #3) with UC
Axial Slices for patient #3
Coronal and Sagittal Views of Patient #3
Follow-up + Summary for Patient #2
Patient #4: Scout and Axial images of Abdomen
Sagittal and Coronal Reformation of Patient #4’s Abdomen
Pseudomembranous Colitis
Pseudomembranous Colitis: Imaging
Pseudomembranous Colitis: CT Findings
Close up Axial and normal Axial images of abdomen in Patient #4
Follow-up + Summary for Patient #4
Complication of P. colitis + UC
Outline
Typhlitis
Appendicitis�
Diverticulitis
Ischemic Colitis
Epiploic Appendagitis
Summary: clinical history is paramount
References
Slide Number 45