Health &medicine.

1. RADIOLOGICAL IMAGING OF COLITIS.
Dr/ ABD ALLAH NAZEER. MD.
Ischemic colitis

2. TYPES OF COLITIS:
• IBD: UC and Crohn’s.
• Infectious colitis.
• Ischemic colitis.
• Diverticulitis (DDX: EA).
• Neutropenic colitis.
• Drug-related colitis.

3. FEATURES OF COLITIS:
Nonspecific signs:
• Wall thickening.
• Target sign.
• Hyperemia (comb sign).
• Pericolonic stranding.
• Ascites.

4. FEATURES OF COLITIS:
Specific signs:
• Distribution
• Lymph nodes.
• Fistulae
• Sinus tract.
Distribution:
• Right, left or diffuse
• Skip areas
• Rectum spared
• Focal only

5. DISTRIBUTION: IBD & INFECTIOUS COLITIS:
Ulcerative Colitis.
CMV (or right).
E. coli.
PMC (or left).
Campylobacter.
Crohn's.
Diffuse in Colon Right Colon(+TI) Left Colon
Crohn’s.
TB.
Yersinia.
Salmonellosis.
Amebiasis.
(Typhlitis).
Ulcerative Colitis.
Shigellosis.
Schistosomiasis.
Herpes.
Lymphogranuloma.
(Drug -induced col.).

6. Segment Thickness Extension
Small
Bowel
Rectum
Halo
Sign
Ischemia G>D 8-10 Long + - +
Crohn's D>G 10-15 Long +++ + +++
Ulcerative
Colitis
G 6-8 Long - +++ +++
Infectious
Colitis
D>G 8-10 Long ++ + +++
Pseudo-
Membranous
Colitis
G>D 10-15 Long - - +++
ETIOLOGIC DIAGNOSIS:

7. Bowel wall thickening.

9. Degree of mural thickening.

11. Crohn's disease is an idiopathic inflammatory bowel disease (IBD) characterized
by widespread gastrointestinal tract involvement typically with skip lesions. It is
also known as regional enteritis, and frequently there is systemic involvement.
Radiographic Features:
Fluoroscopy
Features on barium small bowel follow-through include:
mucosal ulcers
aphthous ulcers initially
deep ulcers (more than 3mm depth)
longitudinal fissures
transverse stripes
when severe leads to cobblestone appearance
may lead to sinus tracts and fistulae
widely separated loops of bowel due to fibro-fatty proliferation (creeping fat)
thickened folds due to edema
Pseudo-diverticula formation: due to contraction at the site of ulcer with
ballooning of the opposite site
string sign: tubular narrowing due to spasm or stricture depending on chronicity
partial obstruction
on control films presence of gall stones, renal oxalate stones, and sacroiliac joint
or lumbosacral spine changes should be sought.

12. CT examination can be carried out with both intravenous and intraluminal
contrast (positive or negative):
fat halo sign
comb sign
bowel wall enhancement
bowel wall thickening (1-2 cm) which is most frequently seen in the terminal
ileum (present in up to 83% of patients).
strictures and fistulae
mesenteric/intra-abdominal abscess or phlegmon formation
abscesses are eventually seen in 15-20% of patients
MRI enterography (MRE)
MR enterography can be a useful technique for evaluation of the bowel.
Inflamed loops of bowel demonstrate thickening and contrast enhancement.
Extramural disease is where MRI excels:
fibrofatty proliferation:
thickening of extramural fat, which separates bowel loops
equivalent to the fat halo sign on CT
vascular engorgement: comb sign
stenosis and strictures.

13. Crohn's Disease – Barium Images.

14. FEATURES OF COLITIS
COLITIS

15. CROHN’S DISEASE: SMALL BOWEL.

17. CT and MR Enterography for Crohn's Disease.

18. Crohn's disease. Coronal fluid sensitive (T2), T2 fat suppressed and T1 post contrast images.
Red arrows outline the diseased colon with wall thickening, abnormal edema and ascites
(thin arrow) and intense post contrast enhancement. Yellow arrows highlight proliferation
of mesenteric vessels in creeping fat, commonly referred to as the “comb” sign.

20. Ulcerative colitis is an inflammatory bowel disease that not only
predominantly affects the colon, but also has extraintestinal manifestations.
Radiographic features
Involvement of the rectum is almost always present (95%), with the disease
involving variable amounts of the most proximal colon, in continuity. The entire
colon may be involved, in which case edema of the terminal ileum may also be
present (so-called backwash ileitis).
Plain radiograph
Non-specific findings, but may show evidence of mural thickening (more
common), with thumbprinting also seen in more severe cases.
Fluoroscopy
Mucosal inflammation leads a granular appearance to the surface of the bowel.
As inflammation increases, the bowel wall and haustra thickened.
Mucosal ulcers are undermined (button-shaped ulcers). When most of the mucosa
has been lost, islands of mucosa remain giving it a pseudopolyp appearance.
In chronic cases, the bowel becomes featureless with the loss of normal haustral
markings, luminal narrowing and bowel shortening (lead pipe sign).
Small islands of residual mucosa can grow into thin worm-like structures (so-
called filiform polyps)
Colorectal carcinoma in the setting of ulcerative colitis is more frequently sessile
and may appear to be a simple stricture.

21. CT: CT will reflect the same changes that are seen with a barium enema,
with the additional advantage of being able to directly visualise the colonic
wall, the terminal ileum and identify extra-colonic complications, such as
perforation or abscess formation. It is important to note however that CT is
insensitive to early mucosal disease.
In chronic cases, fat submucosal deposition is seen particularly in the rectum
(fat halo sign). Also in this region, extramural deposition of fat, leads to
thickening of the perirectal fat, and widening of the presacral space .
Strictures are also common and are not all malignant. These are
predominantly due to marked muscularis mucosa hypertrophy, which is also
in part responsible for the lead pipe sign.
MRI: The most striking abnormalities in ulcerative colitis are wall thickening
and increased enhancement.
The median wall thickness in ulcerative colitis ranges from 4.7 to 9.8 mm. In
general, the more severe the inflammation, the thicker the colonic wall. A
colonic wall thickness <3 mm is usually considered as normal, 3-4 mm as a
"gray zone," and >4 mm as pathological.
Enhancement of the mucosa with no or less enhancement of the submucosa
producing a low SI stripe—the so-called submucosal stripe.

23. Ulcerative colitis with lead pipe appearance.

24. Ulcerative colitis

26. MRI Images with ulcerative colitis.

27. MRI Images with ulcerative colitis.

29. Cytomegalovirus (CMV) is a member of the Herpes viridae family, along with herpes simplex
viruses 1 and 2, Epstein-Barr virus, and varicella-zoster virus. It is a double-stranded DNA virus
with a protein coat and lipoprotein envelope. Similar to other herpes viruses, CMV is
icosahedral and replicates in the host's nucleus. Replication in the host cell typically manifests
pathologically with large intra-nuclear inclusion bodies and smaller cytoplasmic inclusions, and
is accompanied by the presence of CMV viral particles in the plasma.
Radiographic features
Barium studies
CMV oesophagitis
Small well-circumscribed ulcers are present, with the mucosa between them appearing normal.
Larger (~2cm) superficial mid-esophageal ulcers are said to be relatively characteristic of CMV
oesophagitis . Deep ulceration is uncommon.
CMV gastritis
Typically the antrum is involved, and it has a nodular mucosal pattern with luminal narrowing.
CT
CT is particularly useful in CMV enterocolitis. The appearances are similar to that
of inflammatory bowel disease, with mural thickening and surrounding stranding, although
often the thickening is patchy and not circumferential. Ascites is seen in almost half of cases.
Both diffuse and segmental involvement is encountered . In some instances the appearances
are essential normal and biopsy is therefore still required when clinical symptoms are
suspicious.
Involvement of the small bowel is less frequent, seen in only 42% of cases.
Lymph node enlargement is usually not present.
Perforation has the usual imaging hallmarks of free intraperitoneal fluid and gas.

31. CMV ileocolitis in a 30 years old patient with aids: important wall thickening
related to submucosal edema CMV inclusions showed are shown at biopsy.

32. Circumferential ulcerated stricture.
Markedly thickened folds of the transverse and descending
colon, consistent with pseudo- membrane formation.

33. INFECTIOUS COLITIS:
•Diagnosis: clinical aspects suggesting some infections (tuberculosis, amoeba, CMV)
•Confirmed by specific lab tests + colonoscopy and biopsy
•CT features:
–Right colon + ileum = salmonella, amoeba, tuberculosis,, yersinia
–Left colon = schistosoma, shigella, herpes, syphilis
–Pan colonic : CMV, E Coli
•Tuberculosis: (may mimic Crohn's disease)
–Clinical context
–Caecum granuloma with necrosis on biopsy
–Ileocæcal location
–Transmural injury
–Wall thickening
–Enlarged lymph nodes with low attenuation
–Ascites
–Fistulae/abscess
•Amebiasis:
–Endemic countries
–Differential diagnosis : appendicitis
–Diffuse ulcerations at biopsy, with presence of the parasite
–Acute fulminant colitis
–Ìleocaecal is the preferred location but the entire colon can be involved
–Liver abscesses help in the positive diagnosis.

34. Tuberculosis colitis in a 25 years old patient : wall thickening of the caecum , enlarged lymph nodes with low attenuated center and ascites are seen.

37. Amoeba colitis of the Caecum in a 40 years old patient : liver abscesses are seen.

39. Right -sided colitis in a patient with cirrhosis and portal hypertension.
The endoscopic images are of different patient with right-sided colitis.

40. •Pseudomembranous colitis:
- Mean age: 50 years
–Diarrhea
–Abdominal pain
–Fever, anorexia, nausea, dehydration
•Recent use of antibiotics or recent surgery
•Clostridium difficile, toxins in the stools
•Colonoscopy:
–Ulcerations, creamy, white and elevated plaques or nodules,
volcano like eruptions of fibrin and leukocyte from mucosal crypt
•Entire colon+++ involvement
•Small bowel can be involved
•Important wall thickening (mean :11mm)
•Accordion sign, nodular/polypoid = submucosal edema
•Thumbprinting
•Pericolonic fat stranding
•Ascites

41. Pseudomembranous colitis in a 34 years old patient with recent use
of antibiotics: follow up J4, aspecific colonic wall thickening.

42. Pseudomembranous colitis. (Left) Axial CT scan of the mid-abdomen utilizing oral but not intravenous contrast
demonstrates marked thickening of the colonic wall (white arrows) producing the so-called "accordion sign." There
is a small amount of pericolonic stranding (red arrow) and ascites (green arrow). (Right) Axial CT scan through the
pelvis shows marked thickening of the wall of the rectum (yellow arrows) indicating this is a pan-colitis.

43. Pseudomembranous Colitis with dilatation of the sigmoid. Pseudomembranous Colitis.

44. Pseudomembranous colitis.

45. Pseudomembranous colitis.

46. DRUG INDUCED COLITIS:
•Chemotherapy (mucosal ulcerations, inflammation)
•Antibiotics (clostridium difficile)
•Vasoconstrictors, drug for hypertension, oral contraceptives (ischemia, inflammation) NSAID

47. Toxic colitis involving the entire colon in a 40 years old patient, 48H after the colonoscopy.

48. NEUTROPENIC COLITIS:
•Clinical aspects:
–Immunodepression : leukemia, HIV, transplantation,
chemotherapy
–Bacteria, viruses, and fungi grow profusely in the absence of
neutrophils •Lab tests : Immunodepression, non specific
•Colonoscopy:
–Same features than ulcerative colitis or infectious colitis, but only
the right colon is involved
–Hyperemia, edema, and superficial ulcerations
•Ìleocaecal, and right colon involvement
•Important circumferential wall thickening (up to 3 cm for the
caecum, 4mm for ileum)
•Parietal low attenuation, submucosal edema
•Parietal pneumatosis (severity sign)
•Pericolonic stranding
•Sepsis, abscess, intestinal necrosis, hemorrhage may occur

49. Neutropenic colitis involving the entire colon and ileum in a 30 years
old patient : ascites, circumferential wall thickening are shown.

50. Neutropenic colitis. Computed tomography (CT)
in an 18-year-old man with acute myelogenous
leukemia, fever, and neutropenia. A, Axial CT
image shows the marked thickening of the
caecum and a small amount of free
fluid. B, Coronal CT reformat shows pancolitis,
affecting the right colon to a greater extent.

51. Typhlitis in a patient with neutropenia.

52. Radiation induced colitis in a 70 years old woman with radiation
exposure : left colon wall thickening, stricture of is caliber are shown

53. Diverticulitis is one of the presentations of diverticular disease and is most
often a complication of colonic diverticulosis. Differentiating one from the
other is critical since uncomplicated diverticulosis is mostly asymptomatic and
acute diverticulitis is a potentially life-threatening illness.
Radiographic features
CT is the modality of choice for the diagnosis and staging of diverticulitis.
Appearances include:
pericolic stranding, often disproportionately prominent compared to the
amount of bowel wall thickening
segmental thickening of the bowel wall
enhancement of the colonic wall
usually has inner and outer high-attenuation layers, with a thick middle
layer of low attenuation
diverticular perforation
extravasation of air and fluid into the pelvis and peritoneal cavity
abscess formation (seen in up to 30% of cases)
may contain fluid, gas or both
fistula formation
gas in the bladder
direct visualization of a fistulous tract

55. Sigmoid diverticulitis with abscess formation: sigmoid colon displaying mural thickening,
diverticulosis and pericolic fat stranding (arrow). Adjacent low attenuation, septated collection
(circle) representing abscess formation, with adhesion noted to adjacent small bowel loops.

56. Perforated sigmoid diverticulitis: sigmoid colon displaying diverticulosis, mural thickening and pericolic
inflammatory fat stranding (arrow) with adjacent collection of intra-abdominal free air and adjacent
inflammatory fat stranding (circle), again representative of active diverticulitis with perforation.

58. Ischemic colitis refers to inflammation of the colon secondary to vascular
insufficiency and ischemia. It sometimes considered under the same spectrum
of intestinal ischemia. The severity and consequences of the disease are highly variable.
Epidemiology
Ischemic bowel is typically a disease of the elderly (age >60 years) where atherosclerotic
disease or low flow states are usually the cause 2. In younger individuals, the disease is
more likely to be related to vasculitis or hyper coagulable states.
The causes can be categorized as follows:
arterial occlusion:
arteriosclerosis
vasculitides
arterial emboli
venous thrombosis:
hyper coagulative states including malignancy and OCP use
primary mesenteric venous thrombosis
low flow states:
hypotension
congestive heart failure
cardiac arrhythmias
others:
sickle cell disease
radiation therapy

59. Radiographic features
Plain film: abdominal radiograph
Abdominal radiographs are often normal, but signs include:
dilatation due to ileus
'thumbprinting' due to mucosal edema/hemorrhage
localized intramural gas (pneumatosis coli) if necrotic
free intraperitoneal gas if perforated
Fluoroscopy: barium studies
Contrast enema is abnormal in 90% but is rarely used for diagnostic purposes:
segmental region of abnormality
'thumbprinting' which is classically obliterated by air insufflation.
spasm
ulcerations 'serated mucosa’
stricture from fibrosis as a late complication of ischemia
CT
Contrast enhanced imaging is the modality of choice. Features include:
segmental region of abnormality
symmetrical or lobulated thickening of bowel wall
irregularly narrowed lumen
Submucosal edema may produce low-density ring bordering lumen (target sign)
intramural or portal venous gas
Mesenteric edema
superior mesenteric artery or vein thrombus/occlusion may be demonstrated.

60. Angiography
Can show mesenteric artery occlusion if present. Otherwise, angiography
may show increased arterial caliber, accelerated arteriovenous transit
time and dilated draining veins due to the inflammatory response. In
mesenteric venous thrombosis, the veins may not be visualized, and
collateral venous filling may be seen.
Ultrasound
Ultrasound is of limited use due to bowel gas but may show:
luminal thickening over the affected segment with or without
stratification
hypoechoic wall due to edema
areas of increased echogenicity if hemorrhage
echogenic foci with shadowing if intramural gas
reduced peristalsis may be observed
Doppler imaging of the SMA origin can be useful in assessing for stenosis
Nuclear medicine
Increased uptake of Tc99m (V) DMSA tracer in the ischaemic bowel may be
present but is unreliable

61. Ischaemic colitis.

62. Ischemic colitis: parietal pneumatosis is
seen on the right side of the scout view
Ischemic colitis, CT: coronal view showing wall
thickening with pericolonic fat stranding

63. CT Images for Ischemic colitis.

64. CT Images for Ischemic colitis.

65. CT Images for Ischemic colitis.

66. CT Images for Ischemic colitis.

67. Magnetic resonance imaging follow-up of a patients with ischemic colitis resolved promptly. Ischemic colitis (IC) of left side colon in a 57 year old
woman with a recent history of acute hypertensive crisis, who presented with left lower quadrant pain and massive rectal bleeding. A: Endoscopic
procedure showed multiple necrotic area; B and C: Contrast-enhanced computed tomography (CT) and axial T2 fast-recovery fast-spin echo sequence
(FRFSE) magnetic resonance imaging (MRI), after 32 h from CT, showed acute IC (Type I CT and MRI) with wall thickening, three layer sandwich sign
and a mild amount of free fluid in the parabolic gutter; D and E: 2D coronal reformat CT and coronal T2 FRFSE MRI, at the same time, showed the
entire involved tract; F: Ischemia resolved without complications with conservative therapy as shown in the follow-up MRI.

68. Magnetic resonance imaging follow-up of a patient with ischemic colitis and worsening of clinical symptoms. Ischemic colitis (IC) of
sigmoid colon in a 62-year-old man with left lower quadrant pain and elevate lactate dehydrogenase levels, who presented with melena
and a recent history of stenting procedures for ischemic cardiopathy. A: Endoscopic procedure showed multiple necrotic area; B: 2D (two
dimensional) coronal reformat contrast-enhanced computed tomography (CT) showed acute IC (Type I CT); C-E: The patient had 2
magnetic resonance examinations (C and D-E) with an interval of 48 h due to worsening of clinical symptoms, with an increase of the
length and thickness of the involved tract (D-E); F: The ischemic process resolved without complication after parenteral nutrition, as
showed in the follow-up magnetic resonance imaging, performed after 384 h from the date of CT examination.

69. 7T magnetic resonance imaging investigation. A: Image of a 7T magnetic resonance
imaging (MRI) abdominal scan before inferior mesenteric artery (IMA) ligation; B: A 7T
MRI abdominal scan 1 h after IMA ligation; C: At 4 h after IMA ligation; D: At 6 h after
IMA ligation; E: At 8 h after IMA ligation; F: Image of 7T MRI colon enema.

70. Thank You.