Describes the imaging diagnostic criteria of acute diverticulitis in barium studies , ultrasound , computed tomography and MRI .and the classification and complications of acute diverticulitis

1. CT
DR SAKHER-ALKHADERI
CONSULTANT RADIOLOGISTAMC
IMAGING OF ACUTE
DIVERTICULITIS

2. Diverticulosis
Is the condition of having diverticula in
the colon, which are outpocketings of
the colonic mucosa and submucosa through
weaknesses of muscle layers in the colon wall.
It is highly prevalent in western countries.
These are more common in the sigmoid colon,
which is a common place for increased
pressure.

3. Diverticulitis
Is a complication of diverticulosis,
Diverticulitis is the result of obstruction of
the neck of the diverticulum, with
subsequent inflammation, perforation and
infection. Initially inflammation and
infection are contained by inflammatory
phlegmon.The infection may later
progress to abscess formation and/or
generalised peritonitis.

5. Radiography
Plain radiographs usually do not show any findings in
uncomplicated diverticulitis, but a left-sided pelvic mass,
localized ileus, or partial bowel obstruction may occasionally
be seen. Pneumoperitoneum, portal venous gas, and
extraluminal air-fluid levels may be noted in patients with
complicated diverticulitis.

6. Barium study
Prior to the advent of abdominal CT scanning, barium
enema evaluation was the examination of choice for the
diagnosis of diverticulitis. A single-contrast examination is
the preferred method in patients in whom diverticulitis is
suspected.
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.

7. Double contrast barium enema study showing
multiple colonic diverticulosis

8. 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. A
diverticular abscess may cause extrinsic
compression of the colonic lumen. Initially,
this compression occurs on the mesenteric
side of the colon, but it may spread to
encircle the lumen.

9. Single-contrast barium enema study in a patient with diverticulitis
demonstrates tethering of the sigmoid colon as a result of a
diverticular abscess.

10. Single-contrast barium enema study in a patient with
diverticulitis demonstrates an intramural abscess filling
with barium.

11. Single-contrast barium enema study demonstrates sigmoid
diverticulitis with an intramural sinus tract. Fistula
formation in the small bowel is noted.

12. Single-contrast barium enema study demonstrates mild
sigmoid diverticulitis with thickening of the mucosal folds
and luminal narrowing.

13. Single-contrast barium enema study demonstrates sigmoid
diverticulitis with fistula formation in the vagina.

14. Ultrasonography
Ultrasonography in patients with diverticulitis is performed
transabdominally with a 2- to 4-MHz convex-array transducer
and compression.In diverticulitis, ultrasonographic findings
include thickening of the bowel wall by more than 4 mm.
Inflamed diverticula appear as round or ovoid, hypoechogenic
structures with a ring-down artifact. Inflammation of the
pericolic fat is revealed as an area of increased echogenicity
adjacent to the colonic wall.
Abscess formation appears as a well-defined hypoechoic
mass near the colon, and it may demonstrate shadowing
because of the presence of air.The absence of peristalsis is
helpful for differentiating abscess from adjacent loops of
bowel. Intramural sinus tracts appear as linear, echogenic foci,
often with ring-down artifacts. In addition, the patient may
experience pain with compression of the affected region.

15. Sonographic features of uncomplicated diverticulosis.
diverticula appear as bright “ear” out of the bowel wall (a); a
central shadowing echogenicity may indicate the presence
of fecalith (b).

16. Diverticulitis with a hypoechoic diverticulum with
peridiverticulitis with hyperechoic inflamed mesenteric
fat and a small effusion

17. Inflamed diverticulum and abscess

18. Peridiverticulitis and abscess CT and US

19. Diverticulitis with perforation to the abdominal wall

20. ComputedTomography
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 3
-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 visualisation of a fistulous tract

21. Hinchey classification of acute diverticulitis
stage 1a - phlegmon
stage 1b - diverticulitis with pericolic or
mesenteric abscess
stage 2 - diverticulitis with walled off pelvic
abscess
stage 3 - diverticulitis with generalised purulent
peritonitis
stage 4 - diverticulitis with generalised faecal
peritonitis

22. Complications
Recognised complications include:
-abscess formation
-fistula formation
bladder: colovesical fistula
vagina: colovaginal fistula
bowel: coloenteric fistula or colocolic
fistula
skin: colocutaneous fistula
-small bowel obstructions from adhesions
-perforation resulting in pneumoperitoneum

23. Areas of inflammation and fat stranding surrounds the
sigmoid colon , findings are characteristic of diverticultis

25. Diverticulitis, severe colovesical fistula

26. CT scan demonstrates mild diverticulitis of the descending
colon, with wall thickening, a diverticulum, and mild
stranding of the pericolic fat.

27. CT scan in a patient with diverticulitis demonstrates
an abscess adjacent to the sigmoid colon.

28. Colonic diverticulosis , no diverticultis

29. Diverticula (arrowheads) and inflammation around the
sigmoid colon, indicating diverticulitis. A small, adjacent,
early abscess (open arrow) is noted.

30. CT scan of perforated diverticulitis with diverticula (thin arrows) and free
abdominal air (thick arrows).

31. MAGNETIC RESONANCE IMAGING
Magnetic resonance imaging (MRI) can effectively diagnose
acute diverticulitis, with reported sensitivity of 86 to 94% and
specificity of 88 to 92%.It is likely that continually improving
MRI techniques may result in higher sensitivity and specificity
in the future. Buckley et al described MRI findings in patients
with acute colonic diverticulitis, identifying findings similar to
CT: bowel wall thickening, pericolic stranding, presence of
diverticula, and complications . MRI is also comparable with CT
in its ability to identify alternative diagnoses. Similar to
ultrasound, MRI has the benefit of no radiation exposure, but
because it is operator independent, it may be more applicable
as the test of choice as the medical community becomes more
aware of the risks of radiation exposure and seeks alternative
imaging modalities to CT.

32. Magnetic resonance image (MRI) of right-sided diverticulitis. Axial MRI of
a 30-year-old woman with right abdominal pain .T2-weighted MRI shows
ascending colonic wall thickening with fat stranding around inflamed
diverticulum (arrow).

33. THE END